From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
To: Christian Brauner <christian.brauner@ubuntu.com>,
Giuseppe Scrivano <gscrivan@redhat.com>
Cc: linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk,
linux-fsdevel@vger.kernel.org,
containers@lists.linux-foundation.org
Subject: Re: [PATCH 1/2] fs, close_range: add flag CLOSE_RANGE_CLOEXEC
Date: Tue, 13 Oct 2020 23:04:21 +0200 [thread overview]
Message-ID: <22ff41f8-c009-84f4-849b-a807b7382253@rasmusvillemoes.dk> (raw)
In-Reply-To: <20201013205427.clvqno24ctwxbuyv@wittgenstein>
On 13/10/2020 22.54, Christian Brauner wrote:
> On Tue, Oct 13, 2020 at 04:06:08PM +0200, Giuseppe Scrivano wrote:
>
> Hey Guiseppe,
>
> Thanks for the patch!
>
>> When the flag CLOSE_RANGE_CLOEXEC is set, close_range doesn't
>> immediately close the files but it sets the close-on-exec bit.
>
> Hm, please expand on the use-cases a little here so people know where
> and how this is useful. Keeping the rationale for a change in the commit
> log is really important.
>
> I think I don't have quarrels with this patch in principle but I wonder
> if something like the following wouldn't be easier to follow:
>
> diff --git a/fs/file.c b/fs/file.c
> index 21c0893f2f1d..872a4098c3be 100644
> --- a/fs/file.c
> +++ b/fs/file.c
> @@ -672,6 +672,32 @@ int __close_fd(struct files_struct *files, unsigned fd)
> }
> EXPORT_SYMBOL(__close_fd); /* for ksys_close() */
>
> +static inline void __range_cloexec(struct files_struct *cur_fds,
> + unsigned int fd, unsigned max_fd)
> +{
> + struct fdtable *fdt;
> + spin_lock(&cur_fds->file_lock);
> + fdt = files_fdtable(cur_fds);
> + while (fd <= max_fd)
> + __set_close_on_exec(fd++, fdt);
Doesn't that want to be
bitmap_set(fdt->close_on_exec, fd, max_fd - fd + 1)
to do word-at-a-time? I assume this would mostly be called with (3, ~0U)
as arguments or something like that.
Rasmus
next prev parent reply other threads:[~2020-10-13 21:04 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-13 14:06 [PATCH 0/2] fs, close_range: add flag CLOSE_RANGE_CLOEXEC Giuseppe Scrivano
2020-10-13 14:06 ` [PATCH 1/2] " Giuseppe Scrivano
2020-10-13 20:54 ` Christian Brauner
2020-10-13 21:04 ` Rasmus Villemoes [this message]
2020-10-13 21:22 ` Christian Brauner
2020-10-13 22:45 ` Giuseppe Scrivano
2020-10-13 21:09 ` Al Viro
2020-10-13 21:32 ` Christian Brauner
2020-10-13 21:49 ` Rasmus Villemoes
2020-10-13 14:06 ` [PATCH 2/2] selftests: add tests for CLOSE_RANGE_CLOEXEC Giuseppe Scrivano
2020-10-13 15:22 ` David Laight
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