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From: Al Viro <viro@zeniv-ca>
To: Christoph Hellwig <hch@lst.de>
Cc: Johannes Berg <johannes@sipsolutions.net>,
	Oliver Giles <ohw.giles@gmail.com>,
	linux-kernel@vger.kernel.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: Splicing to/from a tty
Date: Mon, 18 Jan 2021 19:34:57 +0000	[thread overview]
Message-ID: <20210118193457.GA736435@zeniv-ca> (raw)
In-Reply-To: <20210118085311.GA2735@lst.de>

On Mon, Jan 18, 2021 at 09:53:11AM +0100, Christoph Hellwig wrote:
> On Sat, Jan 16, 2021 at 05:46:33PM +0100, Johannes Berg wrote:
> > > For my case, I attempted to instead implement splice_write and
> > > splice_read in tty_fops; I managed to get splice_write working calling
> > > ld->ops->write, but splice_read is not so simple because the
> > > tty_ldisc_ops read method expects a userspace buffer. So I cannot see
> > > how to implement this without either (a) using set_fs, or (b)
> > > implementing iter ops on all line disciplines.
> > > 
> > > Is splice()ing between a tty and a pipe worth supporting at all? Not a
> > > big deal for my use case at least, but it used to work.
> > 
> > Is it even strictly related to the tty?
> > 
> > I was just now looking into why my cgit/fcgi/nginx setup no longer
> > works, and the reason is getting -EINVAL from sendfile() when the input
> > is a file and the output is a pipe().
> 
> Yes, pipes do not support ->splice_write currenly.   I think just wiring
> up iter_file_splice_write would work.  Al?

I'd rather have sendfile(2) do what splice(2) does and handle pipes
directly.  Let me take a look,,,

  parent reply	other threads:[~2021-01-18 20:27 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-16  7:35 Splicing to/from a tty Oliver Giles
2021-01-16 16:46 ` Johannes Berg
2021-01-17  6:12   ` Oliver Giles
2021-01-18  8:53   ` Christoph Hellwig
2021-01-18  8:58     ` Johannes Berg
2021-01-18 19:26       ` Linus Torvalds
2021-01-18 19:45         ` Al Viro
2021-01-18 19:49           ` Linus Torvalds
2021-01-18 19:56             ` Al Viro
2021-01-24 19:11           ` Linus Torvalds
2021-01-25  9:16             ` [PATCH] fs/pipe: allow sendfile() to pipe again Johannes Berg
2021-01-25 10:16               ` Christoph Hellwig
2021-01-25 20:34               ` Linus Torvalds
2021-01-26  6:07             ` Splicing to/from a tty Al Viro
2021-01-26  6:08               ` [PATCH 1/3] do_splice_to(): move the logics for limiting the read length in Al Viro
2021-01-26  6:09               ` [PATCH 2/3] take the guts of file-to-pipe splice into a helper function Al Viro
2021-01-26  6:09               ` [PATCH 3/3] teach sendfile(2) to handle send-to-pipe directly Al Viro
2021-01-26 18:57                 ` Linus Torvalds
2021-01-26 19:33                   ` Al Viro
2021-01-26 18:49               ` Splicing to/from a tty Linus Torvalds
2021-01-26 19:42                 ` Al Viro
2021-01-18 19:34     ` Al Viro [this message]
2021-01-18 19:46       ` Linus Torvalds
2021-01-18 19:54         ` Al Viro
2021-01-20 16:26           ` Al Viro
2021-01-20 19:11             ` Al Viro
2021-01-20 19:27               ` Linus Torvalds
2021-01-20 22:25                 ` David Laight
2021-01-20 23:02                   ` Al Viro
2021-01-20 23:14                 ` Al Viro
2021-01-20 23:40                   ` Linus Torvalds
2021-01-21  0:38                     ` Al Viro
2021-01-21  1:04                       ` Linus Torvalds
2021-01-21  1:45                         ` Al Viro
2021-01-21  3:38                           ` Linus Torvalds
2021-01-21  6:05                             ` Willy Tarreau
2021-01-21  8:04                               ` Johannes Berg
2021-01-21 10:08                         ` David Laight
2021-01-18  8:16 ` Christoph Hellwig
2021-01-18 19:36   ` Linus Torvalds
2021-01-18 20:24     ` Linus Torvalds
2021-01-18 21:35       ` Linus Torvalds
2021-01-18 21:54         ` Linus Torvalds
2021-01-18 22:03           ` Linus Torvalds
2021-01-18 22:20             ` Linus Torvalds
2021-01-19  1:38               ` Linus Torvalds
2021-01-19 11:53                 ` Greg Kroah-Hartman
2021-01-19 16:56                   ` Robert Karszniewicz
2021-01-19 17:10                     ` Robert Karszniewicz
2021-01-19 22:09                     ` Oliver Giles
2021-01-19 17:25                   ` Linus Torvalds
2021-01-19 20:24                   ` Linus Torvalds
2021-01-19 20:38                     ` Christoph Hellwig
2021-01-20  1:25                     ` Oliver Giles
2021-01-20  4:44                       ` Linus Torvalds
2021-01-20  8:15                         ` Oliver Giles
2021-01-21  1:18                         ` tty splice branch (was "Re: Splicing to/from a tty") Linus Torvalds
2021-01-21  8:44                           ` Greg Kroah-Hartman
2021-01-21  8:50                           ` Jiri Slaby
2021-01-21  8:58                             ` Jiri Slaby
2021-01-21 17:52                               ` Linus Torvalds
2021-01-21  8:58                             ` Greg Kroah-Hartman
2021-01-21 17:03                         ` Splicing to/from a tty Robert Karszniewicz
2021-01-21 18:43                           ` Linus Torvalds
2021-01-19 11:52         ` Greg Kroah-Hartman

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