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From: Josh Triplett <josh@joshtriplett.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: io-uring@vger.kernel.org, jlayton@kernel.org
Subject: Re: [PATCHSET v2 0/6] Support selectable file descriptors
Date: Wed, 4 Mar 2020 11:56:42 -0800	[thread overview]
Message-ID: <20200304195642.GB16527@localhost> (raw)
In-Reply-To: <121d15a7-4b21-368c-e805-a0660b1c851a@kernel.dk>

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 <josh@joshtriplett.org>
> > 
> > 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.

Do you plan to submit this during the next merge window?

  parent reply	other threads:[~2020-03-04 19:56 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 [this message]
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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