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Commit 88ee5ef157202624de2b43b3512fdcb54fda1ab5

Authored by Jens Axboe
Committed by Jens Axboe
1 parent ef9be1d336

[BLOCK] ll_rw_blk: fastpath get_request() 

Originally from: Nick Piggin <nickpiggin@yahoo.com.au>

Move current_io_context out of the get_request fastpth.  Also try to
streamline a few other things in this area.

Signed-off-by: Jens Axboe <axboe@suse.de>

Showing 1 changed file with 37 additions and 33 deletions Inline Diff

1 /* 1 /*
2 * Copyright (C) 1991, 1992 Linus Torvalds 2 * Copyright (C) 1991, 1992 Linus Torvalds
3 * Copyright (C) 1994, Karl Keyte: Added support for disk statistics 3 * Copyright (C) 1994, Karl Keyte: Added support for disk statistics
4 * Elevator latency, (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE 4 * Elevator latency, (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
5 * Queue request tables / lock, selectable elevator, Jens Axboe <axboe@suse.de> 5 * Queue request tables / lock, selectable elevator, Jens Axboe <axboe@suse.de>
6 * kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au> - July2000 6 * kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au> - July2000
7 * bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001 7 * bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001
8 */ 8 */
9 9
10 /* 10 /*
11 * This handles all read/write requests to block devices 11 * This handles all read/write requests to block devices
12 */ 12 */
13 #include <linux/config.h> 13 #include <linux/config.h>
14 #include <linux/kernel.h> 14 #include <linux/kernel.h>
15 #include <linux/module.h> 15 #include <linux/module.h>
16 #include <linux/backing-dev.h> 16 #include <linux/backing-dev.h>
17 #include <linux/bio.h> 17 #include <linux/bio.h>
18 #include <linux/blkdev.h> 18 #include <linux/blkdev.h>
19 #include <linux/highmem.h> 19 #include <linux/highmem.h>
20 #include <linux/mm.h> 20 #include <linux/mm.h>
21 #include <linux/kernel_stat.h> 21 #include <linux/kernel_stat.h>
22 #include <linux/string.h> 22 #include <linux/string.h>
23 #include <linux/init.h> 23 #include <linux/init.h>
24 #include <linux/bootmem.h> /* for max_pfn/max_low_pfn */ 24 #include <linux/bootmem.h> /* for max_pfn/max_low_pfn */
25 #include <linux/completion.h> 25 #include <linux/completion.h>
26 #include <linux/slab.h> 26 #include <linux/slab.h>
27 #include <linux/swap.h> 27 #include <linux/swap.h>
28 #include <linux/writeback.h> 28 #include <linux/writeback.h>
29 #include <linux/blkdev.h> 29 #include <linux/blkdev.h>
30 30
31 /* 31 /*
32 * for max sense size 32 * for max sense size
33 */ 33 */
34 #include <scsi/scsi_cmnd.h> 34 #include <scsi/scsi_cmnd.h>
35 35
36 static void blk_unplug_work(void *data); 36 static void blk_unplug_work(void *data);
37 static void blk_unplug_timeout(unsigned long data); 37 static void blk_unplug_timeout(unsigned long data);
38 static void drive_stat_acct(struct request *rq, int nr_sectors, int new_io); 38 static void drive_stat_acct(struct request *rq, int nr_sectors, int new_io);
39 39
40 /* 40 /*
41 * For the allocated request tables 41 * For the allocated request tables
42 */ 42 */
43 static kmem_cache_t *request_cachep; 43 static kmem_cache_t *request_cachep;
44 44
45 /* 45 /*
46 * For queue allocation 46 * For queue allocation
47 */ 47 */
48 static kmem_cache_t *requestq_cachep; 48 static kmem_cache_t *requestq_cachep;
49 49
50 /* 50 /*
51 * For io context allocations 51 * For io context allocations
52 */ 52 */
53 static kmem_cache_t *iocontext_cachep; 53 static kmem_cache_t *iocontext_cachep;
54 54
55 static wait_queue_head_t congestion_wqh[2] = { 55 static wait_queue_head_t congestion_wqh[2] = {
56 __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]), 56 __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]),
57 __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1]) 57 __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1])
58 }; 58 };
59 59
60 /* 60 /*
61 * Controlling structure to kblockd 61 * Controlling structure to kblockd
62 */ 62 */
63 static struct workqueue_struct *kblockd_workqueue; 63 static struct workqueue_struct *kblockd_workqueue;
64 64
65 unsigned long blk_max_low_pfn, blk_max_pfn; 65 unsigned long blk_max_low_pfn, blk_max_pfn;
66 66
67 EXPORT_SYMBOL(blk_max_low_pfn); 67 EXPORT_SYMBOL(blk_max_low_pfn);
68 EXPORT_SYMBOL(blk_max_pfn); 68 EXPORT_SYMBOL(blk_max_pfn);
69 69
70 /* Amount of time in which a process may batch requests */ 70 /* Amount of time in which a process may batch requests */
71 #define BLK_BATCH_TIME (HZ/50UL) 71 #define BLK_BATCH_TIME (HZ/50UL)
72 72
73 /* Number of requests a "batching" process may submit */ 73 /* Number of requests a "batching" process may submit */
74 #define BLK_BATCH_REQ 32 74 #define BLK_BATCH_REQ 32
75 75
76 /* 76 /*
77 * Return the threshold (number of used requests) at which the queue is 77 * Return the threshold (number of used requests) at which the queue is
78 * considered to be congested. It include a little hysteresis to keep the 78 * considered to be congested. It include a little hysteresis to keep the
79 * context switch rate down. 79 * context switch rate down.
80 */ 80 */
81 static inline int queue_congestion_on_threshold(struct request_queue *q) 81 static inline int queue_congestion_on_threshold(struct request_queue *q)
82 { 82 {
83 return q->nr_congestion_on; 83 return q->nr_congestion_on;
84 } 84 }
85 85
86 /* 86 /*
87 * The threshold at which a queue is considered to be uncongested 87 * The threshold at which a queue is considered to be uncongested
88 */ 88 */
89 static inline int queue_congestion_off_threshold(struct request_queue *q) 89 static inline int queue_congestion_off_threshold(struct request_queue *q)
90 { 90 {
91 return q->nr_congestion_off; 91 return q->nr_congestion_off;
92 } 92 }
93 93
94 static void blk_queue_congestion_threshold(struct request_queue *q) 94 static void blk_queue_congestion_threshold(struct request_queue *q)
95 { 95 {
96 int nr; 96 int nr;
97 97
98 nr = q->nr_requests - (q->nr_requests / 8) + 1; 98 nr = q->nr_requests - (q->nr_requests / 8) + 1;
99 if (nr > q->nr_requests) 99 if (nr > q->nr_requests)
100 nr = q->nr_requests; 100 nr = q->nr_requests;
101 q->nr_congestion_on = nr; 101 q->nr_congestion_on = nr;
102 102
103 nr = q->nr_requests - (q->nr_requests / 8) - (q->nr_requests / 16) - 1; 103 nr = q->nr_requests - (q->nr_requests / 8) - (q->nr_requests / 16) - 1;
104 if (nr < 1) 104 if (nr < 1)
105 nr = 1; 105 nr = 1;
106 q->nr_congestion_off = nr; 106 q->nr_congestion_off = nr;
107 } 107 }
108 108
109 /* 109 /*
110 * A queue has just exitted congestion. Note this in the global counter of 110 * A queue has just exitted congestion. Note this in the global counter of
111 * congested queues, and wake up anyone who was waiting for requests to be 111 * congested queues, and wake up anyone who was waiting for requests to be
112 * put back. 112 * put back.
113 */ 113 */
114 static void clear_queue_congested(request_queue_t *q, int rw) 114 static void clear_queue_congested(request_queue_t *q, int rw)
115 { 115 {
116 enum bdi_state bit; 116 enum bdi_state bit;
117 wait_queue_head_t *wqh = &congestion_wqh[rw]; 117 wait_queue_head_t *wqh = &congestion_wqh[rw];
118 118
119 bit = (rw == WRITE) ? BDI_write_congested : BDI_read_congested; 119 bit = (rw == WRITE) ? BDI_write_congested : BDI_read_congested;
120 clear_bit(bit, &q->backing_dev_info.state); 120 clear_bit(bit, &q->backing_dev_info.state);
121 smp_mb__after_clear_bit(); 121 smp_mb__after_clear_bit();
122 if (waitqueue_active(wqh)) 122 if (waitqueue_active(wqh))
123 wake_up(wqh); 123 wake_up(wqh);
124 } 124 }
125 125
126 /* 126 /*
127 * A queue has just entered congestion. Flag that in the queue's VM-visible 127 * A queue has just entered congestion. Flag that in the queue's VM-visible
128 * state flags and increment the global gounter of congested queues. 128 * state flags and increment the global gounter of congested queues.
129 */ 129 */
130 static void set_queue_congested(request_queue_t *q, int rw) 130 static void set_queue_congested(request_queue_t *q, int rw)
131 { 131 {
132 enum bdi_state bit; 132 enum bdi_state bit;
133 133
134 bit = (rw == WRITE) ? BDI_write_congested : BDI_read_congested; 134 bit = (rw == WRITE) ? BDI_write_congested : BDI_read_congested;
135 set_bit(bit, &q->backing_dev_info.state); 135 set_bit(bit, &q->backing_dev_info.state);
136 } 136 }
137 137
138 /** 138 /**
139 * blk_get_backing_dev_info - get the address of a queue's backing_dev_info 139 * blk_get_backing_dev_info - get the address of a queue's backing_dev_info
140 * @bdev: device 140 * @bdev: device
141 * 141 *
142 * Locates the passed device's request queue and returns the address of its 142 * Locates the passed device's request queue and returns the address of its
143 * backing_dev_info 143 * backing_dev_info
144 * 144 *
145 * Will return NULL if the request queue cannot be located. 145 * Will return NULL if the request queue cannot be located.
146 */ 146 */
147 struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev) 147 struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev)
148 { 148 {
149 struct backing_dev_info *ret = NULL; 149 struct backing_dev_info *ret = NULL;
150 request_queue_t *q = bdev_get_queue(bdev); 150 request_queue_t *q = bdev_get_queue(bdev);
151 151
152 if (q) 152 if (q)
153 ret = &q->backing_dev_info; 153 ret = &q->backing_dev_info;
154 return ret; 154 return ret;
155 } 155 }
156 156
157 EXPORT_SYMBOL(blk_get_backing_dev_info); 157 EXPORT_SYMBOL(blk_get_backing_dev_info);
158 158
159 void blk_queue_activity_fn(request_queue_t *q, activity_fn *fn, void *data) 159 void blk_queue_activity_fn(request_queue_t *q, activity_fn *fn, void *data)
160 { 160 {
161 q->activity_fn = fn; 161 q->activity_fn = fn;
162 q->activity_data = data; 162 q->activity_data = data;
163 } 163 }
164 164
165 EXPORT_SYMBOL(blk_queue_activity_fn); 165 EXPORT_SYMBOL(blk_queue_activity_fn);
166 166
167 /** 167 /**
168 * blk_queue_prep_rq - set a prepare_request function for queue 168 * blk_queue_prep_rq - set a prepare_request function for queue
169 * @q: queue 169 * @q: queue
170 * @pfn: prepare_request function 170 * @pfn: prepare_request function
171 * 171 *
172 * It's possible for a queue to register a prepare_request callback which 172 * It's possible for a queue to register a prepare_request callback which
173 * is invoked before the request is handed to the request_fn. The goal of 173 * is invoked before the request is handed to the request_fn. The goal of
174 * the function is to prepare a request for I/O, it can be used to build a 174 * the function is to prepare a request for I/O, it can be used to build a
175 * cdb from the request data for instance. 175 * cdb from the request data for instance.
176 * 176 *
177 */ 177 */
178 void blk_queue_prep_rq(request_queue_t *q, prep_rq_fn *pfn) 178 void blk_queue_prep_rq(request_queue_t *q, prep_rq_fn *pfn)
179 { 179 {
180 q->prep_rq_fn = pfn; 180 q->prep_rq_fn = pfn;
181 } 181 }
182 182
183 EXPORT_SYMBOL(blk_queue_prep_rq); 183 EXPORT_SYMBOL(blk_queue_prep_rq);
184 184
185 /** 185 /**
186 * blk_queue_merge_bvec - set a merge_bvec function for queue 186 * blk_queue_merge_bvec - set a merge_bvec function for queue
187 * @q: queue 187 * @q: queue
188 * @mbfn: merge_bvec_fn 188 * @mbfn: merge_bvec_fn
189 * 189 *
190 * Usually queues have static limitations on the max sectors or segments that 190 * Usually queues have static limitations on the max sectors or segments that
191 * we can put in a request. Stacking drivers may have some settings that 191 * we can put in a request. Stacking drivers may have some settings that
192 * are dynamic, and thus we have to query the queue whether it is ok to 192 * are dynamic, and thus we have to query the queue whether it is ok to
193 * add a new bio_vec to a bio at a given offset or not. If the block device 193 * add a new bio_vec to a bio at a given offset or not. If the block device
194 * has such limitations, it needs to register a merge_bvec_fn to control 194 * has such limitations, it needs to register a merge_bvec_fn to control
195 * the size of bio's sent to it. Note that a block device *must* allow a 195 * the size of bio's sent to it. Note that a block device *must* allow a
196 * single page to be added to an empty bio. The block device driver may want 196 * single page to be added to an empty bio. The block device driver may want
197 * to use the bio_split() function to deal with these bio's. By default 197 * to use the bio_split() function to deal with these bio's. By default
198 * no merge_bvec_fn is defined for a queue, and only the fixed limits are 198 * no merge_bvec_fn is defined for a queue, and only the fixed limits are
199 * honored. 199 * honored.
200 */ 200 */
201 void blk_queue_merge_bvec(request_queue_t *q, merge_bvec_fn *mbfn) 201 void blk_queue_merge_bvec(request_queue_t *q, merge_bvec_fn *mbfn)
202 { 202 {
203 q->merge_bvec_fn = mbfn; 203 q->merge_bvec_fn = mbfn;
204 } 204 }
205 205
206 EXPORT_SYMBOL(blk_queue_merge_bvec); 206 EXPORT_SYMBOL(blk_queue_merge_bvec);
207 207
208 /** 208 /**
209 * blk_queue_make_request - define an alternate make_request function for a device 209 * blk_queue_make_request - define an alternate make_request function for a device
210 * @q: the request queue for the device to be affected 210 * @q: the request queue for the device to be affected
211 * @mfn: the alternate make_request function 211 * @mfn: the alternate make_request function
212 * 212 *
213 * Description: 213 * Description:
214 * The normal way for &struct bios to be passed to a device 214 * The normal way for &struct bios to be passed to a device
215 * driver is for them to be collected into requests on a request 215 * driver is for them to be collected into requests on a request
216 * queue, and then to allow the device driver to select requests 216 * queue, and then to allow the device driver to select requests
217 * off that queue when it is ready. This works well for many block 217 * off that queue when it is ready. This works well for many block
218 * devices. However some block devices (typically virtual devices 218 * devices. However some block devices (typically virtual devices
219 * such as md or lvm) do not benefit from the processing on the 219 * such as md or lvm) do not benefit from the processing on the
220 * request queue, and are served best by having the requests passed 220 * request queue, and are served best by having the requests passed
221 * directly to them. This can be achieved by providing a function 221 * directly to them. This can be achieved by providing a function
222 * to blk_queue_make_request(). 222 * to blk_queue_make_request().
223 * 223 *
224 * Caveat: 224 * Caveat:
225 * The driver that does this *must* be able to deal appropriately 225 * The driver that does this *must* be able to deal appropriately
226 * with buffers in "highmemory". This can be accomplished by either calling 226 * with buffers in "highmemory". This can be accomplished by either calling
227 * __bio_kmap_atomic() to get a temporary kernel mapping, or by calling 227 * __bio_kmap_atomic() to get a temporary kernel mapping, or by calling
228 * blk_queue_bounce() to create a buffer in normal memory. 228 * blk_queue_bounce() to create a buffer in normal memory.
229 **/ 229 **/
230 void blk_queue_make_request(request_queue_t * q, make_request_fn * mfn) 230 void blk_queue_make_request(request_queue_t * q, make_request_fn * mfn)
231 { 231 {
232 /* 232 /*
233 * set defaults 233 * set defaults
234 */ 234 */
235 q->nr_requests = BLKDEV_MAX_RQ; 235 q->nr_requests = BLKDEV_MAX_RQ;
236 blk_queue_max_phys_segments(q, MAX_PHYS_SEGMENTS); 236 blk_queue_max_phys_segments(q, MAX_PHYS_SEGMENTS);
237 blk_queue_max_hw_segments(q, MAX_HW_SEGMENTS); 237 blk_queue_max_hw_segments(q, MAX_HW_SEGMENTS);
238 q->make_request_fn = mfn; 238 q->make_request_fn = mfn;
239 q->backing_dev_info.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; 239 q->backing_dev_info.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
240 q->backing_dev_info.state = 0; 240 q->backing_dev_info.state = 0;
241 q->backing_dev_info.capabilities = BDI_CAP_MAP_COPY; 241 q->backing_dev_info.capabilities = BDI_CAP_MAP_COPY;
242 blk_queue_max_sectors(q, SAFE_MAX_SECTORS); 242 blk_queue_max_sectors(q, SAFE_MAX_SECTORS);
243 blk_queue_hardsect_size(q, 512); 243 blk_queue_hardsect_size(q, 512);
244 blk_queue_dma_alignment(q, 511); 244 blk_queue_dma_alignment(q, 511);
245 blk_queue_congestion_threshold(q); 245 blk_queue_congestion_threshold(q);
246 q->nr_batching = BLK_BATCH_REQ; 246 q->nr_batching = BLK_BATCH_REQ;
247 247
248 q->unplug_thresh = 4; /* hmm */ 248 q->unplug_thresh = 4; /* hmm */
249 q->unplug_delay = (3 * HZ) / 1000; /* 3 milliseconds */ 249 q->unplug_delay = (3 * HZ) / 1000; /* 3 milliseconds */
250 if (q->unplug_delay == 0) 250 if (q->unplug_delay == 0)
251 q->unplug_delay = 1; 251 q->unplug_delay = 1;
252 252
253 INIT_WORK(&q->unplug_work, blk_unplug_work, q); 253 INIT_WORK(&q->unplug_work, blk_unplug_work, q);
254 254
255 q->unplug_timer.function = blk_unplug_timeout; 255 q->unplug_timer.function = blk_unplug_timeout;
256 q->unplug_timer.data = (unsigned long)q; 256 q->unplug_timer.data = (unsigned long)q;
257 257
258 /* 258 /*
259 * by default assume old behaviour and bounce for any highmem page 259 * by default assume old behaviour and bounce for any highmem page
260 */ 260 */
261 blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH); 261 blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
262 262
263 blk_queue_activity_fn(q, NULL, NULL); 263 blk_queue_activity_fn(q, NULL, NULL);
264 } 264 }
265 265
266 EXPORT_SYMBOL(blk_queue_make_request); 266 EXPORT_SYMBOL(blk_queue_make_request);
267 267
268 static inline void rq_init(request_queue_t *q, struct request *rq) 268 static inline void rq_init(request_queue_t *q, struct request *rq)
269 { 269 {
270 INIT_LIST_HEAD(&rq->queuelist); 270 INIT_LIST_HEAD(&rq->queuelist);
271 271
272 rq->errors = 0; 272 rq->errors = 0;
273 rq->rq_status = RQ_ACTIVE; 273 rq->rq_status = RQ_ACTIVE;
274 rq->bio = rq->biotail = NULL; 274 rq->bio = rq->biotail = NULL;
275 rq->ioprio = 0; 275 rq->ioprio = 0;
276 rq->buffer = NULL; 276 rq->buffer = NULL;
277 rq->ref_count = 1; 277 rq->ref_count = 1;
278 rq->q = q; 278 rq->q = q;
279 rq->waiting = NULL; 279 rq->waiting = NULL;
280 rq->special = NULL; 280 rq->special = NULL;
281 rq->data_len = 0; 281 rq->data_len = 0;
282 rq->data = NULL; 282 rq->data = NULL;
283 rq->nr_phys_segments = 0; 283 rq->nr_phys_segments = 0;
284 rq->sense = NULL; 284 rq->sense = NULL;
285 rq->end_io = NULL; 285 rq->end_io = NULL;
286 rq->end_io_data = NULL; 286 rq->end_io_data = NULL;
287 } 287 }
288 288
289 /** 289 /**
290 * blk_queue_ordered - does this queue support ordered writes 290 * blk_queue_ordered - does this queue support ordered writes
291 * @q: the request queue 291 * @q: the request queue
292 * @flag: see below 292 * @flag: see below
293 * 293 *
294 * Description: 294 * Description:
295 * For journalled file systems, doing ordered writes on a commit 295 * For journalled file systems, doing ordered writes on a commit
296 * block instead of explicitly doing wait_on_buffer (which is bad 296 * block instead of explicitly doing wait_on_buffer (which is bad
297 * for performance) can be a big win. Block drivers supporting this 297 * for performance) can be a big win. Block drivers supporting this
298 * feature should call this function and indicate so. 298 * feature should call this function and indicate so.
299 * 299 *
300 **/ 300 **/
301 void blk_queue_ordered(request_queue_t *q, int flag) 301 void blk_queue_ordered(request_queue_t *q, int flag)
302 { 302 {
303 switch (flag) { 303 switch (flag) {
304 case QUEUE_ORDERED_NONE: 304 case QUEUE_ORDERED_NONE:
305 if (q->flush_rq) 305 if (q->flush_rq)
306 kmem_cache_free(request_cachep, q->flush_rq); 306 kmem_cache_free(request_cachep, q->flush_rq);
307 q->flush_rq = NULL; 307 q->flush_rq = NULL;
308 q->ordered = flag; 308 q->ordered = flag;
309 break; 309 break;
310 case QUEUE_ORDERED_TAG: 310 case QUEUE_ORDERED_TAG:
311 q->ordered = flag; 311 q->ordered = flag;
312 break; 312 break;
313 case QUEUE_ORDERED_FLUSH: 313 case QUEUE_ORDERED_FLUSH:
314 q->ordered = flag; 314 q->ordered = flag;
315 if (!q->flush_rq) 315 if (!q->flush_rq)
316 q->flush_rq = kmem_cache_alloc(request_cachep, 316 q->flush_rq = kmem_cache_alloc(request_cachep,
317 GFP_KERNEL); 317 GFP_KERNEL);
318 break; 318 break;
319 default: 319 default:
320 printk("blk_queue_ordered: bad value %d\n", flag); 320 printk("blk_queue_ordered: bad value %d\n", flag);
321 break; 321 break;
322 } 322 }
323 } 323 }
324 324
325 EXPORT_SYMBOL(blk_queue_ordered); 325 EXPORT_SYMBOL(blk_queue_ordered);
326 326
327 /** 327 /**
328 * blk_queue_issue_flush_fn - set function for issuing a flush 328 * blk_queue_issue_flush_fn - set function for issuing a flush
329 * @q: the request queue 329 * @q: the request queue
330 * @iff: the function to be called issuing the flush 330 * @iff: the function to be called issuing the flush
331 * 331 *
332 * Description: 332 * Description:
333 * If a driver supports issuing a flush command, the support is notified 333 * If a driver supports issuing a flush command, the support is notified
334 * to the block layer by defining it through this call. 334 * to the block layer by defining it through this call.
335 * 335 *
336 **/ 336 **/
337 void blk_queue_issue_flush_fn(request_queue_t *q, issue_flush_fn *iff) 337 void blk_queue_issue_flush_fn(request_queue_t *q, issue_flush_fn *iff)
338 { 338 {
339 q->issue_flush_fn = iff; 339 q->issue_flush_fn = iff;
340 } 340 }
341 341
342 EXPORT_SYMBOL(blk_queue_issue_flush_fn); 342 EXPORT_SYMBOL(blk_queue_issue_flush_fn);
343 343
344 /* 344 /*
345 * Cache flushing for ordered writes handling 345 * Cache flushing for ordered writes handling
346 */ 346 */
347 static void blk_pre_flush_end_io(struct request *flush_rq) 347 static void blk_pre_flush_end_io(struct request *flush_rq)
348 { 348 {
349 struct request *rq = flush_rq->end_io_data; 349 struct request *rq = flush_rq->end_io_data;
350 request_queue_t *q = rq->q; 350 request_queue_t *q = rq->q;
351 351
352 elv_completed_request(q, flush_rq); 352 elv_completed_request(q, flush_rq);
353 353
354 rq->flags |= REQ_BAR_PREFLUSH; 354 rq->flags |= REQ_BAR_PREFLUSH;
355 355
356 if (!flush_rq->errors) 356 if (!flush_rq->errors)
357 elv_requeue_request(q, rq); 357 elv_requeue_request(q, rq);
358 else { 358 else {
359 q->end_flush_fn(q, flush_rq); 359 q->end_flush_fn(q, flush_rq);
360 clear_bit(QUEUE_FLAG_FLUSH, &q->queue_flags); 360 clear_bit(QUEUE_FLAG_FLUSH, &q->queue_flags);
361 q->request_fn(q); 361 q->request_fn(q);
362 } 362 }
363 } 363 }
364 364
365 static void blk_post_flush_end_io(struct request *flush_rq) 365 static void blk_post_flush_end_io(struct request *flush_rq)
366 { 366 {
367 struct request *rq = flush_rq->end_io_data; 367 struct request *rq = flush_rq->end_io_data;
368 request_queue_t *q = rq->q; 368 request_queue_t *q = rq->q;
369 369
370 elv_completed_request(q, flush_rq); 370 elv_completed_request(q, flush_rq);
371 371
372 rq->flags |= REQ_BAR_POSTFLUSH; 372 rq->flags |= REQ_BAR_POSTFLUSH;
373 373
374 q->end_flush_fn(q, flush_rq); 374 q->end_flush_fn(q, flush_rq);
375 clear_bit(QUEUE_FLAG_FLUSH, &q->queue_flags); 375 clear_bit(QUEUE_FLAG_FLUSH, &q->queue_flags);
376 q->request_fn(q); 376 q->request_fn(q);
377 } 377 }
378 378
379 struct request *blk_start_pre_flush(request_queue_t *q, struct request *rq) 379 struct request *blk_start_pre_flush(request_queue_t *q, struct request *rq)
380 { 380 {
381 struct request *flush_rq = q->flush_rq; 381 struct request *flush_rq = q->flush_rq;
382 382
383 BUG_ON(!blk_barrier_rq(rq)); 383 BUG_ON(!blk_barrier_rq(rq));
384 384
385 if (test_and_set_bit(QUEUE_FLAG_FLUSH, &q->queue_flags)) 385 if (test_and_set_bit(QUEUE_FLAG_FLUSH, &q->queue_flags))
386 return NULL; 386 return NULL;
387 387
388 rq_init(q, flush_rq); 388 rq_init(q, flush_rq);
389 flush_rq->elevator_private = NULL; 389 flush_rq->elevator_private = NULL;
390 flush_rq->flags = REQ_BAR_FLUSH; 390 flush_rq->flags = REQ_BAR_FLUSH;
391 flush_rq->rq_disk = rq->rq_disk; 391 flush_rq->rq_disk = rq->rq_disk;
392 flush_rq->rl = NULL; 392 flush_rq->rl = NULL;
393 393
394 /* 394 /*
395 * prepare_flush returns 0 if no flush is needed, just mark both 395 * prepare_flush returns 0 if no flush is needed, just mark both
396 * pre and post flush as done in that case 396 * pre and post flush as done in that case
397 */ 397 */
398 if (!q->prepare_flush_fn(q, flush_rq)) { 398 if (!q->prepare_flush_fn(q, flush_rq)) {
399 rq->flags |= REQ_BAR_PREFLUSH | REQ_BAR_POSTFLUSH; 399 rq->flags |= REQ_BAR_PREFLUSH | REQ_BAR_POSTFLUSH;
400 clear_bit(QUEUE_FLAG_FLUSH, &q->queue_flags); 400 clear_bit(QUEUE_FLAG_FLUSH, &q->queue_flags);
401 return rq; 401 return rq;
402 } 402 }
403 403
404 /* 404 /*
405 * some drivers dequeue requests right away, some only after io 405 * some drivers dequeue requests right away, some only after io
406 * completion. make sure the request is dequeued. 406 * completion. make sure the request is dequeued.
407 */ 407 */
408 if (!list_empty(&rq->queuelist)) 408 if (!list_empty(&rq->queuelist))
409 blkdev_dequeue_request(rq); 409 blkdev_dequeue_request(rq);
410 410
411 flush_rq->end_io_data = rq; 411 flush_rq->end_io_data = rq;
412 flush_rq->end_io = blk_pre_flush_end_io; 412 flush_rq->end_io = blk_pre_flush_end_io;
413 413
414 __elv_add_request(q, flush_rq, ELEVATOR_INSERT_FRONT, 0); 414 __elv_add_request(q, flush_rq, ELEVATOR_INSERT_FRONT, 0);
415 return flush_rq; 415 return flush_rq;
416 } 416 }
417 417
418 static void blk_start_post_flush(request_queue_t *q, struct request *rq) 418 static void blk_start_post_flush(request_queue_t *q, struct request *rq)
419 { 419 {
420 struct request *flush_rq = q->flush_rq; 420 struct request *flush_rq = q->flush_rq;
421 421
422 BUG_ON(!blk_barrier_rq(rq)); 422 BUG_ON(!blk_barrier_rq(rq));
423 423
424 rq_init(q, flush_rq); 424 rq_init(q, flush_rq);
425 flush_rq->elevator_private = NULL; 425 flush_rq->elevator_private = NULL;
426 flush_rq->flags = REQ_BAR_FLUSH; 426 flush_rq->flags = REQ_BAR_FLUSH;
427 flush_rq->rq_disk = rq->rq_disk; 427 flush_rq->rq_disk = rq->rq_disk;
428 flush_rq->rl = NULL; 428 flush_rq->rl = NULL;
429 429
430 if (q->prepare_flush_fn(q, flush_rq)) { 430 if (q->prepare_flush_fn(q, flush_rq)) {
431 flush_rq->end_io_data = rq; 431 flush_rq->end_io_data = rq;
432 flush_rq->end_io = blk_post_flush_end_io; 432 flush_rq->end_io = blk_post_flush_end_io;
433 433
434 __elv_add_request(q, flush_rq, ELEVATOR_INSERT_FRONT, 0); 434 __elv_add_request(q, flush_rq, ELEVATOR_INSERT_FRONT, 0);
435 q->request_fn(q); 435 q->request_fn(q);
436 } 436 }
437 } 437 }
438 438
439 static inline int blk_check_end_barrier(request_queue_t *q, struct request *rq, 439 static inline int blk_check_end_barrier(request_queue_t *q, struct request *rq,
440 int sectors) 440 int sectors)
441 { 441 {
442 if (sectors > rq->nr_sectors) 442 if (sectors > rq->nr_sectors)
443 sectors = rq->nr_sectors; 443 sectors = rq->nr_sectors;
444 444
445 rq->nr_sectors -= sectors; 445 rq->nr_sectors -= sectors;
446 return rq->nr_sectors; 446 return rq->nr_sectors;
447 } 447 }
448 448
449 static int __blk_complete_barrier_rq(request_queue_t *q, struct request *rq, 449 static int __blk_complete_barrier_rq(request_queue_t *q, struct request *rq,
450 int sectors, int queue_locked) 450 int sectors, int queue_locked)
451 { 451 {
452 if (q->ordered != QUEUE_ORDERED_FLUSH) 452 if (q->ordered != QUEUE_ORDERED_FLUSH)
453 return 0; 453 return 0;
454 if (!blk_fs_request(rq) || !blk_barrier_rq(rq)) 454 if (!blk_fs_request(rq) || !blk_barrier_rq(rq))
455 return 0; 455 return 0;
456 if (blk_barrier_postflush(rq)) 456 if (blk_barrier_postflush(rq))
457 return 0; 457 return 0;
458 458
459 if (!blk_check_end_barrier(q, rq, sectors)) { 459 if (!blk_check_end_barrier(q, rq, sectors)) {
460 unsigned long flags = 0; 460 unsigned long flags = 0;
461 461
462 if (!queue_locked) 462 if (!queue_locked)
463 spin_lock_irqsave(q->queue_lock, flags); 463 spin_lock_irqsave(q->queue_lock, flags);
464 464
465 blk_start_post_flush(q, rq); 465 blk_start_post_flush(q, rq);
466 466
467 if (!queue_locked) 467 if (!queue_locked)
468 spin_unlock_irqrestore(q->queue_lock, flags); 468 spin_unlock_irqrestore(q->queue_lock, flags);
469 } 469 }
470 470
471 return 1; 471 return 1;
472 } 472 }
473 473
474 /** 474 /**
475 * blk_complete_barrier_rq - complete possible barrier request 475 * blk_complete_barrier_rq - complete possible barrier request
476 * @q: the request queue for the device 476 * @q: the request queue for the device
477 * @rq: the request 477 * @rq: the request
478 * @sectors: number of sectors to complete 478 * @sectors: number of sectors to complete
479 * 479 *
480 * Description: 480 * Description:
481 * Used in driver end_io handling to determine whether to postpone 481 * Used in driver end_io handling to determine whether to postpone
482 * completion of a barrier request until a post flush has been done. This 482 * completion of a barrier request until a post flush has been done. This
483 * is the unlocked variant, used if the caller doesn't already hold the 483 * is the unlocked variant, used if the caller doesn't already hold the
484 * queue lock. 484 * queue lock.
