Re: [PATCH io_uring-5.14 v2] io_uring: remove double poll wait entry for pure poll

[Hao Xu <haoxu@linux.alibaba.com>]

在 2021/7/28 上午6:46, Jens Axboe 写道:
> On 7/26/21 8:39 AM, Hao Xu wrote:
>> 在 2021/7/26 下午8:40, Pavel Begunkov 写道:
>>> On 7/24/21 5:48 AM, Hao Xu wrote:
>>>> 在 2021/7/23 下午10:31, Pavel Begunkov 写道:
>>>>> On 7/23/21 10:22 AM, Hao Xu wrote:
>>>>>> For pure poll requests, we should remove the double poll wait entry.
>>>>>> And io_poll_remove_double() is good enough for it compared with
>>>>>> io_poll_remove_waitqs().
>>>>>
>>>>> 5.14 in the subject hints me that it's a fix. Is it?
>>>>> Can you add what it fixes or expand on why it's better?
>>>> Hi Pavel, I found that for poll_add() requests, it doesn't remove the
>>>> double poll wait entry when it's done, neither after vfs_poll() or in
>>>> the poll completion handler. The patch is mainly to fix it.
>>>
>>> Ok, sounds good. Please resend with updated description, and
>>> let's add some tags.
>>>
>>> Fixes: 88e41cf928a6 ("io_uring: add multishot mode for IORING_OP_POLL_ADD")
>>> Cc: stable@vger.kernel.org # 5.13+
>>>
>>> Also, I'd prefer the commit title to make more clear that it's a
>>> fix. E.g. "io_uring: fix poll requests leaking second poll entries".
>>>
>>> Btw, seems it should fix hangs in ./poll-mshot-update
>> Sure，I'll send v3 soon, sorry for my unprofessionalism..
> 
> Are you going to send out v3?
> 
v3 sent. Btw I'm working on letting fast poll support multishot,
I believe that will benefit non-persistent programming, let's see
if it helps accept().