Eric Lee / linux-smarc-t335x-v3.2

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Commit 2c8919dee659928d66cc13333d4e7a5bdd2206d5

Authored by Andi Kleen
Committed by Jens Axboe
1 parent 66ac028019
Exists in master and in 4 other branches v3.2_AM335xPSP_04.06.00.11, v3.2_NEWT335xPSP_04.06.00.11, v3.2_SBC_SMARTMEN, v3.2_SMARCT335xPSP_04.06.00.11

gcc-4.6: block: fix unused but set variables in blk-merge 

Just some dead code.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

Showing 1 changed file with 1 additions and 2 deletions Inline Diff

1 /* 1 /*
2 * Functions related to segment and merge handling 2 * Functions related to segment and merge handling
3 */ 3 */
4 #include <linux/kernel.h> 4 #include <linux/kernel.h>
5 #include <linux/module.h> 5 #include <linux/module.h>
6 #include <linux/bio.h> 6 #include <linux/bio.h>
7 #include <linux/blkdev.h> 7 #include <linux/blkdev.h>
8 #include <linux/scatterlist.h> 8 #include <linux/scatterlist.h>
9 9
10 #include "blk.h" 10 #include "blk.h"
11 11
12 static unsigned int __blk_recalc_rq_segments(struct request_queue *q, 12 static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
13 struct bio *bio) 13 struct bio *bio)
14 { 14 {
15 unsigned int phys_size;
16 struct bio_vec *bv, *bvprv = NULL; 15 struct bio_vec *bv, *bvprv = NULL;
17 int cluster, i, high, highprv = 1; 16 int cluster, i, high, highprv = 1;
18 unsigned int seg_size, nr_phys_segs; 17 unsigned int seg_size, nr_phys_segs;
19 struct bio *fbio, *bbio; 18 struct bio *fbio, *bbio;
20 19
21 if (!bio) 20 if (!bio)
22 return 0; 21 return 0;
23 22
24 fbio = bio; 23 fbio = bio;
25 cluster = test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags); 24 cluster = test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
26 seg_size = 0; 25 seg_size = 0;
27 phys_size = nr_phys_segs = 0; 26 nr_phys_segs = 0;
28 for_each_bio(bio) { 27 for_each_bio(bio) {
29 bio_for_each_segment(bv, bio, i) { 28 bio_for_each_segment(bv, bio, i) {
30 /* 29 /*
31 * the trick here is making sure that a high page is 30 * the trick here is making sure that a high page is
32 * never considered part of another segment, since that 31 * never considered part of another segment, since that
33 * might change with the bounce page. 32 * might change with the bounce page.
34 */ 33 */
35 high = page_to_pfn(bv->bv_page) > queue_bounce_pfn(q); 34 high = page_to_pfn(bv->bv_page) > queue_bounce_pfn(q);
36 if (high || highprv) 35 if (high || highprv)
37 goto new_segment; 36 goto new_segment;
38 if (cluster) { 37 if (cluster) {
39 if (seg_size + bv->bv_len 38 if (seg_size + bv->bv_len
40 > queue_max_segment_size(q)) 39 > queue_max_segment_size(q))
41 goto new_segment; 40 goto new_segment;
42 if (!BIOVEC_PHYS_MERGEABLE(bvprv, bv)) 41 if (!BIOVEC_PHYS_MERGEABLE(bvprv, bv))
43 goto new_segment; 42 goto new_segment;
44 if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bv)) 43 if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bv))
45 goto new_segment; 44 goto new_segment;
46 45
47 seg_size += bv->bv_len; 46 seg_size += bv->bv_len;
48 bvprv = bv; 47 bvprv = bv;
49 continue; 48 continue;
50 } 49 }
51 new_segment: 50 new_segment:
52 if (nr_phys_segs == 1 && seg_size > 51 if (nr_phys_segs == 1 && seg_size >
53 fbio->bi_seg_front_size) 52 fbio->bi_seg_front_size)
54 fbio->bi_seg_front_size = seg_size; 53 fbio->bi_seg_front_size = seg_size;
55 54
56 nr_phys_segs++; 55 nr_phys_segs++;
57 bvprv = bv; 56 bvprv = bv;
