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References: <20240227215146.46487-1-daniel.almeida@collabora.com> <20240227215146.46487-2-daniel.almeida@collabora.com>
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From: Alice Ryhl <aliceryhl@google.com>
Date: Wed, 28 Feb 2024 15:13:28 +0100
Message-ID: <CAH5fLgi_Y0a=XPtgdiA9KcsmMGxn=DjvLMmSq-UF8VQtZVTccg@mail.gmail.com>
Subject: Re: [RFC PATCH 1/1] v4l2-core: rewrite the VP9 library in Rust
To: Daniel Almeida <daniel.almeida@collabora.com>
Cc: wedsonaf@gmail.com, ojeda@kernel.org, mchehab@kernel.org, 
	hverkuil@xs4all.nl, rust-for-linux@vger.kernel.org, 
	linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, 
	kernel@collabora.com
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On Tue, Feb 27, 2024 at 10:56=E2=80=AFPM Daniel Almeida
<daniel.almeida@collabora.com> wrote:
>
> +#[no_mangle]
> +pub extern "C" fn v4l2_vp9_seg_feat_enabled_rs(
> +    feature_enabled: &mut u8,
> +    feature: u32,
> +    segid: u32,
> +) -> bool {
> +    let feature_enabled =3D unsafe { core::slice::from_raw_parts_mut(fea=
ture_enabled, 8) };
> +    let mask =3D 1 << feature;
> +    feature_enabled[segid as usize] & mask !=3D 0
> +}

This seems to be the only unsafe block. Impressive!

I recommend taking an `*mut u8` here instead of `&mut u8` if you're
going to use `slice::from_raw_parts_mut`. Or, if cbindgen allows it,
take an `&mut [u8; 8]` instead and eliminate the unsafe block.

Alice