Re: [RFC 0/4] open/accept directly into io_uring fixed file table

From: Pavel Begunkov
Date: Fri Aug 13 2021 - 12:30:55 EST


On 7/7/21 4:04 PM, Josh Triplett wrote:
> On Wed, Jul 07, 2021 at 07:07:52AM -0600, Jens Axboe wrote:
>> On 7/7/21 5:39 AM, Pavel Begunkov wrote:
>>> Implement an old idea allowing open/accept io_uring requests to register
>>> a newly created file as a io_uring's fixed file instead of placing it
>>> into a task's file table. The switching is encoded in io_uring's SQEs
>>> by setting sqe->buf_index/file_index, so restricted to 2^16-1. Don't
>>> think we need more, but may be a good idea to scrap u32 somewhere
>>> instead.
>>>
>>> From the net side only needs a function doing __sys_accept4_file()
>>> but not installing fd, see 2/4.
>>>
>>> Only RFC for now, the new functionality is tested only for open yet.
>>> I hope we can remember the author of the idea to add attribution.
>>
>> Pretty sure the original suggester of this as Josh, CC'ed.
>
> Thanks for working on this, Pavel!
>
> Original thread at

Totally was thinking it was only a discussion but not an actual patch,
and I even did comment on it! Sorry Josh, would have persuaded you to
finish it, if I remembered that.

> https://lore.kernel.org/io-uring/20200715004209.GA334456@localhost/T/ in
> case that helps.
>

--
Pavel Begunkov