From: Keith Busch <kbusch@kernel.org>
Date: Tue, 7 Apr 2020 03:13:48 +0900
Subject: [PATCH] blk-mq: don't commit_rqs() if none were queued
References: bsc#1175995,jsc#SLE-15608
Git-commit: 536167d47ade11a5540b4b1a7125308b1641da7a
Patch-mainline: v5.7-rc1
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 <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
block/blk-mq.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 3c5be77a1cc8..de8e6c2f9988 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1281,7 +1281,7 @@ 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);
@@ -1856,6 +1856,8 @@ 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,
@@ -1871,7 +1873,8 @@ void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
break;
}
blk_mq_end_request(rq, ret);
- }
+ } else
+ queued++;
}
/*
@@ -1879,7 +1882,7 @@ 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);
}
--
2.16.4