linux-kernel - Re: [PATCH v2] fs: avoid calls to legitimize

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Message-ID: <20251111-entkriminalisierung-chatbot-feeb7455fc74@brauner>
Date: Tue, 11 Nov 2025 10:47:08 +0100
From: Christian Brauner <brauner@...nel.org>
To: Mateusz Guzik <mjguzik@...il.com>
Cc: Christian Brauner <brauner@...nel.org>,
	jack@...e.cz,
	linux-kernel@...r.kernel.org,
	linux-fsdevel@...r.kernel.org,
	viro@...iv.linux.org.uk
Subject: Re: [PATCH v2] fs: avoid calls to legitimize_links() if possible

On Mon, 10 Nov 2025 11:05:03 +0100, Mateusz Guzik wrote:
> The routine is always called towards the end of lookup.
> 
> According to bpftrace on my boxen and boxen of people I asked, the depth
> count is almost always 0, thus the call can be avoided in the common case.
> 
> one-liner:
> bpftrace -e 'kprobe:legitimize_links { @[((struct nameidata *)arg0)->depth] = count(); }'
> 
> [...]

Applied to the vfs-6.19.misc branch of the vfs/vfs.git tree.
Patches in the vfs-6.19.misc branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs-6.19.misc

[1/1] fs: avoid calls to legitimize_links() if possible
      https://git.kernel.org/vfs/vfs/c/ab328bc1eb61