[PATCH v1 3/6] blk-mq: check bio_mergeable() early before merging

From: Ming Lei
Date: Sat Oct 17 2015 - 11:52:59 EST


It isn't necessary to try to merge the bio which is marked
as NOMERGE.

Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxxxxx>
---
block/blk-mq.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 546b3b8..d55d022 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1140,7 +1140,7 @@ static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx *hctx,
struct blk_mq_ctx *ctx,
struct request *rq, struct bio *bio)
{
- if (!hctx_allow_merges(hctx)) {
+ if (!hctx_allow_merges(hctx) || !bio_mergeable(bio)) {
blk_mq_bio_to_request(rq, bio);
spin_lock(&ctx->lock);
insert_rq:
--
1.9.1

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