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From: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
To: Jens Axboe <axboe@kernel.dk>, Pavel Begunkov <asml.silence@gmail.com>
Cc: io-uring@vger.kernel.org
Subject: Re: [RFC 1/1] io_uring: use valid mm in io_req_work_grab_env() in SQPOLL mode
Date: Mon, 22 Jun 2020 13:48:36 -0700	[thread overview]
Message-ID: <e64db48d-6870-3b09-9ad4-85eaf4d3624e@oracle.com> (raw)
In-Reply-To: <e6178e2d-8fa7-4837-a2c1-b167179177dc@kernel.dk>

On 6/20/2020 7:22 AM, Jens Axboe wrote:
> On 6/20/20 3:59 AM, Pavel Begunkov wrote:
>> On 20/06/2020 02:57, Bijan Mottahedeh wrote:
>>> If current->mm is not set in SQPOLL mode, then use ctx->sqo_mm;
>>> otherwise fail thre request.
>>
>> io_sq_thread_acquire_mm() called from io_async_buf_retry() should've
>> guaranteed presence of current->mm. Though, the problem could be in
>> "io_op_defs[req->opcode].needs_mm" check there, which is done only
>> for the first request in a link.
> 
> Right, Bijan are you sure this isn't fixed by one of the fixes that
> went upstream yesterday:
> 
> commit 9d8426a09195e2dcf2aa249de2aaadd792d491c7
> Author: Jens Axboe <axboe@kernel.dk>
> Date:   Tue Jun 16 18:42:49 2020 -0600
> 
>      io_uring: acquire 'mm' for task_work for SQPOLL
> 

I was running next-20200618.

Both 0618 and 0620 contain

io_uring: acquire 'mm' for task_work for SQPOLL


The commit

io_uring: support true async buffered reads, if file provides it

however is different in 0618 and 0620, the 0618 version is missing the call

if (!io_sq_thread_acquire_mm(ctx, req)) {

in io_async_buf_retry().

https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/fs/io_uring.c?h=next-20200618&id=a3bb0c190b85781d7857b7a55cb9cefded5f527b
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/fs/io_uring.c?h=next-20200622&id=3ad1d68c04bf9555942b63b5aba31e446fdcf355

I pulled the 0622 and the read-write test runs fine.

--bijan

  reply	other threads:[~2020-06-22 20:50 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-19 23:57 [RFC 0/1] io_uring: use valid mm in io_req_work_grab_env() in SQPOLL mode Bijan Mottahedeh
2020-06-19 23:57 ` [RFC 1/1] " Bijan Mottahedeh
2020-06-20  9:59   ` Pavel Begunkov
2020-06-20 14:22     ` Jens Axboe
2020-06-22 20:48       ` Bijan Mottahedeh [this message]
2020-06-20 22:23 ` [RFC 0/1] " Jens Axboe

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