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 12:10:08 -0700 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <20200304190341.GB16251@localhost>
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.
--
Jens Axboe
next prev parent reply other threads:[~2020-03-04 19:10 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 [this message]
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
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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