58 seg_size = bv->bv_len; 57 seg_size = bv->bv_len;
59 highprv = high; 58 highprv = high;
60 } 59 }
61 bbio = bio; 60 bbio = bio;
62 } 61 }
63 62
64 if (nr_phys_segs == 1 && seg_size > fbio->bi_seg_front_size) 63 if (nr_phys_segs == 1 && seg_size > fbio->bi_seg_front_size)
65 fbio->bi_seg_front_size = seg_size; 64 fbio->bi_seg_front_size = seg_size;
66 if (seg_size > bbio->bi_seg_back_size) 65 if (seg_size > bbio->bi_seg_back_size)
67 bbio->bi_seg_back_size = seg_size; 66 bbio->bi_seg_back_size = seg_size;
68 67
69 return nr_phys_segs; 68 return nr_phys_segs;
70 } 69 }
71 70
72 void blk_recalc_rq_segments(struct request *rq) 71 void blk_recalc_rq_segments(struct request *rq)
73 { 72 {
74 rq->nr_phys_segments = __blk_recalc_rq_segments(rq->q, rq->bio); 73 rq->nr_phys_segments = __blk_recalc_rq_segments(rq->q, rq->bio);
75 } 74 }
76 75
77 void blk_recount_segments(struct request_queue *q, struct bio *bio) 76 void blk_recount_segments(struct request_queue *q, struct bio *bio)
78 { 77 {
79 struct bio *nxt = bio->bi_next; 78 struct bio *nxt = bio->bi_next;
80 79
81 bio->bi_next = NULL; 80 bio->bi_next = NULL;
82 bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio); 81 bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio);
83 bio->bi_next = nxt; 82 bio->bi_next = nxt;
84 bio->bi_flags |= (1 << BIO_SEG_VALID); 83 bio->bi_flags |= (1 << BIO_SEG_VALID);
85 } 84 }
86 EXPORT_SYMBOL(blk_recount_segments); 85 EXPORT_SYMBOL(blk_recount_segments);
87 86
88 static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio, 87 static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio,
89 struct bio *nxt) 88 struct bio *nxt)
90 { 89 {
91 if (!test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags)) 90 if (!test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags))
92 return 0; 91 return 0;
93 92
94 if (bio->bi_seg_back_size + nxt->bi_seg_front_size > 93 if (bio->bi_seg_back_size + nxt->bi_seg_front_size >
95 queue_max_segment_size(q)) 94 queue_max_segment_size(q))
96 return 0; 95 return 0;
97 96
98 if (!bio_has_data(bio)) 97 if (!bio_has_data(bio))
99 return 1; 98 return 1;
100 99
101 if (!BIOVEC_PHYS_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt))) 100 if (!BIOVEC_PHYS_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt)))
102 return 0; 101 return 0;
103 102
104 /* 103 /*
105 * bio and nxt are contiguous in memory; check if the queue allows 104 * bio and nxt are contiguous in memory; check if the queue allows
106 * these two to be merged into one 105 * these two to be merged into one
107 */ 106 */
108 if (BIO_SEG_BOUNDARY(q, bio, nxt)) 107 if (BIO_SEG_BOUNDARY(q, bio, nxt))
109 return 1; 108 return 1;
110 109
111 return 0; 110 return 0;
112 } 111 }
113 112
114 /* 113 /*
115 * map a request to scatterlist, return number of sg entries setup. Caller 114 * map a request to scatterlist, return number of sg entries setup. Caller
116 * must make sure sg can hold rq->nr_phys_segments entries 115 * must make sure sg can hold rq->nr_phys_segments entries
117 */ 116 */
118 int blk_rq_map_sg(struct request_queue *q, struct request *rq, 117 int blk_rq_map_sg(struct request_queue *q, struct request *rq,
119 struct scatterlist *sglist) 118 struct scatterlist *sglist)
120 { 119 {
121 struct bio_vec *bvec, *bvprv; 120 struct bio_vec *bvec, *bvprv;
122 struct req_iterator iter; 121 struct req_iterator iter;
123 struct scatterlist *sg; 122 struct scatterlist *sg;
124 int nsegs, cluster; 123 int nsegs, cluster;
125 124