485 **/ 485 **/
486 int blk_complete_barrier_rq(request_queue_t *q, struct request *rq, int sectors) 486 int blk_complete_barrier_rq(request_queue_t *q, struct request *rq, int sectors)
487 { 487 {
488 return __blk_complete_barrier_rq(q, rq, sectors, 0); 488 return __blk_complete_barrier_rq(q, rq, sectors, 0);
489 } 489 }
490 EXPORT_SYMBOL(blk_complete_barrier_rq); 490 EXPORT_SYMBOL(blk_complete_barrier_rq);
491 491
492 /** 492 /**
493 * blk_complete_barrier_rq_locked - complete possible barrier request 493 * blk_complete_barrier_rq_locked - complete possible barrier request
494 * @q: the request queue for the device 494 * @q: the request queue for the device
495 * @rq: the request 495 * @rq: the request
496 * @sectors: number of sectors to complete 496 * @sectors: number of sectors to complete
497 * 497 *
498 * Description: 498 * Description:
499 * See blk_complete_barrier_rq(). This variant must be used if the caller 499 * See blk_complete_barrier_rq(). This variant must be used if the caller
500 * holds the queue lock. 500 * holds the queue lock.
501 **/ 501 **/
502 int blk_complete_barrier_rq_locked(request_queue_t *q, struct request *rq, 502 int blk_complete_barrier_rq_locked(request_queue_t *q, struct request *rq,
503 int sectors) 503 int sectors)
504 { 504 {
505 return __blk_complete_barrier_rq(q, rq, sectors, 1); 505 return __blk_complete_barrier_rq(q, rq, sectors, 1);
506 } 506 }
507 EXPORT_SYMBOL(blk_complete_barrier_rq_locked); 507 EXPORT_SYMBOL(blk_complete_barrier_rq_locked);
508 508
509 /** 509 /**
510 * blk_queue_bounce_limit - set bounce buffer limit for queue 510 * blk_queue_bounce_limit - set bounce buffer limit for queue
511 * @q: the request queue for the device 511 * @q: the request queue for the device
512 * @dma_addr: bus address limit 512 * @dma_addr: bus address limit
513 * 513 *
514 * Description: 514 * Description:
515 * Different hardware can have different requirements as to what pages 515 * Different hardware can have different requirements as to what pages
516 * it can do I/O directly to. A low level driver can call 516 * it can do I/O directly to. A low level driver can call
517 * blk_queue_bounce_limit to have lower memory pages allocated as bounce 517 * blk_queue_bounce_limit to have lower memory pages allocated as bounce
518 * buffers for doing I/O to pages residing above @page. By default 518 * buffers for doing I/O to pages residing above @page. By default
519 * the block layer sets this to the highest numbered "low" memory page. 519 * the block layer sets this to the highest numbered "low" memory page.
520 **/ 520 **/
521 void blk_queue_bounce_limit(request_queue_t *q, u64 dma_addr) 521 void blk_queue_bounce_limit(request_queue_t *q, u64 dma_addr)
522 { 522 {
523 unsigned long bounce_pfn = dma_addr >> PAGE_SHIFT; 523 unsigned long bounce_pfn = dma_addr >> PAGE_SHIFT;
524 524
525 /* 525 /*
526 * set appropriate bounce gfp mask -- unfortunately we don't have a 526 * set appropriate bounce gfp mask -- unfortunately we don't have a
527 * full 4GB zone, so we have to resort to low memory for any bounces. 527 * full 4GB zone, so we have to resort to low memory for any bounces.
528 * ISA has its own < 16MB zone. 528 * ISA has its own < 16MB zone.
529 */ 529 */
530 if (bounce_pfn < blk_max_low_pfn) { 530 if (bounce_pfn < blk_max_low_pfn) {
531 BUG_ON(dma_addr < BLK_BOUNCE_ISA); 531 BUG_ON(dma_addr < BLK_BOUNCE_ISA);
532 init_emergency_isa_pool(); 532 init_emergency_isa_pool();
533 q->bounce_gfp = GFP_NOIO | GFP_DMA; 533 q->bounce_gfp = GFP_NOIO | GFP_DMA;
534 } else 534 } else
535 q->bounce_gfp = GFP_NOIO; 535 q->bounce_gfp = GFP_NOIO;
536 536
537 q->bounce_pfn = bounce_pfn; 537 q->bounce_pfn = bounce_pfn;
538 } 538 }
539 539
540 EXPORT_SYMBOL(blk_queue_bounce_limit); 540 EXPORT_SYMBOL(blk_queue_bounce_limit);
541 541
542 /** 542 /**
543 * blk_queue_max_sectors - set max sectors for a request for this queue 543 * blk_queue_max_sectors - set max sectors for a request for this queue
544 * @q: the request queue for the device 544 * @q: the request queue for the device
545 * @max_sectors: max sectors in the usual 512b unit 545 * @max_sectors: max sectors in the usual 512b unit
546 * 546 *
547 * Description: 547 * Description:
548 * Enables a low level driver to set an upper limit on the size of 548 * Enables a low level driver to set an upper limit on the size of
549 * received requests. 549 * received requests.
550 **/ 550 **/
551 void blk_queue_max_sectors(request_queue_t *q, unsigned short max_sectors) 551 void blk_queue_max_sectors(request_queue_t *q, unsigned short max_sectors)
552 { 552 {
553 if ((max_sectors << 9) < PAGE_CACHE_SIZE) { 553 if ((max_sectors << 9) < PAGE_CACHE_SIZE) {
554 max_sectors = 1 << (PAGE_CACHE_SHIFT - 9); 554 max_sectors = 1 << (PAGE_CACHE_SHIFT - 9);
555 printk("%s: set to minimum %d\n", __FUNCTION__, max_sectors); 555 printk("%s: set to minimum %d\n", __FUNCTION__, max_sectors);
556 } 556 }
557 557
558 if (BLK_DEF_MAX_SECTORS > max_sectors) 558 if (BLK_DEF_MAX_SECTORS > max_sectors)
559 q->max_hw_sectors = q->max_sectors = max_sectors; 559 q->max_hw_sectors = q->max_sectors = max_sectors;
560 else { 560 else {
561 q->max_sectors = BLK_DEF_MAX_SECTORS; 561 q->max_sectors = BLK_DEF_MAX_SECTORS;
562 q->max_hw_sectors = max_sectors; 562 q->max_hw_sectors = max_sectors;
563 } 563 }
564 } 564 }
565 565
566 EXPORT_SYMBOL(blk_queue_max_sectors); 566 EXPORT_SYMBOL(blk_queue_max_sectors);
567 567
568 /** 568 /**
569 * blk_queue_max_phys_segments - set max phys segments for a request for this queue 569 * blk_queue_max_phys_segments - set max phys segments for a request for this queue
570 * @q: the request queue for the device 570 * @q: the request queue for the device
571 * @max_segments: max number of segments 571 * @max_segments: max number of segments
572 * 572 *
573 * Description: 573 * Description:
574 * Enables a low level driver to set an upper limit on the number of 574 * Enables a low level driver to set an upper limit on the number of
575 * physical data segments in a request. This would be the largest sized 575 * physical data segments in a request. This would be the largest sized
576 * scatter list the driver could handle. 576 * scatter list the driver could handle.
577 **/ 577 **/
578 void blk_queue_max_phys_segments(request_queue_t *q, unsigned short max_segments) 578 void blk_queue_max_phys_segments(request_queue_t *q, unsigned short max_segments)
579 { 579 {
580 if (!max_segments) { 580 if (!max_segments) {
581 max_segments = 1; 581 max_segments = 1;
582 printk("%s: set to minimum %d\n", __FUNCTION__, max_segments); 582 printk("%s: set to minimum %d\n", __FUNCTION__, max_segments);
583 } 583 }
584 584
585 q->max_phys_segments = max_segments; 585 q->max_phys_segments = max_segments;
586 } 586 }
587 587
588 EXPORT_SYMBOL(blk_queue_max_phys_segments); 588 EXPORT_SYMBOL(blk_queue_max_phys_segments);
589 589
590 /** 590 /**
591 * blk_queue_max_hw_segments - set max hw segments for a request for this queue 591 * blk_queue_max_hw_segments - set max hw segments for a request for this queue
592 * @q: the request queue for the device 592 * @q: the request queue for the device
593 * @max_segments: max number of segments 593 * @max_segments: max number of segments
594 * 594 *
595 * Description: 595 * Description:
596 * Enables a low level driver to set an upper limit on the number of 596 * Enables a low level driver to set an upper limit on the number of
597 * hw data segments in a request. This would be the largest number of 597 * hw data segments in a request. This would be the largest number of
598 * address/length pairs the host adapter can actually give as once 598 * address/length pairs the host adapter can actually give as once
599 * to the device. 599 * to the device.
600 **/ 600 **/
601 void blk_queue_max_hw_segments(request_queue_t *q, unsigned short max_segments) 601 void blk_queue_max_hw_segments(request_queue_t *q, unsigned short max_segments)
602 { 602 {
603 if (!max_segments) { 603 if (!max_segments) {
604 max_segments = 1; 604 max_segments = 1;
605 printk("%s: set to minimum %d\n", __FUNCTION__, max_segments); 605 printk("%s: set to minimum %d\n", __FUNCTION__, max_segments);
606 } 606 }
607 607
608 q->max_hw_segments = max_segments; 608 q->max_hw_segments = max_segments;
609 } 609 }
610 610
611 EXPORT_SYMBOL(blk_queue_max_hw_segments); 611 EXPORT_SYMBOL(blk_queue_max_hw_segments);
612 612
613 /** 613 /**
614 * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg 614 * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg
615 * @q: the request queue for the device 615 * @q: the request queue for the device
616 * @max_size: max size of segment in bytes 616 * @max_size: max size of segment in bytes
617 * 617 *
618 * Description: 618 * Description:
619 * Enables a low level driver to set an upper limit on the size of a 619 * Enables a low level driver to set an upper limit on the size of a
620 * coalesced segment 620 * coalesced segment
621 **/ 621 **/
622 void blk_queue_max_segment_size(request_queue_t *q, unsigned int max_size) 622 void blk_queue_max_segment_size(request_queue_t *q, unsigned int max_size)
623 { 623 {
624 if (max_size < PAGE_CACHE_SIZE) { 624 if (max_size < PAGE_CACHE_SIZE) {
625 max_size = PAGE_CACHE_SIZE; 625 max_size = PAGE_CACHE_SIZE;
626 printk("%s: set to minimum %d\n", __FUNCTION__, max_size); 626 printk("%s: set to minimum %d\n", __FUNCTION__, max_size);
627 } 627 }
628 628
629 q->max_segment_size = max_size; 629 q->max_segment_size = max_size;
630 } 630 }
631 631
632 EXPORT_SYMBOL(blk_queue_max_segment_size); 632 EXPORT_SYMBOL(blk_queue_max_segment_size);
633 633
634 /** 634 /**
635 * blk_queue_hardsect_size - set hardware sector size for the queue 635 * blk_queue_hardsect_size - set hardware sector size for the queue
636 * @q: the request queue for the device 636 * @q: the request queue for the device
637 * @size: the hardware sector size, in bytes 637 * @size: the hardware sector size, in bytes
638 * 638 *
639 * Description: 639 * Description:
640 * This should typically be set to the lowest possible sector size 640 * This should typically be set to the lowest possible sector size
641 * that the hardware can operate on (possible without reverting to 641 * that the hardware can operate on (possible without reverting to
642 * even internal read-modify-write operations). Usually the default 642 * even internal read-modify-write operations). Usually the default
643 * of 512 covers most hardware. 643 * of 512 covers most hardware.
644 **/ 644 **/
645 void blk_queue_hardsect_size(request_queue_t *q, unsigned short size) 645 void blk_queue_hardsect_size(request_queue_t *q, unsigned short size)
646 { 646 {
647 q->hardsect_size = size; 647 q->hardsect_size = size;
648 } 648 }
649 649
650 EXPORT_SYMBOL(blk_queue_hardsect_size); 650 EXPORT_SYMBOL(blk_queue_hardsect_size);
651 651
652 /* 652 /*
653 * Returns the minimum that is _not_ zero, unless both are zero. 653 * Returns the minimum that is _not_ zero, unless both are zero.
654 */ 654 */
655 #define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r)) 655 #define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r))
656 656
657 /** 657 /**
658 * blk_queue_stack_limits - inherit underlying queue limits for stacked drivers 658 * blk_queue_stack_limits - inherit underlying queue limits for stacked drivers
659 * @t: the stacking driver (top) 659 * @t: the stacking driver (top)
660 * @b: the underlying device (bottom) 660 * @b: the underlying device (bottom)
661 **/ 661 **/
662 void blk_queue_stack_limits(request_queue_t *t, request_queue_t *b) 662 void blk_queue_stack_limits(request_queue_t *t, request_queue_t *b)
663 { 663 {
664 /* zero is "infinity" */ 664 /* zero is "infinity" */
665 t->max_sectors = min_not_zero(t->max_sectors,b->max_sectors); 665 t->max_sectors = min_not_zero(t->max_sectors,b->max_sectors);
666 t->max_hw_sectors = min_not_zero(t->max_hw_sectors,b->max_hw_sectors); 666 t->max_hw_sectors = min_not_zero(t->max_hw_sectors,b->max_hw_sectors);
667 667
668 t->max_phys_segments = min(t->max_phys_segments,b->max_phys_segments); 668 t->max_phys_segments = min(t->max_phys_segments,b->max_phys_segments);
669 t->max_hw_segments = min(t->max_hw_segments,b->max_hw_segments); 669 t->max_hw_segments = min(t->max_hw_segments,b->max_hw_segments);
670 t->max_segment_size = min(t->max_segment_size,b->max_segment_size); 670 t->max_segment_size = min(t->max_segment_size,b->max_segment_size);
671 t->hardsect_size = max(t->hardsect_size,b->hardsect_size); 671 t->hardsect_size = max(t->hardsect_size,b->hardsect_size);
672 } 672 }
673 673
674 EXPORT_SYMBOL(blk_queue_stack_limits); 674 EXPORT_SYMBOL(blk_queue_stack_limits);
675 675
676 /** 676 /**
677 * blk_queue_segment_boundary - set boundary rules for segment merging 677 * blk_queue_segment_boundary - set boundary rules for segment merging
678 * @q: the request queue for the device 678 * @q: the request queue for the device
679 * @mask: the memory boundary mask 679 * @mask: the memory boundary mask
680 **/ 680 **/
681 void blk_queue_segment_boundary(request_queue_t *q, unsigned long mask) 681 void blk_queue_segment_boundary(request_queue_t *q, unsigned long mask)
682 { 682 {
683 if (mask < PAGE_CACHE_SIZE - 1) { 683 if (mask < PAGE_CACHE_SIZE - 1) {
684 mask = PAGE_CACHE_SIZE - 1; 684 mask = PAGE_CACHE_SIZE - 1;
685 printk("%s: set to minimum %lx\n", __FUNCTION__, mask); 685 printk("%s: set to minimum %lx\n", __FUNCTION__, mask);
686 } 686 }
687 687
688 q->seg_boundary_mask = mask; 688 q->seg_boundary_mask = mask;
689 } 689 }
690 690
691 EXPORT_SYMBOL(blk_queue_segment_boundary); 691 EXPORT_SYMBOL(blk_queue_segment_boundary);
692 692
693 /** 693 /**
694 * blk_queue_dma_alignment - set dma length and memory alignment 694 * blk_queue_dma_alignment - set dma length and memory alignment
695 * @q: the request queue for the device 695 * @q: the request queue for the device
696 * @mask: alignment mask 696 * @mask: alignment mask
697 * 697 *
698 * description: 698 * description:
699 * set required memory and length aligment for direct dma transactions. 699 * set required memory and length aligment for direct dma transactions.
700 * this is used when buiding direct io requests for the queue. 700 * this is used when buiding direct io requests for the queue.
701 * 701 *
702 **/ 702 **/
703 void blk_queue_dma_alignment(request_queue_t *q, int mask) 703 void blk_queue_dma_alignment(request_queue_t *q, int mask)
704 { 704 {
705 q->dma_alignment = mask; 705 q->dma_alignment = mask;
706 } 706 }
707 707
708 EXPORT_SYMBOL(blk_queue_dma_alignment); 708 EXPORT_SYMBOL(blk_queue_dma_alignment);
709 709
710 /** 710 /**
711 * blk_queue_find_tag - find a request by its tag and queue 711 * blk_queue_find_tag - find a request by its tag and queue
712 * @q: The request queue for the device 712 * @q: The request queue for the device
713 * @tag: The tag of the request 713 * @tag: The tag of the request
714 * 714 *
715 * Notes: 715 * Notes:
716 * Should be used when a device returns a tag and you want to match 716 * Should be used when a device returns a tag and you want to match
717 * it with a request. 717 * it with a request.
718 * 718 *
719 * no locks need be held. 719 * no locks need be held.
720 **/ 720 **/
721 struct request *blk_queue_find_tag(request_queue_t *q, int tag) 721 struct request *blk_queue_find_tag(request_queue_t *q, int tag)
722 { 722 {
723 struct blk_queue_tag *bqt = q->queue_tags; 723 struct blk_queue_tag *bqt = q->queue_tags;
724 724
725 if (unlikely(bqt == NULL || tag >= bqt->real_max_depth)) 725 if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
726 return NULL; 726 return NULL;
727 727
728 return bqt->tag_index[tag]; 728 return bqt->tag_index[tag];
729 } 729 }
730 730
731 EXPORT_SYMBOL(blk_queue_find_tag); 731 EXPORT_SYMBOL(blk_queue_find_tag);
732 732
733 /** 733 /**
734 * __blk_queue_free_tags - release tag maintenance info 734 * __blk_queue_free_tags - release tag maintenance info
735 * @q: the request queue for the device 735 * @q: the request queue for the device
736 * 736 *
737 * Notes: 737 * Notes:
738 * blk_cleanup_queue() will take care of calling this function, if tagging 738 * blk_cleanup_queue() will take care of calling this function, if tagging
739 * has been used. So there's no need to call this directly. 739 * has been used. So there's no need to call this directly.
740 **/ 740 **/
741 static void __blk_queue_free_tags(request_queue_t *q) 741 static void __blk_queue_free_tags(request_queue_t *q)
742 { 742 {
743 struct blk_queue_tag *bqt = q->queue_tags; 743 struct blk_queue_tag *bqt = q->queue_tags;
744 744
745 if (!bqt) 745 if (!bqt)
746 return; 746 return;
747 747
748 if (atomic_dec_and_test(&bqt->refcnt)) { 748 if (atomic_dec_and_test(&bqt->refcnt)) {
749 BUG_ON(bqt->busy); 749 BUG_ON(bqt->busy);
750 BUG_ON(!list_empty(&bqt->busy_list)); 750 BUG_ON(!list_empty(&bqt->busy_list));
751 751
752 kfree(bqt->tag_index); 752 kfree(bqt->tag_index);
753 bqt->tag_index = NULL; 753 bqt->tag_index = NULL;
754 754
755 kfree(bqt->tag_map); 755 kfree(bqt->tag_map);
756 bqt->tag_map = NULL; 756 bqt->tag_map = NULL;
757 757
758 kfree(bqt); 758 kfree(bqt);
759 } 759 }
760 760
761 q->queue_tags = NULL; 761 q->queue_tags = NULL;
762 q->queue_flags &= ~(1 << QUEUE_FLAG_QUEUED); 762 q->queue_flags &= ~(1 << QUEUE_FLAG_QUEUED);
763 } 763 }
764 764
765 /** 765 /**
766 * blk_queue_free_tags - release tag maintenance info 766 * blk_queue_free_tags - release tag maintenance info
767 * @q: the request queue for the device 767 * @q: the request queue for the device
768 * 768 *
769 * Notes: 769 * Notes:
770 * This is used to disabled tagged queuing to a device, yet leave 770 * This is used to disabled tagged queuing to a device, yet leave
771 * queue in function. 771 * queue in function.
772 **/ 772 **/
773 void blk_queue_free_tags(request_queue_t *q) 773 void blk_queue_free_tags(request_queue_t *q)
774 { 774 {
775 clear_bit(QUEUE_FLAG_QUEUED, &q->queue_flags); 775 clear_bit(QUEUE_FLAG_QUEUED, &q->queue_flags);
776 } 776 }
777 777
778 EXPORT_SYMBOL(blk_queue_free_tags); 778 EXPORT_SYMBOL(blk_queue_free_tags);
779 779
780 static int 780 static int
781 init_tag_map(request_queue_t *q, struct blk_queue_tag *tags, int depth) 781 init_tag_map(request_queue_t *q, struct blk_queue_tag *tags, int depth)
782 { 782 {
783 struct request **tag_index; 783 struct request **tag_index;
784 unsigned long *tag_map; 784 unsigned long *tag_map;
785 int nr_ulongs; 785 int nr_ulongs;
786 786
787 if (depth > q->nr_requests * 2) { 787 if (depth > q->nr_requests * 2) {
788 depth = q->nr_requests * 2; 788 depth = q->nr_requests * 2;
789 printk(KERN_ERR "%s: adjusted depth to %d\n", 789 printk(KERN_ERR "%s: adjusted depth to %d\n",
790 __FUNCTION__, depth); 790 __FUNCTION__, depth);
791 } 791 }
792 792
793 tag_index = kmalloc(depth * sizeof(struct request *), GFP_ATOMIC); 793 tag_index = kmalloc(depth * sizeof(struct request *), GFP_ATOMIC);
794 if (!tag_index) 794 if (!tag_index)
795 goto fail; 795 goto fail;
796 796
797 nr_ulongs = ALIGN(depth, BITS_PER_LONG) / BITS_PER_LONG; 797 nr_ulongs = ALIGN(depth, BITS_PER_LONG) / BITS_PER_LONG;
798 tag_map = kmalloc(nr_ulongs * sizeof(unsigned long), GFP_ATOMIC); 798 tag_map = kmalloc(nr_ulongs * sizeof(unsigned long), GFP_ATOMIC);
799 if (!tag_map) 799 if (!tag_map)
800 goto fail; 800 goto fail;
801 801
802 memset(tag_index, 0, depth * sizeof(struct request *)); 802 memset(tag_index, 0, depth * sizeof(struct request *));
803 memset(tag_map, 0, nr_ulongs * sizeof(unsigned long)); 803 memset(tag_map, 0, nr_ulongs * sizeof(unsigned long));
804 tags->real_max_depth = depth; 804 tags->real_max_depth = depth;
805 tags->max_depth = depth; 805 tags->max_depth = depth;
806 tags->tag_index = tag_index; 806 tags->tag_index = tag_index;
807 tags->tag_map = tag_map; 807 tags->tag_map = tag_map;
808 808
809 return 0; 809 return 0;
810 fail: 810 fail:
811 kfree(tag_index); 811 kfree(tag_index);
812 return -ENOMEM; 812 return -ENOMEM;
813 } 813 }
814 814
815 /** 815 /**
816 * blk_queue_init_tags - initialize the queue tag info 816 * blk_queue_init_tags - initialize the queue tag info
817 * @q: the request queue for the device 817 * @q: the request queue for the device
818 * @depth: the maximum queue depth supported 818 * @depth: the maximum queue depth supported
819 * @tags: the tag to use 819 * @tags: the tag to use
820 **/ 820 **/
821 int blk_queue_init_tags(request_queue_t *q, int depth, 821 int blk_queue_init_tags(request_queue_t *q, int depth,
822 struct blk_queue_tag *tags) 822 struct blk_queue_tag *tags)
823 { 823 {
824 int rc; 824 int rc;
825 825
826 BUG_ON(tags && q->queue_tags && tags != q->queue_tags); 826 BUG_ON(tags && q->queue_tags && tags != q->queue_tags);
827 827
828 if (!tags && !q->queue_tags) { 828 if (!tags && !q->queue_tags) {
829 tags = kmalloc(sizeof(struct blk_queue_tag), GFP_ATOMIC); 829 tags = kmalloc(sizeof(struct blk_queue_tag), GFP_ATOMIC);
830 if (!tags) 830 if (!tags)
831 goto fail; 831 goto fail;
832 832
833 if (init_tag_map(q, tags, depth)) 833 if (init_tag_map(q, tags, depth))
834 goto fail; 834 goto fail;
835 835
836 INIT_LIST_HEAD(&tags->busy_list); 836 INIT_LIST_HEAD(&tags->busy_list);
837 tags->busy = 0; 837 tags->busy = 0;
838 atomic_set(&tags->refcnt, 1); 838 atomic_set(&tags->refcnt, 1);
839 } else if (q->queue_tags) { 839 } else if (q->queue_tags) {
840 if ((rc = blk_queue_resize_tags(q, depth))) 840 if ((rc = blk_queue_resize_tags(q, depth)))
841 return rc; 841 return rc;
842 set_bit(QUEUE_FLAG_QUEUED, &q->queue_flags); 842 set_bit(QUEUE_FLAG_QUEUED, &q->queue_flags);
843 return 0; 843 return 0;
844 } else 844 } else
845 atomic_inc(&tags->refcnt); 845 atomic_inc(&tags->refcnt);
846 846
847 /* 847 /*
848 * assign it, all done 848 * assign it, all done
849 */ 849 */
850 q->queue_tags = tags; 850 q->queue_tags = tags;
851 q->queue_flags |= (1 << QUEUE_FLAG_QUEUED); 851 q->queue_flags |= (1 << QUEUE_FLAG_QUEUED);
852 return 0; 852 return 0;
853 fail: 853 fail:
854 kfree(tags); 854 kfree(tags);
855 return -ENOMEM; 855 return -ENOMEM;
856 } 856 }
857 857
858 EXPORT_SYMBOL(blk_queue_init_tags); 858 EXPORT_SYMBOL(blk_queue_init_tags);
859 859
860 /** 860 /**
861 * blk_queue_resize_tags - change the queueing depth 861 * blk_queue_resize_tags - change the queueing depth
862 * @q: the request queue for the device 862 * @q: the request queue for the device
863 * @new_depth: the new max command queueing depth 863 * @new_depth: the new max command queueing depth
864 * 864 *
865 * Notes: 865 * Notes:
866 * Must be called with the queue lock held. 866 * Must be called with the queue lock held.
867 **/ 867 **/
868 int blk_queue_resize_tags(request_queue_t *q, int new_depth) 868 int blk_queue_resize_tags(request_queue_t *q, int new_depth)
869 { 869 {
870 struct blk_queue_tag *bqt = q->queue_tags; 870 struct blk_queue_tag *bqt = q->queue_tags;
871 struct request **tag_index; 871 struct request **tag_index;
872 unsigned long *tag_map; 872 unsigned long *tag_map;
873 int max_depth, nr_ulongs; 873 int max_depth, nr_ulongs;
874 874
875 if (!bqt) 875 if (!bqt)
876 return -ENXIO; 876 return -ENXIO;
877 877
878 /* 878 /*
879 * if we already have large enough real_max_depth. just 879 * if we already have large enough real_max_depth. just
880 * adjust max_depth. *NOTE* as requests with tag value 880 * adjust max_depth. *NOTE* as requests with tag value
881 * between new_depth and real_max_depth can be in-flight, tag 881 * between new_depth and real_max_depth can be in-flight, tag
882 * map can not be shrunk blindly here. 882 * map can not be shrunk blindly here.
883 */ 883 */
884 if (new_depth <= bqt->real_max_depth) { 884 if (new_depth <= bqt->real_max_depth) {
885 bqt->max_depth = new_depth; 885 bqt->max_depth = new_depth;
886 return 0; 886 return 0;
887 } 887 }
888 888
889 /* 889 /*
890 * save the old state info, so we can copy it back 890 * save the old state info, so we can copy it back
891 */ 891 */
892 tag_index = bqt->tag_index; 892 tag_index = bqt->tag_index;
893 tag_map = bqt->tag_map; 893 tag_map = bqt->tag_map;
894 max_depth = bqt->real_max_depth; 894 max_depth = bqt->real_max_depth;
895 895
896 if (init_tag_map(q, bqt, new_depth)) 896 if (init_tag_map(q, bqt, new_depth))
897 return -ENOMEM; 897 return -ENOMEM;
898 898
899 memcpy(bqt->tag_index, tag_index, max_depth * sizeof(struct request *)); 899 memcpy(bqt->tag_index, tag_index, max_depth * sizeof(struct request *));
900 nr_ulongs = ALIGN(max_depth, BITS_PER_LONG) / BITS_PER_LONG; 900 nr_ulongs = ALIGN(max_depth, BITS_PER_LONG) / BITS_PER_LONG;
901 memcpy(bqt->tag_map, tag_map, nr_ulongs * sizeof(unsigned long)); 901 memcpy(bqt->tag_map, tag_map, nr_ulongs * sizeof(unsigned long));
902 902
903 kfree(tag_index); 903 kfree(tag_index);
904 kfree(tag_map); 904 kfree(tag_map);
905 return 0; 905 return 0;
906 } 906 }
907 907
908 EXPORT_SYMBOL(blk_queue_resize_tags); 908 EXPORT_SYMBOL(blk_queue_resize_tags);
909 909
910 /** 910 /**
911 * blk_queue_end_tag - end tag operations for a request 911 * blk_queue_end_tag - end tag operations for a request
912 * @q: the request queue for the device 912 * @q: the request queue for the device
913 * @rq: the request that has completed 913 * @rq: the request that has completed
914 * 914 *
915 * Description: 915 * Description:
916 * Typically called when end_that_request_first() returns 0, meaning 916 * Typically called when end_that_request_first() returns 0, meaning
917 * all transfers have been done for a request. It's important to call 917 * all transfers have been done for a request. It's important to call
918 * this function before end_that_request_last(), as that will put the 918 * this function before end_that_request_last(), as that will put the
919 * request back on the free list thus corrupting the internal tag list. 919 * request back on the free list thus corrupting the internal tag list.
