[SCSI] seperate max_sectors from max_hw_sectors

- export __blk_put_request and blk_execute_rq_nowait needed for async REQ_BLOCK_PC requests - seperate max_hw_sectors and max_sectors for block/scsi_ioctl.c and SG_IO bio.c helpers per Jens's last comments. Since block/scsi_ioctl.c SG_IO was already testing against max_sectors and SCSI-ml was setting max_sectors and max_hw_sectors to the same value this does not change any scsi SG_IO behavior. It only prepares ll_rw_blk.c, scsi_ioctl.c and bio.c for when SCSI-ml begins to set a valid max_hw_sectors for all LLDs. Today if a LLD does not set it SCSI-ml sets it to a safe default and some LLDs set it to a artificial low value to overcome memory and feedback issues. Note: Since we now cap max_sectors to BLK_DEF_MAX_SECTORS, which is 1024, drivers that used to call blk_queue_max_sectors with a large value of max_sectors will now see the fs requests capped to BLK_DEF_MAX_SECTORS. Signed-off-by: Mike Christie <michaelc@cs.wisc.edu> Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

[SCSI] seperate max_sectors from max_hw_sectors
- export __blk_put_request and blk_execute_rq_nowait needed for async REQ_BLOCK_PC requests - seperate max_hw_sectors and max_sectors for block/scsi_ioctl.c and SG_IO bio.c helpers per Jens's last comments. Since block/scsi_ioctl.c SG_IO was already testing against max_sectors and SCSI-ml was setting max_sectors and max_hw_sectors to the same value this does not change any scsi SG_IO behavior. It only prepares ll_rw_blk.c, scsi_ioctl.c and bio.c for when SCSI-ml begins to set a valid max_hw_sectors for all LLDs. Today if a LLD does not set it SCSI-ml sets it to a safe default and some LLDs set it to a artificial low value to overcome memory and feedback issues. Note: Since we now cap max_sectors to BLK_DEF_MAX_SECTORS, which is 1024, drivers that used to call blk_queue_max_sectors with a large value of max_sectors will now see the fs requests capped to BLK_DEF_MAX_SECTORS. Signed-off-by: Mike Christie <michaelc@cs.wisc.edu> Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Mike Christie · James Bottomley
1 parent 8b05b773b6
Showing 6 changed files with 42 additions and 21 deletions Side-by-side Diff
block/ll_rw_blk.c
block/scsi_ioctl.c
drivers/md/dm-table.c
drivers/scsi/scsi_lib.c
fs/bio.c
include/linux/blkdev.h
@@ -239,7 +239,7 @@
 	q->backing_dev_info.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
 	q->backing_dev_info.state = 0;
 	q->backing_dev_info.capabilities = BDI_CAP_MAP_COPY;
-	blk_queue_max_sectors(q, MAX_SECTORS);
+	blk_queue_max_sectors(q, SAFE_MAX_SECTORS);
 	blk_queue_hardsect_size(q, 512);
 	blk_queue_dma_alignment(q, 511);
 	blk_queue_congestion_threshold(q);
@@ -555,7 +555,12 @@
 		printk("%s: set to minimum %d\n", __FUNCTION__, max_sectors);
 	}
  
-	q->max_sectors = q->max_hw_sectors = max_sectors;
+	if (BLK_DEF_MAX_SECTORS > max_sectors)
+		q->max_hw_sectors = q->max_sectors = max_sectors;
+ 	else {
+		q->max_sectors = BLK_DEF_MAX_SECTORS;
+		q->max_hw_sectors = max_sectors;
+	}
 }
  
 EXPORT_SYMBOL(blk_queue_max_sectors);
@@ -657,8 +662,8 @@
 void blk_queue_stack_limits(request_queue_t *t, request_queue_t *b)
 {
 	/* zero is "infinity" */
-	t->max_sectors = t->max_hw_sectors =
-		min_not_zero(t->max_sectors,b->max_sectors);
+	t->max_sectors = min_not_zero(t->max_sectors,b->max_sectors);
+	t->max_hw_sectors = min_not_zero(t->max_hw_sectors,b->max_hw_sectors);
  
 	t->max_phys_segments = min(t->max_phys_segments,b->max_phys_segments);
 	t->max_hw_segments = min(t->max_hw_segments,b->max_hw_segments);
  
@@ -1293,9 +1298,15 @@
 static int ll_back_merge_fn(request_queue_t *q, struct request *req, 
 			    struct bio *bio)
 {
+	unsigned short max_sectors;
 	int len;
  
-	if (req->nr_sectors + bio_sectors(bio) > q->max_sectors) {
+	if (unlikely(blk_pc_request(req)))
+		max_sectors = q->max_hw_sectors;
+	else
+		max_sectors = q->max_sectors;
+
+	if (req->nr_sectors + bio_sectors(bio) > max_sectors) {
 		req->flags |= REQ_NOMERGE;
 		if (req == q->last_merge)
 			q->last_merge = NULL;
  