126 nsegs = 0; 125 nsegs = 0;
127 cluster = test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags); 126 cluster = test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
128 127
129 /* 128 /*
130 * for each bio in rq 129 * for each bio in rq
131 */ 130 */
132 bvprv = NULL; 131 bvprv = NULL;
133 sg = NULL; 132 sg = NULL;
134 rq_for_each_segment(bvec, rq, iter) { 133 rq_for_each_segment(bvec, rq, iter) {
135 int nbytes = bvec->bv_len; 134 int nbytes = bvec->bv_len;
136 135
137 if (bvprv && cluster) { 136 if (bvprv && cluster) {
138 if (sg->length + nbytes > queue_max_segment_size(q)) 137 if (sg->length + nbytes > queue_max_segment_size(q))
139 goto new_segment; 138 goto new_segment;
140 139
141 if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec)) 140 if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec))
142 goto new_segment; 141 goto new_segment;
143 if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec)) 142 if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec))
144 goto new_segment; 143 goto new_segment;
145 144
146 sg->length += nbytes; 145 sg->length += nbytes;
147 } else { 146 } else {
148 new_segment: 147 new_segment:
149 if (!sg) 148 if (!sg)
150 sg = sglist; 149 sg = sglist;
151 else { 150 else {
152 /* 151 /*
153 * If the driver previously mapped a shorter 152 * If the driver previously mapped a shorter
154 * list, we could see a termination bit 153 * list, we could see a termination bit
155 * prematurely unless it fully inits the sg 154 * prematurely unless it fully inits the sg
156 * table on each mapping. We KNOW that there 155 * table on each mapping. We KNOW that there
157 * must be more entries here or the driver 156 * must be more entries here or the driver
158 * would be buggy, so force clear the 157 * would be buggy, so force clear the
159 * termination bit to avoid doing a full 158 * termination bit to avoid doing a full
160 * sg_init_table() in drivers for each command. 159 * sg_init_table() in drivers for each command.
161 */ 160 */
162 sg->page_link &= ~0x02; 161 sg->page_link &= ~0x02;
163 sg = sg_next(sg); 162 sg = sg_next(sg);
164 } 163 }
165 164
166 sg_set_page(sg, bvec->bv_page, nbytes, bvec->bv_offset); 165 sg_set_page(sg, bvec->bv_page, nbytes, bvec->bv_offset);
167 nsegs++; 166 nsegs++;
168 } 167 }
169 bvprv = bvec; 168 bvprv = bvec;
170 } /* segments in rq */ 169 } /* segments in rq */
171 170
172 171
173 if (unlikely(rq->cmd_flags & REQ_COPY_USER) && 172 if (unlikely(rq->cmd_flags & REQ_COPY_USER) &&
174 (blk_rq_bytes(rq) & q->dma_pad_mask)) { 173 (blk_rq_bytes(rq) & q->dma_pad_mask)) {
175 unsigned int pad_len = 174 unsigned int pad_len =
176 (q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1; 175 (q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1;
177 176
178 sg->length += pad_len; 177 sg->length += pad_len;
179 rq->extra_len += pad_len; 178 rq->extra_len += pad_len;
180 } 179 }
181 180
182 if (q->dma_drain_size && q->dma_drain_needed(rq)) { 181 if (q->dma_drain_size && q->dma_drain_needed(rq)) {
183 if (rq->cmd_flags & REQ_WRITE) 182 if (rq->cmd_flags & REQ_WRITE)
184 memset(q->dma_drain_buffer, 0, q->dma_drain_size); 183 memset(q->dma_drain_buffer, 0, q->dma_drain_size);
185 184
186 sg->page_link &= ~0x02; 185 sg->page_link &= ~0x02;
187 sg = sg_next(sg); 186 sg = sg_next(sg);
188 sg_set_page(sg, virt_to_page(q->dma_drain_buffer), 187 sg_set_page(sg, virt_to_page(q->dma_drain_buffer),
189 q->dma_drain_size, 188 q->dma_drain_size,