920 * 920 *
921 * Notes: 921 * Notes:
922 * queue lock must be held. 922 * queue lock must be held.
923 **/ 923 **/
924 void blk_queue_end_tag(request_queue_t *q, struct request *rq) 924 void blk_queue_end_tag(request_queue_t *q, struct request *rq)
925 { 925 {
926 struct blk_queue_tag *bqt = q->queue_tags; 926 struct blk_queue_tag *bqt = q->queue_tags;
927 int tag = rq->tag; 927 int tag = rq->tag;
928 928
929 BUG_ON(tag == -1); 929 BUG_ON(tag == -1);
930 930
931 if (unlikely(tag >= bqt->real_max_depth)) 931 if (unlikely(tag >= bqt->real_max_depth))
932 /* 932 /*
933 * This can happen after tag depth has been reduced. 933 * This can happen after tag depth has been reduced.
934 * FIXME: how about a warning or info message here? 934 * FIXME: how about a warning or info message here?
935 */ 935 */
936 return; 936 return;
937 937
938 if (unlikely(!__test_and_clear_bit(tag, bqt->tag_map))) { 938 if (unlikely(!__test_and_clear_bit(tag, bqt->tag_map))) {
939 printk(KERN_ERR "%s: attempt to clear non-busy tag (%d)\n", 939 printk(KERN_ERR "%s: attempt to clear non-busy tag (%d)\n",
940 __FUNCTION__, tag); 940 __FUNCTION__, tag);
941 return; 941 return;
942 } 942 }
943 943
944 list_del_init(&rq->queuelist); 944 list_del_init(&rq->queuelist);
945 rq->flags &= ~REQ_QUEUED; 945 rq->flags &= ~REQ_QUEUED;
946 rq->tag = -1; 946 rq->tag = -1;
947 947
948 if (unlikely(bqt->tag_index[tag] == NULL)) 948 if (unlikely(bqt->tag_index[tag] == NULL))
949 printk(KERN_ERR "%s: tag %d is missing\n", 949 printk(KERN_ERR "%s: tag %d is missing\n",
950 __FUNCTION__, tag); 950 __FUNCTION__, tag);
951 951
952 bqt->tag_index[tag] = NULL; 952 bqt->tag_index[tag] = NULL;
953 bqt->busy--; 953 bqt->busy--;
954 } 954 }
955 955
956 EXPORT_SYMBOL(blk_queue_end_tag); 956 EXPORT_SYMBOL(blk_queue_end_tag);
957 957
958 /** 958 /**
959 * blk_queue_start_tag - find a free tag and assign it 959 * blk_queue_start_tag - find a free tag and assign it
960 * @q: the request queue for the device 960 * @q: the request queue for the device
961 * @rq: the block request that needs tagging 961 * @rq: the block request that needs tagging
962 * 962 *
963 * Description: 963 * Description:
964 * This can either be used as a stand-alone helper, or possibly be 964 * This can either be used as a stand-alone helper, or possibly be
965 * assigned as the queue &prep_rq_fn (in which case &struct request 965 * assigned as the queue &prep_rq_fn (in which case &struct request
966 * automagically gets a tag assigned). Note that this function 966 * automagically gets a tag assigned). Note that this function
967 * assumes that any type of request can be queued! if this is not 967 * assumes that any type of request can be queued! if this is not
968 * true for your device, you must check the request type before 968 * true for your device, you must check the request type before
969 * calling this function. The request will also be removed from 969 * calling this function. The request will also be removed from
970 * the request queue, so it's the drivers responsibility to readd 970 * the request queue, so it's the drivers responsibility to readd
971 * it if it should need to be restarted for some reason. 971 * it if it should need to be restarted for some reason.
972 * 972 *
973 * Notes: 973 * Notes:
974 * queue lock must be held. 974 * queue lock must be held.
975 **/ 975 **/
976 int blk_queue_start_tag(request_queue_t *q, struct request *rq) 976 int blk_queue_start_tag(request_queue_t *q, struct request *rq)
977 { 977 {
978 struct blk_queue_tag *bqt = q->queue_tags; 978 struct blk_queue_tag *bqt = q->queue_tags;
979 int tag; 979 int tag;
980 980
981 if (unlikely((rq->flags & REQ_QUEUED))) { 981 if (unlikely((rq->flags & REQ_QUEUED))) {
982 printk(KERN_ERR 982 printk(KERN_ERR
983 "%s: request %p for device [%s] already tagged %d", 983 "%s: request %p for device [%s] already tagged %d",
984 __FUNCTION__, rq, 984 __FUNCTION__, rq,
985 rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->tag); 985 rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->tag);
986 BUG(); 986 BUG();
987 } 987 }
988 988
989 tag = find_first_zero_bit(bqt->tag_map, bqt->max_depth); 989 tag = find_first_zero_bit(bqt->tag_map, bqt->max_depth);
990 if (tag >= bqt->max_depth) 990 if (tag >= bqt->max_depth)
991 return 1; 991 return 1;
992 992
993 __set_bit(tag, bqt->tag_map); 993 __set_bit(tag, bqt->tag_map);
994 994
995 rq->flags |= REQ_QUEUED; 995 rq->flags |= REQ_QUEUED;
996 rq->tag = tag; 996 rq->tag = tag;
997 bqt->tag_index[tag] = rq; 997 bqt->tag_index[tag] = rq;
998 blkdev_dequeue_request(rq); 998 blkdev_dequeue_request(rq);
999 list_add(&rq->queuelist, &bqt->busy_list); 999 list_add(&rq->queuelist, &bqt->busy_list);
1000 bqt->busy++; 1000 bqt->busy++;
1001 return 0; 1001 return 0;
1002 } 1002 }
1003 1003
1004 EXPORT_SYMBOL(blk_queue_start_tag); 1004 EXPORT_SYMBOL(blk_queue_start_tag);
1005 1005
1006 /** 1006 /**
1007 * blk_queue_invalidate_tags - invalidate all pending tags 1007 * blk_queue_invalidate_tags - invalidate all pending tags
1008 * @q: the request queue for the device 1008 * @q: the request queue for the device
1009 * 1009 *
1010 * Description: 1010 * Description:
1011 * Hardware conditions may dictate a need to stop all pending requests. 1011 * Hardware conditions may dictate a need to stop all pending requests.
1012 * In this case, we will safely clear the block side of the tag queue and 1012 * In this case, we will safely clear the block side of the tag queue and
1013 * readd all requests to the request queue in the right order. 1013 * readd all requests to the request queue in the right order.
1014 * 1014 *
1015 * Notes: 1015 * Notes:
1016 * queue lock must be held. 1016 * queue lock must be held.
1017 **/ 1017 **/
1018 void blk_queue_invalidate_tags(request_queue_t *q) 1018 void blk_queue_invalidate_tags(request_queue_t *q)
1019 { 1019 {
1020 struct blk_queue_tag *bqt = q->queue_tags; 1020 struct blk_queue_tag *bqt = q->queue_tags;
1021 struct list_head *tmp, *n; 1021 struct list_head *tmp, *n;
1022 struct request *rq; 1022 struct request *rq;
1023 1023
1024 list_for_each_safe(tmp, n, &bqt->busy_list) { 1024 list_for_each_safe(tmp, n, &bqt->busy_list) {
1025 rq = list_entry_rq(tmp); 1025 rq = list_entry_rq(tmp);
1026 1026
1027 if (rq->tag == -1) { 1027 if (rq->tag == -1) {
1028 printk(KERN_ERR 1028 printk(KERN_ERR
1029 "%s: bad tag found on list\n", __FUNCTION__); 1029 "%s: bad tag found on list\n", __FUNCTION__);
1030 list_del_init(&rq->queuelist); 1030 list_del_init(&rq->queuelist);
1031 rq->flags &= ~REQ_QUEUED; 1031 rq->flags &= ~REQ_QUEUED;
1032 } else 1032 } else
1033 blk_queue_end_tag(q, rq); 1033 blk_queue_end_tag(q, rq);
1034 1034
1035 rq->flags &= ~REQ_STARTED; 1035 rq->flags &= ~REQ_STARTED;
1036 __elv_add_request(q, rq, ELEVATOR_INSERT_BACK, 0); 1036 __elv_add_request(q, rq, ELEVATOR_INSERT_BACK, 0);
1037 } 1037 }
1038 } 1038 }
1039 1039
1040 EXPORT_SYMBOL(blk_queue_invalidate_tags); 1040 EXPORT_SYMBOL(blk_queue_invalidate_tags);
1041 1041
1042 static char *rq_flags[] = { 1042 static char *rq_flags[] = {
1043 "REQ_RW", 1043 "REQ_RW",
1044 "REQ_FAILFAST", 1044 "REQ_FAILFAST",
1045 "REQ_SORTED", 1045 "REQ_SORTED",
1046 "REQ_SOFTBARRIER", 1046 "REQ_SOFTBARRIER",
1047 "REQ_HARDBARRIER", 1047 "REQ_HARDBARRIER",
1048 "REQ_CMD", 1048 "REQ_CMD",
1049 "REQ_NOMERGE", 1049 "REQ_NOMERGE",
1050 "REQ_STARTED", 1050 "REQ_STARTED",
1051 "REQ_DONTPREP", 1051 "REQ_DONTPREP",
1052 "REQ_QUEUED", 1052 "REQ_QUEUED",
1053 "REQ_ELVPRIV", 1053 "REQ_ELVPRIV",
1054 "REQ_PC", 1054 "REQ_PC",
1055 "REQ_BLOCK_PC", 1055 "REQ_BLOCK_PC",
1056 "REQ_SENSE", 1056 "REQ_SENSE",
1057 "REQ_FAILED", 1057 "REQ_FAILED",
1058 "REQ_QUIET", 1058 "REQ_QUIET",
1059 "REQ_SPECIAL", 1059 "REQ_SPECIAL",
1060 "REQ_DRIVE_CMD", 1060 "REQ_DRIVE_CMD",
1061 "REQ_DRIVE_TASK", 1061 "REQ_DRIVE_TASK",
1062 "REQ_DRIVE_TASKFILE", 1062 "REQ_DRIVE_TASKFILE",
1063 "REQ_PREEMPT", 1063 "REQ_PREEMPT",
1064 "REQ_PM_SUSPEND", 1064 "REQ_PM_SUSPEND",
1065 "REQ_PM_RESUME", 1065 "REQ_PM_RESUME",
1066 "REQ_PM_SHUTDOWN", 1066 "REQ_PM_SHUTDOWN",
1067 }; 1067 };
1068 1068
1069 void blk_dump_rq_flags(struct request *rq, char *msg) 1069 void blk_dump_rq_flags(struct request *rq, char *msg)
1070 { 1070 {
1071 int bit; 1071 int bit;
1072 1072
1073 printk("%s: dev %s: flags = ", msg, 1073 printk("%s: dev %s: flags = ", msg,
1074 rq->rq_disk ? rq->rq_disk->disk_name : "?"); 1074 rq->rq_disk ? rq->rq_disk->disk_name : "?");
1075 bit = 0; 1075 bit = 0;
1076 do { 1076 do {
1077 if (rq->flags & (1 << bit)) 1077 if (rq->flags & (1 << bit))
1078 printk("%s ", rq_flags[bit]); 1078 printk("%s ", rq_flags[bit]);
1079 bit++; 1079 bit++;
1080 } while (bit < __REQ_NR_BITS); 1080 } while (bit < __REQ_NR_BITS);
1081 1081
1082 printk("\nsector %llu, nr/cnr %lu/%u\n", (unsigned long long)rq->sector, 1082 printk("\nsector %llu, nr/cnr %lu/%u\n", (unsigned long long)rq->sector,
1083 rq->nr_sectors, 1083 rq->nr_sectors,
1084 rq->current_nr_sectors); 1084 rq->current_nr_sectors);
1085 printk("bio %p, biotail %p, buffer %p, data %p, len %u\n", rq->bio, rq->biotail, rq->buffer, rq->data, rq->data_len); 1085 printk("bio %p, biotail %p, buffer %p, data %p, len %u\n", rq->bio, rq->biotail, rq->buffer, rq->data, rq->data_len);
1086 1086
1087 if (rq->flags & (REQ_BLOCK_PC | REQ_PC)) { 1087 if (rq->flags & (REQ_BLOCK_PC | REQ_PC)) {
1088 printk("cdb: "); 1088 printk("cdb: ");
1089 for (bit = 0; bit < sizeof(rq->cmd); bit++) 1089 for (bit = 0; bit < sizeof(rq->cmd); bit++)
1090 printk("%02x ", rq->cmd[bit]); 1090 printk("%02x ", rq->cmd[bit]);
1091 printk("\n"); 1091 printk("\n");
1092 } 1092 }
1093 } 1093 }
1094 1094
1095 EXPORT_SYMBOL(blk_dump_rq_flags); 1095 EXPORT_SYMBOL(blk_dump_rq_flags);
1096 1096
1097 void blk_recount_segments(request_queue_t *q, struct bio *bio) 1097 void blk_recount_segments(request_queue_t *q, struct bio *bio)
1098 { 1098 {
1099 struct bio_vec *bv, *bvprv = NULL; 1099 struct bio_vec *bv, *bvprv = NULL;
1100 int i, nr_phys_segs, nr_hw_segs, seg_size, hw_seg_size, cluster; 1100 int i, nr_phys_segs, nr_hw_segs, seg_size, hw_seg_size, cluster;
1101 int high, highprv = 1; 1101 int high, highprv = 1;
1102 1102
1103 if (unlikely(!bio->bi_io_vec)) 1103 if (unlikely(!bio->bi_io_vec))
1104 return; 1104 return;
1105 1105
1106 cluster = q->queue_flags & (1 << QUEUE_FLAG_CLUSTER); 1106 cluster = q->queue_flags & (1 << QUEUE_FLAG_CLUSTER);
1107 hw_seg_size = seg_size = nr_phys_segs = nr_hw_segs = 0; 1107 hw_seg_size = seg_size = nr_phys_segs = nr_hw_segs = 0;
1108 bio_for_each_segment(bv, bio, i) { 1108 bio_for_each_segment(bv, bio, i) {
1109 /* 1109 /*
1110 * the trick here is making sure that a high page is never 1110 * the trick here is making sure that a high page is never
1111 * considered part of another segment, since that might 1111 * considered part of another segment, since that might
1112 * change with the bounce page. 1112 * change with the bounce page.
1113 */ 1113 */
1114 high = page_to_pfn(bv->bv_page) >= q->bounce_pfn; 1114 high = page_to_pfn(bv->bv_page) >= q->bounce_pfn;
1115 if (high || highprv) 1115 if (high || highprv)
1116 goto new_hw_segment; 1116 goto new_hw_segment;
1117 if (cluster) { 1117 if (cluster) {
1118 if (seg_size + bv->bv_len > q->max_segment_size) 1118 if (seg_size + bv->bv_len > q->max_segment_size)
1119 goto new_segment; 1119 goto new_segment;
1120 if (!BIOVEC_PHYS_MERGEABLE(bvprv, bv)) 1120 if (!BIOVEC_PHYS_MERGEABLE(bvprv, bv))
1121 goto new_segment; 1121 goto new_segment;
1122 if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bv)) 1122 if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bv))
1123 goto new_segment; 1123 goto new_segment;
1124 if (BIOVEC_VIRT_OVERSIZE(hw_seg_size + bv->bv_len)) 1124 if (BIOVEC_VIRT_OVERSIZE(hw_seg_size + bv->bv_len))
1125 goto new_hw_segment; 1125 goto new_hw_segment;
1126 1126
1127 seg_size += bv->bv_len; 1127 seg_size += bv->bv_len;
1128 hw_seg_size += bv->bv_len; 1128 hw_seg_size += bv->bv_len;
1129 bvprv = bv; 1129 bvprv = bv;
1130 continue; 1130 continue;
1131 } 1131 }
1132 new_segment: 1132 new_segment:
1133 if (BIOVEC_VIRT_MERGEABLE(bvprv, bv) && 1133 if (BIOVEC_VIRT_MERGEABLE(bvprv, bv) &&
1134 !BIOVEC_VIRT_OVERSIZE(hw_seg_size + bv->bv_len)) { 1134 !BIOVEC_VIRT_OVERSIZE(hw_seg_size + bv->bv_len)) {
1135 hw_seg_size += bv->bv_len; 1135 hw_seg_size += bv->bv_len;
1136 } else { 1136 } else {
1137 new_hw_segment: 1137 new_hw_segment:
1138 if (hw_seg_size > bio->bi_hw_front_size) 1138 if (hw_seg_size > bio->bi_hw_front_size)
1139 bio->bi_hw_front_size = hw_seg_size; 1139 bio->bi_hw_front_size = hw_seg_size;
1140 hw_seg_size = BIOVEC_VIRT_START_SIZE(bv) + bv->bv_len; 1140 hw_seg_size = BIOVEC_VIRT_START_SIZE(bv) + bv->bv_len;
1141 nr_hw_segs++; 1141 nr_hw_segs++;
1142 } 1142 }
1143 1143
1144 nr_phys_segs++; 1144 nr_phys_segs++;
1145 bvprv = bv; 1145 bvprv = bv;
1146 seg_size = bv->bv_len; 1146 seg_size = bv->bv_len;
1147 highprv = high; 1147 highprv = high;
1148 } 1148 }
1149 if (hw_seg_size > bio->bi_hw_back_size) 1149 if (hw_seg_size > bio->bi_hw_back_size)
1150 bio->bi_hw_back_size = hw_seg_size; 1150 bio->bi_hw_back_size = hw_seg_size;
1151 if (nr_hw_segs == 1 && hw_seg_size > bio->bi_hw_front_size) 1151 if (nr_hw_segs == 1 && hw_seg_size > bio->bi_hw_front_size)
1152 bio->bi_hw_front_size = hw_seg_size; 1152 bio->bi_hw_front_size = hw_seg_size;
1153 bio->bi_phys_segments = nr_phys_segs; 1153 bio->bi_phys_segments = nr_phys_segs;
1154 bio->bi_hw_segments = nr_hw_segs; 1154 bio->bi_hw_segments = nr_hw_segs;
1155 bio->bi_flags |= (1 << BIO_SEG_VALID); 1155 bio->bi_flags |= (1 << BIO_SEG_VALID);
1156 } 1156 }
1157 1157
1158 1158
1159 static int blk_phys_contig_segment(request_queue_t *q, struct bio *bio, 1159 static int blk_phys_contig_segment(request_queue_t *q, struct bio *bio,
1160 struct bio *nxt) 1160 struct bio *nxt)
1161 { 1161 {
1162 if (!(q->queue_flags & (1 << QUEUE_FLAG_CLUSTER))) 1162 if (!(q->queue_flags & (1 << QUEUE_FLAG_CLUSTER)))
1163 return 0; 1163 return 0;
1164 1164
1165 if (!BIOVEC_PHYS_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt))) 1165 if (!BIOVEC_PHYS_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt)))
1166 return 0; 1166 return 0;
1167 if (bio->bi_size + nxt->bi_size > q->max_segment_size) 1167 if (bio->bi_size + nxt->bi_size > q->max_segment_size)
1168 return 0; 1168 return 0;
1169 1169
1170 /* 1170 /*
1171 * bio and nxt are contigous in memory, check if the queue allows 1171 * bio and nxt are contigous in memory, check if the queue allows
1172 * these two to be merged into one 1172 * these two to be merged into one
1173 */ 1173 */
1174 if (BIO_SEG_BOUNDARY(q, bio, nxt)) 1174 if (BIO_SEG_BOUNDARY(q, bio, nxt))
1175 return 1; 1175 return 1;
1176 1176
1177 return 0; 1177 return 0;
1178 } 1178 }
1179 1179
1180 static int blk_hw_contig_segment(request_queue_t *q, struct bio *bio, 1180 static int blk_hw_contig_segment(request_queue_t *q, struct bio *bio,
1181 struct bio *nxt) 1181 struct bio *nxt)
1182 { 1182 {
1183 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) 1183 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
1184 blk_recount_segments(q, bio); 1184 blk_recount_segments(q, bio);
1185 if (unlikely(!bio_flagged(nxt, BIO_SEG_VALID))) 1185 if (unlikely(!bio_flagged(nxt, BIO_SEG_VALID)))
1186 blk_recount_segments(q, nxt); 1186 blk_recount_segments(q, nxt);
1187 if (!BIOVEC_VIRT_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt)) || 1187 if (!BIOVEC_VIRT_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt)) ||
1188 BIOVEC_VIRT_OVERSIZE(bio->bi_hw_front_size + bio->bi_hw_back_size)) 1188 BIOVEC_VIRT_OVERSIZE(bio->bi_hw_front_size + bio->bi_hw_back_size))
1189 return 0; 1189 return 0;
1190 if (bio->bi_size + nxt->bi_size > q->max_segment_size) 1190 if (bio->bi_size + nxt->bi_size > q->max_segment_size)
1191 return 0; 1191 return 0;
1192 1192
1193 return 1; 1193 return 1;
1194 } 1194 }
1195 1195
1196 /* 1196 /*
1197 * map a request to scatterlist, return number of sg entries setup. Caller 1197 * map a request to scatterlist, return number of sg entries setup. Caller
1198 * must make sure sg can hold rq->nr_phys_segments entries 1198 * must make sure sg can hold rq->nr_phys_segments entries
1199 */ 1199 */
1200 int blk_rq_map_sg(request_queue_t *q, struct request *rq, struct scatterlist *sg) 1200 int blk_rq_map_sg(request_queue_t *q, struct request *rq, struct scatterlist *sg)
1201 { 1201 {
1202 struct bio_vec *bvec, *bvprv; 1202 struct bio_vec *bvec, *bvprv;
1203 struct bio *bio; 1203 struct bio *bio;
1204 int nsegs, i, cluster; 1204 int nsegs, i, cluster;
1205 1205
1206 nsegs = 0; 1206 nsegs = 0;
1207 cluster = q->queue_flags & (1 << QUEUE_FLAG_CLUSTER); 1207 cluster = q->queue_flags & (1 << QUEUE_FLAG_CLUSTER);
1208 1208
1209 /* 1209 /*
1210 * for each bio in rq 1210 * for each bio in rq
1211 */ 1211 */
1212 bvprv = NULL; 1212 bvprv = NULL;
1213 rq_for_each_bio(bio, rq) { 1213 rq_for_each_bio(bio, rq) {
1214 /* 1214 /*
1215 * for each segment in bio 1215 * for each segment in bio
1216 */ 1216 */
1217 bio_for_each_segment(bvec, bio, i) { 1217 bio_for_each_segment(bvec, bio, i) {
1218 int nbytes = bvec->bv_len; 1218 int nbytes = bvec->bv_len;
1219 1219
1220 if (bvprv && cluster) { 1220 if (bvprv && cluster) {
1221 if (sg[nsegs - 1].length + nbytes > q->max_segment_size) 1221 if (sg[nsegs - 1].length + nbytes > q->max_segment_size)
1222 goto new_segment; 1222 goto new_segment;
1223 1223
1224 if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec)) 1224 if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec))
1225 goto new_segment; 1225 goto new_segment;
1226 if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec)) 1226 if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec))
1227 goto new_segment; 1227 goto new_segment;
1228 1228
1229 sg[nsegs - 1].length += nbytes; 1229 sg[nsegs - 1].length += nbytes;
1230 } else { 1230 } else {
1231 new_segment: 1231 new_segment:
1232 memset(&sg[nsegs],0,sizeof(struct scatterlist)); 1232 memset(&sg[nsegs],0,sizeof(struct scatterlist));
1233 sg[nsegs].page = bvec->bv_page; 1233 sg[nsegs].page = bvec->bv_page;
1234 sg[nsegs].length = nbytes; 1234 sg[nsegs].length = nbytes;
1235 sg[nsegs].offset = bvec->bv_offset; 1235 sg[nsegs].offset = bvec->bv_offset;
1236 1236
1237 nsegs++; 1237 nsegs++;
1238 } 1238 }
1239 bvprv = bvec; 1239 bvprv = bvec;
1240 } /* segments in bio */ 1240 } /* segments in bio */
1241 } /* bios in rq */ 1241 } /* bios in rq */
1242 1242
1243 return nsegs; 1243 return nsegs;
1244 } 1244 }
1245 1245
1246 EXPORT_SYMBOL(blk_rq_map_sg); 1246 EXPORT_SYMBOL(blk_rq_map_sg);
1247 1247
1248 /* 1248 /*
1249 * the standard queue merge functions, can be overridden with device 1249 * the standard queue merge functions, can be overridden with device
1250 * specific ones if so desired 1250 * specific ones if so desired
1251 */ 1251 */
1252 1252
1253 static inline int ll_new_mergeable(request_queue_t *q, 1253 static inline int ll_new_mergeable(request_queue_t *q,
1254 struct request *req, 1254 struct request *req,
1255 struct bio *bio) 1255 struct bio *bio)
1256 { 1256 {
1257 int nr_phys_segs = bio_phys_segments(q, bio); 1257 int nr_phys_segs = bio_phys_segments(q, bio);
1258 1258
1259 if (req->nr_phys_segments + nr_phys_segs > q->max_phys_segments) { 1259 if (req->nr_phys_segments + nr_phys_segs > q->max_phys_segments) {
1260 req->flags |= REQ_NOMERGE; 1260 req->flags |= REQ_NOMERGE;
1261 if (req == q->last_merge) 1261 if (req == q->last_merge)
1262 q->last_merge = NULL; 1262 q->last_merge = NULL;
1263 return 0; 1263 return 0;
1264 } 1264 }
1265 1265
1266 /* 1266 /*
1267 * A hw segment is just getting larger, bump just the phys 1267 * A hw segment is just getting larger, bump just the phys
1268 * counter. 1268 * counter.
1269 */ 1269 */
1270 req->nr_phys_segments += nr_phys_segs; 1270 req->nr_phys_segments += nr_phys_segs;
1271 return 1; 1271 return 1;
1272 } 1272 }
1273 1273
1274 static inline int ll_new_hw_segment(request_queue_t *q, 1274 static inline int ll_new_hw_segment(request_queue_t *q,
1275 struct request *req, 1275 struct request *req,
1276 struct bio *bio) 1276 struct bio *bio)
1277 { 1277 {
1278 int nr_hw_segs = bio_hw_segments(q, bio); 1278 int nr_hw_segs = bio_hw_segments(q, bio);
1279 int nr_phys_segs = bio_phys_segments(q, bio); 1279 int nr_phys_segs = bio_phys_segments(q, bio);
1280 1280
1281 if (req->nr_hw_segments + nr_hw_segs > q->max_hw_segments 1281 if (req->nr_hw_segments + nr_hw_segs > q->max_hw_segments
1282 || req->nr_phys_segments + nr_phys_segs > q->max_phys_segments) { 1282 || req->nr_phys_segments + nr_phys_segs > q->max_phys_segments) {
1283 req->flags |= REQ_NOMERGE; 1283 req->flags |= REQ_NOMERGE;
1284 if (req == q->last_merge) 1284 if (req == q->last_merge)
1285 q->last_merge = NULL; 1285 q->last_merge = NULL;
1286 return 0; 1286 return 0;
1287 } 1287 }
1288 1288
1289 /* 1289 /*
1290 * This will form the start of a new hw segment. Bump both 1290 * This will form the start of a new hw segment. Bump both
1291 * counters. 1291 * counters.
1292 */ 1292 */
1293 req->nr_hw_segments += nr_hw_segs; 1293 req->nr_hw_segments += nr_hw_segs;
1294 req->nr_phys_segments += nr_phys_segs; 1294 req->nr_phys_segments += nr_phys_segs;
1295 return 1; 1295 return 1;
1296 } 1296 }
1297 1297
1298 static int ll_back_merge_fn(request_queue_t *q, struct request *req, 1298 static int ll_back_merge_fn(request_queue_t *q, struct request *req,
1299 struct bio *bio) 1299 struct bio *bio)
1300 { 1300 {
1301 unsigned short max_sectors; 1301 unsigned short max_sectors;
1302 int len; 1302 int len;
1303 1303
1304 if (unlikely(blk_pc_request(req))) 1304 if (unlikely(blk_pc_request(req)))
1305 max_sectors = q->max_hw_sectors; 1305 max_sectors = q->max_hw_sectors;
1306 else 1306 else
1307 max_sectors = q->max_sectors; 1307 max_sectors = q->max_sectors;
1308 1308
1309 if (req->nr_sectors + bio_sectors(bio) > max_sectors) { 1309 if (req->nr_sectors + bio_sectors(bio) > max_sectors) {
1310 req->flags |= REQ_NOMERGE; 1310 req->flags |= REQ_NOMERGE;
1311 if (req == q->last_merge) 1311 if (req == q->last_merge)
1312 q->last_merge = NULL; 1312 q->last_merge = NULL;
1313 return 0; 1313 return 0;
1314 } 1314 }
1315 if (unlikely(!bio_flagged(req->biotail, BIO_SEG_VALID))) 1315 if (unlikely(!bio_flagged(req->biotail, BIO_SEG_VALID)))
1316 blk_recount_segments(q, req->biotail); 1316 blk_recount_segments(q, req->biotail);
1317 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) 1317 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
1318 blk_recount_segments(q, bio); 1318 blk_recount_segments(q, bio);
1319 len = req->biotail->bi_hw_back_size + bio->bi_hw_front_size; 1319 len = req->biotail->bi_hw_back_size + bio->bi_hw_front_size;
1320 if (BIOVEC_VIRT_MERGEABLE(__BVEC_END(req->biotail), __BVEC_START(bio)) && 1320 if (BIOVEC_VIRT_MERGEABLE(__BVEC_END(req->biotail), __BVEC_START(bio)) &&
1321 !BIOVEC_VIRT_OVERSIZE(len)) { 1321 !BIOVEC_VIRT_OVERSIZE(len)) {
1322 int mergeable = ll_new_mergeable(q, req, bio); 1322 int mergeable = ll_new_mergeable(q, req, bio);
1323 1323
1324 if (mergeable) { 1324 if (mergeable) {
1325 if (req->nr_hw_segments == 1) 1325 if (req->nr_hw_segments == 1)
1326 req->bio->bi_hw_front_size = len; 1326 req->bio->bi_hw_front_size = len;
1327 if (bio->bi_hw_segments == 1) 1327 if (bio->bi_hw_segments == 1)
1328 bio->bi_hw_back_size = len; 1328 bio->bi_hw_back_size = len;
1329 } 1329 }
1330 return mergeable; 1330 return mergeable;
1331 } 1331 }
1332 1332
1333 return ll_new_hw_segment(q, req, bio); 1333 return ll_new_hw_segment(q, req, bio);
1334 } 1334 }
1335 1335
1336 static int ll_front_merge_fn(request_queue_t *q, struct request *req, 1336 static int ll_front_merge_fn(request_queue_t *q, struct request *req,
1337 struct bio *bio) 1337 struct bio *bio)
1338 { 1338 {
1339 unsigned short max_sectors; 1339 unsigned short max_sectors;
1340 int len; 1340 int len;
1341 1341
1342 if (unlikely(blk_pc_request(req))) 1342 if (unlikely(blk_pc_request(req)))
1343 max_sectors = q->max_hw_sectors; 1343 max_sectors = q->max_hw_sectors;
1344 else 1344 else
1345 max_sectors = q->max_sectors; 1345 max_sectors = q->max_sectors;
1346 1346
1347 1347
1348 if (req->nr_sectors + bio_sectors(bio) > max_sectors) { 1348 if (req->nr_sectors + bio_sectors(bio) > max_sectors) {
1349 req->flags |= REQ_NOMERGE; 1349 req->flags |= REQ_NOMERGE;
1350 if (req == q->last_merge) 1350 if (req == q->last_merge)
1351 q->last_merge = NULL; 1351 q->last_merge = NULL;
1352 return 0; 1352 return 0;
1353 } 1353 }
1354 len = bio->bi_hw_back_size + req->bio->bi_hw_front_size; 1354 len = bio->bi_hw_back_size + req->bio->bi_hw_front_size;
1355 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) 1355 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
1356 blk_recount_segments(q, bio); 1356 blk_recount_segments(q, bio);
1357 if (unlikely(!bio_flagged(req->bio, BIO_SEG_VALID))) 1357 if (unlikely(!bio_flagged(req->bio, BIO_SEG_VALID)))
1358 blk_recount_segments(q, req->bio); 1358 blk_recount_segments(q, req->bio);
1359 if (BIOVEC_VIRT_MERGEABLE(__BVEC_END(bio), __BVEC_START(req->bio)) && 1359 if (BIOVEC_VIRT_MERGEABLE(__BVEC_END(bio), __BVEC_START(req->bio)) &&
1360 !BIOVEC_VIRT_OVERSIZE(len)) { 1360 !BIOVEC_VIRT_OVERSIZE(len)) {
1361 int mergeable = ll_new_mergeable(q, req, bio); 1361 int mergeable = ll_new_mergeable(q, req, bio);
1362 1362
1363 if (mergeable) { 1363 if (mergeable) {
1364 if (bio->bi_hw_segments == 1) 1364 if (bio->bi_hw_segments == 1)
1365 bio->bi_hw_front_size = len; 1365 bio->bi_hw_front_size = len;
1366 if (req->nr_hw_segments == 1) 1366 if (req->nr_hw_segments == 1)
1367 req->biotail->bi_hw_back_size = len; 1367 req->biotail->bi_hw_back_size = len;
1368 } 1368 }
1369 return mergeable; 1369 return mergeable;
1370 } 1370 }
1371 1371
1372 return ll_new_hw_segment(q, req, bio); 1372 return ll_new_hw_segment(q, req, bio);
1373 } 1373 }
1374 1374
1375 static int ll_merge_requests_fn(request_queue_t *q, struct request *req, 1375 static int ll_merge_requests_fn(request_queue_t *q, struct request *req,
1376 struct request *next) 1376 struct request *next)
1377 { 1377 {
1378 int total_phys_segments; 1378 int total_phys_segments;
1379 int total_hw_segments; 1379 int total_hw_segments;
1380 1380
1381 /* 1381 /*
1382 * First check if the either of the requests are re-queued 1382 * First check if the either of the requests are re-queued
1383 * requests. Can't merge them if they are. 1383 * requests. Can't merge them if they are.
