[PATCH V2 1/3] blk-mq: only try to run plug merge if request has same queue with incoming bio

[Ming Lei <ming.lei@redhat.com>]

It is obvious that io merge can't be done between two different queues, so
just try to run io merge in case of same queue.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 block/blk-merge.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/block/blk-merge.c b/block/blk-merge.c
index df69f4bb7717..893c1a60b701 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -1101,9 +1101,11 @@ bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
 		 * the same queue, there should be only one such rq in a queue
 		 */
 		*same_queue_rq = true;
+
+		if (blk_attempt_bio_merge(q, rq, bio, nr_segs, false) ==
+				BIO_MERGE_OK)
+			return true;
 	}
-	if (blk_attempt_bio_merge(q, rq, bio, nr_segs, false) == BIO_MERGE_OK)
-		return true;
 	return false;
 }
 
-- 
2.31.1