@@ -1325,9 +1336,16 @@
 static int ll_front_merge_fn(request_queue_t *q, struct request *req, 
 			     struct bio *bio)
 {
+	unsigned short max_sectors;
 	int len;
  
-	if (req->nr_sectors + bio_sectors(bio) > q->max_sectors) {
+	if (unlikely(blk_pc_request(req)))
+		max_sectors = q->max_hw_sectors;
+	else
+		max_sectors = q->max_sectors;
+
+
+	if (req->nr_sectors + bio_sectors(bio) > max_sectors) {
 		req->flags |= REQ_NOMERGE;
 		if (req == q->last_merge)
 			q->last_merge = NULL;
@@ -2144,7 +2162,7 @@
 	struct bio *bio;
 	int reading;
  
-	if (len > (q->max_sectors << 9))
+	if (len > (q->max_hw_sectors << 9))
 		return -EINVAL;
 	if (!len || !ubuf)
 		return -EINVAL;
@@ -2259,7 +2277,7 @@
 {
 	struct bio *bio;
  
-	if (len > (q->max_sectors << 9))
+	if (len > (q->max_hw_sectors << 9))
 		return -EINVAL;
 	if (!len || !kbuf)
 		return -EINVAL;
@@ -233,7 +233,7 @@
 	if (verify_command(file, cmd))
 		return -EPERM;
  
-	if (hdr->dxfer_len > (q->max_sectors << 9))
+	if (hdr->dxfer_len > (q->max_hw_sectors << 9))
 		return -EIO;
  
 	if (hdr->dxfer_len)
@@ -638,7 +638,7 @@
 static void check_for_valid_limits(struct io_restrictions *rs)
 {
 	if (!rs->max_sectors)
-		rs->max_sectors = MAX_SECTORS;
+		rs->max_sectors = SAFE_MAX_SECTORS;
 	if (!rs->max_phys_segments)
 		rs->max_phys_segments = MAX_PHYS_SEGMENTS;
 	if (!rs->max_hw_segments)
@@ -462,6 +462,7 @@
 	req = blk_get_request(sdev->request_queue, write, gfp);
 	if (!req)
 		goto free_sense;
+	req->flags |= REQ_BLOCK_PC | REQ_QUIET;
  
 	if (use_sg)
 		err = scsi_req_map_sg(req, buffer, use_sg, bufflen, gfp);
@@ -477,7 +478,6 @@
 	req->sense_len = 0;
 	req->timeout = timeout;
 	req->retries = retries;
-	req->flags |= REQ_BLOCK_PC | REQ_QUIET;
 	req->end_io_data = sioc;
  
 	sioc->data = privdata;
@@ -313,7 +313,8 @@
 }
  
 static int __bio_add_page(request_queue_t *q, struct bio *bio, struct page
-			  *page, unsigned int len, unsigned int offset)
+			  *page, unsigned int len, unsigned int offset,
+			  unsigned short max_sectors)
 {
 	int retried_segments = 0;
 	struct bio_vec *bvec;
@@ -327,7 +328,7 @@
 	if (bio->bi_vcnt >= bio->bi_max_vecs)
 		return 0;
  
-	if (((bio->bi_size + len) >> 9) > q->max_sectors)
+	if (((bio->bi_size + len) >> 9) > max_sectors)
 		return 0;
  
 	/*
@@ -401,7 +402,7 @@
 int bio_add_pc_page(request_queue_t *q, struct bio *bio, struct page *page,
 		    unsigned int len, unsigned int offset)
 {
-	return __bio_add_page(q, bio, page, len, offset);
+	return __bio_add_page(q, bio, page, len, offset, q->max_hw_sectors);
 }
  
 /**
@@ -420,8 +421,8 @@
 int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
 		 unsigned int offset)
 {
-	return __bio_add_page(bdev_get_queue(bio->bi_bdev), bio, page,
-			      len, offset);
+	struct request_queue *q = bdev_get_queue(bio->bi_bdev);
+	return __bio_add_page(q, bio, page, len, offset, q->max_sectors);
 }
  
 struct bio_map_data {
@@ -533,7 +534,7 @@
 			break;
 		}
  
-		if (__bio_add_page(q, bio, page, bytes, 0) < bytes) {
+		if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes) {
 			ret = -EINVAL;
 			break;
 		}
@@ -647,7 +648,8 @@
 			/*
 			 * sorry...
 			 */
-			if (__bio_add_page(q, bio, pages[j], bytes, offset) < bytes)
+			if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
+					    bytes)
 				break;
  
 			len -= bytes;
@@ -820,8 +822,8 @@
 		if (bytes > len)
 			bytes = len;
  
