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authorMartin K. Petersen <martin.petersen@oracle.com>2012-09-18 12:19:26 -0400
committerJens Axboe <axboe@kernel.dk>2012-09-20 14:31:41 +0200
commitf31dc1cd490539e2b62a126bc4dc2495b165d772 (patch)
treee8a917161111266f72a7aea539c9562dc2f2653d /block/blk-merge.c
parente2a60da74fc8215c68509a89e9a69c66363153db (diff)
downloadlinux-rt-f31dc1cd490539e2b62a126bc4dc2495b165d772.tar.gz
block: Consolidate command flag and queue limit checks for merges
- blk_check_merge_flags() verifies that cmd_flags / bi_rw are compatible. This function is called for both req-req and req-bio merging. - blk_rq_get_max_sectors() and blk_queue_get_max_sectors() can be used to query the maximum sector count for a given request or queue. The calls will return the right value from the queue limits given the type of command (RW, discard, write same, etc.) Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-merge.c')
-rw-r--r--block/blk-merge.c30
1 files changed, 12 insertions, 18 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 86710ca408b8..642b862608a1 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -275,14 +275,8 @@ no_merge:
int ll_back_merge_fn(struct request_queue *q, struct request *req,
struct bio *bio)
{
- unsigned short max_sectors;
-
- if (unlikely(req->cmd_type == REQ_TYPE_BLOCK_PC))
- max_sectors = queue_max_hw_sectors(q);
- else
- max_sectors = queue_max_sectors(q);
-
- if (blk_rq_sectors(req) + bio_sectors(bio) > max_sectors) {
+ if (blk_rq_sectors(req) + bio_sectors(bio) >
+ blk_rq_get_max_sectors(req)) {
req->cmd_flags |= REQ_NOMERGE;
if (req == q->last_merge)
q->last_merge = NULL;
@@ -299,15 +293,8 @@ int ll_back_merge_fn(struct request_queue *q, struct request *req,
int ll_front_merge_fn(struct request_queue *q, struct request *req,
struct bio *bio)
{
- unsigned short max_sectors;
-
- if (unlikely(req->cmd_type == REQ_TYPE_BLOCK_PC))
- max_sectors = queue_max_hw_sectors(q);
- else
- max_sectors = queue_max_sectors(q);
-
-
- if (blk_rq_sectors(req) + bio_sectors(bio) > max_sectors) {
+ if (blk_rq_sectors(req) + bio_sectors(bio) >
+ blk_rq_get_max_sectors(req)) {
req->cmd_flags |= REQ_NOMERGE;
if (req == q->last_merge)
q->last_merge = NULL;
@@ -338,7 +325,8 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
/*
* Will it become too large?
*/
- if ((blk_rq_sectors(req) + blk_rq_sectors(next)) > queue_max_sectors(q))
+ if ((blk_rq_sectors(req) + blk_rq_sectors(next)) >
+ blk_rq_get_max_sectors(req))
return 0;
total_phys_segments = req->nr_phys_segments + next->nr_phys_segments;
@@ -417,6 +405,9 @@ static int attempt_merge(struct request_queue *q, struct request *req,
if (!rq_mergeable(req) || !rq_mergeable(next))
return 0;
+ if (!blk_check_merge_flags(req->cmd_flags, next->cmd_flags))
+ return 0;
+
/*
* not contiguous
*/
@@ -512,6 +503,9 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
if (!rq_mergeable(rq) || !bio_mergeable(bio))
return false;
+ if (!blk_check_merge_flags(rq->cmd_flags, bio->bi_rw))
+ return false;
+
/* different data direction or already started, don't merge */
if (bio_data_dir(bio) != rq_data_dir(rq))
return false;