From caf8eb0d604a0eaeb8111eb4d36853a6d08eebe7 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Sat, 14 Oct 2017 17:22:26 +0800 Subject: [PATCH] blk-mq-sched: move actual dispatching into one helper So that it becomes easy to support to dispatch from sw queue in the following patch. No functional change. Reviewed-by: Bart Van Assche Reviewed-by: Omar Sandoval Suggested-by: Christoph Hellwig # for simplifying dispatch logic Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- block/blk-mq-sched.c | 43 ++++++++++++++++++++++++------------------- 1 file changed, 24 insertions(+), 19 deletions(-) diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c index eca011fdfa0e..be29ba849408 100644 --- a/block/blk-mq-sched.c +++ b/block/blk-mq-sched.c @@ -89,12 +89,26 @@ static bool blk_mq_sched_restart_hctx(struct blk_mq_hw_ctx *hctx) return false; } +static void blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx) +{ + struct request_queue *q = hctx->queue; + struct elevator_queue *e = q->elevator; + LIST_HEAD(rq_list); + + do { + struct request *rq = e->type->ops.mq.dispatch_request(hctx); + + if (!rq) + break; + list_add(&rq->queuelist, &rq_list); + } while (blk_mq_dispatch_rq_list(q, &rq_list)); +} + void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) { struct request_queue *q = hctx->queue; struct elevator_queue *e = q->elevator; const bool has_sched_dispatch = e && e->type->ops.mq.dispatch_request; - bool do_sched_dispatch = true; LIST_HEAD(rq_list); /* RCU or SRCU read lock is needed before checking quiesced flag */ @@ -122,30 +136,21 @@ void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) * scheduler, we can no longer merge or sort them. So it's best to * leave them there for as long as we can. Mark the hw queue as * needing a restart in that case. + * + * We want to dispatch from the scheduler if there was nothing + * on the dispatch list or we were able to dispatch from the + * dispatch list. */ if (!list_empty(&rq_list)) { blk_mq_sched_mark_restart_hctx(hctx); - do_sched_dispatch = blk_mq_dispatch_rq_list(q, &rq_list); - } else if (!has_sched_dispatch) { + if (blk_mq_dispatch_rq_list(q, &rq_list) && has_sched_dispatch) + blk_mq_do_dispatch_sched(hctx); + } else if (has_sched_dispatch) { + blk_mq_do_dispatch_sched(hctx); + } else { blk_mq_flush_busy_ctxs(hctx, &rq_list); blk_mq_dispatch_rq_list(q, &rq_list); } - - /* - * We want to dispatch from the scheduler if there was nothing - * on the dispatch list or we were able to dispatch from the - * dispatch list. - */ - if (do_sched_dispatch && has_sched_dispatch) { - do { - struct request *rq; - - rq = e->type->ops.mq.dispatch_request(hctx); - if (!rq) - break; - list_add(&rq->queuelist, &rq_list); - } while (blk_mq_dispatch_rq_list(q, &rq_list)); - } } bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio, -- 2.30.2