-		if (__bio_add_page(q, bio, virt_to_page(data), bytes,
-				   offset) < bytes)
+		if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
+				    offset) < bytes)
 			break;
  
 		data += bytes;
@@ -702,7 +702,8 @@
  
 #define MAX_PHYS_SEGMENTS 128
 #define MAX_HW_SEGMENTS 128
-#define MAX_SECTORS 255
+#define SAFE_MAX_SECTORS 255
+#define BLK_DEF_MAX_SECTORS 1024
  
 #define MAX_SEGMENT_SIZE	65536
...	...	@@ -239,7 +239,7 @@
239	239	q->backing_dev_info.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
240	240	q->backing_dev_info.state = 0;
241	241	q->backing_dev_info.capabilities = BDI_CAP_MAP_COPY;
242		- blk_queue_max_sectors(q, MAX_SECTORS);
	242	+ blk_queue_max_sectors(q, SAFE_MAX_SECTORS);
243	243	blk_queue_hardsect_size(q, 512);
244	244	blk_queue_dma_alignment(q, 511);
245	245	blk_queue_congestion_threshold(q);
...	...	@@ -555,7 +555,12 @@
555	555	printk("%s: set to minimum %d\n", __FUNCTION__, max_sectors);
556	556	}
557	557
558		- q->max_sectors = q->max_hw_sectors = max_sectors;
	558	+ if (BLK_DEF_MAX_SECTORS > max_sectors)
	559	+ q->max_hw_sectors = q->max_sectors = max_sectors;
	560	+ else {
	561	+ q->max_sectors = BLK_DEF_MAX_SECTORS;
	562	+ q->max_hw_sectors = max_sectors;
	563	+ }
559	564	}
560	565
561	566	EXPORT_SYMBOL(blk_queue_max_sectors);
...	...	@@ -657,8 +662,8 @@
657	662	void blk_queue_stack_limits(request_queue_t t, request_queue_t b)
658	663	{
659	664	/* zero is "infinity" */
660		- t->max_sectors = t->max_hw_sectors =
661		- 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);
662	667
663	668	t->max_phys_segments = min(t->max_phys_segments,b->max_phys_segments);
664	669	t->max_hw_segments = min(t->max_hw_segments,b->max_hw_segments);
665	670
...	...	@@ -1293,9 +1298,15 @@
1293	1298	static int ll_back_merge_fn(request_queue_t q, struct request req,
1294	1299	struct bio *bio)
1295	1300	{
	1301	+ unsigned short max_sectors;
1296	1302	int len;
1297	1303
1298		- if (req->nr_sectors + bio_sectors(bio) > q->max_sectors) {
	1304	+ if (unlikely(blk_pc_request(req)))
	1305	+ max_sectors = q->max_hw_sectors;
	1306	+ else
	1307	+ max_sectors = q->max_sectors;
	1308	+
	1309	+ if (req->nr_sectors + bio_sectors(bio) > max_sectors) {
1299	1310	req->flags \|= REQ_NOMERGE;
1300	1311	if (req == q->last_merge)
1301	1312	q->last_merge = NULL;
1302	1313
...	...	@@ -1325,9 +1336,16 @@
1325	1336	static int ll_front_merge_fn(request_queue_t q, struct request req,
1326	1337	struct bio *bio)
1327	1338	{
	1339	+ unsigned short max_sectors;
1328	1340	int len;
1329	1341
1330		- if (req->nr_sectors + bio_sectors(bio) > q->max_sectors) {
	1342	+ if (unlikely(blk_pc_request(req)))
	1343	+ max_sectors = q->max_hw_sectors;
	1344	+ else
	1345	+ max_sectors = q->max_sectors;
	1346	+
	1347	+
	1348	+ if (req->nr_sectors + bio_sectors(bio) > max_sectors) {
1331	1349	req->flags \|= REQ_NOMERGE;
1332	1350	if (req == q->last_merge)
1333	1351	q->last_merge = NULL;
...	...	@@ -2144,7 +2162,7 @@
2144	2162	struct bio *bio;
2145	2163	int reading;
2146	2164
2147		- if (len > (q->max_sectors << 9))
	2165	+ if (len > (q->max_hw_sectors << 9))
2148	2166	return -EINVAL;
2149	2167	if (!len \|\| !ubuf)
2150	2168	return -EINVAL;
...	...	@@ -2259,7 +2277,7 @@
2259	2277	{
2260	2278	struct bio *bio;
2261	2279
2262		- if (len > (q->max_sectors << 9))
	2280	+ if (len > (q->max_hw_sectors << 9))
2263	2281	return -EINVAL;
2264	2282	if (!len \|\| !kbuf)
2265	2283	return -EINVAL;
...	...	@@ -233,7 +233,7 @@
233	233	if (verify_command(file, cmd))
