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: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAGudoHG6zYMfFmhizJDPAw=CF8QY8dzbvg0cSEW4XVcvTYhELw@mail.gmail.com>
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
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