Re: [PATCH v4 2/3] rust: block: add rnull, Rust null_blk implementation

[Keith Busch]

On Sat, Jun 01, 2024 at 03:40:04PM +0200, Andreas Hindborg wrote:
> +impl kernel::Module for NullBlkModule {
> +    fn init(_module: &'static ThisModule) -> Result<Self> {
> +        pr_info!("Rust null_blk loaded\n");
> +        let tagset = Arc::pin_init(TagSet::try_new(1, 256, 1), flags::GFP_KERNEL)?;
> +
> +        let disk = {
> +            let block_size: u16 = 4096;
> +            if block_size % 512 != 0 || !(512..=4096).contains(&block_size) {
> +                return Err(kernel::error::code::EINVAL);
> +            }

You've set block_size to the literal 4096, then validate its value
immediately after? Am I missing some way this could ever be invalid?