Re: [PATCH v12 4/5] rust: add find_bit_benchmark_rust module.

[Alice Ryhl <aliceryhl@google.com>]

On Wed, Jun 11, 2025 at 07:48:37PM +0000, Burak Emir wrote:
> +    let mut bitmap = Bitmap::new(BITMAP_LEN, GFP_KERNEL).expect("alloc sparse bitmap failed");
> +    let nbits = BITMAP_LEN / SPARSENESS;
> +    for _i in 0..nbits {
> +        // SAFETY: BITMAP_LEN fits in 32 bits.
> +        let bit: usize =
> +            unsafe { bindings::__get_random_u32_below(BITMAP_LEN.try_into().unwrap()) as _ };

This safety comment argues why the .unwrap() will not result in a panic,
but it should instead argue why the call to __get_random_u32_below() is
okay. I guess that it's because __get_random_u32_below() is always safe
to call?

I'm not a big fan of these .try_into().unwrap() conversions. I would
probably just have written `BITMAP_LEN as u32`. But I know that this is
a point of disagreement with other Rust maintainers.

Alice