>From 82d8018412c12407fbfb134c7be5410ba5a76084 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 22 May 2018 11:41:46 -0600 Subject: [PATCH 1/2] blk-mq: abstract out blk-mq-sched rq list iteration bio merge helper No functional changes in this patch, just a prep patch for utilizing this in an IO scheduler. Signed-off-by: Jens Axboe --- block/blk-mq-sched.c | 34 ++++++++++++++++++++++++---------- include/linux/blk-mq.h | 3 ++- 2 files changed, 26 insertions(+), 11 deletions(-) diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c index 25c14c58385c..b0f2c2a40a0c 100644 --- a/block/blk-mq-sched.c +++ b/block/blk-mq-sched.c @@ -268,19 +268,16 @@ bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio, EXPORT_SYMBOL_GPL(blk_mq_sched_try_merge); /* - * Reverse check our software queue for entries that we could potentially - * merge with. Currently includes a hand-wavy stop count of 8, to not spend - * too much time checking for merges. + * Iterate list of requests and see if we can merge this bio with any + * of them. */ -static bool blk_mq_attempt_merge(struct request_queue *q, - struct blk_mq_ctx *ctx, struct bio *bio) +bool blk_mq_bio_list_merge(struct request_queue *q, struct list_head *list, + struct bio *bio) { struct request *rq; int checked = 8; - lockdep_assert_held(&ctx->lock); - - list_for_each_entry_reverse(rq, &ctx->rq_list, queuelist) { + list_for_each_entry_reverse(rq, list, queuelist) { bool merged = false; if (!checked--) @@ -305,13 +302,30 @@ static bool blk_mq_attempt_merge(struct request_queue *q, continue; } - if (merged) - ctx->rq_merged++; return merged; } return false; } +EXPORT_SYMBOL_GPL(blk_mq_bio_list_merge); + +/* + * Reverse check our software queue for entries that we could potentially + * merge with. Currently includes a hand-wavy stop count of 8, to not spend + * too much time checking for merges. + */ +static bool blk_mq_attempt_merge(struct request_queue *q, + struct blk_mq_ctx *ctx, struct bio *bio) +{ + lockdep_assert_held(&ctx->lock); + + if (blk_mq_bio_list_merge(q, &ctx->rq_list, bio)) { + ctx->rq_merged++; + return true; + } + + return false; +} bool __blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio) { diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index ebc34a5686dc..fb355173f3c7 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -259,7 +259,8 @@ void blk_mq_add_to_requeue_list(struct request *rq, bool at_head, void blk_mq_kick_requeue_list(struct request_queue *q); void blk_mq_delay_kick_requeue_list(struct request_queue *q, unsigned long msecs); void blk_mq_complete_request(struct request *rq); - +bool blk_mq_bio_list_merge(struct request_queue *q, struct list_head *list, + struct bio *bio); bool blk_mq_queue_stopped(struct request_queue *q); void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx); void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx); -- 2.7.4