1384 */ 1384 */
1385 if (req->special || next->special) 1385 if (req->special || next->special)
1386 return 0; 1386 return 0;
1387 1387
1388 /* 1388 /*
1389 * Will it become too large? 1389 * Will it become too large?
1390 */ 1390 */
1391 if ((req->nr_sectors + next->nr_sectors) > q->max_sectors) 1391 if ((req->nr_sectors + next->nr_sectors) > q->max_sectors)
1392 return 0; 1392 return 0;
1393 1393
1394 total_phys_segments = req->nr_phys_segments + next->nr_phys_segments; 1394 total_phys_segments = req->nr_phys_segments + next->nr_phys_segments;
1395 if (blk_phys_contig_segment(q, req->biotail, next->bio)) 1395 if (blk_phys_contig_segment(q, req->biotail, next->bio))
1396 total_phys_segments--; 1396 total_phys_segments--;
1397 1397
1398 if (total_phys_segments > q->max_phys_segments) 1398 if (total_phys_segments > q->max_phys_segments)
1399 return 0; 1399 return 0;
1400 1400
1401 total_hw_segments = req->nr_hw_segments + next->nr_hw_segments; 1401 total_hw_segments = req->nr_hw_segments + next->nr_hw_segments;
1402 if (blk_hw_contig_segment(q, req->biotail, next->bio)) { 1402 if (blk_hw_contig_segment(q, req->biotail, next->bio)) {
1403 int len = req->biotail->bi_hw_back_size + next->bio->bi_hw_front_size; 1403 int len = req->biotail->bi_hw_back_size + next->bio->bi_hw_front_size;
1404 /* 1404 /*
1405 * propagate the combined length to the end of the requests 1405 * propagate the combined length to the end of the requests
1406 */ 1406 */
1407 if (req->nr_hw_segments == 1) 1407 if (req->nr_hw_segments == 1)
1408 req->bio->bi_hw_front_size = len; 1408 req->bio->bi_hw_front_size = len;
1409 if (next->nr_hw_segments == 1) 1409 if (next->nr_hw_segments == 1)
1410 next->biotail->bi_hw_back_size = len; 1410 next->biotail->bi_hw_back_size = len;
1411 total_hw_segments--; 1411 total_hw_segments--;
1412 } 1412 }
1413 1413
1414 if (total_hw_segments > q->max_hw_segments) 1414 if (total_hw_segments > q->max_hw_segments)
1415 return 0; 1415 return 0;
1416 1416
1417 /* Merge is OK... */ 1417 /* Merge is OK... */
1418 req->nr_phys_segments = total_phys_segments; 1418 req->nr_phys_segments = total_phys_segments;
1419 req->nr_hw_segments = total_hw_segments; 1419 req->nr_hw_segments = total_hw_segments;
1420 return 1; 1420 return 1;
1421 } 1421 }
1422 1422
1423 /* 1423 /*
1424 * "plug" the device if there are no outstanding requests: this will 1424 * "plug" the device if there are no outstanding requests: this will
1425 * force the transfer to start only after we have put all the requests 1425 * force the transfer to start only after we have put all the requests
1426 * on the list. 1426 * on the list.
1427 * 1427 *
1428 * This is called with interrupts off and no requests on the queue and 1428 * This is called with interrupts off and no requests on the queue and
1429 * with the queue lock held. 1429 * with the queue lock held.
1430 */ 1430 */
1431 void blk_plug_device(request_queue_t *q) 1431 void blk_plug_device(request_queue_t *q)
1432 { 1432 {
1433 WARN_ON(!irqs_disabled()); 1433 WARN_ON(!irqs_disabled());
1434 1434
1435 /* 1435 /*
1436 * don't plug a stopped queue, it must be paired with blk_start_queue() 1436 * don't plug a stopped queue, it must be paired with blk_start_queue()
1437 * which will restart the queueing 1437 * which will restart the queueing
1438 */ 1438 */
1439 if (test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags)) 1439 if (test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags))
1440 return; 1440 return;
1441 1441
1442 if (!test_and_set_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags)) 1442 if (!test_and_set_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags))
1443 mod_timer(&q->unplug_timer, jiffies + q->unplug_delay); 1443 mod_timer(&q->unplug_timer, jiffies + q->unplug_delay);
1444 } 1444 }
1445 1445
1446 EXPORT_SYMBOL(blk_plug_device); 1446 EXPORT_SYMBOL(blk_plug_device);
1447 1447
1448 /* 1448 /*
1449 * remove the queue from the plugged list, if present. called with 1449 * remove the queue from the plugged list, if present. called with
1450 * queue lock held and interrupts disabled. 1450 * queue lock held and interrupts disabled.
1451 */ 1451 */
1452 int blk_remove_plug(request_queue_t *q) 1452 int blk_remove_plug(request_queue_t *q)
1453 { 1453 {
1454 WARN_ON(!irqs_disabled()); 1454 WARN_ON(!irqs_disabled());
1455 1455
1456 if (!test_and_clear_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags)) 1456 if (!test_and_clear_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags))
1457 return 0; 1457 return 0;
1458 1458
1459 del_timer(&q->unplug_timer); 1459 del_timer(&q->unplug_timer);
1460 return 1; 1460 return 1;
1461 } 1461 }
1462 1462
1463 EXPORT_SYMBOL(blk_remove_plug); 1463 EXPORT_SYMBOL(blk_remove_plug);
1464 1464
1465 /* 1465 /*
1466 * remove the plug and let it rip.. 1466 * remove the plug and let it rip..
1467 */ 1467 */
1468 void __generic_unplug_device(request_queue_t *q) 1468 void __generic_unplug_device(request_queue_t *q)
1469 { 1469 {
1470 if (unlikely(test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags))) 1470 if (unlikely(test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags)))
1471 return; 1471 return;
1472 1472
1473 if (!blk_remove_plug(q)) 1473 if (!blk_remove_plug(q))
1474 return; 1474 return;
1475 1475
1476 q->request_fn(q); 1476 q->request_fn(q);
1477 } 1477 }
1478 EXPORT_SYMBOL(__generic_unplug_device); 1478 EXPORT_SYMBOL(__generic_unplug_device);
1479 1479
1480 /** 1480 /**
1481 * generic_unplug_device - fire a request queue 1481 * generic_unplug_device - fire a request queue
1482 * @q: The &request_queue_t in question 1482 * @q: The &request_queue_t in question
1483 * 1483 *
1484 * Description: 1484 * Description:
1485 * Linux uses plugging to build bigger requests queues before letting 1485 * Linux uses plugging to build bigger requests queues before letting
1486 * the device have at them. If a queue is plugged, the I/O scheduler 1486 * the device have at them. If a queue is plugged, the I/O scheduler
1487 * is still adding and merging requests on the queue. Once the queue 1487 * is still adding and merging requests on the queue. Once the queue
1488 * gets unplugged, the request_fn defined for the queue is invoked and 1488 * gets unplugged, the request_fn defined for the queue is invoked and
1489 * transfers started. 1489 * transfers started.
1490 **/ 1490 **/
1491 void generic_unplug_device(request_queue_t *q) 1491 void generic_unplug_device(request_queue_t *q)
1492 { 1492 {
1493 spin_lock_irq(q->queue_lock); 1493 spin_lock_irq(q->queue_lock);
1494 __generic_unplug_device(q); 1494 __generic_unplug_device(q);
1495 spin_unlock_irq(q->queue_lock); 1495 spin_unlock_irq(q->queue_lock);
1496 } 1496 }
1497 EXPORT_SYMBOL(generic_unplug_device); 1497 EXPORT_SYMBOL(generic_unplug_device);
1498 1498
1499 static void blk_backing_dev_unplug(struct backing_dev_info *bdi, 1499 static void blk_backing_dev_unplug(struct backing_dev_info *bdi,
1500 struct page *page) 1500 struct page *page)
1501 { 1501 {
1502 request_queue_t *q = bdi->unplug_io_data; 1502 request_queue_t *q = bdi->unplug_io_data;
1503 1503
1504 /* 1504 /*
1505 * devices don't necessarily have an ->unplug_fn defined 1505 * devices don't necessarily have an ->unplug_fn defined
1506 */ 1506 */
1507 if (q->unplug_fn) 1507 if (q->unplug_fn)
1508 q->unplug_fn(q); 1508 q->unplug_fn(q);
1509 } 1509 }
1510 1510
1511 static void blk_unplug_work(void *data) 1511 static void blk_unplug_work(void *data)
1512 { 1512 {
1513 request_queue_t *q = data; 1513 request_queue_t *q = data;
1514 1514
1515 q->unplug_fn(q); 1515 q->unplug_fn(q);
1516 } 1516 }
1517 1517
1518 static void blk_unplug_timeout(unsigned long data) 1518 static void blk_unplug_timeout(unsigned long data)
1519 { 1519 {
1520 request_queue_t *q = (request_queue_t *)data; 1520 request_queue_t *q = (request_queue_t *)data;
1521 1521
1522 kblockd_schedule_work(&q->unplug_work); 1522 kblockd_schedule_work(&q->unplug_work);
1523 } 1523 }
1524 1524
1525 /** 1525 /**
1526 * blk_start_queue - restart a previously stopped queue 1526 * blk_start_queue - restart a previously stopped queue
1527 * @q: The &request_queue_t in question 1527 * @q: The &request_queue_t in question
1528 * 1528 *
1529 * Description: 1529 * Description:
1530 * blk_start_queue() will clear the stop flag on the queue, and call 1530 * blk_start_queue() will clear the stop flag on the queue, and call
1531 * the request_fn for the queue if it was in a stopped state when 1531 * the request_fn for the queue if it was in a stopped state when
1532 * entered. Also see blk_stop_queue(). Queue lock must be held. 1532 * entered. Also see blk_stop_queue(). Queue lock must be held.
1533 **/ 1533 **/
1534 void blk_start_queue(request_queue_t *q) 1534 void blk_start_queue(request_queue_t *q)
1535 { 1535 {
1536 clear_bit(QUEUE_FLAG_STOPPED, &q->queue_flags); 1536 clear_bit(QUEUE_FLAG_STOPPED, &q->queue_flags);
1537 1537
1538 /* 1538 /*
1539 * one level of recursion is ok and is much faster than kicking 1539 * one level of recursion is ok and is much faster than kicking
1540 * the unplug handling 1540 * the unplug handling
1541 */ 1541 */
1542 if (!test_and_set_bit(QUEUE_FLAG_REENTER, &q->queue_flags)) { 1542 if (!test_and_set_bit(QUEUE_FLAG_REENTER, &q->queue_flags)) {
1543 q->request_fn(q); 1543 q->request_fn(q);
1544 clear_bit(QUEUE_FLAG_REENTER, &q->queue_flags); 1544 clear_bit(QUEUE_FLAG_REENTER, &q->queue_flags);
1545 } else { 1545 } else {
1546 blk_plug_device(q); 1546 blk_plug_device(q);
1547 kblockd_schedule_work(&q->unplug_work); 1547 kblockd_schedule_work(&q->unplug_work);
1548 } 1548 }
1549 } 1549 }
1550 1550
1551 EXPORT_SYMBOL(blk_start_queue); 1551 EXPORT_SYMBOL(blk_start_queue);
1552 1552
1553 /** 1553 /**
1554 * blk_stop_queue - stop a queue 1554 * blk_stop_queue - stop a queue
1555 * @q: The &request_queue_t in question 1555 * @q: The &request_queue_t in question
1556 * 1556 *
1557 * Description: 1557 * Description:
1558 * The Linux block layer assumes that a block driver will consume all 1558 * The Linux block layer assumes that a block driver will consume all
1559 * entries on the request queue when the request_fn strategy is called. 1559 * entries on the request queue when the request_fn strategy is called.
1560 * Often this will not happen, because of hardware limitations (queue 1560 * Often this will not happen, because of hardware limitations (queue
1561 * depth settings). If a device driver gets a 'queue full' response, 1561 * depth settings). If a device driver gets a 'queue full' response,
1562 * or if it simply chooses not to queue more I/O at one point, it can 1562 * or if it simply chooses not to queue more I/O at one point, it can
1563 * call this function to prevent the request_fn from being called until 1563 * call this function to prevent the request_fn from being called until
1564 * the driver has signalled it's ready to go again. This happens by calling 1564 * the driver has signalled it's ready to go again. This happens by calling
1565 * blk_start_queue() to restart queue operations. Queue lock must be held. 1565 * blk_start_queue() to restart queue operations. Queue lock must be held.
1566 **/ 1566 **/
1567 void blk_stop_queue(request_queue_t *q) 1567 void blk_stop_queue(request_queue_t *q)
1568 { 1568 {
1569 blk_remove_plug(q); 1569 blk_remove_plug(q);
1570 set_bit(QUEUE_FLAG_STOPPED, &q->queue_flags); 1570 set_bit(QUEUE_FLAG_STOPPED, &q->queue_flags);
1571 } 1571 }
1572 EXPORT_SYMBOL(blk_stop_queue); 1572 EXPORT_SYMBOL(blk_stop_queue);
1573 1573
1574 /** 1574 /**
1575 * blk_sync_queue - cancel any pending callbacks on a queue 1575 * blk_sync_queue - cancel any pending callbacks on a queue
1576 * @q: the queue 1576 * @q: the queue
1577 * 1577 *
1578 * Description: 1578 * Description:
1579 * The block layer may perform asynchronous callback activity 1579 * The block layer may perform asynchronous callback activity
1580 * on a queue, such as calling the unplug function after a timeout. 1580 * on a queue, such as calling the unplug function after a timeout.
1581 * A block device may call blk_sync_queue to ensure that any 1581 * A block device may call blk_sync_queue to ensure that any
1582 * such activity is cancelled, thus allowing it to release resources 1582 * such activity is cancelled, thus allowing it to release resources
1583 * the the callbacks might use. The caller must already have made sure 1583 * the the callbacks might use. The caller must already have made sure
1584 * that its ->make_request_fn will not re-add plugging prior to calling 1584 * that its ->make_request_fn will not re-add plugging prior to calling
1585 * this function. 1585 * this function.
1586 * 1586 *
1587 */ 1587 */
1588 void blk_sync_queue(struct request_queue *q) 1588 void blk_sync_queue(struct request_queue *q)
1589 { 1589 {
1590 del_timer_sync(&q->unplug_timer); 1590 del_timer_sync(&q->unplug_timer);
1591 kblockd_flush(); 1591 kblockd_flush();
1592 } 1592 }
1593 EXPORT_SYMBOL(blk_sync_queue); 1593 EXPORT_SYMBOL(blk_sync_queue);
1594 1594
1595 /** 1595 /**
1596 * blk_run_queue - run a single device queue 1596 * blk_run_queue - run a single device queue
1597 * @q: The queue to run 1597 * @q: The queue to run
1598 */ 1598 */
1599 void blk_run_queue(struct request_queue *q) 1599 void blk_run_queue(struct request_queue *q)
1600 { 1600 {
1601 unsigned long flags; 1601 unsigned long flags;
1602 1602
1603 spin_lock_irqsave(q->queue_lock, flags); 1603 spin_lock_irqsave(q->queue_lock, flags);
1604 blk_remove_plug(q); 1604 blk_remove_plug(q);
1605 if (!elv_queue_empty(q)) 1605 if (!elv_queue_empty(q))
1606 q->request_fn(q); 1606 q->request_fn(q);
1607 spin_unlock_irqrestore(q->queue_lock, flags); 1607 spin_unlock_irqrestore(q->queue_lock, flags);
1608 } 1608 }
1609 EXPORT_SYMBOL(blk_run_queue); 1609 EXPORT_SYMBOL(blk_run_queue);
1610 1610
1611 /** 1611 /**
1612 * blk_cleanup_queue: - release a &request_queue_t when it is no longer needed 1612 * blk_cleanup_queue: - release a &request_queue_t when it is no longer needed
1613 * @q: the request queue to be released 1613 * @q: the request queue to be released
1614 * 1614 *
1615 * Description: 1615 * Description:
1616 * blk_cleanup_queue is the pair to blk_init_queue() or 1616 * blk_cleanup_queue is the pair to blk_init_queue() or
1617 * blk_queue_make_request(). It should be called when a request queue is 1617 * blk_queue_make_request(). It should be called when a request queue is
1618 * being released; typically when a block device is being de-registered. 1618 * being released; typically when a block device is being de-registered.
1619 * Currently, its primary task it to free all the &struct request 1619 * Currently, its primary task it to free all the &struct request
1620 * structures that were allocated to the queue and the queue itself. 1620 * structures that were allocated to the queue and the queue itself.
1621 * 1621 *
1622 * Caveat: 1622 * Caveat:
1623 * Hopefully the low level driver will have finished any 1623 * Hopefully the low level driver will have finished any
1624 * outstanding requests first... 1624 * outstanding requests first...
1625 **/ 1625 **/
1626 void blk_cleanup_queue(request_queue_t * q) 1626 void blk_cleanup_queue(request_queue_t * q)
1627 { 1627 {
1628 struct request_list *rl = &q->rq; 1628 struct request_list *rl = &q->rq;
1629 1629
1630 if (!atomic_dec_and_test(&q->refcnt)) 1630 if (!atomic_dec_and_test(&q->refcnt))
1631 return; 1631 return;
1632 1632
1633 if (q->elevator) 1633 if (q->elevator)
1634 elevator_exit(q->elevator); 1634 elevator_exit(q->elevator);
1635 1635
1636 blk_sync_queue(q); 1636 blk_sync_queue(q);
1637 1637
1638 if (rl->rq_pool) 1638 if (rl->rq_pool)
1639 mempool_destroy(rl->rq_pool); 1639 mempool_destroy(rl->rq_pool);
1640 1640
1641 if (q->queue_tags) 1641 if (q->queue_tags)
1642 __blk_queue_free_tags(q); 1642 __blk_queue_free_tags(q);
1643 1643
1644 blk_queue_ordered(q, QUEUE_ORDERED_NONE); 1644 blk_queue_ordered(q, QUEUE_ORDERED_NONE);
1645 1645
1646 kmem_cache_free(requestq_cachep, q); 1646 kmem_cache_free(requestq_cachep, q);
1647 } 1647 }
1648 1648
1649 EXPORT_SYMBOL(blk_cleanup_queue); 1649 EXPORT_SYMBOL(blk_cleanup_queue);
1650 1650
1651 static int blk_init_free_list(request_queue_t *q) 1651 static int blk_init_free_list(request_queue_t *q)
1652 { 1652 {
1653 struct request_list *rl = &q->rq; 1653 struct request_list *rl = &q->rq;
1654 1654
1655 rl->count[READ] = rl->count[WRITE] = 0; 1655 rl->count[READ] = rl->count[WRITE] = 0;
1656 rl->starved[READ] = rl->starved[WRITE] = 0; 1656 rl->starved[READ] = rl->starved[WRITE] = 0;
1657 rl->elvpriv = 0; 1657 rl->elvpriv = 0;
1658 init_waitqueue_head(&rl->wait[READ]); 1658 init_waitqueue_head(&rl->wait[READ]);
1659 init_waitqueue_head(&rl->wait[WRITE]); 1659 init_waitqueue_head(&rl->wait[WRITE]);
1660 1660
1661 rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab, 1661 rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab,
1662 mempool_free_slab, request_cachep, q->node); 1662 mempool_free_slab, request_cachep, q->node);
1663 1663
1664 if (!rl->rq_pool) 1664 if (!rl->rq_pool)
1665 return -ENOMEM; 1665 return -ENOMEM;
1666 1666
1667 return 0; 1667 return 0;
1668 } 1668 }
1669 1669
1670 static int __make_request(request_queue_t *, struct bio *); 1670 static int __make_request(request_queue_t *, struct bio *);
1671 1671
1672 request_queue_t *blk_alloc_queue(gfp_t gfp_mask) 1672 request_queue_t *blk_alloc_queue(gfp_t gfp_mask)
1673 { 1673 {
1674 return blk_alloc_queue_node(gfp_mask, -1); 1674 return blk_alloc_queue_node(gfp_mask, -1);
1675 } 1675 }
1676 EXPORT_SYMBOL(blk_alloc_queue); 1676 EXPORT_SYMBOL(blk_alloc_queue);
1677 1677
1678 request_queue_t *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) 1678 request_queue_t *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
1679 { 1679 {
1680 request_queue_t *q; 1680 request_queue_t *q;
1681 1681
1682 q = kmem_cache_alloc_node(requestq_cachep, gfp_mask, node_id); 1682 q = kmem_cache_alloc_node(requestq_cachep, gfp_mask, node_id);
1683 if (!q) 1683 if (!q)
1684 return NULL; 1684 return NULL;
1685 1685
1686 memset(q, 0, sizeof(*q)); 1686 memset(q, 0, sizeof(*q));
1687 init_timer(&q->unplug_timer); 1687 init_timer(&q->unplug_timer);
1688 atomic_set(&q->refcnt, 1); 1688 atomic_set(&q->refcnt, 1);
1689 1689
1690 q->backing_dev_info.unplug_io_fn = blk_backing_dev_unplug; 1690 q->backing_dev_info.unplug_io_fn = blk_backing_dev_unplug;
1691 q->backing_dev_info.unplug_io_data = q; 1691 q->backing_dev_info.unplug_io_data = q;
1692 1692
1693 return q; 1693 return q;
1694 } 1694 }
1695 EXPORT_SYMBOL(blk_alloc_queue_node); 1695 EXPORT_SYMBOL(blk_alloc_queue_node);
1696 1696
1697 /** 1697 /**
1698 * blk_init_queue - prepare a request queue for use with a block device 1698 * blk_init_queue - prepare a request queue for use with a block device
1699 * @rfn: The function to be called to process requests that have been 1699 * @rfn: The function to be called to process requests that have been
1700 * placed on the queue. 1700 * placed on the queue.
1701 * @lock: Request queue spin lock 1701 * @lock: Request queue spin lock
1702 * 1702 *
1703 * Description: 1703 * Description:
1704 * If a block device wishes to use the standard request handling procedures, 1704 * If a block device wishes to use the standard request handling procedures,
1705 * which sorts requests and coalesces adjacent requests, then it must 1705 * which sorts requests and coalesces adjacent requests, then it must
1706 * call blk_init_queue(). The function @rfn will be called when there 1706 * call blk_init_queue(). The function @rfn will be called when there
1707 * are requests on the queue that need to be processed. If the device 1707 * are requests on the queue that need to be processed. If the device
1708 * supports plugging, then @rfn may not be called immediately when requests 1708 * supports plugging, then @rfn may not be called immediately when requests
1709 * are available on the queue, but may be called at some time later instead. 1709 * are available on the queue, but may be called at some time later instead.
1710 * Plugged queues are generally unplugged when a buffer belonging to one 1710 * Plugged queues are generally unplugged when a buffer belonging to one
1711 * of the requests on the queue is needed, or due to memory pressure. 1711 * of the requests on the queue is needed, or due to memory pressure.
1712 * 1712 *
1713 * @rfn is not required, or even expected, to remove all requests off the 1713 * @rfn is not required, or even expected, to remove all requests off the
1714 * queue, but only as many as it can handle at a time. If it does leave 1714 * queue, but only as many as it can handle at a time. If it does leave
1715 * requests on the queue, it is responsible for arranging that the requests 1715 * requests on the queue, it is responsible for arranging that the requests
1716 * get dealt with eventually. 1716 * get dealt with eventually.
1717 * 1717 *
1718 * The queue spin lock must be held while manipulating the requests on the 1718 * The queue spin lock must be held while manipulating the requests on the
1719 * request queue. 1719 * request queue.
1720 * 1720 *
1721 * Function returns a pointer to the initialized request queue, or NULL if 1721 * Function returns a pointer to the initialized request queue, or NULL if
1722 * it didn't succeed. 1722 * it didn't succeed.
1723 * 1723 *
1724 * Note: 1724 * Note:
1725 * blk_init_queue() must be paired with a blk_cleanup_queue() call 1725 * blk_init_queue() must be paired with a blk_cleanup_queue() call
1726 * when the block device is deactivated (such as at module unload). 1726 * when the block device is deactivated (such as at module unload).
1727 **/ 1727 **/
1728 1728
1729 request_queue_t *blk_init_queue(request_fn_proc *rfn, spinlock_t *lock) 1729 request_queue_t *blk_init_queue(request_fn_proc *rfn, spinlock_t *lock)
1730 { 1730 {
1731 return blk_init_queue_node(rfn, lock, -1); 1731 return blk_init_queue_node(rfn, lock, -1);
1732 } 1732 }
1733 EXPORT_SYMBOL(blk_init_queue); 1733 EXPORT_SYMBOL(blk_init_queue);
1734 1734
1735 request_queue_t * 1735 request_queue_t *
1736 blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id) 1736 blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id)
1737 { 1737 {
1738 request_queue_t *q = blk_alloc_queue_node(GFP_KERNEL, node_id); 1738 request_queue_t *q = blk_alloc_queue_node(GFP_KERNEL, node_id);
1739 1739
1740 if (!q) 1740 if (!q)
1741 return NULL; 1741 return NULL;
1742 1742
1743 q->node = node_id; 1743 q->node = node_id;
1744 if (blk_init_free_list(q)) 1744 if (blk_init_free_list(q))
1745 goto out_init; 1745 goto out_init;
1746 1746
1747 /* 1747 /*
1748 * if caller didn't supply a lock, they get per-queue locking with 1748 * if caller didn't supply a lock, they get per-queue locking with
1749 * our embedded lock 1749 * our embedded lock
1750 */ 1750 */
1751 if (!lock) { 1751 if (!lock) {
1752 spin_lock_init(&q->__queue_lock); 1752 spin_lock_init(&q->__queue_lock);
1753 lock = &q->__queue_lock; 1753 lock = &q->__queue_lock;
1754 } 1754 }
1755 1755
1756 q->request_fn = rfn; 1756 q->request_fn = rfn;
1757 q->back_merge_fn = ll_back_merge_fn; 1757 q->back_merge_fn = ll_back_merge_fn;
1758 q->front_merge_fn = ll_front_merge_fn; 1758 q->front_merge_fn = ll_front_merge_fn;
1759 q->merge_requests_fn = ll_merge_requests_fn; 1759 q->merge_requests_fn = ll_merge_requests_fn;
1760 q->prep_rq_fn = NULL; 1760 q->prep_rq_fn = NULL;
1761 q->unplug_fn = generic_unplug_device; 1761 q->unplug_fn = generic_unplug_device;
1762 q->queue_flags = (1 << QUEUE_FLAG_CLUSTER); 1762 q->queue_flags = (1 << QUEUE_FLAG_CLUSTER);
1763 q->queue_lock = lock; 1763 q->queue_lock = lock;
1764 1764
1765 blk_queue_segment_boundary(q, 0xffffffff); 1765 blk_queue_segment_boundary(q, 0xffffffff);
1766 1766
1767 blk_queue_make_request(q, __make_request); 1767 blk_queue_make_request(q, __make_request);
1768 blk_queue_max_segment_size(q, MAX_SEGMENT_SIZE); 1768 blk_queue_max_segment_size(q, MAX_SEGMENT_SIZE);
1769 1769
1770 blk_queue_max_hw_segments(q, MAX_HW_SEGMENTS); 1770 blk_queue_max_hw_segments(q, MAX_HW_SEGMENTS);
1771 blk_queue_max_phys_segments(q, MAX_PHYS_SEGMENTS); 1771 blk_queue_max_phys_segments(q, MAX_PHYS_SEGMENTS);
1772 1772
1773 /* 1773 /*
1774 * all done 1774 * all done
1775 */ 1775 */
1776 if (!elevator_init(q, NULL)) { 1776 if (!elevator_init(q, NULL)) {
1777 blk_queue_congestion_threshold(q); 1777 blk_queue_congestion_threshold(q);
1778 return q; 1778 return q;
1779 } 1779 }
1780 1780
1781 blk_cleanup_queue(q); 1781 blk_cleanup_queue(q);
1782 out_init: 1782 out_init:
1783 kmem_cache_free(requestq_cachep, q); 1783 kmem_cache_free(requestq_cachep, q);
1784 return NULL; 1784 return NULL;
1785 } 1785 }
1786 EXPORT_SYMBOL(blk_init_queue_node); 1786 EXPORT_SYMBOL(blk_init_queue_node);
1787 1787
1788 int blk_get_queue(request_queue_t *q) 1788 int blk_get_queue(request_queue_t *q)
1789 { 1789 {
1790 if (likely(!test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) { 1790 if (likely(!test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) {
1791 atomic_inc(&q->refcnt); 1791 atomic_inc(&q->refcnt);
1792 return 0; 1792 return 0;
1793 } 1793 }
1794 1794
1795 return 1; 1795 return 1;
1796 } 1796 }
1797 1797
1798 EXPORT_SYMBOL(blk_get_queue); 1798 EXPORT_SYMBOL(blk_get_queue);
1799 1799
1800 static inline void blk_free_request(request_queue_t *q, struct request *rq) 1800 static inline void blk_free_request(request_queue_t *q, struct request *rq)
1801 { 1801 {
1802 if (rq->flags & REQ_ELVPRIV) 1802 if (rq->flags & REQ_ELVPRIV)
1803 elv_put_request(q, rq); 1803 elv_put_request(q, rq);
1804 mempool_free(rq, q->rq.rq_pool); 1804 mempool_free(rq, q->rq.rq_pool);
1805 } 1805 }
1806 1806
1807 static inline struct request * 1807 static inline struct request *
1808 blk_alloc_request(request_queue_t *q, int rw, struct bio *bio, 1808 blk_alloc_request(request_queue_t *q, int rw, struct bio *bio,
1809 int priv, gfp_t gfp_mask) 1809 int priv, gfp_t gfp_mask)
1810 { 1810 {
1811 struct request *rq = mempool_alloc(q->rq.rq_pool, gfp_mask); 1811 struct request *rq = mempool_alloc(q->rq.rq_pool, gfp_mask);
1812 1812
1813 if (!rq) 1813 if (!rq)
1814 return NULL; 1814 return NULL;
1815 1815
1816 /* 1816 /*
1817 * first three bits are identical in rq->flags and bio->bi_rw, 1817 * first three bits are identical in rq->flags and bio->bi_rw,
1818 * see bio.h and blkdev.h 1818 * see bio.h and blkdev.h
1819 */ 1819 */
1820 rq->flags = rw; 1820 rq->flags = rw;
1821 1821
1822 if (priv) { 1822 if (priv) {
1823 if (unlikely(elv_set_request(q, rq, bio, gfp_mask))) { 1823 if (unlikely(elv_set_request(q, rq, bio, gfp_mask))) {
1824 mempool_free(rq, q->rq.rq_pool); 1824 mempool_free(rq, q->rq.rq_pool);
1825 return NULL; 1825 return NULL;
1826 } 1826 }
1827 rq->flags |= REQ_ELVPRIV; 1827 rq->flags |= REQ_ELVPRIV;
1828 } 1828 }
1829 1829
1830 return rq; 1830 return rq;
1831 } 1831 }
1832 1832
1833 /* 1833 /*
1834 * ioc_batching returns true if the ioc is a valid batching request and 1834 * ioc_batching returns true if the ioc is a valid batching request and
1835 * should be given priority access to a request. 1835 * should be given priority access to a request.
