linux-kernel - Re: [PATCH RESEND] rust: transmute: add `from_bytes

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Message-Id: <DDXEOPKO5RV5.37NXWB7O9AA6K@kernel.org>
Date: Sat, 01 Nov 2025 14:52:00 +0100
From: "Danilo Krummrich" <dakr@...nel.org>
To: "Alexandre Courbot" <acourbot@...dia.com>
Cc: "Miguel Ojeda" <ojeda@...nel.org>, "Alex Gaynor"
 <alex.gaynor@...il.com>, "Boqun Feng" <boqun.feng@...il.com>, "Gary Guo"
 <gary@...yguo.net>, Björn Roy Baron
 <bjorn3_gh@...tonmail.com>, "Benno Lossin" <lossin@...nel.org>, "Andreas
 Hindborg" <a.hindborg@...nel.org>, "Alice Ryhl" <aliceryhl@...gle.com>,
 "Trevor Gross" <tmgross@...ch.edu>, <rust-for-linux@...r.kernel.org>,
 <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH RESEND] rust: transmute: add `from_bytes_prefix` family
 of methods

On Sat Nov 1, 2025 at 2:41 PM CET, Alexandre Courbot wrote:
> The `from_bytes*` family of functions expect a slice of the exact same
> size as the requested type. This can be sometimes cumbersome for callers
> that deal with dynamic stream of data that needs to be manually cut
> before each invocation of `from_bytes`.
>
> To simplify such callers, introduce a new `from_bytes*_prefix` family of
> methods, which split the input slice at the index required for the
> equivalent `from_bytes` method to succeed, and return its result
> alongside with the remainder of the slice.
>
> This design is inspired by zerocopy's `try_*_from_prefix` family of
> methods.
>
> Signed-off-by: Alexandre Courbot <acourbot@...dia.com>

Reviewed-by: Danilo Krummrich <dakr@...nel.org>

One nit below:

> +    /// Converts the beginning of `bytes` to a reference to `Self`.
> +    ///
> +    /// This method is similar to [`Self::from_bytes`], with the difference that `bytes` does not
> +    /// need to be the same size of `Self` - the appropriate portion is cut from the beginning of
> +    /// `bytes`, and the remainder returned alongside the result.

Maybe "alongside `&Self`"? "alongside the result" sounds a bit like the method
would return `Result<&Self>, &[u8]`.