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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>,
	Johannes Berg <johannes@sipsolutions.net>,
	Oliver Giles <ohw.giles@gmail.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: Splicing to/from a tty
Date: Wed, 20 Jan 2021 11:27:26 -0800	[thread overview]
Message-ID: <CAHk-=wjtTC_jNL+K1Ey_wY_KpTYZOR5XwhkZ+Eu7vviVi5itDQ@mail.gmail.com> (raw)
In-Reply-To: <20210120191116.GC740243@zeniv-ca>

On Wed, Jan 20, 2021 at 11:11 AM Al Viro <viro@zeniv.linux.org.uk> wrote:
>
> Why do we care about O_APPEND on anything without FMODE_PWRITE (including
> pipes), anyway?  All writes there ignore position, after all...

We shouldn't care.

Also, I think we should try to move away from FMODE_PWRITE/PREAD
entirely, and use FMODE_STREAM as the primary "this thing doesn't have
a position at all".

That's what gets rid of all the f_pos locking etc after all. The
FMODE_PWRITE/PREAD flags are I think legacy (although we do seem to
have the seq_file case that normally allows position on reads, but not
on writes, so we may need to keep all three bits).

Anyway, I think that with FMODE_STREAM, O_APPEND definitely should be a no-op.

            Linus

  reply	other threads:[~2021-01-20 19:33 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
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 [this message]
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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