1836 */ 1836 */
1837 static inline int ioc_batching(request_queue_t *q, struct io_context *ioc) 1837 static inline int ioc_batching(request_queue_t *q, struct io_context *ioc)
1838 { 1838 {
1839 if (!ioc) 1839 if (!ioc)
1840 return 0; 1840 return 0;
1841 1841
1842 /* 1842 /*
1843 * Make sure the process is able to allocate at least 1 request 1843 * Make sure the process is able to allocate at least 1 request
1844 * even if the batch times out, otherwise we could theoretically 1844 * even if the batch times out, otherwise we could theoretically
1845 * lose wakeups. 1845 * lose wakeups.
1846 */ 1846 */
1847 return ioc->nr_batch_requests == q->nr_batching || 1847 return ioc->nr_batch_requests == q->nr_batching ||
1848 (ioc->nr_batch_requests > 0 1848 (ioc->nr_batch_requests > 0
1849 && time_before(jiffies, ioc->last_waited + BLK_BATCH_TIME)); 1849 && time_before(jiffies, ioc->last_waited + BLK_BATCH_TIME));
1850 } 1850 }
1851 1851
1852 /* 1852 /*
1853 * ioc_set_batching sets ioc to be a new "batcher" if it is not one. This 1853 * ioc_set_batching sets ioc to be a new "batcher" if it is not one. This
1854 * will cause the process to be a "batcher" on all queues in the system. This 1854 * will cause the process to be a "batcher" on all queues in the system. This
1855 * is the behaviour we want though - once it gets a wakeup it should be given 1855 * is the behaviour we want though - once it gets a wakeup it should be given
1856 * a nice run. 1856 * a nice run.
1857 */ 1857 */
1858 static void ioc_set_batching(request_queue_t *q, struct io_context *ioc) 1858 static void ioc_set_batching(request_queue_t *q, struct io_context *ioc)
1859 { 1859 {
1860 if (!ioc || ioc_batching(q, ioc)) 1860 if (!ioc || ioc_batching(q, ioc))
1861 return; 1861 return;
1862 1862
1863 ioc->nr_batch_requests = q->nr_batching; 1863 ioc->nr_batch_requests = q->nr_batching;
1864 ioc->last_waited = jiffies; 1864 ioc->last_waited = jiffies;
1865 } 1865 }
1866 1866
1867 static void __freed_request(request_queue_t *q, int rw) 1867 static void __freed_request(request_queue_t *q, int rw)
1868 { 1868 {
1869 struct request_list *rl = &q->rq; 1869 struct request_list *rl = &q->rq;
1870 1870
1871 if (rl->count[rw] < queue_congestion_off_threshold(q)) 1871 if (rl->count[rw] < queue_congestion_off_threshold(q))
1872 clear_queue_congested(q, rw); 1872 clear_queue_congested(q, rw);
1873 1873
1874 if (rl->count[rw] + 1 <= q->nr_requests) { 1874 if (rl->count[rw] + 1 <= q->nr_requests) {
1875 if (waitqueue_active(&rl->wait[rw])) 1875 if (waitqueue_active(&rl->wait[rw]))
1876 wake_up(&rl->wait[rw]); 1876 wake_up(&rl->wait[rw]);
1877 1877
1878 blk_clear_queue_full(q, rw); 1878 blk_clear_queue_full(q, rw);
1879 } 1879 }
1880 } 1880 }
1881 1881
1882 /* 1882 /*
1883 * A request has just been released. Account for it, update the full and 1883 * A request has just been released. Account for it, update the full and
1884 * congestion status, wake up any waiters. Called under q->queue_lock. 1884 * congestion status, wake up any waiters. Called under q->queue_lock.
1885 */ 1885 */
1886 static void freed_request(request_queue_t *q, int rw, int priv) 1886 static void freed_request(request_queue_t *q, int rw, int priv)
1887 { 1887 {
1888 struct request_list *rl = &q->rq; 1888 struct request_list *rl = &q->rq;
1889 1889
1890 rl->count[rw]--; 1890 rl->count[rw]--;
1891 if (priv) 1891 if (priv)
1892 rl->elvpriv--; 1892 rl->elvpriv--;
1893 1893
1894 __freed_request(q, rw); 1894 __freed_request(q, rw);
1895 1895
1896 if (unlikely(rl->starved[rw ^ 1])) 1896 if (unlikely(rl->starved[rw ^ 1]))
1897 __freed_request(q, rw ^ 1); 1897 __freed_request(q, rw ^ 1);
1898 } 1898 }
1899 1899
1900 #define blkdev_free_rq(list) list_entry((list)->next, struct request, queuelist) 1900 #define blkdev_free_rq(list) list_entry((list)->next, struct request, queuelist)
1901 /* 1901 /*
1902 * Get a free request, queue_lock must be held. 1902 * Get a free request, queue_lock must be held.
1903 * Returns NULL on failure, with queue_lock held. 1903 * Returns NULL on failure, with queue_lock held.
1904 * Returns !NULL on success, with queue_lock *not held*. 1904 * Returns !NULL on success, with queue_lock *not held*.
1905 */ 1905 */
1906 static struct request *get_request(request_queue_t *q, int rw, struct bio *bio, 1906 static struct request *get_request(request_queue_t *q, int rw, struct bio *bio,
1907 gfp_t gfp_mask) 1907 gfp_t gfp_mask)
1908 { 1908 {
1909 struct request *rq = NULL; 1909 struct request *rq = NULL;
1910 struct request_list *rl = &q->rq; 1910 struct request_list *rl = &q->rq;
1911 struct io_context *ioc = current_io_context(GFP_ATOMIC); 1911 struct io_context *ioc = NULL;
1912 int priv; 1912 int may_queue, priv;
1913 1913
1914 if (rl->count[rw]+1 >= q->nr_requests) { 1914 may_queue = elv_may_queue(q, rw, bio);
1915 /* 1915 if (may_queue == ELV_MQUEUE_NO)
1916 * The queue will fill after this allocation, so set it as 1916 goto rq_starved;
1917 * full, and mark this process as "batching". This process 1917
1918 * will be allowed to complete a batch of requests, others 1918 if (rl->count[rw]+1 >= queue_congestion_on_threshold(q)) {
1919 * will be blocked. 1919 if (rl->count[rw]+1 >= q->nr_requests) {
1920 */ 1920 ioc = current_io_context(GFP_ATOMIC);
1921 if (!blk_queue_full(q, rw)) { 1921 /*
1922 ioc_set_batching(q, ioc); 1922 * The queue will fill after this allocation, so set
1923 blk_set_queue_full(q, rw); 1923 * it as full, and mark this process as "batching".
1924 * This process will be allowed to complete a batch of
1925 * requests, others will be blocked.
1926 */
1927 if (!blk_queue_full(q, rw)) {
1928 ioc_set_batching(q, ioc);
1929 blk_set_queue_full(q, rw);
1930 } else {
1931 if (may_queue != ELV_MQUEUE_MUST
1932 && !ioc_batching(q, ioc)) {
1933 /*
1934 * The queue is full and the allocating
1935 * process is not a "batcher", and not
1936 * exempted by the IO scheduler
1937 */
1938 goto out;
1939 }
1940 }
1924 } 1941 }
1942 set_queue_congested(q, rw);
1925 } 1943 }
1926 1944
1927 switch (elv_may_queue(q, rw, bio)) {
1928 case ELV_MQUEUE_NO:
1929 goto rq_starved;
1930 case ELV_MQUEUE_MAY:
1931 break;
1932 case ELV_MQUEUE_MUST:
1933 goto get_rq;
1934 }
1935
1936 if (blk_queue_full(q, rw) && !ioc_batching(q, ioc)) {
1937 /*
1938 * The queue is full and the allocating process is not a
1939 * "batcher", and not exempted by the IO scheduler
1940 */
1941 goto out;
1942 }
1943
1944 get_rq:
1945 /* 1945 /*
1946 * Only allow batching queuers to allocate up to 50% over the defined 1946 * Only allow batching queuers to allocate up to 50% over the defined
1947 * limit of requests, otherwise we could have thousands of requests 1947 * limit of requests, otherwise we could have thousands of requests
1948 * allocated with any setting of ->nr_requests 1948 * allocated with any setting of ->nr_requests
1949 */ 1949 */
1950 if (rl->count[rw] >= (3 * q->nr_requests / 2)) 1950 if (rl->count[rw] >= (3 * q->nr_requests / 2))
1951 goto out; 1951 goto out;
1952 1952
1953 rl->count[rw]++; 1953 rl->count[rw]++;
1954 rl->starved[rw] = 0; 1954 rl->starved[rw] = 0;
1955 if (rl->count[rw] >= queue_congestion_on_threshold(q))
1956 set_queue_congested(q, rw);
1957 1955
1958 priv = !test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags); 1956 priv = !test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
1959 if (priv) 1957 if (priv)
1960 rl->elvpriv++; 1958 rl->elvpriv++;
1961 1959
1962 spin_unlock_irq(q->queue_lock); 1960 spin_unlock_irq(q->queue_lock);
1963 1961
1964 rq = blk_alloc_request(q, rw, bio, priv, gfp_mask); 1962 rq = blk_alloc_request(q, rw, bio, priv, gfp_mask);
1965 if (!rq) { 1963 if (unlikely(!rq)) {
1966 /* 1964 /*
1967 * Allocation failed presumably due to memory. Undo anything 1965 * Allocation failed presumably due to memory. Undo anything
1968 * we might have messed up. 1966 * we might have messed up.
1969 * 1967 *
1970 * Allocating task should really be put onto the front of the 1968 * Allocating task should really be put onto the front of the
1971 * wait queue, but this is pretty rare. 1969 * wait queue, but this is pretty rare.
1972 */ 1970 */
1973 spin_lock_irq(q->queue_lock); 1971 spin_lock_irq(q->queue_lock);
1974 freed_request(q, rw, priv); 1972 freed_request(q, rw, priv);
1975 1973
1976 /* 1974 /*
1977 * in the very unlikely event that allocation failed and no 1975 * in the very unlikely event that allocation failed and no
1978 * requests for this direction was pending, mark us starved 1976 * requests for this direction was pending, mark us starved
1979 * so that freeing of a request in the other direction will 1977 * so that freeing of a request in the other direction will
1980 * notice us. another possible fix would be to split the 1978 * notice us. another possible fix would be to split the
1981 * rq mempool into READ and WRITE 1979 * rq mempool into READ and WRITE
1982 */ 1980 */
1983 rq_starved: 1981 rq_starved:
1984 if (unlikely(rl->count[rw] == 0)) 1982 if (unlikely(rl->count[rw] == 0))
1985 rl->starved[rw] = 1; 1983 rl->starved[rw] = 1;
1986 1984
1987 goto out; 1985 goto out;
1988 } 1986 }
1989 1987
1988 /*
1989 * ioc may be NULL here, and ioc_batching will be false. That's
1990 * OK, if the queue is under the request limit then requests need
1991 * not count toward the nr_batch_requests limit. There will always
1992 * be some limit enforced by BLK_BATCH_TIME.
1993 */
1990 if (ioc_batching(q, ioc)) 1994 if (ioc_batching(q, ioc))
1991 ioc->nr_batch_requests--; 1995 ioc->nr_batch_requests--;
1992 1996
1993 rq_init(q, rq); 1997 rq_init(q, rq);
1994 rq->rl = rl; 1998 rq->rl = rl;
1995 out: 1999 out:
1996 return rq; 2000 return rq;
1997 } 2001 }
1998 2002
1999 /* 2003 /*
2000 * No available requests for this queue, unplug the device and wait for some 2004 * No available requests for this queue, unplug the device and wait for some
2001 * requests to become available. 2005 * requests to become available.
2002 * 2006 *
2003 * Called with q->queue_lock held, and returns with it unlocked. 2007 * Called with q->queue_lock held, and returns with it unlocked.
2004 */ 2008 */
2005 static struct request *get_request_wait(request_queue_t *q, int rw, 2009 static struct request *get_request_wait(request_queue_t *q, int rw,
2006 struct bio *bio) 2010 struct bio *bio)
2007 { 2011 {
2008 struct request *rq; 2012 struct request *rq;
2009 2013
2010 rq = get_request(q, rw, bio, GFP_NOIO); 2014 rq = get_request(q, rw, bio, GFP_NOIO);
2011 while (!rq) { 2015 while (!rq) {
2012 DEFINE_WAIT(wait); 2016 DEFINE_WAIT(wait);
2013 struct request_list *rl = &q->rq; 2017 struct request_list *rl = &q->rq;
2014 2018
2015 prepare_to_wait_exclusive(&rl->wait[rw], &wait, 2019 prepare_to_wait_exclusive(&rl->wait[rw], &wait,
2016 TASK_UNINTERRUPTIBLE); 2020 TASK_UNINTERRUPTIBLE);
2017 2021
2018 rq = get_request(q, rw, bio, GFP_NOIO); 2022 rq = get_request(q, rw, bio, GFP_NOIO);
2019 2023
2020 if (!rq) { 2024 if (!rq) {
2021 struct io_context *ioc; 2025 struct io_context *ioc;
2022 2026
2023 __generic_unplug_device(q); 2027 __generic_unplug_device(q);
2024 spin_unlock_irq(q->queue_lock); 2028 spin_unlock_irq(q->queue_lock);
2025 io_schedule(); 2029 io_schedule();
2026 2030
2027 /* 2031 /*
2028 * After sleeping, we become a "batching" process and 2032 * After sleeping, we become a "batching" process and
2029 * will be able to allocate at least one request, and 2033 * will be able to allocate at least one request, and
2030 * up to a big batch of them for a small period time. 2034 * up to a big batch of them for a small period time.
2031 * See ioc_batching, ioc_set_batching 2035 * See ioc_batching, ioc_set_batching
2032 */ 2036 */
2033 ioc = current_io_context(GFP_NOIO); 2037 ioc = current_io_context(GFP_NOIO);
2034 ioc_set_batching(q, ioc); 2038 ioc_set_batching(q, ioc);
2035 2039
2036 spin_lock_irq(q->queue_lock); 2040 spin_lock_irq(q->queue_lock);
2037 } 2041 }
2038 finish_wait(&rl->wait[rw], &wait); 2042 finish_wait(&rl->wait[rw], &wait);
2039 } 2043 }
2040 2044
2041 return rq; 2045 return rq;
2042 } 2046 }
2043 2047
2044 struct request *blk_get_request(request_queue_t *q, int rw, gfp_t gfp_mask) 2048 struct request *blk_get_request(request_queue_t *q, int rw, gfp_t gfp_mask)
2045 { 2049 {
2046 struct request *rq; 2050 struct request *rq;
2047 2051
2048 BUG_ON(rw != READ && rw != WRITE); 2052 BUG_ON(rw != READ && rw != WRITE);
2049 2053
2050 spin_lock_irq(q->queue_lock); 2054 spin_lock_irq(q->queue_lock);
2051 if (gfp_mask & __GFP_WAIT) { 2055 if (gfp_mask & __GFP_WAIT) {
2052 rq = get_request_wait(q, rw, NULL); 2056 rq = get_request_wait(q, rw, NULL);
2053 } else { 2057 } else {
2054 rq = get_request(q, rw, NULL, gfp_mask); 2058 rq = get_request(q, rw, NULL, gfp_mask);
2055 if (!rq) 2059 if (!rq)
2056 spin_unlock_irq(q->queue_lock); 2060 spin_unlock_irq(q->queue_lock);
2057 } 2061 }
2058 /* q->queue_lock is unlocked at this point */ 2062 /* q->queue_lock is unlocked at this point */
2059 2063
2060 return rq; 2064 return rq;
2061 } 2065 }
2062 EXPORT_SYMBOL(blk_get_request); 2066 EXPORT_SYMBOL(blk_get_request);
2063 2067
2064 /** 2068 /**
2065 * blk_requeue_request - put a request back on queue 2069 * blk_requeue_request - put a request back on queue
2066 * @q: request queue where request should be inserted 2070 * @q: request queue where request should be inserted
2067 * @rq: request to be inserted 2071 * @rq: request to be inserted
2068 * 2072 *
2069 * Description: 2073 * Description:
2070 * Drivers often keep queueing requests until the hardware cannot accept 2074 * Drivers often keep queueing requests until the hardware cannot accept
2071 * more, when that condition happens we need to put the request back 2075 * more, when that condition happens we need to put the request back
2072 * on the queue. Must be called with queue lock held. 2076 * on the queue. Must be called with queue lock held.
2073 */ 2077 */
2074 void blk_requeue_request(request_queue_t *q, struct request *rq) 2078 void blk_requeue_request(request_queue_t *q, struct request *rq)
2075 { 2079 {
2076 if (blk_rq_tagged(rq)) 2080 if (blk_rq_tagged(rq))
2077 blk_queue_end_tag(q, rq); 2081 blk_queue_end_tag(q, rq);
2078 2082
2079 elv_requeue_request(q, rq); 2083 elv_requeue_request(q, rq);
2080 } 2084 }
2081 2085
2082 EXPORT_SYMBOL(blk_requeue_request); 2086 EXPORT_SYMBOL(blk_requeue_request);
2083 2087
2084 /** 2088 /**
2085 * blk_insert_request - insert a special request in to a request queue 2089 * blk_insert_request - insert a special request in to a request queue
2086 * @q: request queue where request should be inserted 2090 * @q: request queue where request should be inserted
2087 * @rq: request to be inserted 2091 * @rq: request to be inserted
2088 * @at_head: insert request at head or tail of queue 2092 * @at_head: insert request at head or tail of queue
2089 * @data: private data 2093 * @data: private data
2090 * 2094 *
2091 * Description: 2095 * Description:
2092 * Many block devices need to execute commands asynchronously, so they don't 2096 * Many block devices need to execute commands asynchronously, so they don't
2093 * block the whole kernel from preemption during request execution. This is 2097 * block the whole kernel from preemption during request execution. This is
2094 * accomplished normally by inserting aritficial requests tagged as 2098 * accomplished normally by inserting aritficial requests tagged as
2095 * REQ_SPECIAL in to the corresponding request queue, and letting them be 2099 * REQ_SPECIAL in to the corresponding request queue, and letting them be
2096 * scheduled for actual execution by the request queue. 2100 * scheduled for actual execution by the request queue.
2097 * 2101 *
2098 * We have the option of inserting the head or the tail of the queue. 2102 * We have the option of inserting the head or the tail of the queue.
2099 * Typically we use the tail for new ioctls and so forth. We use the head 2103 * Typically we use the tail for new ioctls and so forth. We use the head
2100 * of the queue for things like a QUEUE_FULL message from a device, or a 2104 * of the queue for things like a QUEUE_FULL message from a device, or a
2101 * host that is unable to accept a particular command. 2105 * host that is unable to accept a particular command.
2102 */ 2106 */
2103 void blk_insert_request(request_queue_t *q, struct request *rq, 2107 void blk_insert_request(request_queue_t *q, struct request *rq,
2104 int at_head, void *data) 2108 int at_head, void *data)
2105 { 2109 {
2106 int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK; 2110 int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
2107 unsigned long flags; 2111 unsigned long flags;
2108 2112
2109 /* 2113 /*
2110 * tell I/O scheduler that this isn't a regular read/write (ie it 2114 * tell I/O scheduler that this isn't a regular read/write (ie it
2111 * must not attempt merges on this) and that it acts as a soft 2115 * must not attempt merges on this) and that it acts as a soft
2112 * barrier 2116 * barrier
2113 */ 2117 */
2114 rq->flags |= REQ_SPECIAL | REQ_SOFTBARRIER; 2118 rq->flags |= REQ_SPECIAL | REQ_SOFTBARRIER;
2115 2119
2116 rq->special = data; 2120 rq->special = data;
2117 2121
2118 spin_lock_irqsave(q->queue_lock, flags); 2122 spin_lock_irqsave(q->queue_lock, flags);
2119 2123
2120 /* 2124 /*
2121 * If command is tagged, release the tag 2125 * If command is tagged, release the tag
2122 */ 2126 */
2123 if (blk_rq_tagged(rq)) 2127 if (blk_rq_tagged(rq))
2124 blk_queue_end_tag(q, rq); 2128 blk_queue_end_tag(q, rq);
2125 2129
2126 drive_stat_acct(rq, rq->nr_sectors, 1); 2130 drive_stat_acct(rq, rq->nr_sectors, 1);
2127 __elv_add_request(q, rq, where, 0); 2131 __elv_add_request(q, rq, where, 0);
2128 2132
2129 if (blk_queue_plugged(q)) 2133 if (blk_queue_plugged(q))
2130 __generic_unplug_device(q); 2134 __generic_unplug_device(q);
2131 else 2135 else
2132 q->request_fn(q); 2136 q->request_fn(q);
2133 spin_unlock_irqrestore(q->queue_lock, flags); 2137 spin_unlock_irqrestore(q->queue_lock, flags);
2134 } 2138 }
2135 2139
2136 EXPORT_SYMBOL(blk_insert_request); 2140 EXPORT_SYMBOL(blk_insert_request);
2137 2141
2138 /** 2142 /**
2139 * blk_rq_map_user - map user data to a request, for REQ_BLOCK_PC usage 2143 * blk_rq_map_user - map user data to a request, for REQ_BLOCK_PC usage
2140 * @q: request queue where request should be inserted 2144 * @q: request queue where request should be inserted
2141 * @rq: request structure to fill 2145 * @rq: request structure to fill
2142 * @ubuf: the user buffer 2146 * @ubuf: the user buffer
2143 * @len: length of user data 2147 * @len: length of user data
2144 * 2148 *
2145 * Description: 2149 * Description:
2146 * Data will be mapped directly for zero copy io, if possible. Otherwise 2150 * Data will be mapped directly for zero copy io, if possible. Otherwise
2147 * a kernel bounce buffer is used. 2151 * a kernel bounce buffer is used.
2148 * 2152 *
2149 * A matching blk_rq_unmap_user() must be issued at the end of io, while 2153 * A matching blk_rq_unmap_user() must be issued at the end of io, while
2150 * still in process context. 2154 * still in process context.
2151 * 2155 *
2152 * Note: The mapped bio may need to be bounced through blk_queue_bounce() 2156 * Note: The mapped bio may need to be bounced through blk_queue_bounce()
2153 * before being submitted to the device, as pages mapped may be out of 2157 * before being submitted to the device, as pages mapped may be out of
2154 * reach. It's the callers responsibility to make sure this happens. The 2158 * reach. It's the callers responsibility to make sure this happens. The
2155 * original bio must be passed back in to blk_rq_unmap_user() for proper 2159 * original bio must be passed back in to blk_rq_unmap_user() for proper
2156 * unmapping. 2160 * unmapping.
2157 */ 2161 */
2158 int blk_rq_map_user(request_queue_t *q, struct request *rq, void __user *ubuf, 2162 int blk_rq_map_user(request_queue_t *q, struct request *rq, void __user *ubuf,
2159 unsigned int len) 2163 unsigned int len)
2160 { 2164 {
2161 unsigned long uaddr; 2165 unsigned long uaddr;
2162 struct bio *bio; 2166 struct bio *bio;
2163 int reading; 2167 int reading;
2164 2168
2165 if (len > (q->max_hw_sectors << 9)) 2169 if (len > (q->max_hw_sectors << 9))
2166 return -EINVAL; 2170 return -EINVAL;
2167 if (!len || !ubuf) 2171 if (!len || !ubuf)
2168 return -EINVAL; 2172 return -EINVAL;
2169 2173
2170 reading = rq_data_dir(rq) == READ; 2174 reading = rq_data_dir(rq) == READ;
2171 2175
2172 /* 2176 /*
2173 * if alignment requirement is satisfied, map in user pages for 2177 * if alignment requirement is satisfied, map in user pages for
2174 * direct dma. else, set up kernel bounce buffers 2178 * direct dma. else, set up kernel bounce buffers
2175 */ 2179 */
2176 uaddr = (unsigned long) ubuf; 2180 uaddr = (unsigned long) ubuf;
2177 if (!(uaddr & queue_dma_alignment(q)) && !(len & queue_dma_alignment(q))) 2181 if (!(uaddr & queue_dma_alignment(q)) && !(len & queue_dma_alignment(q)))
2178 bio = bio_map_user(q, NULL, uaddr, len, reading); 2182 bio = bio_map_user(q, NULL, uaddr, len, reading);
2179 else 2183 else
2180 bio = bio_copy_user(q, uaddr, len, reading); 2184 bio = bio_copy_user(q, uaddr, len, reading);
2181 2185
2182 if (!IS_ERR(bio)) { 2186 if (!IS_ERR(bio)) {
2183 rq->bio = rq->biotail = bio; 2187 rq->bio = rq->biotail = bio;
2184 blk_rq_bio_prep(q, rq, bio); 2188 blk_rq_bio_prep(q, rq, bio);
2185 2189
2186 rq->buffer = rq->data = NULL; 2190 rq->buffer = rq->data = NULL;
2187 rq->data_len = len; 2191 rq->data_len = len;
2188 return 0; 2192 return 0;
2189 } 2193 }
2190 2194
2191 /* 2195 /*
2192 * bio is the err-ptr 2196 * bio is the err-ptr
2193 */ 2197 */
2194 return PTR_ERR(bio); 2198 return PTR_ERR(bio);
2195 } 2199 }
2196 2200
2197 EXPORT_SYMBOL(blk_rq_map_user); 2201 EXPORT_SYMBOL(blk_rq_map_user);
2198 2202
2199 /** 2203 /**
2200 * blk_rq_map_user_iov - map user data to a request, for REQ_BLOCK_PC usage 2204 * blk_rq_map_user_iov - map user data to a request, for REQ_BLOCK_PC usage
2201 * @q: request queue where request should be inserted 2205 * @q: request queue where request should be inserted
2202 * @rq: request to map data to 2206 * @rq: request to map data to
2203 * @iov: pointer to the iovec 2207 * @iov: pointer to the iovec
2204 * @iov_count: number of elements in the iovec 2208 * @iov_count: number of elements in the iovec
2205 * 2209 *
2206 * Description: 2210 * Description:
2207 * Data will be mapped directly for zero copy io, if possible. Otherwise 2211 * Data will be mapped directly for zero copy io, if possible. Otherwise
2208 * a kernel bounce buffer is used. 2212 * a kernel bounce buffer is used.
2209 * 2213 *
2210 * A matching blk_rq_unmap_user() must be issued at the end of io, while 2214 * A matching blk_rq_unmap_user() must be issued at the end of io, while
2211 * still in process context. 2215 * still in process context.
2212 * 2216 *
2213 * Note: The mapped bio may need to be bounced through blk_queue_bounce() 2217 * Note: The mapped bio may need to be bounced through blk_queue_bounce()
2214 * before being submitted to the device, as pages mapped may be out of 2218 * before being submitted to the device, as pages mapped may be out of
2215 * reach. It's the callers responsibility to make sure this happens. The 2219 * reach. It's the callers responsibility to make sure this happens. The
2216 * original bio must be passed back in to blk_rq_unmap_user() for proper 2220 * original bio must be passed back in to blk_rq_unmap_user() for proper
2217 * unmapping. 2221 * unmapping.
2218 */ 2222 */
2219 int blk_rq_map_user_iov(request_queue_t *q, struct request *rq, 2223 int blk_rq_map_user_iov(request_queue_t *q, struct request *rq,
2220 struct sg_iovec *iov, int iov_count) 2224 struct sg_iovec *iov, int iov_count)
2221 { 2225 {
2222 struct bio *bio; 2226 struct bio *bio;
2223 2227
2224 if (!iov || iov_count <= 0) 2228 if (!iov || iov_count <= 0)
2225 return -EINVAL; 2229 return -EINVAL;
2226 2230
2227 /* we don't allow misaligned data like bio_map_user() does. If the 2231 /* we don't allow misaligned data like bio_map_user() does. If the
2228 * user is using sg, they're expected to know the alignment constraints 2232 * user is using sg, they're expected to know the alignment constraints
2229 * and respect them accordingly */ 2233 * and respect them accordingly */
2230 bio = bio_map_user_iov(q, NULL, iov, iov_count, rq_data_dir(rq)== READ); 2234 bio = bio_map_user_iov(q, NULL, iov, iov_count, rq_data_dir(rq)== READ);
2231 if (IS_ERR(bio)) 2235 if (IS_ERR(bio))
2232 return PTR_ERR(bio); 2236 return PTR_ERR(bio);
2233 2237
2234 rq->bio = rq->biotail = bio; 2238 rq->bio = rq->biotail = bio;
2235 blk_rq_bio_prep(q, rq, bio); 2239 blk_rq_bio_prep(q, rq, bio);
2236 rq->buffer = rq->data = NULL; 2240 rq->buffer = rq->data = NULL;
2237 rq->data_len = bio->bi_size; 2241 rq->data_len = bio->bi_size;
2238 return 0; 2242 return 0;
2239 } 2243 }
2240 2244
2241 EXPORT_SYMBOL(blk_rq_map_user_iov); 2245 EXPORT_SYMBOL(blk_rq_map_user_iov);
2242 2246
2243 /** 2247 /**
2244 * blk_rq_unmap_user - unmap a request with user data 2248 * blk_rq_unmap_user - unmap a request with user data
2245 * @bio: bio to be unmapped 2249 * @bio: bio to be unmapped
2246 * @ulen: length of user buffer 2250 * @ulen: length of user buffer
2247 * 2251 *
2248 * Description: 2252 * Description:
2249 * Unmap a bio previously mapped by blk_rq_map_user(). 2253 * Unmap a bio previously mapped by blk_rq_map_user().
