From 536167d47ade11a5540b4b1a7125308b1641da7a Mon Sep 17 00:00:00 2001 From: Keith Busch Date: Tue, 7 Apr 2020 03:13:48 +0900 Subject: blk-mq: don't commit_rqs() if none were queued Unburden the drivers from checking if a call to commit_rqs() is valid by not calling it when there are no requests to commit. Signed-off-by: Keith Busch Signed-off-by: Jens Axboe --- block/blk-mq.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'block') diff --git a/block/blk-mq.c b/block/blk-mq.c index f6291ceedee4..8e56884fd2e9 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1289,7 +1289,7 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list, * the driver there was more coming, but that turned out to * be a lie. */ - if (q->mq_ops->commit_rqs) + if (q->mq_ops->commit_rqs && queued) q->mq_ops->commit_rqs(hctx); spin_lock(&hctx->lock); @@ -1911,6 +1911,8 @@ blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last) void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx, struct list_head *list) { + int queued = 0; + while (!list_empty(list)) { blk_status_t ret; struct request *rq = list_first_entry(list, struct request, @@ -1926,7 +1928,8 @@ void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx, break; } blk_mq_end_request(rq, ret); - } + } else + queued++; } /* @@ -1934,7 +1937,7 @@ void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx, * the driver there was more coming, but that turned out to * be a lie. */ - if (!list_empty(list) && hctx->queue->mq_ops->commit_rqs) + if (!list_empty(list) && hctx->queue->mq_ops->commit_rqs && queued) hctx->queue->mq_ops->commit_rqs(hctx); } -- cgit