linux-kernel - Re: [PATCH] rust: dma: require mutable reference for as_slice

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aGO3QgrGSgN5X2hz@google.com>
Date: Tue, 1 Jul 2025 10:24:33 +0000
From: Alice Ryhl <aliceryhl@...gle.com>
To: Danilo Krummrich <dakr@...nel.org>
Cc: abdiel.janulgue@...il.com, daniel.almeida@...labora.com, 
	robin.murphy@....com, a.hindborg@...nel.org, ojeda@...nel.org, 
	alex.gaynor@...il.com, boqun.feng@...il.com, gary@...yguo.net, 
	bjorn3_gh@...tonmail.com, lossin@...nel.org, tmgross@...ch.edu, 
	acourbot@...dia.com, rust-for-linux@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] rust: dma: require mutable reference for as_slice_mut()
 and write()

On Sat, Jun 28, 2025 at 06:49:54PM +0200, Danilo Krummrich wrote:
> Given the safety requirements of as_slice_mut() and write() taking an
> immutable reference is technically not incorrect.
> 
> However, let's leverage the compiler's capabilities and require a
> mutable reference to ensure exclusive access.
> 
> This also fixes a clippy warning introduced with 1.88:
> 
>   warning: mutable borrow from immutable input(s)
>      --> rust/kernel/dma.rs:297:78
>       |
>   297 |     pub unsafe fn as_slice_mut(&self, offset: usize, count: usize) -> Result<&mut [T]> {
>       |                                                                              ^^^^^^^^
> 
> Fixes: d37a39f607c4 ("rust: dma: add as_slice/write functions for CoherentAllocation")
> Signed-off-by: Danilo Krummrich <dakr@...nel.org>

I'm not sure if `as_slice_mut()` is exactly the right API we want
long-term, but this is a step in the right direction.

Reviewed-by: Alice Ryhl <aliceryhl@...gle.com>