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From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Thu, 9 May 2024 08:48:20 -0700
Message-ID: <CAHk-=wgKdWwdVUvjSNLL-ne9ezQN=BrwN34Kq38_=9yF8c03uA@mail.gmail.com>
Subject: Re: [Linaro-mm-sig] Re: [PATCH] epoll: try to be a _bit_ better about
 file lifetimes
To: Christian Brauner <brauner@kernel.org>
Cc: Daniel Vetter <daniel@ffwll.ch>, Simon Ser <contact@emersion.fr>, 
	Pekka Paalanen <pekka.paalanen@collabora.com>, 
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	Al Viro <viro@zeniv.linux.org.uk>, keescook@chromium.org, axboe@kernel.dk, 
	christian.koenig@amd.com, dri-devel@lists.freedesktop.org, 
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On Thu, 9 May 2024 at 04:39, Christian Brauner <brauner@kernel.org> wrote:
>
> Not worth it without someone explaining in detail why imho. First pass
> should be to try and replace kcmp() in scenarios where it's obviously
> not needed or overkill.

Ack.

> I've added a CLASS(fd_raw) in a preliminary patch since we'll need that
> anyway which means that your comparison patch becomes even simpler imho.
> I've also added a selftest patch:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git/log/?h=vfs.misc

LGTM.

Maybe worth adding an explicit test for "open same file, but two
separate opens, F_DUPFD_QUERY returns 0? Just to clarify the "it's not
testing the file on the filesystem for equality, but the file pointer
itself".

             Linus