Linux io-uring development
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From: Jens Axboe <axboe@kernel.dk>
To: Caleb Sander Mateos <csander@purestorage.com>,
	Yang Xiuwei <yangxiuwei@kylinos.cn>
Cc: io-uring@vger.kernel.org
Subject: Re: [PATCH 1/2] io_uring/uring_cmd: copy SQE before issue_blocking punt
Date: Thu, 2 Jul 2026 14:15:04 -0600	[thread overview]
Message-ID: <ce98e216-98bf-42cf-b1a0-89a2ea62f897@kernel.dk> (raw)
In-Reply-To: <CADUfDZp4DmCvwGyp9dJEEojSbkkcW8Bj9ZZEXVg3vw_7KsWhyQ@mail.gmail.com>

On 7/2/26 12:06 PM, Caleb Sander Mateos wrote:
> On Thu, Jul 2, 2026 at 10:43 AM Caleb Sander Mateos
> <csander@purestorage.com> wrote:
>>
>> On Thu, Jul 2, 2026 at 1:41 AM Yang Xiuwei <yangxiuwei@kylinos.cn> wrote:
>>>
>>> io_uring_cmd_issue_blocking() punts to io-wq without copying the SQE
>>> off the submission queue, unlike the -EAGAIN and fallback paths. Copy
>>> the SQE into async data before queuing the work.
>>
>> Add a Fixes tag?
>> Fixes: ecf47d452ced ("io_uring/uring_cmd: implement ->sqe_copy() to
>> avoid unnecessary copies")
> 
> Actually I'm not convinced this is an issue at all. Since commit
> 212ec34e4e72 ("block: only read from sqe on initial invocation of
> blkdev_uring_cmd()"), blkdev_uring_cmd() only accesses the SQE on the
> initial issue. Even if the uring_cmd is re-issued asynchronously, it
> doesn't rely on the SQE having been preserved.

Yeah I agree, after taking a closer look. I'll kill this patch. I do
like your followup cleaning up the punting, will queue that for 7.3.

-- 
Jens Axboe


  reply	other threads:[~2026-07-02 20:15 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-02  8:29 [PATCH 0/2] io_uring/uring_cmd cleanups Yang Xiuwei
2026-07-02  8:29 ` [PATCH 1/2] io_uring/uring_cmd: copy SQE before issue_blocking punt Yang Xiuwei
2026-07-02 17:43   ` Caleb Sander Mateos
2026-07-02 18:06     ` Caleb Sander Mateos
2026-07-02 20:15       ` Jens Axboe [this message]
2026-07-02  8:29 ` [PATCH 2/2] io_uring/uring_cmd: fix uring_cmd.c comments Yang Xiuwei
2026-07-02 17:19   ` Caleb Sander Mateos
2026-07-02 12:28 ` [PATCH 0/2] io_uring/uring_cmd cleanups Jens Axboe

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