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Date: Tue, 21 Nov 2023 15:56:35 +0100
From: Christian Brauner <brauner@kernel.org>
To: Amir Goldstein <amir73il@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>, Jan Kara <jack@suse.cz>,
	Jens Axboe <axboe@kernel.dk>, Miklos Szeredi <miklos@szeredi.hu>,
	David Howells <dhowells@redhat.com>, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 05/15] splice: remove permission hook from
 iter_file_splice_write()
Message-ID: <20231121-einband-erwidern-a606cece3bc0@brauner>
References: <20231114153321.1716028-1-amir73il@gmail.com>
 <20231114153321.1716028-6-amir73il@gmail.com>
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In-Reply-To: <20231114153321.1716028-6-amir73il@gmail.com>

On Tue, Nov 14, 2023 at 05:33:11PM +0200, Amir Goldstein wrote:
> All the callers of ->splice_write(), (e.g. do_splice_direct() and
> do_splice()) already check rw_verify_area() for the entire range
> and perform all the other checks that are in vfs_write_iter().
> 
> Create a helper do_iter_writev(), that performs the write without the
> checks and use it in iter_file_splice_write() to avoid the redundant
> rw_verify_area() checks.
> 
> This is needed for fanotify "pre content" events.
> 
> Suggested-by: Jan Kara <jack@suse.cz>
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> ---

If you resend anyway, for the low-level splice helpers specifically it
would be nice to add a comment that mentions that the caller is expected
to perform basic rw checks.