linux-kernel - Re: [PATCH v2 00/16] expand mmap_prepare functionality, port more users

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Message-Id: <20250910143845.7ecfed713e436ed532c93491@linux-foundation.org>
Date: Wed, 10 Sep 2025 14:38:45 -0700
From: Andrew Morton <akpm@...ux-foundation.org>
To: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
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Subject: Re: [PATCH v2 00/16] expand mmap_prepare functionality, port more
 users

On Wed, 10 Sep 2025 21:21:55 +0100 Lorenzo Stoakes <lorenzo.stoakes@...cle.com> wrote:

> Since commit c84bf6dd2b83 ("mm: introduce new .mmap_prepare() file
> callback"), The f_op->mmap hook has been deprecated in favour of
> f_op->mmap_prepare.
> 
> This was introduced in order to make it possible for us to eventually
> eliminate the f_op->mmap hook which is highly problematic as it allows
> drivers and filesystems raw access to a VMA which is not yet correctly
> initialised.
> 
> This hook also introduced complexity for the memory mapping operation, as
> we must correctly unwind what we do should an error arises.
> 
> Overall this interface being so open has caused significant problems for
> us, including security issues, it is important for us to simply eliminate
> this as a source of problems.
> 
> Therefore this series continues what was established by extending the
> functionality further to permit more drivers and filesystems to use
> mmap_prepare.

Cool, I'll add this to mm-new but I'll suppress the usual emails.