2250 */ 2254 */
2251 int blk_rq_unmap_user(struct bio *bio, unsigned int ulen) 2255 int blk_rq_unmap_user(struct bio *bio, unsigned int ulen)
2252 { 2256 {
2253 int ret = 0; 2257 int ret = 0;
2254 2258
2255 if (bio) { 2259 if (bio) {
2256 if (bio_flagged(bio, BIO_USER_MAPPED)) 2260 if (bio_flagged(bio, BIO_USER_MAPPED))
2257 bio_unmap_user(bio); 2261 bio_unmap_user(bio);
2258 else 2262 else
2259 ret = bio_uncopy_user(bio); 2263 ret = bio_uncopy_user(bio);
2260 } 2264 }
2261 2265
2262 return 0; 2266 return 0;
2263 } 2267 }
2264 2268
2265 EXPORT_SYMBOL(blk_rq_unmap_user); 2269 EXPORT_SYMBOL(blk_rq_unmap_user);
2266 2270
2267 /** 2271 /**
2268 * blk_rq_map_kern - map kernel data to a request, for REQ_BLOCK_PC usage 2272 * blk_rq_map_kern - map kernel data to a request, for REQ_BLOCK_PC usage
2269 * @q: request queue where request should be inserted 2273 * @q: request queue where request should be inserted
2270 * @rq: request to fill 2274 * @rq: request to fill
2271 * @kbuf: the kernel buffer 2275 * @kbuf: the kernel buffer
2272 * @len: length of user data 2276 * @len: length of user data
2273 * @gfp_mask: memory allocation flags 2277 * @gfp_mask: memory allocation flags
2274 */ 2278 */
2275 int blk_rq_map_kern(request_queue_t *q, struct request *rq, void *kbuf, 2279 int blk_rq_map_kern(request_queue_t *q, struct request *rq, void *kbuf,
2276 unsigned int len, gfp_t gfp_mask) 2280 unsigned int len, gfp_t gfp_mask)
2277 { 2281 {
2278 struct bio *bio; 2282 struct bio *bio;
2279 2283
2280 if (len > (q->max_hw_sectors << 9)) 2284 if (len > (q->max_hw_sectors << 9))
2281 return -EINVAL; 2285 return -EINVAL;
2282 if (!len || !kbuf) 2286 if (!len || !kbuf)
2283 return -EINVAL; 2287 return -EINVAL;
2284 2288
2285 bio = bio_map_kern(q, kbuf, len, gfp_mask); 2289 bio = bio_map_kern(q, kbuf, len, gfp_mask);
2286 if (IS_ERR(bio)) 2290 if (IS_ERR(bio))
2287 return PTR_ERR(bio); 2291 return PTR_ERR(bio);
2288 2292
2289 if (rq_data_dir(rq) == WRITE) 2293 if (rq_data_dir(rq) == WRITE)
2290 bio->bi_rw |= (1 << BIO_RW); 2294 bio->bi_rw |= (1 << BIO_RW);
2291 2295
2292 rq->bio = rq->biotail = bio; 2296 rq->bio = rq->biotail = bio;
2293 blk_rq_bio_prep(q, rq, bio); 2297 blk_rq_bio_prep(q, rq, bio);
2294 2298
2295 rq->buffer = rq->data = NULL; 2299 rq->buffer = rq->data = NULL;
2296 rq->data_len = len; 2300 rq->data_len = len;
2297 return 0; 2301 return 0;
2298 } 2302 }
2299 2303
2300 EXPORT_SYMBOL(blk_rq_map_kern); 2304 EXPORT_SYMBOL(blk_rq_map_kern);
2301 2305
2302 /** 2306 /**
2303 * blk_execute_rq_nowait - insert a request into queue for execution 2307 * blk_execute_rq_nowait - insert a request into queue for execution
2304 * @q: queue to insert the request in 2308 * @q: queue to insert the request in
2305 * @bd_disk: matching gendisk 2309 * @bd_disk: matching gendisk
2306 * @rq: request to insert 2310 * @rq: request to insert
2307 * @at_head: insert request at head or tail of queue 2311 * @at_head: insert request at head or tail of queue
2308 * @done: I/O completion handler 2312 * @done: I/O completion handler
2309 * 2313 *
2310 * Description: 2314 * Description:
2311 * Insert a fully prepared request at the back of the io scheduler queue 2315 * Insert a fully prepared request at the back of the io scheduler queue
2312 * for execution. Don't wait for completion. 2316 * for execution. Don't wait for completion.
2313 */ 2317 */
2314 void blk_execute_rq_nowait(request_queue_t *q, struct gendisk *bd_disk, 2318 void blk_execute_rq_nowait(request_queue_t *q, struct gendisk *bd_disk,
2315 struct request *rq, int at_head, 2319 struct request *rq, int at_head,
2316 void (*done)(struct request *)) 2320 void (*done)(struct request *))
2317 { 2321 {
2318 int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK; 2322 int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
2319 2323
2320 rq->rq_disk = bd_disk; 2324 rq->rq_disk = bd_disk;
2321 rq->flags |= REQ_NOMERGE; 2325 rq->flags |= REQ_NOMERGE;
2322 rq->end_io = done; 2326 rq->end_io = done;
2323 elv_add_request(q, rq, where, 1); 2327 elv_add_request(q, rq, where, 1);
2324 generic_unplug_device(q); 2328 generic_unplug_device(q);
2325 } 2329 }
2326 2330
2327 EXPORT_SYMBOL_GPL(blk_execute_rq_nowait); 2331 EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
2328 2332
2329 /** 2333 /**
2330 * blk_execute_rq - insert a request into queue for execution 2334 * blk_execute_rq - insert a request into queue for execution
2331 * @q: queue to insert the request in 2335 * @q: queue to insert the request in
2332 * @bd_disk: matching gendisk 2336 * @bd_disk: matching gendisk
2333 * @rq: request to insert 2337 * @rq: request to insert
2334 * @at_head: insert request at head or tail of queue 2338 * @at_head: insert request at head or tail of queue
2335 * 2339 *
2336 * Description: 2340 * Description:
2337 * Insert a fully prepared request at the back of the io scheduler queue 2341 * Insert a fully prepared request at the back of the io scheduler queue
2338 * for execution and wait for completion. 2342 * for execution and wait for completion.
2339 */ 2343 */
2340 int blk_execute_rq(request_queue_t *q, struct gendisk *bd_disk, 2344 int blk_execute_rq(request_queue_t *q, struct gendisk *bd_disk,
2341 struct request *rq, int at_head) 2345 struct request *rq, int at_head)
2342 { 2346 {
2343 DECLARE_COMPLETION(wait); 2347 DECLARE_COMPLETION(wait);
2344 char sense[SCSI_SENSE_BUFFERSIZE]; 2348 char sense[SCSI_SENSE_BUFFERSIZE];
2345 int err = 0; 2349 int err = 0;
2346 2350
2347 /* 2351 /*
2348 * we need an extra reference to the request, so we can look at 2352 * we need an extra reference to the request, so we can look at
2349 * it after io completion 2353 * it after io completion
2350 */ 2354 */
2351 rq->ref_count++; 2355 rq->ref_count++;
2352 2356
2353 if (!rq->sense) { 2357 if (!rq->sense) {
2354 memset(sense, 0, sizeof(sense)); 2358 memset(sense, 0, sizeof(sense));
2355 rq->sense = sense; 2359 rq->sense = sense;
2356 rq->sense_len = 0; 2360 rq->sense_len = 0;
2357 } 2361 }
2358 2362
2359 rq->waiting = &wait; 2363 rq->waiting = &wait;
2360 blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq); 2364 blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
2361 wait_for_completion(&wait); 2365 wait_for_completion(&wait);
2362 rq->waiting = NULL; 2366 rq->waiting = NULL;
2363 2367
2364 if (rq->errors) 2368 if (rq->errors)
2365 err = -EIO; 2369 err = -EIO;
2366 2370
2367 return err; 2371 return err;
2368 } 2372 }
2369 2373
2370 EXPORT_SYMBOL(blk_execute_rq); 2374 EXPORT_SYMBOL(blk_execute_rq);
2371 2375
2372 /** 2376 /**
2373 * blkdev_issue_flush - queue a flush 2377 * blkdev_issue_flush - queue a flush
2374 * @bdev: blockdev to issue flush for 2378 * @bdev: blockdev to issue flush for
2375 * @error_sector: error sector 2379 * @error_sector: error sector
2376 * 2380 *
2377 * Description: 2381 * Description:
2378 * Issue a flush for the block device in question. Caller can supply 2382 * Issue a flush for the block device in question. Caller can supply
2379 * room for storing the error offset in case of a flush error, if they 2383 * room for storing the error offset in case of a flush error, if they
2380 * wish to. Caller must run wait_for_completion() on its own. 2384 * wish to. Caller must run wait_for_completion() on its own.
2381 */ 2385 */
2382 int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector) 2386 int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector)
2383 { 2387 {
2384 request_queue_t *q; 2388 request_queue_t *q;
2385 2389
2386 if (bdev->bd_disk == NULL) 2390 if (bdev->bd_disk == NULL)
2387 return -ENXIO; 2391 return -ENXIO;
2388 2392
2389 q = bdev_get_queue(bdev); 2393 q = bdev_get_queue(bdev);
2390 if (!q) 2394 if (!q)
2391 return -ENXIO; 2395 return -ENXIO;
2392 if (!q->issue_flush_fn) 2396 if (!q->issue_flush_fn)
2393 return -EOPNOTSUPP; 2397 return -EOPNOTSUPP;
2394 2398
2395 return q->issue_flush_fn(q, bdev->bd_disk, error_sector); 2399 return q->issue_flush_fn(q, bdev->bd_disk, error_sector);
2396 } 2400 }
2397 2401
2398 EXPORT_SYMBOL(blkdev_issue_flush); 2402 EXPORT_SYMBOL(blkdev_issue_flush);
2399 2403
2400 static void drive_stat_acct(struct request *rq, int nr_sectors, int new_io) 2404 static void drive_stat_acct(struct request *rq, int nr_sectors, int new_io)
2401 { 2405 {
2402 int rw = rq_data_dir(rq); 2406 int rw = rq_data_dir(rq);
2403 2407
2404 if (!blk_fs_request(rq) || !rq->rq_disk) 2408 if (!blk_fs_request(rq) || !rq->rq_disk)
2405 return; 2409 return;
2406 2410
2407 if (!new_io) { 2411 if (!new_io) {
2408 __disk_stat_inc(rq->rq_disk, merges[rw]); 2412 __disk_stat_inc(rq->rq_disk, merges[rw]);
2409 } else { 2413 } else {
2410 disk_round_stats(rq->rq_disk); 2414 disk_round_stats(rq->rq_disk);
2411 rq->rq_disk->in_flight++; 2415 rq->rq_disk->in_flight++;
2412 } 2416 }
2413 } 2417 }
2414 2418
2415 /* 2419 /*
2416 * add-request adds a request to the linked list. 2420 * add-request adds a request to the linked list.
2417 * queue lock is held and interrupts disabled, as we muck with the 2421 * queue lock is held and interrupts disabled, as we muck with the
2418 * request queue list. 2422 * request queue list.
2419 */ 2423 */
2420 static inline void add_request(request_queue_t * q, struct request * req) 2424 static inline void add_request(request_queue_t * q, struct request * req)
2421 { 2425 {
2422 drive_stat_acct(req, req->nr_sectors, 1); 2426 drive_stat_acct(req, req->nr_sectors, 1);
2423 2427
2424 if (q->activity_fn) 2428 if (q->activity_fn)
2425 q->activity_fn(q->activity_data, rq_data_dir(req)); 2429 q->activity_fn(q->activity_data, rq_data_dir(req));
2426 2430
2427 /* 2431 /*
2428 * elevator indicated where it wants this request to be 2432 * elevator indicated where it wants this request to be
2429 * inserted at elevator_merge time 2433 * inserted at elevator_merge time
2430 */ 2434 */
2431 __elv_add_request(q, req, ELEVATOR_INSERT_SORT, 0); 2435 __elv_add_request(q, req, ELEVATOR_INSERT_SORT, 0);
2432 } 2436 }
2433 2437
2434 /* 2438 /*
2435 * disk_round_stats() - Round off the performance stats on a struct 2439 * disk_round_stats() - Round off the performance stats on a struct
2436 * disk_stats. 2440 * disk_stats.
2437 * 2441 *
2438 * The average IO queue length and utilisation statistics are maintained 2442 * The average IO queue length and utilisation statistics are maintained
2439 * by observing the current state of the queue length and the amount of 2443 * by observing the current state of the queue length and the amount of
2440 * time it has been in this state for. 2444 * time it has been in this state for.
2441 * 2445 *
2442 * Normally, that accounting is done on IO completion, but that can result 2446 * Normally, that accounting is done on IO completion, but that can result
2443 * in more than a second's worth of IO being accounted for within any one 2447 * in more than a second's worth of IO being accounted for within any one
2444 * second, leading to >100% utilisation. To deal with that, we call this 2448 * second, leading to >100% utilisation. To deal with that, we call this
2445 * function to do a round-off before returning the results when reading 2449 * function to do a round-off before returning the results when reading
2446 * /proc/diskstats. This accounts immediately for all queue usage up to 2450 * /proc/diskstats. This accounts immediately for all queue usage up to
2447 * the current jiffies and restarts the counters again. 2451 * the current jiffies and restarts the counters again.
2448 */ 2452 */
2449 void disk_round_stats(struct gendisk *disk) 2453 void disk_round_stats(struct gendisk *disk)
2450 { 2454 {
2451 unsigned long now = jiffies; 2455 unsigned long now = jiffies;
2452 2456
2453 if (now == disk->stamp) 2457 if (now == disk->stamp)
2454 return; 2458 return;
2455 2459
2456 if (disk->in_flight) { 2460 if (disk->in_flight) {
2457 __disk_stat_add(disk, time_in_queue, 2461 __disk_stat_add(disk, time_in_queue,
2458 disk->in_flight * (now - disk->stamp)); 2462 disk->in_flight * (now - disk->stamp));
2459 __disk_stat_add(disk, io_ticks, (now - disk->stamp)); 2463 __disk_stat_add(disk, io_ticks, (now - disk->stamp));
2460 } 2464 }
2461 disk->stamp = now; 2465 disk->stamp = now;
2462 } 2466 }
2463 2467
2464 /* 2468 /*
2465 * queue lock must be held 2469 * queue lock must be held
2466 */ 2470 */
2467 void __blk_put_request(request_queue_t *q, struct request *req) 2471 void __blk_put_request(request_queue_t *q, struct request *req)
2468 { 2472 {
2469 struct request_list *rl = req->rl; 2473 struct request_list *rl = req->rl;
2470 2474
2471 if (unlikely(!q)) 2475 if (unlikely(!q))
2472 return; 2476 return;
2473 if (unlikely(--req->ref_count)) 2477 if (unlikely(--req->ref_count))
2474 return; 2478 return;
2475 2479
2476 elv_completed_request(q, req); 2480 elv_completed_request(q, req);
2477 2481
2478 req->rq_status = RQ_INACTIVE; 2482 req->rq_status = RQ_INACTIVE;
2479 req->rl = NULL; 2483 req->rl = NULL;
2480 2484
2481 /* 2485 /*
2482 * Request may not have originated from ll_rw_blk. if not, 2486 * Request may not have originated from ll_rw_blk. if not,
2483 * it didn't come out of our reserved rq pools 2487 * it didn't come out of our reserved rq pools
2484 */ 2488 */
2485 if (rl) { 2489 if (rl) {
2486 int rw = rq_data_dir(req); 2490 int rw = rq_data_dir(req);
2487 int priv = req->flags & REQ_ELVPRIV; 2491 int priv = req->flags & REQ_ELVPRIV;
2488 2492
2489 BUG_ON(!list_empty(&req->queuelist)); 2493 BUG_ON(!list_empty(&req->queuelist));
2490 2494
2491 blk_free_request(q, req); 2495 blk_free_request(q, req);
2492 freed_request(q, rw, priv); 2496 freed_request(q, rw, priv);
2493 } 2497 }
2494 } 2498 }
2495 2499
2496 EXPORT_SYMBOL_GPL(__blk_put_request); 2500 EXPORT_SYMBOL_GPL(__blk_put_request);
2497 2501
2498 void blk_put_request(struct request *req) 2502 void blk_put_request(struct request *req)
2499 { 2503 {
2500 unsigned long flags; 2504 unsigned long flags;
2501 request_queue_t *q = req->q; 2505 request_queue_t *q = req->q;
2502 2506
2503 /* 2507 /*
2504 * Gee, IDE calls in w/ NULL q. Fix IDE and remove the 2508 * Gee, IDE calls in w/ NULL q. Fix IDE and remove the
2505 * following if (q) test. 2509 * following if (q) test.
2506 */ 2510 */
2507 if (q) { 2511 if (q) {
2508 spin_lock_irqsave(q->queue_lock, flags); 2512 spin_lock_irqsave(q->queue_lock, flags);
2509 __blk_put_request(q, req); 2513 __blk_put_request(q, req);
2510 spin_unlock_irqrestore(q->queue_lock, flags); 2514 spin_unlock_irqrestore(q->queue_lock, flags);
2511 } 2515 }
2512 } 2516 }
2513 2517
2514 EXPORT_SYMBOL(blk_put_request); 2518 EXPORT_SYMBOL(blk_put_request);
2515 2519
2516 /** 2520 /**
2517 * blk_end_sync_rq - executes a completion event on a request 2521 * blk_end_sync_rq - executes a completion event on a request
2518 * @rq: request to complete 2522 * @rq: request to complete
2519 */ 2523 */
2520 void blk_end_sync_rq(struct request *rq) 2524 void blk_end_sync_rq(struct request *rq)
2521 { 2525 {
2522 struct completion *waiting = rq->waiting; 2526 struct completion *waiting = rq->waiting;
2523 2527
2524 rq->waiting = NULL; 2528 rq->waiting = NULL;
2525 __blk_put_request(rq->q, rq); 2529 __blk_put_request(rq->q, rq);
2526 2530
2527 /* 2531 /*
2528 * complete last, if this is a stack request the process (and thus 2532 * complete last, if this is a stack request the process (and thus
2529 * the rq pointer) could be invalid right after this complete() 2533 * the rq pointer) could be invalid right after this complete()
2530 */ 2534 */
2531 complete(waiting); 2535 complete(waiting);
2532 } 2536 }
2533 EXPORT_SYMBOL(blk_end_sync_rq); 2537 EXPORT_SYMBOL(blk_end_sync_rq);
2534 2538
2535 /** 2539 /**
2536 * blk_congestion_wait - wait for a queue to become uncongested 2540 * blk_congestion_wait - wait for a queue to become uncongested
2537 * @rw: READ or WRITE 2541 * @rw: READ or WRITE
2538 * @timeout: timeout in jiffies 2542 * @timeout: timeout in jiffies
2539 * 2543 *
2540 * Waits for up to @timeout jiffies for a queue (any queue) to exit congestion. 2544 * Waits for up to @timeout jiffies for a queue (any queue) to exit congestion.
2541 * If no queues are congested then just wait for the next request to be 2545 * If no queues are congested then just wait for the next request to be
2542 * returned. 2546 * returned.
2543 */ 2547 */
2544 long blk_congestion_wait(int rw, long timeout) 2548 long blk_congestion_wait(int rw, long timeout)
2545 { 2549 {
2546 long ret; 2550 long ret;
2547 DEFINE_WAIT(wait); 2551 DEFINE_WAIT(wait);
2548 wait_queue_head_t *wqh = &congestion_wqh[rw]; 2552 wait_queue_head_t *wqh = &congestion_wqh[rw];
2549 2553
2550 prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); 2554 prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE);
2551 ret = io_schedule_timeout(timeout); 2555 ret = io_schedule_timeout(timeout);
2552 finish_wait(wqh, &wait); 2556 finish_wait(wqh, &wait);
2553 return ret; 2557 return ret;
2554 } 2558 }
2555 2559
2556 EXPORT_SYMBOL(blk_congestion_wait); 2560 EXPORT_SYMBOL(blk_congestion_wait);
2557 2561
2558 /* 2562 /*
2559 * Has to be called with the request spinlock acquired 2563 * Has to be called with the request spinlock acquired
2560 */ 2564 */
2561 static int attempt_merge(request_queue_t *q, struct request *req, 2565 static int attempt_merge(request_queue_t *q, struct request *req,
2562 struct request *next) 2566 struct request *next)
2563 { 2567 {
2564 if (!rq_mergeable(req) || !rq_mergeable(next)) 2568 if (!rq_mergeable(req) || !rq_mergeable(next))
2565 return 0; 2569 return 0;
2566 2570
2567 /* 2571 /*
2568 * not contigious 2572 * not contigious
2569 */ 2573 */
2570 if (req->sector + req->nr_sectors != next->sector) 2574 if (req->sector + req->nr_sectors != next->sector)
2571 return 0; 2575 return 0;
2572 2576
2573 if (rq_data_dir(req) != rq_data_dir(next) 2577 if (rq_data_dir(req) != rq_data_dir(next)
2574 || req->rq_disk != next->rq_disk 2578 || req->rq_disk != next->rq_disk
2575 || next->waiting || next->special) 2579 || next->waiting || next->special)
2576 return 0; 2580 return 0;
2577 2581
2578 /* 2582 /*
2579 * If we are allowed to merge, then append bio list 2583 * If we are allowed to merge, then append bio list
2580 * from next to rq and release next. merge_requests_fn 2584 * from next to rq and release next. merge_requests_fn
2581 * will have updated segment counts, update sector 2585 * will have updated segment counts, update sector
2582 * counts here. 2586 * counts here.
2583 */ 2587 */
2584 if (!q->merge_requests_fn(q, req, next)) 2588 if (!q->merge_requests_fn(q, req, next))
2585 return 0; 2589 return 0;
2586 2590
2587 /* 2591 /*
2588 * At this point we have either done a back merge 2592 * At this point we have either done a back merge
2589 * or front merge. We need the smaller start_time of 2593 * or front merge. We need the smaller start_time of
2590 * the merged requests to be the current request 2594 * the merged requests to be the current request
2591 * for accounting purposes. 2595 * for accounting purposes.
2592 */ 2596 */
2593 if (time_after(req->start_time, next->start_time)) 2597 if (time_after(req->start_time, next->start_time))
2594 req->start_time = next->start_time; 2598 req->start_time = next->start_time;
2595 2599
2596 req->biotail->bi_next = next->bio; 2600 req->biotail->bi_next = next->bio;
2597 req->biotail = next->biotail; 2601 req->biotail = next->biotail;
2598 2602
2599 req->nr_sectors = req->hard_nr_sectors += next->hard_nr_sectors; 2603 req->nr_sectors = req->hard_nr_sectors += next->hard_nr_sectors;
2600 2604
2601 elv_merge_requests(q, req, next); 2605 elv_merge_requests(q, req, next);
2602 2606
2603 if (req->rq_disk) { 2607 if (req->rq_disk) {
2604 disk_round_stats(req->rq_disk); 2608 disk_round_stats(req->rq_disk);
2605 req->rq_disk->in_flight--; 2609 req->rq_disk->in_flight--;
2606 } 2610 }
2607 2611
2608 req->ioprio = ioprio_best(req->ioprio, next->ioprio); 2612 req->ioprio = ioprio_best(req->ioprio, next->ioprio);
2609 2613
2610 __blk_put_request(q, next); 2614 __blk_put_request(q, next);
2611 return 1; 2615 return 1;
2612 } 2616 }
2613 2617
2614 static inline int attempt_back_merge(request_queue_t *q, struct request *rq) 2618 static inline int attempt_back_merge(request_queue_t *q, struct request *rq)
2615 { 2619 {
2616 struct request *next = elv_latter_request(q, rq); 2620 struct request *next = elv_latter_request(q, rq);
2617 2621
2618 if (next) 2622 if (next)
2619 return attempt_merge(q, rq, next); 2623 return attempt_merge(q, rq, next);
2620 2624
2621 return 0; 2625 return 0;
2622 } 2626 }
2623 2627
2624 static inline int attempt_front_merge(request_queue_t *q, struct request *rq) 2628 static inline int attempt_front_merge(request_queue_t *q, struct request *rq)
2625 { 2629 {
2626 struct request *prev = elv_former_request(q, rq); 2630 struct request *prev = elv_former_request(q, rq);
2627 2631
2628 if (prev) 2632 if (prev)
2629 return attempt_merge(q, prev, rq); 2633 return attempt_merge(q, prev, rq);
2630 2634
2631 return 0; 2635 return 0;
2632 } 2636 }
2633 2637
2634 /** 2638 /**
2635 * blk_attempt_remerge - attempt to remerge active head with next request 2639 * blk_attempt_remerge - attempt to remerge active head with next request
2636 * @q: The &request_queue_t belonging to the device 2640 * @q: The &request_queue_t belonging to the device
2637 * @rq: The head request (usually) 2641 * @rq: The head request (usually)
2638 * 2642 *
2639 * Description: 2643 * Description:
2640 * For head-active devices, the queue can easily be unplugged so quickly 2644 * For head-active devices, the queue can easily be unplugged so quickly
2641 * that proper merging is not done on the front request. This may hurt 2645 * that proper merging is not done on the front request. This may hurt
2642 * performance greatly for some devices. The block layer cannot safely 2646 * performance greatly for some devices. The block layer cannot safely
2643 * do merging on that first request for these queues, but the driver can 2647 * do merging on that first request for these queues, but the driver can
2644 * call this function and make it happen any way. Only the driver knows 2648 * call this function and make it happen any way. Only the driver knows
2645 * when it is safe to do so. 2649 * when it is safe to do so.
2646 **/ 2650 **/
2647 void blk_attempt_remerge(request_queue_t *q, struct request *rq) 2651 void blk_attempt_remerge(request_queue_t *q, struct request *rq)
2648 { 2652 {
2649 unsigned long flags; 2653 unsigned long flags;
2650 2654
2651 spin_lock_irqsave(q->queue_lock, flags); 2655 spin_lock_irqsave(q->queue_lock, flags);
2652 attempt_back_merge(q, rq); 2656 attempt_back_merge(q, rq);
2653 spin_unlock_irqrestore(q->queue_lock, flags); 2657 spin_unlock_irqrestore(q->queue_lock, flags);
2654 } 2658 }
2655 2659
2656 EXPORT_SYMBOL(blk_attempt_remerge); 2660 EXPORT_SYMBOL(blk_attempt_remerge);
2657 2661
2658 static int __make_request(request_queue_t *q, struct bio *bio) 2662 static int __make_request(request_queue_t *q, struct bio *bio)
2659 { 2663 {
2660 struct request *req; 2664 struct request *req;
2661 int el_ret, rw, nr_sectors, cur_nr_sectors, barrier, err, sync; 2665 int el_ret, rw, nr_sectors, cur_nr_sectors, barrier, err, sync;
2662 unsigned short prio; 2666 unsigned short prio;
2663 sector_t sector; 2667 sector_t sector;
2664 2668
2665 sector = bio->bi_sector; 2669 sector = bio->bi_sector;
2666 nr_sectors = bio_sectors(bio); 2670 nr_sectors = bio_sectors(bio);
2667 cur_nr_sectors = bio_cur_sectors(bio); 2671 cur_nr_sectors = bio_cur_sectors(bio);
2668 prio = bio_prio(bio); 2672 prio = bio_prio(bio);
2669 2673
2670 rw = bio_data_dir(bio); 2674 rw = bio_data_dir(bio);
2671 sync = bio_sync(bio); 2675 sync = bio_sync(bio);
2672 2676
2673 /* 2677 /*
2674 * low level driver can indicate that it wants pages above a 2678 * low level driver can indicate that it wants pages above a
2675 * certain limit bounced to low memory (ie for highmem, or even 2679 * certain limit bounced to low memory (ie for highmem, or even
2676 * ISA dma in theory) 2680 * ISA dma in theory)
2677 */ 2681 */
2678 blk_queue_bounce(q, &bio); 2682 blk_queue_bounce(q, &bio);
2679 2683
2680 spin_lock_prefetch(q->queue_lock); 2684 spin_lock_prefetch(q->queue_lock);
2681 2685
2682 barrier = bio_barrier(bio); 2686 barrier = bio_barrier(bio);
2683 if (unlikely(barrier) && (q->ordered == QUEUE_ORDERED_NONE)) { 2687 if (unlikely(barrier) && (q->ordered == QUEUE_ORDERED_NONE)) {
2684 err = -EOPNOTSUPP; 2688 err = -EOPNOTSUPP;
2685 goto end_io; 2689 goto end_io;
2686 } 2690 }
2687 2691
2688 spin_lock_irq(q->queue_lock); 2692 spin_lock_irq(q->queue_lock);
2689 2693
2690 if (unlikely(barrier) || elv_queue_empty(q)) 2694 if (unlikely(barrier) || elv_queue_empty(q))
2691 goto get_rq; 2695 goto get_rq;
2692 2696
2693 el_ret = elv_merge(q, &req, bio); 2697 el_ret = elv_merge(q, &req, bio);
2694 switch (el_ret) { 2698 switch (el_ret) {
2695 case ELEVATOR_BACK_MERGE: 2699 case ELEVATOR_BACK_MERGE:
2696 BUG_ON(!rq_mergeable(req)); 2700 BUG_ON(!rq_mergeable(req));
2697 2701
2698 if (!q->back_merge_fn(q, req, bio)) 2702 if (!q->back_merge_fn(q, req, bio))
2699 break; 2703 break;
2700 2704
2701 req->biotail->bi_next = bio; 2705 req->biotail->bi_next = bio;
2702 req->biotail = bio; 2706 req->biotail = bio;
2703 req->nr_sectors = req->hard_nr_sectors += nr_sectors; 2707 req->nr_sectors = req->hard_nr_sectors += nr_sectors;
2704 req->ioprio = ioprio_best(req->ioprio, prio); 2708 req->ioprio = ioprio_best(req->ioprio, prio);
2705 drive_stat_acct(req, nr_sectors, 0); 2709 drive_stat_acct(req, nr_sectors, 0);
2706 if (!attempt_back_merge(q, req)) 2710 if (!attempt_back_merge(q, req))
2707 elv_merged_request(q, req); 2711 elv_merged_request(q, req);
2708 goto out; 2712 goto out;
2709 2713
2710 case ELEVATOR_FRONT_MERGE: 2714 case ELEVATOR_FRONT_MERGE:
2711 BUG_ON(!rq_mergeable(req)); 2715 BUG_ON(!rq_mergeable(req));
2712 2716
2713 if (!q->front_merge_fn(q, req, bio)) 2717 if (!q->front_merge_fn(q, req, bio))
2714 break; 2718 break;
2715 2719
2716 bio->bi_next = req->bio; 2720 bio->bi_next = req->bio;
2717 req->bio = bio; 2721 req->bio = bio;
2718 2722
2719 /* 2723 /*
2720 * may not be valid. if the low level driver said 2724 * may not be valid. if the low level driver said
2721 * it didn't need a bounce buffer then it better 2725 * it didn't need a bounce buffer then it better
2722 * not touch req->buffer either... 2726 * not touch req->buffer either...
