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From: Pavel Begunkov <[email protected]>
To: Jens Axboe <[email protected]>,
	Norman Maurer <[email protected]>,
	[email protected]
Cc: Josef <[email protected]>
Subject: Re: IORING_OP_READ and O_NONBLOCK behaviour
Date: Wed, 2 Sep 2020 18:26:19 +0300	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

On 02/09/2020 17:45, Jens Axboe wrote:
> On 9/2/20 4:09 AM, Norman Maurer wrote:
>> Hi there,
>>
>> We are currently working on integrating io_uring into netty and found
>> some “suprising” behaviour which seems like a bug to me.
>>
>> When a socket is marked as non blocking (accepted with O_NONBLOCK flag
>> set) and there is no data to be read IORING_OP_READ should complete
>> directly with EAGAIN or EWOULDBLOCK. This is not the case and it
>> basically blocks forever until there is some data to read. Is this
>> expected ?
>>
>> This seems to be somehow related to a bug that was fixed for
>> IO_URING_ACCEPT with non blocking sockets:
>>
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v5.8&id=e697deed834de15d2322d0619d51893022c90ea2
> 
> I agree with you that this is a bug, in general it's useful (and
> expected) that we'd return -EAGAIN for that case. I'll take a look.
> 

That's I mentioned that doing retries for nonblock requests in
io_wq_submit_work() doesn't look consistent. I think killing it
off may help.

-- 
Pavel Begunkov

  reply	other threads:[~2020-09-02 15:29 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-02 10:09 IORING_OP_READ and O_NONBLOCK behaviour Norman Maurer
2020-09-02 14:45 ` Jens Axboe
2020-09-02 15:26   ` Pavel Begunkov [this message]
2020-09-02 15:35     ` Jens Axboe
2020-09-02 16:00       ` Pavel Begunkov
2020-09-02 16:02         ` Pavel Begunkov
2020-09-02 16:05         ` Jens Axboe

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