linux-kernel - [PATCH RESEND 2/5] block: Remove redundant blk_mq_sched_allow

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Date:   Mon, 17 Aug 2020 12:09:16 +0800
From:   Baolin Wang <baolin.wang@...ux.alibaba.com>
To:     axboe@...nel.dk
Cc:     ming.lei@...hat.com, hch@....de, baolin.wang@...ux.alibaba.com,
        baolin.wang7@...il.com, linux-block@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH RESEND 2/5] block: Remove redundant blk_mq_sched_allow_merge() validation

Only software queue and kyber IO scheduler will call blk_mq_bio_list_merge()
to merge a bio, and kyber IO scheduler did not implement the ops->allow_merge().
Thus we can remove the redundant blk_mq_sched_allow_merge() in
blk_mq_bio_list_merge() function.

Signed-off-by: Baolin Wang <baolin.wang@...ux.alibaba.com>
---
 block/blk-mq-sched.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index a19cdf1..bf62b34 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -403,14 +403,10 @@ bool blk_mq_bio_list_merge(struct request_queue *q, struct list_head *list,
 
 		switch (blk_try_merge(rq, bio)) {
 		case ELEVATOR_BACK_MERGE:
-			if (blk_mq_sched_allow_merge(q, rq, bio))
-				merged = bio_attempt_back_merge(rq, bio,
-						nr_segs);
+			merged = bio_attempt_back_merge(rq, bio, nr_segs);
 			break;
 		case ELEVATOR_FRONT_MERGE:
-			if (blk_mq_sched_allow_merge(q, rq, bio))
-				merged = bio_attempt_front_merge(rq, bio,
-						nr_segs);
+			merged = bio_attempt_front_merge(rq, bio, nr_segs);
 			break;
 		case ELEVATOR_DISCARD_MERGE:
 			merged = bio_attempt_discard_merge(q, rq, bio);
-- 
1.8.3.1