From: Josh Triplett <[email protected]>
To: Jens Axboe <[email protected]>
Cc: [email protected], [email protected]
Subject: Re: [PATCHSET v2 0/6] Support selectable file descriptors
Date: Wed, 4 Mar 2020 11:03:41 -0800 [thread overview]
Message-ID: <20200304190341.GB16251@localhost> (raw)
In-Reply-To: <[email protected]>
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!
next prev parent reply other threads:[~2020-03-04 19:03 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 ` Josh Triplett [this message]
2020-03-04 19:10 ` [PATCHSET v2 0/6] Support selectable file descriptors 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
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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