On Tue, Oct 19, 2021 at 10:24:15PM +0100, Pavel Begunkov wrote:
> Combine blk_mq_sched_bio_merge() and blk_attempt_plug_merge() under a
> common if, so we don't check it twice. Also honor bio_mergeable() for
> blk_mq_sched_bio_merge().
>
> Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
> ---
> block/blk-mq-sched.c | 2 +-
> block/blk-mq-sched.h | 12 +-----------
> block/blk-mq.c | 13 +++++++------
> 3 files changed, 9 insertions(+), 18 deletions(-)
>
> diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
> index e85b7556b096..5b259fdea794 100644
> --- a/block/blk-mq-sched.c
> +++ b/block/blk-mq-sched.c
> @@ -361,7 +361,7 @@ void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)
> }
> }
>
> -bool __blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio,
> +bool blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio,
> unsigned int nr_segs)
> {
> struct elevator_queue *e = q->elevator;
> diff --git a/block/blk-mq-sched.h b/block/blk-mq-sched.h
> index 98836106b25f..25d1034952b6 100644
> --- a/block/blk-mq-sched.h
> +++ b/block/blk-mq-sched.h
> @@ -12,7 +12,7 @@ void blk_mq_sched_assign_ioc(struct request *rq);
>
> bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio,
> unsigned int nr_segs, struct request **merged_request);
> -bool __blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio,
> +bool blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio,
> unsigned int nr_segs);
> bool blk_mq_sched_try_insert_merge(struct request_queue *q, struct request *rq,
> struct list_head *free);
> @@ -42,16 +42,6 @@ static inline bool bio_mergeable(struct bio *bio)
> return !(bio->bi_opf & REQ_NOMERGE_FLAGS);
> }
>
> -static inline bool
> -blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio,
> - unsigned int nr_segs)
> -{
> - if (blk_queue_nomerges(q) || !bio_mergeable(bio))
> - return false;
> -
> - return __blk_mq_sched_bio_merge(q, bio, nr_segs);
> -}
> -
> static inline bool
> blk_mq_sched_allow_merge(struct request_queue *q, struct request *rq,
> struct bio *bio)
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index bab1fccda6ca..218bfaa98591 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -2482,12 +2482,13 @@ void blk_mq_submit_bio(struct bio *bio)
> if (!bio_integrity_prep(bio))
> goto queue_exit;
>
> - if (!is_flush_fua && !blk_queue_nomerges(q) &&
> - blk_attempt_plug_merge(q, bio, nr_segs, &same_queue_rq))
> - goto queue_exit;
> -
> - if (blk_mq_sched_bio_merge(q, bio, nr_segs))
> - goto queue_exit;
> + if (!blk_queue_nomerges(q) && bio_mergeable(bio)) {
bio_mergeable just checks REQ_NOMERGE_FLAGS, which includes
REQ_PREFLUSH and REQ_FUA...
> + if (!is_flush_fua &&
... so this is not needed.