190 ((unsigned long)q->dma_drain_buffer) & 189 ((unsigned long)q->dma_drain_buffer) &
191 (PAGE_SIZE - 1)); 190 (PAGE_SIZE - 1));
192 nsegs++; 191 nsegs++;
193 rq->extra_len += q->dma_drain_size; 192 rq->extra_len += q->dma_drain_size;
194 } 193 }
195 194
196 if (sg) 195 if (sg)
197 sg_mark_end(sg); 196 sg_mark_end(sg);
198 197
199 return nsegs; 198 return nsegs;
200 } 199 }
201 EXPORT_SYMBOL(blk_rq_map_sg); 200 EXPORT_SYMBOL(blk_rq_map_sg);
202 201
203 static inline int ll_new_hw_segment(struct request_queue *q, 202 static inline int ll_new_hw_segment(struct request_queue *q,
204 struct request *req, 203 struct request *req,
205 struct bio *bio) 204 struct bio *bio)
206 { 205 {
207 int nr_phys_segs = bio_phys_segments(q, bio); 206 int nr_phys_segs = bio_phys_segments(q, bio);
208 207
209 if (req->nr_phys_segments + nr_phys_segs > queue_max_segments(q)) { 208 if (req->nr_phys_segments + nr_phys_segs > queue_max_segments(q)) {
210 req->cmd_flags |= REQ_NOMERGE; 209 req->cmd_flags |= REQ_NOMERGE;
211 if (req == q->last_merge) 210 if (req == q->last_merge)
212 q->last_merge = NULL; 211 q->last_merge = NULL;
213 return 0; 212 return 0;
214 } 213 }
215 214
216 /* 215 /*
217 * This will form the start of a new hw segment. Bump both 216 * This will form the start of a new hw segment. Bump both
218 * counters. 217 * counters.
219 */ 218 */
220 req->nr_phys_segments += nr_phys_segs; 219 req->nr_phys_segments += nr_phys_segs;
221 return 1; 220 return 1;
222 } 221 }
223 222
224 int ll_back_merge_fn(struct request_queue *q, struct request *req, 223 int ll_back_merge_fn(struct request_queue *q, struct request *req,
225 struct bio *bio) 224 struct bio *bio)
226 { 225 {
227 unsigned short max_sectors; 226 unsigned short max_sectors;
228 227
229 if (unlikely(req->cmd_type == REQ_TYPE_BLOCK_PC)) 228 if (unlikely(req->cmd_type == REQ_TYPE_BLOCK_PC))
230 max_sectors = queue_max_hw_sectors(q); 229 max_sectors = queue_max_hw_sectors(q);
231 else 230 else
232 max_sectors = queue_max_sectors(q); 231 max_sectors = queue_max_sectors(q);
233 232
234 if (blk_rq_sectors(req) + bio_sectors(bio) > max_sectors) { 233 if (blk_rq_sectors(req) + bio_sectors(bio) > max_sectors) {
235 req->cmd_flags |= REQ_NOMERGE; 234 req->cmd_flags |= REQ_NOMERGE;
236 if (req == q->last_merge) 235 if (req == q->last_merge)
237 q->last_merge = NULL; 236 q->last_merge = NULL;
238 return 0; 237 return 0;
239 } 238 }
240 if (!bio_flagged(req->biotail, BIO_SEG_VALID)) 239 if (!bio_flagged(req->biotail, BIO_SEG_VALID))
241 blk_recount_segments(q, req->biotail); 240 blk_recount_segments(q, req->biotail);
242 if (!bio_flagged(bio, BIO_SEG_VALID)) 241 if (!bio_flagged(bio, BIO_SEG_VALID))
243 blk_recount_segments(q, bio); 242 blk_recount_segments(q, bio);
244 243
245 return ll_new_hw_segment(q, req, bio); 244 return ll_new_hw_segment(q, req, bio);
246 } 245 }
247 246
248 int ll_front_merge_fn(struct request_queue *q, struct request *req, 247 int ll_front_merge_fn(struct request_queue *q, struct request *req,
249 struct bio *bio) 248 struct bio *bio)
250 { 249 {
251 unsigned short max_sectors; 250 unsigned short max_sectors;
252 251
253 if (unlikely(req->cmd_type == REQ_TYPE_BLOCK_PC)) 252 if (unlikely(req->cmd_type == REQ_TYPE_BLOCK_PC))
254 max_sectors = queue_max_hw_sectors(q); 253 max_sectors = queue_max_hw_sectors(q);
255 else 254 else
256 max_sectors = queue_max_sectors(q); 255 max_sectors = queue_max_sectors(q);
257 256
258 257
