From: Jens Axboe <[email protected]>
To: Josh Triplett <[email protected]>
Cc: [email protected], [email protected]
Subject: Re: [PATCHSET v2 0/6] Support selectable file descriptors
Date: Wed, 4 Mar 2020 13:00:05 -0700 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <20200304195642.GB16527@localhost>
On 3/4/20 12:56 PM, Josh Triplett wrote:
> On Wed, Mar 04, 2020 at 12:10:08PM -0700, Jens Axboe wrote:
>> On 3/4/20 12:03 PM, Josh Triplett wrote:
>>> On Wed, Mar 04, 2020 at 11:00:10AM -0700, Jens Axboe wrote:
>>>> One of the fabled features with chains has long been the desire to
>>>> support things like:
>>>>
>>>> <open fileX><read from fileX><close fileX>
>>>>
>>>> in a single chain. This currently doesn't work, since the read/close
>>>> depends on what file descriptor we get on open.
>>>>
>>>> The original attempt at solving this provided a means to pass
>>>> descriptors between chains in a link, this version takes a different
>>>> route. Based on Josh's support for O_SPECIFIC_FD, we can instead control
>>>> what fd value we're going to get out of open (or accept). With that in
>>>> place, we don't need to do any magic to make this work. The above chain
>>>> then becomes:
>>>>
>>>> <open fileX with fd Y><read from fd Y><close fd Y>
>>>>
>>>> which is a lot more useful, and allows any sort of weird chains without
>>>> needing to nest "last open" file descriptors.
>>>>
>>>> Updated the test program to use this approach:
>>>>
>>>> https://git.kernel.dk/cgit/liburing/plain/test/orc.c?h=fd-select
>>>>
>>>> which forces the use of fd==89 for the open, and then uses that for the
>>>> read and close.
>>>>
>>>> Outside of this adaptation, fixed a few bugs and cleaned things up.
>>>
>>> I posted one comment about an issue in patch 6.
>>>
>>> Patches 2-5 look great; for those:
>>> Reviewed-by: Josh Triplett <[email protected]>
>>>
>>> Thanks for picking this up and running with it!
>>
>> Thanks for doing the prep work! I think it turned out that much better
>> for it.
>>
>> Are you going to post your series for general review? I just stole
>> your 1 patch that was needed for me.
>
> Since your patch series depends on mine, please feel free to run with
> the series. Would you mind adding my patch 1 and 3 at the end of your
> series? You need patch 1 to make this more usable for userspace, and
> patch 3 would allow for an OP_PIPE which I'd love to have.
Let me add patch 1 to the top of the stack, for the pipe part that
probably should be taken in separately. But not a huge deal to me,
as long as we can get it reviewed.
I'll post the series broader soon.
> Do you plan to submit this during the next merge window?
Maybe? In terms of timing, I think we're well within the opportunity
to do so, at least.
--
Jens Axboe
next prev parent reply other threads:[~2020-03-04 20:00 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-04 18:00 [PATCHSET v2 0/6] Support selectable file descriptors Jens Axboe
2020-03-04 18:00 ` [PATCH 1/6] fs: openat2: Extend open_how to allow userspace-selected fds Jens Axboe
2020-03-04 18:00 ` [PATCH 2/6] io_uring: move CLOSE req->file checking into handler Jens Axboe
2020-03-04 18:00 ` [PATCH 3/6] io_uring: move read/write side file based prep into op handler Jens Axboe
2020-03-04 18:00 ` [PATCH 4/6] io_uring: support deferred retrival of file from fd Jens Axboe
2020-03-04 18:00 ` [PATCH 5/6] net: allow specific fd selection for __sys_accept4_file() Jens Axboe
2020-03-04 18:00 ` [PATCH 6/6] io_uring: allow specific fd for IORING_OP_ACCEPT Jens Axboe
2020-03-04 19:02 ` Josh Triplett
2020-03-04 19:09 ` Jens Axboe
2020-03-04 19:51 ` Josh Triplett
2020-03-04 19:03 ` [PATCHSET v2 0/6] Support selectable file descriptors Josh Triplett
2020-03-04 19:10 ` Jens Axboe
2020-03-04 19:28 ` Jeff Layton
2020-03-04 19:50 ` Jens Axboe
2020-03-04 19:56 ` Josh Triplett
2020-03-04 20:00 ` Jens Axboe [this message]
2020-03-04 20:09 ` Josh Triplett
2020-03-04 20:14 ` Jens Axboe
2020-03-09 20:33 ` Stefan Metzmacher
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