[PATCH 1/1] blk-mq: do not reset plug->rq_count before the list is sorted

From: Dongli Zhang
Date: Wed Apr 03 2019 - 22:53:54 EST


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")
Signed-off-by: Dongli Zhang <dongli.zhang@xxxxxxxxxx>
---
block/blk-mq.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 3ff3d7b..c162718 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;
--
2.7.4