* [PATCH 1/1] blk-mq: do not reset plug->rq_count before the list is sorted
@ 2019-04-04 2:57 Dongli Zhang
2019-04-04 6:53 ` Ming Lei
2019-04-04 14:37 ` Jens Axboe
0 siblings, 2 replies; 3+ messages in thread
From: Dongli Zhang @ 2019-04-04 2:57 UTC (permalink / raw)
To: axboe; +Cc: linux-block, linux-kernel
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@oracle.com>
---
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
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 1/1] blk-mq: do not reset plug->rq_count before the list is sorted
2019-04-04 2:57 [PATCH 1/1] blk-mq: do not reset plug->rq_count before the list is sorted Dongli Zhang
@ 2019-04-04 6:53 ` Ming Lei
2019-04-04 14:37 ` Jens Axboe
1 sibling, 0 replies; 3+ messages in thread
From: Ming Lei @ 2019-04-04 6:53 UTC (permalink / raw)
To: Dongli Zhang; +Cc: Jens Axboe, linux-block, Linux Kernel Mailing List
On Thu, Apr 4, 2019 at 10:54 AM Dongli Zhang <dongli.zhang@oracle.com> wrote:
>
> 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@oracle.com>
> ---
> 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
>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Thanks,
Ming Lei
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 1/1] blk-mq: do not reset plug->rq_count before the list is sorted
2019-04-04 2:57 [PATCH 1/1] blk-mq: do not reset plug->rq_count before the list is sorted Dongli Zhang
2019-04-04 6:53 ` Ming Lei
@ 2019-04-04 14:37 ` Jens Axboe
1 sibling, 0 replies; 3+ messages in thread
From: Jens Axboe @ 2019-04-04 14:37 UTC (permalink / raw)
To: Dongli Zhang; +Cc: linux-block, linux-kernel
On 4/3/19 8:57 PM, Dongli Zhang wrote:
> We would never be able to sort the list if we first reset plug->rq_count
> which is used in conditional check later.
Well, that was pretty stupid. Thanks for the patch, applied.
--
Jens Axboe
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2019-04-04 14:37 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2019-04-04 2:57 [PATCH 1/1] blk-mq: do not reset plug->rq_count before the list is sorted Dongli Zhang
2019-04-04 6:53 ` Ming Lei
2019-04-04 14:37 ` Jens Axboe
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