From: Ming Lei <ming.lei@redhat.com>
To: John Garry <john.garry@huawei.com>
Cc: axboe@kernel.dk, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] blk-mq: Put driver tag in blk_mq_dispatch_rq_list() when no budget
Date: Thu, 16 Apr 2020 22:12:16 +0800 [thread overview]
Message-ID: <20200416141216.GA2907988@T590> (raw)
In-Reply-To: <1587035931-125028-1-git-send-email-john.garry@huawei.com>
On Thu, Apr 16, 2020 at 07:18:51PM +0800, John Garry wrote:
> If in blk_mq_dispatch_rq_list() we find no budget, then we break of the
> dispatch loop, but the request may keep the driver tag, evaulated
> in 'nxt' in the previous loop iteration.
>
> Fix by putting the driver tag for that request.
>
> Signed-off-by: John Garry <john.garry@huawei.com>
>
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 8e56884fd2e9..a7785df2c944 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -1222,8 +1222,10 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
> rq = list_first_entry(list, struct request, queuelist);
>
> hctx = rq->mq_hctx;
> - if (!got_budget && !blk_mq_get_dispatch_budget(hctx))
> + if (!got_budget && !blk_mq_get_dispatch_budget(hctx)) {
> + blk_mq_put_driver_tag(rq);
> break;
> + }
>
> if (!blk_mq_get_driver_tag(rq)) {
> /*
> --
> 2.16.4
>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
--
Ming
next prev parent reply other threads:[~2020-04-16 14:13 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-16 11:18 [PATCH] blk-mq: Put driver tag in blk_mq_dispatch_rq_list() when no budget John Garry
2020-04-16 14:12 ` Ming Lei [this message]
2020-04-16 15:27 ` Jens Axboe
2020-04-18 2:43 ` Bart Van Assche
2020-04-20 8:22 ` John Garry
2020-04-20 12:48 ` Bart Van Assche
2020-04-23 22:42 ` Doug Anderson
2020-04-24 1:35 ` Ming Lei
2020-04-24 7:18 ` John Garry
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