2723 */ 2727 */
2724 req->buffer = bio_data(bio); 2728 req->buffer = bio_data(bio);
2725 req->current_nr_sectors = cur_nr_sectors; 2729 req->current_nr_sectors = cur_nr_sectors;
2726 req->hard_cur_sectors = cur_nr_sectors; 2730 req->hard_cur_sectors = cur_nr_sectors;
2727 req->sector = req->hard_sector = sector; 2731 req->sector = req->hard_sector = sector;
2728 req->nr_sectors = req->hard_nr_sectors += nr_sectors; 2732 req->nr_sectors = req->hard_nr_sectors += nr_sectors;
2729 req->ioprio = ioprio_best(req->ioprio, prio); 2733 req->ioprio = ioprio_best(req->ioprio, prio);
2730 drive_stat_acct(req, nr_sectors, 0); 2734 drive_stat_acct(req, nr_sectors, 0);
2731 if (!attempt_front_merge(q, req)) 2735 if (!attempt_front_merge(q, req))
2732 elv_merged_request(q, req); 2736 elv_merged_request(q, req);
2733 goto out; 2737 goto out;
2734 2738
2735 /* ELV_NO_MERGE: elevator says don't/can't merge. */ 2739 /* ELV_NO_MERGE: elevator says don't/can't merge. */
2736 default: 2740 default:
2737 ; 2741 ;
2738 } 2742 }
2739 2743
2740 get_rq: 2744 get_rq:
2741 /* 2745 /*
2742 * Grab a free request. This is might sleep but can not fail. 2746 * Grab a free request. This is might sleep but can not fail.
2743 * Returns with the queue unlocked. 2747 * Returns with the queue unlocked.
2744 */ 2748 */
2745 req = get_request_wait(q, rw, bio); 2749 req = get_request_wait(q, rw, bio);
2746 2750
2747 /* 2751 /*
2748 * After dropping the lock and possibly sleeping here, our request 2752 * After dropping the lock and possibly sleeping here, our request
2749 * may now be mergeable after it had proven unmergeable (above). 2753 * may now be mergeable after it had proven unmergeable (above).
2750 * We don't worry about that case for efficiency. It won't happen 2754 * We don't worry about that case for efficiency. It won't happen
2751 * often, and the elevators are able to handle it. 2755 * often, and the elevators are able to handle it.
2752 */ 2756 */
2753 2757
2754 req->flags |= REQ_CMD; 2758 req->flags |= REQ_CMD;
2755 2759
2756 /* 2760 /*
2757 * inherit FAILFAST from bio (for read-ahead, and explicit FAILFAST) 2761 * inherit FAILFAST from bio (for read-ahead, and explicit FAILFAST)
2758 */ 2762 */
2759 if (bio_rw_ahead(bio) || bio_failfast(bio)) 2763 if (bio_rw_ahead(bio) || bio_failfast(bio))
2760 req->flags |= REQ_FAILFAST; 2764 req->flags |= REQ_FAILFAST;
2761 2765
2762 /* 2766 /*
2763 * REQ_BARRIER implies no merging, but lets make it explicit 2767 * REQ_BARRIER implies no merging, but lets make it explicit
2764 */ 2768 */
2765 if (unlikely(barrier)) 2769 if (unlikely(barrier))
2766 req->flags |= (REQ_HARDBARRIER | REQ_NOMERGE); 2770 req->flags |= (REQ_HARDBARRIER | REQ_NOMERGE);
2767 2771
2768 req->errors = 0; 2772 req->errors = 0;
2769 req->hard_sector = req->sector = sector; 2773 req->hard_sector = req->sector = sector;
2770 req->hard_nr_sectors = req->nr_sectors = nr_sectors; 2774 req->hard_nr_sectors = req->nr_sectors = nr_sectors;
2771 req->current_nr_sectors = req->hard_cur_sectors = cur_nr_sectors; 2775 req->current_nr_sectors = req->hard_cur_sectors = cur_nr_sectors;
2772 req->nr_phys_segments = bio_phys_segments(q, bio); 2776 req->nr_phys_segments = bio_phys_segments(q, bio);
2773 req->nr_hw_segments = bio_hw_segments(q, bio); 2777 req->nr_hw_segments = bio_hw_segments(q, bio);
2774 req->buffer = bio_data(bio); /* see ->buffer comment above */ 2778 req->buffer = bio_data(bio); /* see ->buffer comment above */
2775 req->waiting = NULL; 2779 req->waiting = NULL;
2776 req->bio = req->biotail = bio; 2780 req->bio = req->biotail = bio;
2777 req->ioprio = prio; 2781 req->ioprio = prio;
2778 req->rq_disk = bio->bi_bdev->bd_disk; 2782 req->rq_disk = bio->bi_bdev->bd_disk;
2779 req->start_time = jiffies; 2783 req->start_time = jiffies;
2780 2784
2781 spin_lock_irq(q->queue_lock); 2785 spin_lock_irq(q->queue_lock);
2782 if (elv_queue_empty(q)) 2786 if (elv_queue_empty(q))
2783 blk_plug_device(q); 2787 blk_plug_device(q);
2784 add_request(q, req); 2788 add_request(q, req);
2785 out: 2789 out:
2786 if (sync) 2790 if (sync)
2787 __generic_unplug_device(q); 2791 __generic_unplug_device(q);
2788 2792
2789 spin_unlock_irq(q->queue_lock); 2793 spin_unlock_irq(q->queue_lock);
2790 return 0; 2794 return 0;
2791 2795
2792 end_io: 2796 end_io:
2793 bio_endio(bio, nr_sectors << 9, err); 2797 bio_endio(bio, nr_sectors << 9, err);
2794 return 0; 2798 return 0;
2795 } 2799 }
2796 2800
2797 /* 2801 /*
2798 * If bio->bi_dev is a partition, remap the location 2802 * If bio->bi_dev is a partition, remap the location
2799 */ 2803 */
2800 static inline void blk_partition_remap(struct bio *bio) 2804 static inline void blk_partition_remap(struct bio *bio)
2801 { 2805 {
2802 struct block_device *bdev = bio->bi_bdev; 2806 struct block_device *bdev = bio->bi_bdev;
2803 2807
2804 if (bdev != bdev->bd_contains) { 2808 if (bdev != bdev->bd_contains) {
2805 struct hd_struct *p = bdev->bd_part; 2809 struct hd_struct *p = bdev->bd_part;
2806 const int rw = bio_data_dir(bio); 2810 const int rw = bio_data_dir(bio);
2807 2811
2808 p->sectors[rw] += bio_sectors(bio); 2812 p->sectors[rw] += bio_sectors(bio);
2809 p->ios[rw]++; 2813 p->ios[rw]++;
2810 2814
2811 bio->bi_sector += p->start_sect; 2815 bio->bi_sector += p->start_sect;
2812 bio->bi_bdev = bdev->bd_contains; 2816 bio->bi_bdev = bdev->bd_contains;
2813 } 2817 }
2814 } 2818 }
2815 2819
2816 static void handle_bad_sector(struct bio *bio) 2820 static void handle_bad_sector(struct bio *bio)
2817 { 2821 {
2818 char b[BDEVNAME_SIZE]; 2822 char b[BDEVNAME_SIZE];
2819 2823
2820 printk(KERN_INFO "attempt to access beyond end of device\n"); 2824 printk(KERN_INFO "attempt to access beyond end of device\n");
2821 printk(KERN_INFO "%s: rw=%ld, want=%Lu, limit=%Lu\n", 2825 printk(KERN_INFO "%s: rw=%ld, want=%Lu, limit=%Lu\n",
2822 bdevname(bio->bi_bdev, b), 2826 bdevname(bio->bi_bdev, b),
2823 bio->bi_rw, 2827 bio->bi_rw,
2824 (unsigned long long)bio->bi_sector + bio_sectors(bio), 2828 (unsigned long long)bio->bi_sector + bio_sectors(bio),
2825 (long long)(bio->bi_bdev->bd_inode->i_size >> 9)); 2829 (long long)(bio->bi_bdev->bd_inode->i_size >> 9));
2826 2830
2827 set_bit(BIO_EOF, &bio->bi_flags); 2831 set_bit(BIO_EOF, &bio->bi_flags);
2828 } 2832 }
2829 2833
2830 /** 2834 /**
2831 * generic_make_request: hand a buffer to its device driver for I/O 2835 * generic_make_request: hand a buffer to its device driver for I/O
2832 * @bio: The bio describing the location in memory and on the device. 2836 * @bio: The bio describing the location in memory and on the device.
2833 * 2837 *
2834 * generic_make_request() is used to make I/O requests of block 2838 * generic_make_request() is used to make I/O requests of block
2835 * devices. It is passed a &struct bio, which describes the I/O that needs 2839 * devices. It is passed a &struct bio, which describes the I/O that needs
2836 * to be done. 2840 * to be done.
2837 * 2841 *
2838 * generic_make_request() does not return any status. The 2842 * generic_make_request() does not return any status. The
2839 * success/failure status of the request, along with notification of 2843 * success/failure status of the request, along with notification of
2840 * completion, is delivered asynchronously through the bio->bi_end_io 2844 * completion, is delivered asynchronously through the bio->bi_end_io
2841 * function described (one day) else where. 2845 * function described (one day) else where.
2842 * 2846 *
2843 * The caller of generic_make_request must make sure that bi_io_vec 2847 * The caller of generic_make_request must make sure that bi_io_vec
2844 * are set to describe the memory buffer, and that bi_dev and bi_sector are 2848 * are set to describe the memory buffer, and that bi_dev and bi_sector are
2845 * set to describe the device address, and the 2849 * set to describe the device address, and the
2846 * bi_end_io and optionally bi_private are set to describe how 2850 * bi_end_io and optionally bi_private are set to describe how
2847 * completion notification should be signaled. 2851 * completion notification should be signaled.
2848 * 2852 *
2849 * generic_make_request and the drivers it calls may use bi_next if this 2853 * generic_make_request and the drivers it calls may use bi_next if this
2850 * bio happens to be merged with someone else, and may change bi_dev and 2854 * bio happens to be merged with someone else, and may change bi_dev and
2851 * bi_sector for remaps as it sees fit. So the values of these fields 2855 * bi_sector for remaps as it sees fit. So the values of these fields
2852 * should NOT be depended on after the call to generic_make_request. 2856 * should NOT be depended on after the call to generic_make_request.
2853 */ 2857 */
2854 void generic_make_request(struct bio *bio) 2858 void generic_make_request(struct bio *bio)
2855 { 2859 {
2856 request_queue_t *q; 2860 request_queue_t *q;
2857 sector_t maxsector; 2861 sector_t maxsector;
2858 int ret, nr_sectors = bio_sectors(bio); 2862 int ret, nr_sectors = bio_sectors(bio);
2859 2863
2860 might_sleep(); 2864 might_sleep();
2861 /* Test device or partition size, when known. */ 2865 /* Test device or partition size, when known. */
2862 maxsector = bio->bi_bdev->bd_inode->i_size >> 9; 2866 maxsector = bio->bi_bdev->bd_inode->i_size >> 9;
2863 if (maxsector) { 2867 if (maxsector) {
2864 sector_t sector = bio->bi_sector; 2868 sector_t sector = bio->bi_sector;
2865 2869
2866 if (maxsector < nr_sectors || maxsector - nr_sectors < sector) { 2870 if (maxsector < nr_sectors || maxsector - nr_sectors < sector) {
2867 /* 2871 /*
2868 * This may well happen - the kernel calls bread() 2872 * This may well happen - the kernel calls bread()
2869 * without checking the size of the device, e.g., when 2873 * without checking the size of the device, e.g., when
2870 * mounting a device. 2874 * mounting a device.
2871 */ 2875 */
2872 handle_bad_sector(bio); 2876 handle_bad_sector(bio);
2873 goto end_io; 2877 goto end_io;
2874 } 2878 }
2875 } 2879 }
2876 2880
2877 /* 2881 /*
2878 * Resolve the mapping until finished. (drivers are 2882 * Resolve the mapping until finished. (drivers are
2879 * still free to implement/resolve their own stacking 2883 * still free to implement/resolve their own stacking
2880 * by explicitly returning 0) 2884 * by explicitly returning 0)
2881 * 2885 *
2882 * NOTE: we don't repeat the blk_size check for each new device. 2886 * NOTE: we don't repeat the blk_size check for each new device.
2883 * Stacking drivers are expected to know what they are doing. 2887 * Stacking drivers are expected to know what they are doing.
2884 */ 2888 */
2885 do { 2889 do {
2886 char b[BDEVNAME_SIZE]; 2890 char b[BDEVNAME_SIZE];
2887 2891
2888 q = bdev_get_queue(bio->bi_bdev); 2892 q = bdev_get_queue(bio->bi_bdev);
2889 if (!q) { 2893 if (!q) {
2890 printk(KERN_ERR 2894 printk(KERN_ERR
2891 "generic_make_request: Trying to access " 2895 "generic_make_request: Trying to access "
2892 "nonexistent block-device %s (%Lu)\n", 2896 "nonexistent block-device %s (%Lu)\n",
2893 bdevname(bio->bi_bdev, b), 2897 bdevname(bio->bi_bdev, b),
2894 (long long) bio->bi_sector); 2898 (long long) bio->bi_sector);
2895 end_io: 2899 end_io:
2896 bio_endio(bio, bio->bi_size, -EIO); 2900 bio_endio(bio, bio->bi_size, -EIO);
2897 break; 2901 break;
2898 } 2902 }
2899 2903
2900 if (unlikely(bio_sectors(bio) > q->max_hw_sectors)) { 2904 if (unlikely(bio_sectors(bio) > q->max_hw_sectors)) {
2901 printk("bio too big device %s (%u > %u)\n", 2905 printk("bio too big device %s (%u > %u)\n",
2902 bdevname(bio->bi_bdev, b), 2906 bdevname(bio->bi_bdev, b),
2903 bio_sectors(bio), 2907 bio_sectors(bio),
2904 q->max_hw_sectors); 2908 q->max_hw_sectors);
2905 goto end_io; 2909 goto end_io;
2906 } 2910 }
2907 2911
2908 if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) 2912 if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)))
2909 goto end_io; 2913 goto end_io;
2910 2914
2911 /* 2915 /*
2912 * If this device has partitions, remap block n 2916 * If this device has partitions, remap block n
2913 * of partition p to block n+start(p) of the disk. 2917 * of partition p to block n+start(p) of the disk.
2914 */ 2918 */
2915 blk_partition_remap(bio); 2919 blk_partition_remap(bio);
2916 2920
2917 ret = q->make_request_fn(q, bio); 2921 ret = q->make_request_fn(q, bio);
2918 } while (ret); 2922 } while (ret);
2919 } 2923 }
2920 2924
2921 EXPORT_SYMBOL(generic_make_request); 2925 EXPORT_SYMBOL(generic_make_request);
2922 2926
2923 /** 2927 /**
2924 * submit_bio: submit a bio to the block device layer for I/O 2928 * submit_bio: submit a bio to the block device layer for I/O
2925 * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead) 2929 * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead)
2926 * @bio: The &struct bio which describes the I/O 2930 * @bio: The &struct bio which describes the I/O
2927 * 2931 *
2928 * submit_bio() is very similar in purpose to generic_make_request(), and 2932 * submit_bio() is very similar in purpose to generic_make_request(), and
2929 * uses that function to do most of the work. Both are fairly rough 2933 * uses that function to do most of the work. Both are fairly rough
2930 * interfaces, @bio must be presetup and ready for I/O. 2934 * interfaces, @bio must be presetup and ready for I/O.
2931 * 2935 *
2932 */ 2936 */
2933 void submit_bio(int rw, struct bio *bio) 2937 void submit_bio(int rw, struct bio *bio)
2934 { 2938 {
2935 int count = bio_sectors(bio); 2939 int count = bio_sectors(bio);
2936 2940
2937 BIO_BUG_ON(!bio->bi_size); 2941 BIO_BUG_ON(!bio->bi_size);
2938 BIO_BUG_ON(!bio->bi_io_vec); 2942 BIO_BUG_ON(!bio->bi_io_vec);
2939 bio->bi_rw |= rw; 2943 bio->bi_rw |= rw;
2940 if (rw & WRITE) 2944 if (rw & WRITE)
2941 mod_page_state(pgpgout, count); 2945 mod_page_state(pgpgout, count);
2942 else 2946 else
2943 mod_page_state(pgpgin, count); 2947 mod_page_state(pgpgin, count);
2944 2948
2945 if (unlikely(block_dump)) { 2949 if (unlikely(block_dump)) {
2946 char b[BDEVNAME_SIZE]; 2950 char b[BDEVNAME_SIZE];
2947 printk(KERN_DEBUG "%s(%d): %s block %Lu on %s\n", 2951 printk(KERN_DEBUG "%s(%d): %s block %Lu on %s\n",
2948 current->comm, current->pid, 2952 current->comm, current->pid,
2949 (rw & WRITE) ? "WRITE" : "READ", 2953 (rw & WRITE) ? "WRITE" : "READ",
2950 (unsigned long long)bio->bi_sector, 2954 (unsigned long long)bio->bi_sector,
2951 bdevname(bio->bi_bdev,b)); 2955 bdevname(bio->bi_bdev,b));
2952 } 2956 }
2953 2957
2954 generic_make_request(bio); 2958 generic_make_request(bio);
2955 } 2959 }
2956 2960
2957 EXPORT_SYMBOL(submit_bio); 2961 EXPORT_SYMBOL(submit_bio);
2958 2962
2959 static void blk_recalc_rq_segments(struct request *rq) 2963 static void blk_recalc_rq_segments(struct request *rq)
2960 { 2964 {
2961 struct bio *bio, *prevbio = NULL; 2965 struct bio *bio, *prevbio = NULL;
2962 int nr_phys_segs, nr_hw_segs; 2966 int nr_phys_segs, nr_hw_segs;
2963 unsigned int phys_size, hw_size; 2967 unsigned int phys_size, hw_size;
2964 request_queue_t *q = rq->q; 2968 request_queue_t *q = rq->q;
2965 2969
2966 if (!rq->bio) 2970 if (!rq->bio)
2967 return; 2971 return;
2968 2972
2969 phys_size = hw_size = nr_phys_segs = nr_hw_segs = 0; 2973 phys_size = hw_size = nr_phys_segs = nr_hw_segs = 0;
2970 rq_for_each_bio(bio, rq) { 2974 rq_for_each_bio(bio, rq) {
2971 /* Force bio hw/phys segs to be recalculated. */ 2975 /* Force bio hw/phys segs to be recalculated. */
2972 bio->bi_flags &= ~(1 << BIO_SEG_VALID); 2976 bio->bi_flags &= ~(1 << BIO_SEG_VALID);
2973 2977
2974 nr_phys_segs += bio_phys_segments(q, bio); 2978 nr_phys_segs += bio_phys_segments(q, bio);
2975 nr_hw_segs += bio_hw_segments(q, bio); 2979 nr_hw_segs += bio_hw_segments(q, bio);
2976 if (prevbio) { 2980 if (prevbio) {
2977 int pseg = phys_size + prevbio->bi_size + bio->bi_size; 2981 int pseg = phys_size + prevbio->bi_size + bio->bi_size;
2978 int hseg = hw_size + prevbio->bi_size + bio->bi_size; 2982 int hseg = hw_size + prevbio->bi_size + bio->bi_size;
2979 2983
2980 if (blk_phys_contig_segment(q, prevbio, bio) && 2984 if (blk_phys_contig_segment(q, prevbio, bio) &&
2981 pseg <= q->max_segment_size) { 2985 pseg <= q->max_segment_size) {
2982 nr_phys_segs--; 2986 nr_phys_segs--;
2983 phys_size += prevbio->bi_size + bio->bi_size; 2987 phys_size += prevbio->bi_size + bio->bi_size;
2984 } else 2988 } else
2985 phys_size = 0; 2989 phys_size = 0;
2986 2990
2987 if (blk_hw_contig_segment(q, prevbio, bio) && 2991 if (blk_hw_contig_segment(q, prevbio, bio) &&
2988 hseg <= q->max_segment_size) { 2992 hseg <= q->max_segment_size) {
2989 nr_hw_segs--; 2993 nr_hw_segs--;
2990 hw_size += prevbio->bi_size + bio->bi_size; 2994 hw_size += prevbio->bi_size + bio->bi_size;
2991 } else 2995 } else
2992 hw_size = 0; 2996 hw_size = 0;
2993 } 2997 }
2994 prevbio = bio; 2998 prevbio = bio;
2995 } 2999 }
2996 3000
2997 rq->nr_phys_segments = nr_phys_segs; 3001 rq->nr_phys_segments = nr_phys_segs;
2998 rq->nr_hw_segments = nr_hw_segs; 3002 rq->nr_hw_segments = nr_hw_segs;
2999 } 3003 }
3000 3004
3001 static void blk_recalc_rq_sectors(struct request *rq, int nsect) 3005 static void blk_recalc_rq_sectors(struct request *rq, int nsect)
3002 { 3006 {
3003 if (blk_fs_request(rq)) { 3007 if (blk_fs_request(rq)) {
3004 rq->hard_sector += nsect; 3008 rq->hard_sector += nsect;
3005 rq->hard_nr_sectors -= nsect; 3009 rq->hard_nr_sectors -= nsect;
3006 3010
3007 /* 3011 /*
3008 * Move the I/O submission pointers ahead if required. 3012 * Move the I/O submission pointers ahead if required.
3009 */ 3013 */
3010 if ((rq->nr_sectors >= rq->hard_nr_sectors) && 3014 if ((rq->nr_sectors >= rq->hard_nr_sectors) &&
3011 (rq->sector <= rq->hard_sector)) { 3015 (rq->sector <= rq->hard_sector)) {
3012 rq->sector = rq->hard_sector; 3016 rq->sector = rq->hard_sector;
3013 rq->nr_sectors = rq->hard_nr_sectors; 3017 rq->nr_sectors = rq->hard_nr_sectors;
3014 rq->hard_cur_sectors = bio_cur_sectors(rq->bio); 3018 rq->hard_cur_sectors = bio_cur_sectors(rq->bio);
3015 rq->current_nr_sectors = rq->hard_cur_sectors; 3019 rq->current_nr_sectors = rq->hard_cur_sectors;
3016 rq->buffer = bio_data(rq->bio); 3020 rq->buffer = bio_data(rq->bio);
3017 } 3021 }
3018 3022
3019 /* 3023 /*
3020 * if total number of sectors is less than the first segment 3024 * if total number of sectors is less than the first segment
3021 * size, something has gone terribly wrong 3025 * size, something has gone terribly wrong
3022 */ 3026 */
3023 if (rq->nr_sectors < rq->current_nr_sectors) { 3027 if (rq->nr_sectors < rq->current_nr_sectors) {
3024 printk("blk: request botched\n"); 3028 printk("blk: request botched\n");
3025 rq->nr_sectors = rq->current_nr_sectors; 3029 rq->nr_sectors = rq->current_nr_sectors;
3026 } 3030 }
3027 } 3031 }
3028 } 3032 }
3029 3033
3030 static int __end_that_request_first(struct request *req, int uptodate, 3034 static int __end_that_request_first(struct request *req, int uptodate,
3031 int nr_bytes) 3035 int nr_bytes)
3032 { 3036 {
3033 int total_bytes, bio_nbytes, error, next_idx = 0; 3037 int total_bytes, bio_nbytes, error, next_idx = 0;
3034 struct bio *bio; 3038 struct bio *bio;
3035 3039
3036 /* 3040 /*
3037 * extend uptodate bool to allow < 0 value to be direct io error 3041 * extend uptodate bool to allow < 0 value to be direct io error
3038 */ 3042 */
3039 error = 0; 3043 error = 0;
3040 if (end_io_error(uptodate)) 3044 if (end_io_error(uptodate))
3041 error = !uptodate ? -EIO : uptodate; 3045 error = !uptodate ? -EIO : uptodate;
3042 3046
3043 /* 3047 /*
3044 * for a REQ_BLOCK_PC request, we want to carry any eventual 3048 * for a REQ_BLOCK_PC request, we want to carry any eventual
3045 * sense key with us all the way through 3049 * sense key with us all the way through
3046 */ 3050 */
3047 if (!blk_pc_request(req)) 3051 if (!blk_pc_request(req))
3048 req->errors = 0; 3052 req->errors = 0;
3049 3053
3050 if (!uptodate) { 3054 if (!uptodate) {
3051 if (blk_fs_request(req) && !(req->flags & REQ_QUIET)) 3055 if (blk_fs_request(req) && !(req->flags & REQ_QUIET))
3052 printk("end_request: I/O error, dev %s, sector %llu\n", 3056 printk("end_request: I/O error, dev %s, sector %llu\n",
3053 req->rq_disk ? req->rq_disk->disk_name : "?", 3057 req->rq_disk ? req->rq_disk->disk_name : "?",
3054 (unsigned long long)req->sector); 3058 (unsigned long long)req->sector);
3055 } 3059 }
3056 3060
3057 if (blk_fs_request(req) && req->rq_disk) { 3061 if (blk_fs_request(req) && req->rq_disk) {
3058 const int rw = rq_data_dir(req); 3062 const int rw = rq_data_dir(req);
3059 3063
3060 __disk_stat_add(req->rq_disk, sectors[rw], nr_bytes >> 9); 3064 __disk_stat_add(req->rq_disk, sectors[rw], nr_bytes >> 9);
3061 } 3065 }
3062 3066
3063 total_bytes = bio_nbytes = 0; 3067 total_bytes = bio_nbytes = 0;
3064 while ((bio = req->bio) != NULL) { 3068 while ((bio = req->bio) != NULL) {
3065 int nbytes; 3069 int nbytes;
3066 3070
3067 if (nr_bytes >= bio->bi_size) { 3071 if (nr_bytes >= bio->bi_size) {
3068 req->bio = bio->bi_next; 3072 req->bio = bio->bi_next;
3069 nbytes = bio->bi_size; 3073 nbytes = bio->bi_size;
3070 bio_endio(bio, nbytes, error); 3074 bio_endio(bio, nbytes, error);
3071 next_idx = 0; 3075 next_idx = 0;
3072 bio_nbytes = 0; 3076 bio_nbytes = 0;
3073 } else { 3077 } else {
3074 int idx = bio->bi_idx + next_idx; 3078 int idx = bio->bi_idx + next_idx;
3075 3079
3076 if (unlikely(bio->bi_idx >= bio->bi_vcnt)) { 3080 if (unlikely(bio->bi_idx >= bio->bi_vcnt)) {
3077 blk_dump_rq_flags(req, "__end_that"); 3081 blk_dump_rq_flags(req, "__end_that");
3078 printk("%s: bio idx %d >= vcnt %d\n", 3082 printk("%s: bio idx %d >= vcnt %d\n",
3079 __FUNCTION__, 3083 __FUNCTION__,
3080 bio->bi_idx, bio->bi_vcnt); 3084 bio->bi_idx, bio->bi_vcnt);
3081 break; 3085 break;
3082 } 3086 }
3083 3087
3084 nbytes = bio_iovec_idx(bio, idx)->bv_len; 3088 nbytes = bio_iovec_idx(bio, idx)->bv_len;
3085 BIO_BUG_ON(nbytes > bio->bi_size); 3089 BIO_BUG_ON(nbytes > bio->bi_size);
3086 3090
3087 /* 3091 /*
3088 * not a complete bvec done 3092 * not a complete bvec done
3089 */ 3093 */
3090 if (unlikely(nbytes > nr_bytes)) { 3094 if (unlikely(nbytes > nr_bytes)) {
3091 bio_nbytes += nr_bytes; 3095 bio_nbytes += nr_bytes;
3092 total_bytes += nr_bytes; 3096 total_bytes += nr_bytes;
3093 break; 3097 break;
3094 } 3098 }
3095 3099
3096 /* 3100 /*
3097 * advance to the next vector 3101 * advance to the next vector
3098 */ 3102 */
3099 next_idx++; 3103 next_idx++;
3100 bio_nbytes += nbytes; 3104 bio_nbytes += nbytes;
3101 } 3105 }
3102 3106
3103 total_bytes += nbytes; 3107 total_bytes += nbytes;
3104 nr_bytes -= nbytes; 3108 nr_bytes -= nbytes;
3105 3109
3106 if ((bio = req->bio)) { 3110 if ((bio = req->bio)) {
3107 /* 3111 /*
3108 * end more in this run, or just return 'not-done' 3112 * end more in this run, or just return 'not-done'
3109 */ 3113 */
3110 if (unlikely(nr_bytes <= 0)) 3114 if (unlikely(nr_bytes <= 0))
3111 break; 3115 break;
3112 } 3116 }
3113 } 3117 }
3114 3118
3115 /* 3119 /*
3116 * completely done 3120 * completely done
3117 */ 3121 */
3118 if (!req->bio) 3122 if (!req->bio)
3119 return 0; 3123 return 0;
3120 3124
3121 /* 3125 /*
3122 * if the request wasn't completed, update state 3126 * if the request wasn't completed, update state
3123 */ 3127 */
3124 if (bio_nbytes) { 3128 if (bio_nbytes) {
3125 bio_endio(bio, bio_nbytes, error); 3129 bio_endio(bio, bio_nbytes, error);
3126 bio->bi_idx += next_idx; 3130 bio->bi_idx += next_idx;
3127 bio_iovec(bio)->bv_offset += nr_bytes; 3131 bio_iovec(bio)->bv_offset += nr_bytes;
3128 bio_iovec(bio)->bv_len -= nr_bytes; 3132 bio_iovec(bio)->bv_len -= nr_bytes;
3129 } 3133 }
3130 3134
3131 blk_recalc_rq_sectors(req, total_bytes >> 9); 3135 blk_recalc_rq_sectors(req, total_bytes >> 9);
3132 blk_recalc_rq_segments(req); 3136 blk_recalc_rq_segments(req);
3133 return 1; 3137 return 1;
3134 } 3138 }
3135 3139
3136 /** 3140 /**
3137 * end_that_request_first - end I/O on a request 3141 * end_that_request_first - end I/O on a request
3138 * @req: the request being processed 3142 * @req: the request being processed
3139 * @uptodate: 1 for success, 0 for I/O error, < 0 for specific error 3143 * @uptodate: 1 for success, 0 for I/O error, < 0 for specific error
3140 * @nr_sectors: number of sectors to end I/O on 3144 * @nr_sectors: number of sectors to end I/O on
3141 * 3145 *
3142 * Description: 3146 * Description:
3143 * Ends I/O on a number of sectors attached to @req, and sets it up 3147 * Ends I/O on a number of sectors attached to @req, and sets it up
3144 * for the next range of segments (if any) in the cluster. 3148 * for the next range of segments (if any) in the cluster.
