Re: [PATCH v4 1/3] rust: ptr: add `KnownSize` trait to support DST size info extraction

["Benno Lossin" <lossin@kernel.org>]

On Mon Mar 2, 2026 at 5:42 PM CET, Gary Guo wrote:
> From: Gary Guo <gary@garyguo.net>
>
> Add a `KnownSize` trait which is used obtain a size from a raw pointer's
> metadata. This makes it possible to obtain size information on a raw slice
> pointer. This is similar to Rust `core::mem::size_of_val_raw` which is not
> yet stable.
>
> Signed-off-by: Gary Guo <gary@garyguo.net>
> ---
>  rust/kernel/lib.rs |  1 +
>  rust/kernel/ptr.rs | 27 ++++++++++++++++++++++++++-
>  2 files changed, 27 insertions(+), 1 deletion(-)
>
> diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
> index 3da92f18f4ee..510cc7fe4961 100644
> --- a/rust/kernel/lib.rs
> +++ b/rust/kernel/lib.rs
> @@ -20,6 +20,7 @@
>  #![feature(generic_nonzero)]
>  #![feature(inline_const)]
>  #![feature(pointer_is_aligned)]
> +#![feature(slice_ptr_len)]

Oh and this is also missing a stability comment.

Cheers,
Benno

>  //
>  // Stable since Rust 1.80.0.
>  #![feature(slice_flatten)]