From: Ming Lei <ming.lei@redhat.com>
Date: Tue, 2 Nov 2021 21:35:00 +0800
Subject: [PATCH] blk-mq: only try to run plug merge if request has same queue
Git-commit: a1cb65377e707500819b2c2c34064e5ceb32798b
Patch-mainline: v5.16-rc1
References: jsc#PED-1183
 with incoming bio

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>
Link: https://lore.kernel.org/r/20211102133502.3619184-2-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.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;
 }
 
-- 
2.35.3