From 87c037d11b83b93e9ab5eda9fb03c114f67024ff Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 18 Oct 2021 10:07:09 -0600 Subject: [PATCH] block: return whether or not to unplug through boolean Instead of returning the same queue request through a request pointer, use a boolean to accomplish the same. Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe --- block/blk-merge.c | 11 +++++------ block/blk-mq.c | 16 +++++++++------- block/blk.h | 2 +- 3 files changed, 15 insertions(+), 14 deletions(-) diff --git a/block/blk-merge.c b/block/blk-merge.c index ec72723..c273b58 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -1067,9 +1067,8 @@ static enum bio_merge_status blk_attempt_bio_merge(struct request_queue *q, * @q: request_queue new bio is being queued at * @bio: new bio being queued * @nr_segs: number of segments in @bio - * @same_queue_rq: pointer to &struct request that gets filled in when - * another request associated with @q is found on the plug list - * (optional, may be %NULL) + * @same_queue_rq: output value, will be true if there's an existing request + * from the passed in @q already in the plug list * * Determine whether @bio being queued on @q can be merged with the previous * request on %current's plugged list. Returns %true if merge was successful, @@ -1085,7 +1084,7 @@ static enum bio_merge_status blk_attempt_bio_merge(struct request_queue *q, * Caller must ensure !blk_queue_nomerges(q) beforehand. */ bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio, - unsigned int nr_segs, struct request **same_queue_rq) + unsigned int nr_segs, bool *same_queue_rq) { struct blk_plug *plug; struct request *rq; @@ -1096,12 +1095,12 @@ bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio, /* check the previously added entry for a quick merge attempt */ rq = list_last_entry(&plug->mq_list, struct request, queuelist); - if (rq->q == q && same_queue_rq) { + if (rq->q == q) { /* * Only blk-mq multiple hardware queues case checks the rq in * the same queue, there should be only one such rq in a queue */ - *same_queue_rq = rq; + *same_queue_rq = true; } if (blk_attempt_bio_merge(q, rq, bio, nr_segs, false) == BIO_MERGE_OK) return true; diff --git a/block/blk-mq.c b/block/blk-mq.c index 59809ec2..335ec3a 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2432,7 +2432,7 @@ void blk_mq_submit_bio(struct bio *bio) const int is_flush_fua = op_is_flush(bio->bi_opf); struct request *rq; struct blk_plug *plug; - struct request *same_queue_rq = NULL; + bool same_queue_rq = false; unsigned int nr_segs = 1; blk_status_t ret; @@ -2525,6 +2525,8 @@ void blk_mq_submit_bio(struct bio *bio) /* Insert the request at the IO scheduler queue */ blk_mq_sched_insert_request(rq, false, true, true); } else if (plug && !blk_queue_nomerges(q)) { + struct request *next_rq = NULL; + /* * We do limited plugging. If the bio can be merged, do that. * Otherwise the existing request in the plug list will be @@ -2532,19 +2534,19 @@ void blk_mq_submit_bio(struct bio *bio) * The plug list might get flushed before this. If that happens, * the plug list is empty, and same_queue_rq is invalid. */ - if (list_empty(&plug->mq_list)) - same_queue_rq = NULL; if (same_queue_rq) { - list_del_init(&same_queue_rq->queuelist); + next_rq = list_last_entry(&plug->mq_list, + struct request, + queuelist); + list_del_init(&next_rq->queuelist); plug->rq_count--; } blk_add_rq_to_plug(plug, rq); trace_block_plug(q); - if (same_queue_rq) { + if (next_rq) { trace_block_unplug(q, 1, true); - blk_mq_try_issue_directly(same_queue_rq->mq_hctx, - same_queue_rq); + blk_mq_try_issue_directly(next_rq->mq_hctx, next_rq); } } else if ((q->nr_hw_queues > 1 && is_sync) || !rq->mq_hctx->dispatch_busy) { diff --git a/block/blk.h b/block/blk.h index e803503..b9729c1 100644 --- a/block/blk.h +++ b/block/blk.h @@ -218,7 +218,7 @@ void blk_add_timer(struct request *req); void blk_print_req_error(struct request *req, blk_status_t status); bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio, - unsigned int nr_segs, struct request **same_queue_rq); + unsigned int nr_segs, bool *same_queue_rq); bool blk_bio_list_merge(struct request_queue *q, struct list_head *list, struct bio *bio, unsigned int nr_segs); -- 2.7.4