259 if (blk_rq_sectors(req) + bio_sectors(bio) > max_sectors) { 258 if (blk_rq_sectors(req) + bio_sectors(bio) > max_sectors) {
260 req->cmd_flags |= REQ_NOMERGE; 259 req->cmd_flags |= REQ_NOMERGE;
261 if (req == q->last_merge) 260 if (req == q->last_merge)
262 q->last_merge = NULL; 261 q->last_merge = NULL;
263 return 0; 262 return 0;
264 } 263 }
265 if (!bio_flagged(bio, BIO_SEG_VALID)) 264 if (!bio_flagged(bio, BIO_SEG_VALID))
266 blk_recount_segments(q, bio); 265 blk_recount_segments(q, bio);
267 if (!bio_flagged(req->bio, BIO_SEG_VALID)) 266 if (!bio_flagged(req->bio, BIO_SEG_VALID))
268 blk_recount_segments(q, req->bio); 267 blk_recount_segments(q, req->bio);
269 268
270 return ll_new_hw_segment(q, req, bio); 269 return ll_new_hw_segment(q, req, bio);
271 } 270 }
272 271
273 static int ll_merge_requests_fn(struct request_queue *q, struct request *req, 272 static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
274 struct request *next) 273 struct request *next)
275 { 274 {
276 int total_phys_segments; 275 int total_phys_segments;
277 unsigned int seg_size = 276 unsigned int seg_size =
278 req->biotail->bi_seg_back_size + next->bio->bi_seg_front_size; 277 req->biotail->bi_seg_back_size + next->bio->bi_seg_front_size;
279 278
280 /* 279 /*
281 * First check if the either of the requests are re-queued 280 * First check if the either of the requests are re-queued
282 * requests. Can't merge them if they are. 281 * requests. Can't merge them if they are.
283 */ 282 */
284 if (req->special || next->special) 283 if (req->special || next->special)
285 return 0; 284 return 0;
286 285
287 /* 286 /*
288 * Will it become too large? 287 * Will it become too large?
289 */ 288 */
290 if ((blk_rq_sectors(req) + blk_rq_sectors(next)) > queue_max_sectors(q)) 289 if ((blk_rq_sectors(req) + blk_rq_sectors(next)) > queue_max_sectors(q))
291 return 0; 290 return 0;
292 291
293 total_phys_segments = req->nr_phys_segments + next->nr_phys_segments; 292 total_phys_segments = req->nr_phys_segments + next->nr_phys_segments;
294 if (blk_phys_contig_segment(q, req->biotail, next->bio)) { 293 if (blk_phys_contig_segment(q, req->biotail, next->bio)) {
295 if (req->nr_phys_segments == 1) 294 if (req->nr_phys_segments == 1)
296 req->bio->bi_seg_front_size = seg_size; 295 req->bio->bi_seg_front_size = seg_size;
297 if (next->nr_phys_segments == 1) 296 if (next->nr_phys_segments == 1)
298 next->biotail->bi_seg_back_size = seg_size; 297 next->biotail->bi_seg_back_size = seg_size;
299 total_phys_segments--; 298 total_phys_segments--;
300 } 299 }
301 300
302 if (total_phys_segments > queue_max_segments(q)) 301 if (total_phys_segments > queue_max_segments(q))
303 return 0; 302 return 0;
304 303
305 /* Merge is OK... */ 304 /* Merge is OK... */
306 req->nr_phys_segments = total_phys_segments; 305 req->nr_phys_segments = total_phys_segments;
307 return 1; 306 return 1;
308 } 307 }
309 308
310 /** 309 /**
311 * blk_rq_set_mixed_merge - mark a request as mixed merge 310 * blk_rq_set_mixed_merge - mark a request as mixed merge
312 * @rq: request to mark as mixed merge 311 * @rq: request to mark as mixed merge
313 * 312 *
314 * Description: 313 * Description:
315 * @rq is about to be mixed merged. Make sure the attributes 314 * @rq is about to be mixed merged. Make sure the attributes
316 * which can be mixed are set in each bio and mark @rq as mixed 315 * which can be mixed are set in each bio and mark @rq as mixed
317 * merged. 316 * merged.
