From: Dongli Zhang <dongli.zhang@oracle.com>
Date: Thu, 4 Apr 2019 02:57:44 +0000 (+0800)
Subject: blk-mq: do not reset plug->rq_count before the list is sorted
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=bcc816dfe51ab86ca94663c7b225f2d6eb0fddb9;p=openwrt%2Fstaging%2Fblogic.git

blk-mq: do not reset plug->rq_count before the list is sorted

We would never be able to sort the list if we first reset plug->rq_count
which is used in conditional check later.

Fixes: ce5b009cff19 ("block: improve logic around when to sort a plug list")
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 22074a1e37cd..ac61bcc67a89 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1711,11 +1711,12 @@ void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
 	unsigned int depth;
 
 	list_splice_init(&plug->mq_list, &list);
-	plug->rq_count = 0;
 
 	if (plug->rq_count > 2 && plug->multiple_queues)
 		list_sort(NULL, &list, plug_rq_cmp);
 
+	plug->rq_count = 0;
+
 	this_q = NULL;
 	this_hctx = NULL;
 	this_ctx = NULL;