3145 * 3149 *
3146 * Return: 3150 * Return:
3147 * 0 - we are done with this request, call end_that_request_last() 3151 * 0 - we are done with this request, call end_that_request_last()
3148 * 1 - still buffers pending for this request 3152 * 1 - still buffers pending for this request
3149 **/ 3153 **/
3150 int end_that_request_first(struct request *req, int uptodate, int nr_sectors) 3154 int end_that_request_first(struct request *req, int uptodate, int nr_sectors)
3151 { 3155 {
3152 return __end_that_request_first(req, uptodate, nr_sectors << 9); 3156 return __end_that_request_first(req, uptodate, nr_sectors << 9);
3153 } 3157 }
3154 3158
3155 EXPORT_SYMBOL(end_that_request_first); 3159 EXPORT_SYMBOL(end_that_request_first);
3156 3160
3157 /** 3161 /**
3158 * end_that_request_chunk - end I/O on a request 3162 * end_that_request_chunk - end I/O on a request
3159 * @req: the request being processed 3163 * @req: the request being processed
3160 * @uptodate: 1 for success, 0 for I/O error, < 0 for specific error 3164 * @uptodate: 1 for success, 0 for I/O error, < 0 for specific error
3161 * @nr_bytes: number of bytes to complete 3165 * @nr_bytes: number of bytes to complete
3162 * 3166 *
3163 * Description: 3167 * Description:
3164 * Ends I/O on a number of bytes attached to @req, and sets it up 3168 * Ends I/O on a number of bytes attached to @req, and sets it up
3165 * for the next range of segments (if any). Like end_that_request_first(), 3169 * for the next range of segments (if any). Like end_that_request_first(),
3166 * but deals with bytes instead of sectors. 3170 * but deals with bytes instead of sectors.
3167 * 3171 *
3168 * Return: 3172 * Return:
3169 * 0 - we are done with this request, call end_that_request_last() 3173 * 0 - we are done with this request, call end_that_request_last()
3170 * 1 - still buffers pending for this request 3174 * 1 - still buffers pending for this request
3171 **/ 3175 **/
3172 int end_that_request_chunk(struct request *req, int uptodate, int nr_bytes) 3176 int end_that_request_chunk(struct request *req, int uptodate, int nr_bytes)
3173 { 3177 {
3174 return __end_that_request_first(req, uptodate, nr_bytes); 3178 return __end_that_request_first(req, uptodate, nr_bytes);
3175 } 3179 }
3176 3180
3177 EXPORT_SYMBOL(end_that_request_chunk); 3181 EXPORT_SYMBOL(end_that_request_chunk);
3178 3182
3179 /* 3183 /*
3180 * queue lock must be held 3184 * queue lock must be held
3181 */ 3185 */
3182 void end_that_request_last(struct request *req) 3186 void end_that_request_last(struct request *req)
3183 { 3187 {
3184 struct gendisk *disk = req->rq_disk; 3188 struct gendisk *disk = req->rq_disk;
3185 3189
3186 if (unlikely(laptop_mode) && blk_fs_request(req)) 3190 if (unlikely(laptop_mode) && blk_fs_request(req))
3187 laptop_io_completion(); 3191 laptop_io_completion();
3188 3192
3189 if (disk && blk_fs_request(req)) { 3193 if (disk && blk_fs_request(req)) {
3190 unsigned long duration = jiffies - req->start_time; 3194 unsigned long duration = jiffies - req->start_time;
3191 const int rw = rq_data_dir(req); 3195 const int rw = rq_data_dir(req);
3192 3196
3193 __disk_stat_inc(disk, ios[rw]); 3197 __disk_stat_inc(disk, ios[rw]);
3194 __disk_stat_add(disk, ticks[rw], duration); 3198 __disk_stat_add(disk, ticks[rw], duration);
3195 disk_round_stats(disk); 3199 disk_round_stats(disk);
3196 disk->in_flight--; 3200 disk->in_flight--;
3197 } 3201 }
3198 if (req->end_io) 3202 if (req->end_io)
3199 req->end_io(req); 3203 req->end_io(req);
3200 else 3204 else
3201 __blk_put_request(req->q, req); 3205 __blk_put_request(req->q, req);
3202 } 3206 }
3203 3207
3204 EXPORT_SYMBOL(end_that_request_last); 3208 EXPORT_SYMBOL(end_that_request_last);
3205 3209
3206 void end_request(struct request *req, int uptodate) 3210 void end_request(struct request *req, int uptodate)
3207 { 3211 {
3208 if (!end_that_request_first(req, uptodate, req->hard_cur_sectors)) { 3212 if (!end_that_request_first(req, uptodate, req->hard_cur_sectors)) {
3209 add_disk_randomness(req->rq_disk); 3213 add_disk_randomness(req->rq_disk);
3210 blkdev_dequeue_request(req); 3214 blkdev_dequeue_request(req);
3211 end_that_request_last(req); 3215 end_that_request_last(req);
3212 } 3216 }
3213 } 3217 }
3214 3218
3215 EXPORT_SYMBOL(end_request); 3219 EXPORT_SYMBOL(end_request);
3216 3220
3217 void blk_rq_bio_prep(request_queue_t *q, struct request *rq, struct bio *bio) 3221 void blk_rq_bio_prep(request_queue_t *q, struct request *rq, struct bio *bio)
3218 { 3222 {
3219 /* first three bits are identical in rq->flags and bio->bi_rw */ 3223 /* first three bits are identical in rq->flags and bio->bi_rw */
3220 rq->flags |= (bio->bi_rw & 7); 3224 rq->flags |= (bio->bi_rw & 7);
3221 3225
3222 rq->nr_phys_segments = bio_phys_segments(q, bio); 3226 rq->nr_phys_segments = bio_phys_segments(q, bio);
3223 rq->nr_hw_segments = bio_hw_segments(q, bio); 3227 rq->nr_hw_segments = bio_hw_segments(q, bio);
3224 rq->current_nr_sectors = bio_cur_sectors(bio); 3228 rq->current_nr_sectors = bio_cur_sectors(bio);
3225 rq->hard_cur_sectors = rq->current_nr_sectors; 3229 rq->hard_cur_sectors = rq->current_nr_sectors;
3226 rq->hard_nr_sectors = rq->nr_sectors = bio_sectors(bio); 3230 rq->hard_nr_sectors = rq->nr_sectors = bio_sectors(bio);
3227 rq->buffer = bio_data(bio); 3231 rq->buffer = bio_data(bio);
3228 3232
3229 rq->bio = rq->biotail = bio; 3233 rq->bio = rq->biotail = bio;
3230 } 3234 }
3231 3235
3232 EXPORT_SYMBOL(blk_rq_bio_prep); 3236 EXPORT_SYMBOL(blk_rq_bio_prep);
3233 3237
3234 int kblockd_schedule_work(struct work_struct *work) 3238 int kblockd_schedule_work(struct work_struct *work)
3235 { 3239 {
3236 return queue_work(kblockd_workqueue, work); 3240 return queue_work(kblockd_workqueue, work);
3237 } 3241 }
3238 3242
3239 EXPORT_SYMBOL(kblockd_schedule_work); 3243 EXPORT_SYMBOL(kblockd_schedule_work);
3240 3244
3241 void kblockd_flush(void) 3245 void kblockd_flush(void)
3242 { 3246 {
3243 flush_workqueue(kblockd_workqueue); 3247 flush_workqueue(kblockd_workqueue);
3244 } 3248 }
3245 EXPORT_SYMBOL(kblockd_flush); 3249 EXPORT_SYMBOL(kblockd_flush);
3246 3250
3247 int __init blk_dev_init(void) 3251 int __init blk_dev_init(void)
3248 { 3252 {
3249 kblockd_workqueue = create_workqueue("kblockd"); 3253 kblockd_workqueue = create_workqueue("kblockd");
3250 if (!kblockd_workqueue) 3254 if (!kblockd_workqueue)
3251 panic("Failed to create kblockd\n"); 3255 panic("Failed to create kblockd\n");
3252 3256
3253 request_cachep = kmem_cache_create("blkdev_requests", 3257 request_cachep = kmem_cache_create("blkdev_requests",
3254 sizeof(struct request), 0, SLAB_PANIC, NULL, NULL); 3258 sizeof(struct request), 0, SLAB_PANIC, NULL, NULL);
3255 3259
3256 requestq_cachep = kmem_cache_create("blkdev_queue", 3260 requestq_cachep = kmem_cache_create("blkdev_queue",
3257 sizeof(request_queue_t), 0, SLAB_PANIC, NULL, NULL); 3261 sizeof(request_queue_t), 0, SLAB_PANIC, NULL, NULL);
3258 3262
3259 iocontext_cachep = kmem_cache_create("blkdev_ioc", 3263 iocontext_cachep = kmem_cache_create("blkdev_ioc",
3260 sizeof(struct io_context), 0, SLAB_PANIC, NULL, NULL); 3264 sizeof(struct io_context), 0, SLAB_PANIC, NULL, NULL);
3261 3265
3262 blk_max_low_pfn = max_low_pfn; 3266 blk_max_low_pfn = max_low_pfn;
3263 blk_max_pfn = max_pfn; 3267 blk_max_pfn = max_pfn;
3264 3268
3265 return 0; 3269 return 0;
3266 } 3270 }
3267 3271
3268 /* 3272 /*
3269 * IO Context helper functions 3273 * IO Context helper functions
3270 */ 3274 */
3271 void put_io_context(struct io_context *ioc) 3275 void put_io_context(struct io_context *ioc)
3272 { 3276 {
3273 if (ioc == NULL) 3277 if (ioc == NULL)
3274 return; 3278 return;
3275 3279
3276 BUG_ON(atomic_read(&ioc->refcount) == 0); 3280 BUG_ON(atomic_read(&ioc->refcount) == 0);
3277 3281
3278 if (atomic_dec_and_test(&ioc->refcount)) { 3282 if (atomic_dec_and_test(&ioc->refcount)) {
3279 if (ioc->aic && ioc->aic->dtor) 3283 if (ioc->aic && ioc->aic->dtor)
3280 ioc->aic->dtor(ioc->aic); 3284 ioc->aic->dtor(ioc->aic);
3281 if (ioc->cic && ioc->cic->dtor) 3285 if (ioc->cic && ioc->cic->dtor)
3282 ioc->cic->dtor(ioc->cic); 3286 ioc->cic->dtor(ioc->cic);
3283 3287
3284 kmem_cache_free(iocontext_cachep, ioc); 3288 kmem_cache_free(iocontext_cachep, ioc);
3285 } 3289 }
3286 } 3290 }
3287 EXPORT_SYMBOL(put_io_context); 3291 EXPORT_SYMBOL(put_io_context);
3288 3292
3289 /* Called by the exitting task */ 3293 /* Called by the exitting task */
3290 void exit_io_context(void) 3294 void exit_io_context(void)
3291 { 3295 {
3292 unsigned long flags; 3296 unsigned long flags;
3293 struct io_context *ioc; 3297 struct io_context *ioc;
3294 3298
3295 local_irq_save(flags); 3299 local_irq_save(flags);
3296 task_lock(current); 3300 task_lock(current);
3297 ioc = current->io_context; 3301 ioc = current->io_context;
3298 current->io_context = NULL; 3302 current->io_context = NULL;
3299 ioc->task = NULL; 3303 ioc->task = NULL;
3300 task_unlock(current); 3304 task_unlock(current);
3301 local_irq_restore(flags); 3305 local_irq_restore(flags);
3302 3306
3303 if (ioc->aic && ioc->aic->exit) 3307 if (ioc->aic && ioc->aic->exit)
3304 ioc->aic->exit(ioc->aic); 3308 ioc->aic->exit(ioc->aic);
3305 if (ioc->cic && ioc->cic->exit) 3309 if (ioc->cic && ioc->cic->exit)
3306 ioc->cic->exit(ioc->cic); 3310 ioc->cic->exit(ioc->cic);
3307 3311
3308 put_io_context(ioc); 3312 put_io_context(ioc);
3309 } 3313 }
3310 3314
3311 /* 3315 /*
3312 * If the current task has no IO context then create one and initialise it. 3316 * If the current task has no IO context then create one and initialise it.
3313 * Otherwise, return its existing IO context. 3317 * Otherwise, return its existing IO context.
3314 * 3318 *
3315 * This returned IO context doesn't have a specifically elevated refcount, 3319 * This returned IO context doesn't have a specifically elevated refcount,
3316 * but since the current task itself holds a reference, the context can be 3320 * but since the current task itself holds a reference, the context can be
3317 * used in general code, so long as it stays within `current` context. 3321 * used in general code, so long as it stays within `current` context.
3318 */ 3322 */
3319 struct io_context *current_io_context(gfp_t gfp_flags) 3323 struct io_context *current_io_context(gfp_t gfp_flags)
3320 { 3324 {
3321 struct task_struct *tsk = current; 3325 struct task_struct *tsk = current;
3322 struct io_context *ret; 3326 struct io_context *ret;
3323 3327
3324 ret = tsk->io_context; 3328 ret = tsk->io_context;
3325 if (likely(ret)) 3329 if (likely(ret))
3326 return ret; 3330 return ret;
3327 3331
3328 ret = kmem_cache_alloc(iocontext_cachep, gfp_flags); 3332 ret = kmem_cache_alloc(iocontext_cachep, gfp_flags);
3329 if (ret) { 3333 if (ret) {
3330 atomic_set(&ret->refcount, 1); 3334 atomic_set(&ret->refcount, 1);
3331 ret->task = current; 3335 ret->task = current;
3332 ret->set_ioprio = NULL; 3336 ret->set_ioprio = NULL;
3333 ret->last_waited = jiffies; /* doesn't matter... */ 3337 ret->last_waited = jiffies; /* doesn't matter... */
3334 ret->nr_batch_requests = 0; /* because this is 0 */ 3338 ret->nr_batch_requests = 0; /* because this is 0 */
3335 ret->aic = NULL; 3339 ret->aic = NULL;
3336 ret->cic = NULL; 3340 ret->cic = NULL;
3337 tsk->io_context = ret; 3341 tsk->io_context = ret;
3338 } 3342 }
3339 3343
3340 return ret; 3344 return ret;
3341 } 3345 }
3342 EXPORT_SYMBOL(current_io_context); 3346 EXPORT_SYMBOL(current_io_context);
3343 3347
3344 /* 3348 /*
3345 * If the current task has no IO context then create one and initialise it. 3349 * If the current task has no IO context then create one and initialise it.
3346 * If it does have a context, take a ref on it. 3350 * If it does have a context, take a ref on it.
3347 * 3351 *
3348 * This is always called in the context of the task which submitted the I/O. 3352 * This is always called in the context of the task which submitted the I/O.
3349 */ 3353 */
3350 struct io_context *get_io_context(gfp_t gfp_flags) 3354 struct io_context *get_io_context(gfp_t gfp_flags)
3351 { 3355 {
3352 struct io_context *ret; 3356 struct io_context *ret;
3353 ret = current_io_context(gfp_flags); 3357 ret = current_io_context(gfp_flags);
3354 if (likely(ret)) 3358 if (likely(ret))
3355 atomic_inc(&ret->refcount); 3359 atomic_inc(&ret->refcount);
3356 return ret; 3360 return ret;
3357 } 3361 }
3358 EXPORT_SYMBOL(get_io_context); 3362 EXPORT_SYMBOL(get_io_context);
3359 3363
3360 void copy_io_context(struct io_context **pdst, struct io_context **psrc) 3364 void copy_io_context(struct io_context **pdst, struct io_context **psrc)
3361 { 3365 {
3362 struct io_context *src = *psrc; 3366 struct io_context *src = *psrc;
3363 struct io_context *dst = *pdst; 3367 struct io_context *dst = *pdst;
3364 3368
3365 if (src) { 3369 if (src) {
3366 BUG_ON(atomic_read(&src->refcount) == 0); 3370 BUG_ON(atomic_read(&src->refcount) == 0);
3367 atomic_inc(&src->refcount); 3371 atomic_inc(&src->refcount);
3368 put_io_context(dst); 3372 put_io_context(dst);
3369 *pdst = src; 3373 *pdst = src;
3370 } 3374 }
3371 } 3375 }
3372 EXPORT_SYMBOL(copy_io_context); 3376 EXPORT_SYMBOL(copy_io_context);
3373 3377
3374 void swap_io_context(struct io_context **ioc1, struct io_context **ioc2) 3378 void swap_io_context(struct io_context **ioc1, struct io_context **ioc2)
3375 { 3379 {
3376 struct io_context *temp; 3380 struct io_context *temp;
3377 temp = *ioc1; 3381 temp = *ioc1;
3378 *ioc1 = *ioc2; 3382 *ioc1 = *ioc2;
3379 *ioc2 = temp; 3383 *ioc2 = temp;
3380 } 3384 }
3381 EXPORT_SYMBOL(swap_io_context); 3385 EXPORT_SYMBOL(swap_io_context);
3382 3386
3383 /* 3387 /*
3384 * sysfs parts below 3388 * sysfs parts below
3385 */ 3389 */
3386 struct queue_sysfs_entry { 3390 struct queue_sysfs_entry {
3387 struct attribute attr; 3391 struct attribute attr;
3388 ssize_t (*show)(struct request_queue *, char *); 3392 ssize_t (*show)(struct request_queue *, char *);
3389 ssize_t (*store)(struct request_queue *, const char *, size_t); 3393 ssize_t (*store)(struct request_queue *, const char *, size_t);
3390 }; 3394 };
3391 3395
3392 static ssize_t 3396 static ssize_t
3393 queue_var_show(unsigned int var, char *page) 3397 queue_var_show(unsigned int var, char *page)
3394 { 3398 {
3395 return sprintf(page, "%d\n", var); 3399 return sprintf(page, "%d\n", var);
3396 } 3400 }
3397 3401
3398 static ssize_t 3402 static ssize_t
3399 queue_var_store(unsigned long *var, const char *page, size_t count) 3403 queue_var_store(unsigned long *var, const char *page, size_t count)
3400 { 3404 {
3401 char *p = (char *) page; 3405 char *p = (char *) page;
3402 3406
3403 *var = simple_strtoul(p, &p, 10); 3407 *var = simple_strtoul(p, &p, 10);
3404 return count; 3408 return count;
3405 } 3409 }
3406 3410
3407 static ssize_t queue_requests_show(struct request_queue *q, char *page) 3411 static ssize_t queue_requests_show(struct request_queue *q, char *page)
3408 { 3412 {
3409 return queue_var_show(q->nr_requests, (page)); 3413 return queue_var_show(q->nr_requests, (page));
3410 } 3414 }
3411 3415
3412 static ssize_t 3416 static ssize_t
3413 queue_requests_store(struct request_queue *q, const char *page, size_t count) 3417 queue_requests_store(struct request_queue *q, const char *page, size_t count)
3414 { 3418 {
3415 struct request_list *rl = &q->rq; 3419 struct request_list *rl = &q->rq;
3416 3420
3417 int ret = queue_var_store(&q->nr_requests, page, count); 3421 int ret = queue_var_store(&q->nr_requests, page, count);
3418 if (q->nr_requests < BLKDEV_MIN_RQ) 3422 if (q->nr_requests < BLKDEV_MIN_RQ)
3419 q->nr_requests = BLKDEV_MIN_RQ; 3423 q->nr_requests = BLKDEV_MIN_RQ;
3420 blk_queue_congestion_threshold(q); 3424 blk_queue_congestion_threshold(q);
3421 3425
3422 if (rl->count[READ] >= queue_congestion_on_threshold(q)) 3426 if (rl->count[READ] >= queue_congestion_on_threshold(q))
3423 set_queue_congested(q, READ); 3427 set_queue_congested(q, READ);
3424 else if (rl->count[READ] < queue_congestion_off_threshold(q)) 3428 else if (rl->count[READ] < queue_congestion_off_threshold(q))
3425 clear_queue_congested(q, READ); 3429 clear_queue_congested(q, READ);
3426 3430
3427 if (rl->count[WRITE] >= queue_congestion_on_threshold(q)) 3431 if (rl->count[WRITE] >= queue_congestion_on_threshold(q))
3428 set_queue_congested(q, WRITE); 3432 set_queue_congested(q, WRITE);
3429 else if (rl->count[WRITE] < queue_congestion_off_threshold(q)) 3433 else if (rl->count[WRITE] < queue_congestion_off_threshold(q))
3430 clear_queue_congested(q, WRITE); 3434 clear_queue_congested(q, WRITE);
3431 3435
3432 if (rl->count[READ] >= q->nr_requests) { 3436 if (rl->count[READ] >= q->nr_requests) {
3433 blk_set_queue_full(q, READ); 3437 blk_set_queue_full(q, READ);
3434 } else if (rl->count[READ]+1 <= q->nr_requests) { 3438 } else if (rl->count[READ]+1 <= q->nr_requests) {
3435 blk_clear_queue_full(q, READ); 3439 blk_clear_queue_full(q, READ);
3436 wake_up(&rl->wait[READ]); 3440 wake_up(&rl->wait[READ]);
3437 } 3441 }
3438 3442
3439 if (rl->count[WRITE] >= q->nr_requests) { 3443 if (rl->count[WRITE] >= q->nr_requests) {
3440 blk_set_queue_full(q, WRITE); 3444 blk_set_queue_full(q, WRITE);
3441 } else if (rl->count[WRITE]+1 <= q->nr_requests) { 3445 } else if (rl->count[WRITE]+1 <= q->nr_requests) {
3442 blk_clear_queue_full(q, WRITE); 3446 blk_clear_queue_full(q, WRITE);
3443 wake_up(&rl->wait[WRITE]); 3447 wake_up(&rl->wait[WRITE]);
3444 } 3448 }
3445 return ret; 3449 return ret;
3446 } 3450 }
3447 3451
3448 static ssize_t queue_ra_show(struct request_queue *q, char *page) 3452 static ssize_t queue_ra_show(struct request_queue *q, char *page)
3449 { 3453 {
3450 int ra_kb = q->backing_dev_info.ra_pages << (PAGE_CACHE_SHIFT - 10); 3454 int ra_kb = q->backing_dev_info.ra_pages << (PAGE_CACHE_SHIFT - 10);
3451 3455
3452 return queue_var_show(ra_kb, (page)); 3456 return queue_var_show(ra_kb, (page));
3453 } 3457 }
3454 3458
3455 static ssize_t 3459 static ssize_t
3456 queue_ra_store(struct request_queue *q, const char *page, size_t count) 3460 queue_ra_store(struct request_queue *q, const char *page, size_t count)
3457 { 3461 {
3458 unsigned long ra_kb; 3462 unsigned long ra_kb;
3459 ssize_t ret = queue_var_store(&ra_kb, page, count); 3463 ssize_t ret = queue_var_store(&ra_kb, page, count);
3460 3464
3461 spin_lock_irq(q->queue_lock); 3465 spin_lock_irq(q->queue_lock);
3462 if (ra_kb > (q->max_sectors >> 1)) 3466 if (ra_kb > (q->max_sectors >> 1))
3463 ra_kb = (q->max_sectors >> 1); 3467 ra_kb = (q->max_sectors >> 1);
3464 3468
3465 q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10); 3469 q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
3466 spin_unlock_irq(q->queue_lock); 3470 spin_unlock_irq(q->queue_lock);
3467 3471
3468 return ret; 3472 return ret;
3469 } 3473 }
3470 3474
3471 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page) 3475 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
3472 { 3476 {
3473 int max_sectors_kb = q->max_sectors >> 1; 3477 int max_sectors_kb = q->max_sectors >> 1;
3474 3478
3475 return queue_var_show(max_sectors_kb, (page)); 3479 return queue_var_show(max_sectors_kb, (page));
3476 } 3480 }
3477 3481
3478 static ssize_t 3482 static ssize_t
3479 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count) 3483 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
3480 { 3484 {
3481 unsigned long max_sectors_kb, 3485 unsigned long max_sectors_kb,
3482 max_hw_sectors_kb = q->max_hw_sectors >> 1, 3486 max_hw_sectors_kb = q->max_hw_sectors >> 1,
3483 page_kb = 1 << (PAGE_CACHE_SHIFT - 10); 3487 page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
3484 ssize_t ret = queue_var_store(&max_sectors_kb, page, count); 3488 ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
3485 int ra_kb; 3489 int ra_kb;
3486 3490
3487 if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb) 3491 if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
3488 return -EINVAL; 3492 return -EINVAL;
3489 /* 3493 /*
3490 * Take the queue lock to update the readahead and max_sectors 3494 * Take the queue lock to update the readahead and max_sectors
3491 * values synchronously: 3495 * values synchronously:
3492 */ 3496 */
3493 spin_lock_irq(q->queue_lock); 3497 spin_lock_irq(q->queue_lock);
3494 /* 3498 /*
3495 * Trim readahead window as well, if necessary: 3499 * Trim readahead window as well, if necessary:
3496 */ 3500 */
3497 ra_kb = q->backing_dev_info.ra_pages << (PAGE_CACHE_SHIFT - 10); 3501 ra_kb = q->backing_dev_info.ra_pages << (PAGE_CACHE_SHIFT - 10);
3498 if (ra_kb > max_sectors_kb) 3502 if (ra_kb > max_sectors_kb)
3499 q->backing_dev_info.ra_pages = 3503 q->backing_dev_info.ra_pages =
3500 max_sectors_kb >> (PAGE_CACHE_SHIFT - 10); 3504 max_sectors_kb >> (PAGE_CACHE_SHIFT - 10);
3501 3505
3502 q->max_sectors = max_sectors_kb << 1; 3506 q->max_sectors = max_sectors_kb << 1;
3503 spin_unlock_irq(q->queue_lock); 3507 spin_unlock_irq(q->queue_lock);
3504 3508
3505 return ret; 3509 return ret;
3506 } 3510 }
3507 3511
3508 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page) 3512 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
3509 { 3513 {
3510 int max_hw_sectors_kb = q->max_hw_sectors >> 1; 3514 int max_hw_sectors_kb = q->max_hw_sectors >> 1;
3511 3515
3512 return queue_var_show(max_hw_sectors_kb, (page)); 3516 return queue_var_show(max_hw_sectors_kb, (page));
3513 } 3517 }
3514 3518
3515 3519
3516 static struct queue_sysfs_entry queue_requests_entry = { 3520 static struct queue_sysfs_entry queue_requests_entry = {
3517 .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR }, 3521 .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
3518 .show = queue_requests_show, 3522 .show = queue_requests_show,
3519 .store = queue_requests_store, 3523 .store = queue_requests_store,
3520 }; 3524 };
3521 3525
3522 static struct queue_sysfs_entry queue_ra_entry = { 3526 static struct queue_sysfs_entry queue_ra_entry = {
3523 .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR }, 3527 .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
3524 .show = queue_ra_show, 3528 .show = queue_ra_show,
3525 .store = queue_ra_store, 3529 .store = queue_ra_store,
3526 }; 3530 };
3527 3531
3528 static struct queue_sysfs_entry queue_max_sectors_entry = { 3532 static struct queue_sysfs_entry queue_max_sectors_entry = {
3529 .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR }, 3533 .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
3530 .show = queue_max_sectors_show, 3534 .show = queue_max_sectors_show,
3531 .store = queue_max_sectors_store, 3535 .store = queue_max_sectors_store,
3532 }; 3536 };
3533 3537
3534 static struct queue_sysfs_entry queue_max_hw_sectors_entry = { 3538 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
3535 .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO }, 3539 .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
3536 .show = queue_max_hw_sectors_show, 3540 .show = queue_max_hw_sectors_show,
3537 }; 3541 };
3538 3542
3539 static struct queue_sysfs_entry queue_iosched_entry = { 3543 static struct queue_sysfs_entry queue_iosched_entry = {
3540 .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR }, 3544 .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
3541 .show = elv_iosched_show, 3545 .show = elv_iosched_show,
3542 .store = elv_iosched_store, 3546 .store = elv_iosched_store,
3543 }; 3547 };
3544 3548
3545 static struct attribute *default_attrs[] = { 3549 static struct attribute *default_attrs[] = {
3546 &queue_requests_entry.attr, 3550 &queue_requests_entry.attr,
3547 &queue_ra_entry.attr, 3551 &queue_ra_entry.attr,
3548 &queue_max_hw_sectors_entry.attr, 3552 &queue_max_hw_sectors_entry.attr,
3549 &queue_max_sectors_entry.attr, 3553 &queue_max_sectors_entry.attr,
3550 &queue_iosched_entry.attr, 3554 &queue_iosched_entry.attr,
3551 NULL, 3555 NULL,
3552 }; 3556 };
3553 3557
3554 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr) 3558 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
3555 3559
3556 static ssize_t 3560 static ssize_t
3557 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page) 3561 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
3558 { 3562 {
3559 struct queue_sysfs_entry *entry = to_queue(attr); 3563 struct queue_sysfs_entry *entry = to_queue(attr);
3560 struct request_queue *q; 3564 struct request_queue *q;
3561 3565
3562 q = container_of(kobj, struct request_queue, kobj); 3566 q = container_of(kobj, struct request_queue, kobj);
3563 if (!entry->show) 3567 if (!entry->show)
3564 return -EIO; 3568 return -EIO;
3565 3569
3566 return entry->show(q, page); 3570 return entry->show(q, page);
3567 } 3571 }
3568 3572
3569 static ssize_t 3573 static ssize_t
3570 queue_attr_store(struct kobject *kobj, struct attribute *attr, 3574 queue_attr_store(struct kobject *kobj, struct attribute *attr,
3571 const char *page, size_t length) 3575 const char *page, size_t length)
3572 { 3576 {
3573 struct queue_sysfs_entry *entry = to_queue(attr); 3577 struct queue_sysfs_entry *entry = to_queue(attr);
3574 struct request_queue *q; 3578 struct request_queue *q;
3575 3579
3576 q = container_of(kobj, struct request_queue, kobj); 3580 q = container_of(kobj, struct request_queue, kobj);
3577 if (!entry->store) 3581 if (!entry->store)
3578 return -EIO; 3582 return -EIO;
3579 3583
3580 return entry->store(q, page, length); 3584 return entry->store(q, page, length);
3581 } 3585 }
3582 3586
3583 static struct sysfs_ops queue_sysfs_ops = { 3587 static struct sysfs_ops queue_sysfs_ops = {
3584 .show = queue_attr_show, 3588 .show = queue_attr_show,
3585 .store = queue_attr_store, 3589 .store = queue_attr_store,
3586 }; 3590 };
3587 3591
3588 static struct kobj_type queue_ktype = { 3592 static struct kobj_type queue_ktype = {
3589 .sysfs_ops = &queue_sysfs_ops, 3593 .sysfs_ops = &queue_sysfs_ops,
3590 .default_attrs = default_attrs, 3594 .default_attrs = default_attrs,
3591 }; 3595 };
3592 3596
3593 int blk_register_queue(struct gendisk *disk) 3597 int blk_register_queue(struct gendisk *disk)
3594 { 3598 {
3595 int ret; 3599 int ret;
3596 3600
3597 request_queue_t *q = disk->queue; 3601 request_queue_t *q = disk->queue;
3598 3602
3599 if (!q || !q->request_fn) 3603 if (!q || !q->request_fn)
3600 return -ENXIO; 3604 return -ENXIO;
3601 3605
3602 q->kobj.parent = kobject_get(&disk->kobj); 3606 q->kobj.parent = kobject_get(&disk->kobj);
3603 if (!q->kobj.parent) 3607 if (!q->kobj.parent)
3604 return -EBUSY; 3608 return -EBUSY;
3605 3609
3606 snprintf(q->kobj.name, KOBJ_NAME_LEN, "%s", "queue"); 3610 snprintf(q->kobj.name, KOBJ_NAME_LEN, "%s", "queue");
3607 q->kobj.ktype = &queue_ktype; 3611 q->kobj.ktype = &queue_ktype;
3608 3612
3609 ret = kobject_register(&q->kobj); 3613 ret = kobject_register(&q->kobj);
3610 if (ret < 0) 3614 if (ret < 0)
3611 return ret; 3615 return ret;
3612 3616
3613 ret = elv_register_queue(q); 3617 ret = elv_register_queue(q);