318 */ 317 */
319 void blk_rq_set_mixed_merge(struct request *rq) 318 void blk_rq_set_mixed_merge(struct request *rq)
320 { 319 {
321 unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK; 320 unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK;
322 struct bio *bio; 321 struct bio *bio;
323 322
324 if (rq->cmd_flags & REQ_MIXED_MERGE) 323 if (rq->cmd_flags & REQ_MIXED_MERGE)
325 return; 324 return;
326 325
327 /* 326 /*
328 * @rq will no longer represent mixable attributes for all the 327 * @rq will no longer represent mixable attributes for all the
329 * contained bios. It will just track those of the first one. 328 * contained bios. It will just track those of the first one.
330 * Distributes the attributs to each bio. 329 * Distributes the attributs to each bio.
331 */ 330 */
332 for (bio = rq->bio; bio; bio = bio->bi_next) { 331 for (bio = rq->bio; bio; bio = bio->bi_next) {
333 WARN_ON_ONCE((bio->bi_rw & REQ_FAILFAST_MASK) && 332 WARN_ON_ONCE((bio->bi_rw & REQ_FAILFAST_MASK) &&
334 (bio->bi_rw & REQ_FAILFAST_MASK) != ff); 333 (bio->bi_rw & REQ_FAILFAST_MASK) != ff);
335 bio->bi_rw |= ff; 334 bio->bi_rw |= ff;
336 } 335 }
337 rq->cmd_flags |= REQ_MIXED_MERGE; 336 rq->cmd_flags |= REQ_MIXED_MERGE;
338 } 337 }
339 338
340 static void blk_account_io_merge(struct request *req) 339 static void blk_account_io_merge(struct request *req)
341 { 340 {
342 if (blk_do_io_stat(req)) { 341 if (blk_do_io_stat(req)) {
343 struct hd_struct *part; 342 struct hd_struct *part;
344 int cpu; 343 int cpu;
345 344
346 cpu = part_stat_lock(); 345 cpu = part_stat_lock();
347 part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req)); 346 part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
348 347
349 part_round_stats(cpu, part); 348 part_round_stats(cpu, part);
350 part_dec_in_flight(part, rq_data_dir(req)); 349 part_dec_in_flight(part, rq_data_dir(req));
351 350
352 part_stat_unlock(); 351 part_stat_unlock();
353 } 352 }
354 } 353 }
355 354
356 /* 355 /*
357 * Has to be called with the request spinlock acquired 356 * Has to be called with the request spinlock acquired
358 */ 357 */
359 static int attempt_merge(struct request_queue *q, struct request *req, 358 static int attempt_merge(struct request_queue *q, struct request *req,
360 struct request *next) 359 struct request *next)
361 { 360 {
362 if (!rq_mergeable(req) || !rq_mergeable(next)) 361 if (!rq_mergeable(req) || !rq_mergeable(next))
363 return 0; 362 return 0;
364 363
365 /* 364 /*
366 * not contiguous 365 * not contiguous
367 */ 366 */
368 if (blk_rq_pos(req) + blk_rq_sectors(req) != blk_rq_pos(next)) 367 if (blk_rq_pos(req) + blk_rq_sectors(req) != blk_rq_pos(next))
369 return 0; 368 return 0;
370 369
371 if (rq_data_dir(req) != rq_data_dir(next) 370 if (rq_data_dir(req) != rq_data_dir(next)
372 || req->rq_disk != next->rq_disk 371 || req->rq_disk != next->rq_disk
373 || next->special) 372 || next->special)
374 return 0; 373 return 0;
375 374
376 if (blk_integrity_rq(req) != blk_integrity_rq(next)) 375 if (blk_integrity_rq(req) != blk_integrity_rq(next))
377 return 0; 376 return 0;
378 377
379 /* 378 /*
380 * If we are allowed to merge, then append bio list 379 * If we are allowed to merge, then append bio list
381 * from next to rq and release next. merge_requests_fn 380 * from next to rq and release next. merge_requests_fn
382 * will have updated segment counts, update sector 381 * will have updated segment counts, update sector
383 * counts here. 382 * counts here.
