From: Al Viro <viro@zeniv.linux.org.uk>
To: Mateusz Guzik <mjguzik@gmail.com>
Cc: paulmck@kernel.org, brauner@kernel.org, jack@suse.cz,
linux-fsdevel@vger.kernel.org, torvalds@linux-foundation.org,
edumazet@google.com, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH] fs: elide the smp_rmb fence in fd_install()
Date: Thu, 5 Dec 2024 14:18:50 +0000 [thread overview]
Message-ID: <20241205141850.GS3387508@ZenIV> (raw)
In-Reply-To: <20241205120332.1578562-1-mjguzik@gmail.com>
On Thu, Dec 05, 2024 at 01:03:32PM +0100, Mateusz Guzik wrote:
> void fd_install(unsigned int fd, struct file *file)
> {
> - struct files_struct *files = current->files;
> + struct files_struct *files;
> struct fdtable *fdt;
>
> if (WARN_ON_ONCE(unlikely(file->f_mode & FMODE_BACKING)))
> return;
>
> + /*
> + * Synchronized with expand_fdtable(), see that routine for an
> + * explanation.
> + */
> rcu_read_lock_sched();
> + files = READ_ONCE(current->files);
What are you trying to do with that READ_ONCE()? current->files
itself is *not* changed by any of that code; current->files->fdtab is.
next prev parent reply other threads:[~2024-12-05 14:18 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-08 2:50 [RFC] why do we need smp_rmb/smp_wmb pair in fd_install()/expand_fdtable()? Al Viro
2024-08-08 3:06 ` Linus Torvalds
2024-08-08 3:35 ` Al Viro
2024-08-08 3:46 ` Al Viro
2024-08-08 6:08 ` Mateusz Guzik
2024-12-05 12:03 ` [RFC PATCH] fs: elide the smp_rmb fence in fd_install() Mateusz Guzik
2024-12-05 14:18 ` Al Viro [this message]
2024-12-05 14:43 ` Mateusz Guzik
2024-12-05 18:41 ` Paul E. McKenney
2024-12-05 19:03 ` Mateusz Guzik
2024-12-05 20:01 ` Paul E. McKenney
2024-12-05 20:15 ` Mateusz Guzik
2024-12-05 21:17 ` Paul E. McKenney
2024-12-05 19:26 ` Linus Torvalds
2024-12-05 19:47 ` Mateusz Guzik
2024-12-05 20:11 ` Paul E. McKenney
2024-12-06 12:11 ` Christian Brauner
2024-12-05 20:06 ` Paul E. McKenney
2024-12-05 14:46 ` Jan Kara
2024-12-05 15:01 ` Mateusz Guzik
2024-12-05 15:29 ` Jan Kara
2024-12-05 15:36 ` Mateusz Guzik
2024-12-06 15:32 ` Jan Kara
2024-12-05 14:58 ` Christian Brauner
2024-12-05 15:06 ` Mateusz Guzik
2024-08-08 13:20 ` [RFC] why do we need smp_rmb/smp_wmb pair in fd_install()/expand_fdtable()? Christian Brauner
2024-08-08 16:11 ` Linus Torvalds
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20241205141850.GS3387508@ZenIV \
--to=viro@zeniv.linux.org.uk \
--cc=brauner@kernel.org \
--cc=edumazet@google.com \
--cc=jack@suse.cz \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mjguzik@gmail.com \
--cc=paulmck@kernel.org \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.