diff mbox series

[RESEND,2/5] block: Remove redundant blk_mq_sched_allow_merge() validation

Message ID b9d51f4bc9f0ff4ec3b8fb7fa6dc366afd69290e.1597637287.git.baolin.wang@linux.alibaba.com (mailing list archive)
State New, archived
Headers show
Series Some clean-ups for bio merge | expand

Commit Message

Baolin Wang Aug. 17, 2020, 4:09 a.m. UTC 
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@linux.alibaba.com>
---
 block/blk-mq-sched.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

Comments

Christoph Hellwig Aug. 17, 2020, 6:22 a.m. UTC | #1 
On Mon, Aug 17, 2020 at 12:09:16PM +0800, Baolin Wang wrote:
> 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().

Please line wrap your changelogs after 73 characters.

> Thus we can remove the redundant blk_mq_sched_allow_merge() in
> blk_mq_bio_list_merge() function.

This seems potentially dangerous, and I don't think it really buys
us much.
Baolin Wang Aug. 17, 2020, 12:06 p.m. UTC | #2 
On Mon, Aug 17, 2020 at 08:22:24AM +0200, Christoph Hellwig wrote:
> On Mon, Aug 17, 2020 at 12:09:16PM +0800, Baolin Wang wrote:
> > 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().
> 
> Please line wrap your changelogs after 73 characters.

Sure.

> 
> > Thus we can remove the redundant blk_mq_sched_allow_merge() in
> > blk_mq_bio_list_merge() function.
> 
> This seems potentially dangerous, and I don't think it really buys
> us much.

OK. I can remove this in next version.
diff mbox series

Patch

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);