384 */ 383 */
385 if (!ll_merge_requests_fn(q, req, next)) 384 if (!ll_merge_requests_fn(q, req, next))
386 return 0; 385 return 0;
387 386
388 /* 387 /*
389 * If failfast settings disagree or any of the two is already 388 * If failfast settings disagree or any of the two is already
390 * a mixed merge, mark both as mixed before proceeding. This 389 * a mixed merge, mark both as mixed before proceeding. This
391 * makes sure that all involved bios have mixable attributes 390 * makes sure that all involved bios have mixable attributes
392 * set properly. 391 * set properly.
393 */ 392 */
394 if ((req->cmd_flags | next->cmd_flags) & REQ_MIXED_MERGE || 393 if ((req->cmd_flags | next->cmd_flags) & REQ_MIXED_MERGE ||
395 (req->cmd_flags & REQ_FAILFAST_MASK) != 394 (req->cmd_flags & REQ_FAILFAST_MASK) !=
396 (next->cmd_flags & REQ_FAILFAST_MASK)) { 395 (next->cmd_flags & REQ_FAILFAST_MASK)) {
397 blk_rq_set_mixed_merge(req); 396 blk_rq_set_mixed_merge(req);
398 blk_rq_set_mixed_merge(next); 397 blk_rq_set_mixed_merge(next);
399 } 398 }
400 399
401 /* 400 /*
402 * At this point we have either done a back merge 401 * At this point we have either done a back merge
403 * or front merge. We need the smaller start_time of 402 * or front merge. We need the smaller start_time of
404 * the merged requests to be the current request 403 * the merged requests to be the current request
405 * for accounting purposes. 404 * for accounting purposes.
406 */ 405 */
407 if (time_after(req->start_time, next->start_time)) 406 if (time_after(req->start_time, next->start_time))
408 req->start_time = next->start_time; 407 req->start_time = next->start_time;
409 408
410 req->biotail->bi_next = next->bio; 409 req->biotail->bi_next = next->bio;
411 req->biotail = next->biotail; 410 req->biotail = next->biotail;
412 411
413 req->__data_len += blk_rq_bytes(next); 412 req->__data_len += blk_rq_bytes(next);
414 413
415 elv_merge_requests(q, req, next); 414 elv_merge_requests(q, req, next);
416 415
417 /* 416 /*
418 * 'next' is going away, so update stats accordingly 417 * 'next' is going away, so update stats accordingly
419 */ 418 */
420 blk_account_io_merge(next); 419 blk_account_io_merge(next);
421 420
422 req->ioprio = ioprio_best(req->ioprio, next->ioprio); 421 req->ioprio = ioprio_best(req->ioprio, next->ioprio);
423 if (blk_rq_cpu_valid(next)) 422 if (blk_rq_cpu_valid(next))
424 req->cpu = next->cpu; 423 req->cpu = next->cpu;
425 424
426 /* owner-ship of bio passed from next to req */ 425 /* owner-ship of bio passed from next to req */
427 next->bio = NULL; 426 next->bio = NULL;
428 __blk_put_request(q, next); 427 __blk_put_request(q, next);
429 return 1; 428 return 1;
430 } 429 }
431 430
432 int attempt_back_merge(struct request_queue *q, struct request *rq) 431 int attempt_back_merge(struct request_queue *q, struct request *rq)
433 { 432 {
434 struct request *next = elv_latter_request(q, rq); 433 struct request *next = elv_latter_request(q, rq);
435 434
436 if (next) 435 if (next)
437 return attempt_merge(q, rq, next); 436 return attempt_merge(q, rq, next);
438 437
439 return 0; 438 return 0;
440 } 439 }
441 440
442 int attempt_front_merge(struct request_queue *q, struct request *rq) 441 int attempt_front_merge(struct request_queue *q, struct request *rq)
443 { 442 {
444 struct request *prev = elv_former_request(q, rq); 443 struct request *prev = elv_former_request(q, rq);
445 444
446 if (prev) 445 if (prev)
447 return attempt_merge(q, prev, rq); 446 return attempt_merge(q, prev, rq);
448 447
449 return 0; 448 return 0;
450 } 449 }
451 450