234	234	return -EPERM;
235	235
236		- if (hdr->dxfer_len > (q->max_sectors << 9))
	236	+ if (hdr->dxfer_len > (q->max_hw_sectors << 9))
237	237	return -EIO;
238	238
239	239	if (hdr->dxfer_len)
...	...	@@ -638,7 +638,7 @@
638	638	static void check_for_valid_limits(struct io_restrictions *rs)
639	639	{
640	640	if (!rs->max_sectors)
641		- rs->max_sectors = MAX_SECTORS;
	641	+ rs->max_sectors = SAFE_MAX_SECTORS;
642	642	if (!rs->max_phys_segments)
643	643	rs->max_phys_segments = MAX_PHYS_SEGMENTS;
644	644	if (!rs->max_hw_segments)
...	...	@@ -462,6 +462,7 @@
462	462	req = blk_get_request(sdev->request_queue, write, gfp);
463	463	if (!req)
464	464	goto free_sense;
	465	+ req->flags \|= REQ_BLOCK_PC \| REQ_QUIET;
465	466
466	467	if (use_sg)
467	468	err = scsi_req_map_sg(req, buffer, use_sg, bufflen, gfp);
...	...	@@ -477,7 +478,6 @@
477	478	req->sense_len = 0;
478	479	req->timeout = timeout;
479	480	req->retries = retries;
480		- req->flags \|= REQ_BLOCK_PC \| REQ_QUIET;
481	481	req->end_io_data = sioc;
482	482
483	483	sioc->data = privdata;
...	...	@@ -313,7 +313,8 @@
313	313	}
314	314
315	315	static int __bio_add_page(request_queue_t q, struct bio bio, struct page
316		- *page, unsigned int len, unsigned int offset)
	316	+ *page, unsigned int len, unsigned int offset,
	317	+ unsigned short max_sectors)
317	318	{
318	319	int retried_segments = 0;
319	320	struct bio_vec *bvec;
...	...	@@ -327,7 +328,7 @@
327	328	if (bio->bi_vcnt >= bio->bi_max_vecs)
328	329	return 0;
329	330
330		- if (((bio->bi_size + len) >> 9) > q->max_sectors)
	331	+ if (((bio->bi_size + len) >> 9) > max_sectors)
331	332	return 0;
332	333
333	334	/*
...	...	@@ -401,7 +402,7 @@
401	402	int bio_add_pc_page(request_queue_t q, struct bio bio, struct page *page,
402	403	unsigned int len, unsigned int offset)
403	404	{
404		- return __bio_add_page(q, bio, page, len, offset);
	405	+ return __bio_add_page(q, bio, page, len, offset, q->max_hw_sectors);
405	406	}
406	407
407	408	/**
...	...	@@ -420,8 +421,8 @@
420	421	int bio_add_page(struct bio bio, struct page page, unsigned int len,
421	422	unsigned int offset)
422	423	{
423		- return __bio_add_page(bdev_get_queue(bio->bi_bdev), bio, page,
424		- len, offset);
	424	+ struct request_queue *q = bdev_get_queue(bio->bi_bdev);
	425	+ return __bio_add_page(q, bio, page, len, offset, q->max_sectors);
425	426	}
426	427
427	428	struct bio_map_data {
...	...	@@ -533,7 +534,7 @@
533	534	break;
534	535	}
535	536
536		- if (__bio_add_page(q, bio, page, bytes, 0) < bytes) {
	537	+ if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes) {
537	538	ret = -EINVAL;
538	539	break;
539	540	}
...	...	@@ -647,7 +648,8 @@
647	648	/*
648	649	* sorry...
649	650	*/
650		- if (__bio_add_page(q, bio, pages[j], bytes, offset) < bytes)
	651	+ if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
	652	+ bytes)
651	653	break;
652	654
653	655	len -= bytes;
...	...	@@ -820,8 +822,8 @@
820	822	if (bytes > len)
821	823	bytes = len;
822	824
823		- if (__bio_add_page(q, bio, virt_to_page(data), bytes,
824		- offset) < bytes)
	825	+ if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
	826	+ offset) < bytes)
825	827	break;
826	828
827	829	data += bytes;
...	...	@@ -702,7 +702,8 @@
702	702
703	703	#define MAX_PHYS_SEGMENTS 128
704	704	#define MAX_HW_SEGMENTS 128
705		-#define MAX_SECTORS 255
	705	+#define SAFE_MAX_SECTORS 255
	706	+#define BLK_DEF_MAX_SECTORS 1024
706	707
707	708	#define MAX_SEGMENT_SIZE 65536
708	709