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From: Jens Axboe <axboe@kernel.dk>
To: Chengming Zhou <zhouchengming@bytedance.com>
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] blk-mq: move bio merge attempt to blk_mq_submit_bio()
Date: Fri, 12 Aug 2022 06:40:32 -0600	[thread overview]
Message-ID: <330468da-a778-6cfc-ce46-a62566d71c8d@kernel.dk> (raw)
In-Reply-To: <20220812083944.79616-1-zhouchengming@bytedance.com>

On 8/12/22 2:39 AM, Chengming Zhou wrote:
> We will try to get request from cache before alloc request, in
> both cases will first attempt bio merge.
> 
> This patch move this common part to blk_mq_submit_bio(), which
> simplify the code and avoid passing in the pointer of bio.

I don't think this will work. If we get a cached request, then we
know we have a reference to the queue. If you swap these around,
then that's no longer the case and we can have a use-after-free if
the queue goes away.

-- 
Jens Axboe


  reply	other threads:[~2022-08-12 12:40 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-12  8:39 [PATCH] blk-mq: move bio merge attempt to blk_mq_submit_bio() Chengming Zhou
2022-08-12 12:40 ` Jens Axboe [this message]
2022-08-12 14:48   ` Chengming Zhou

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