Re: [PATCH] rust: Return Option from page_align and ensure no usize overflow

[Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>]

On Fri, Nov 28, 2025 at 1:29 AM Alexandre Courbot <acourbot@nvidia.com> wrote:
>
> Ah, indeed. In that case, can we make the if arms symmetric:
>
>     if let Some(sum) = addr.checked_add(PAGE_SIZE - 1) {
>         Some(sum & PAGE_MASK);
>     } else {
>         None
>     }

Early return style makes the happy path less indented and is more
consistent with the C side. However, here the happy case would be the
indented case, so `let else` would be better:

    let Some(sum) = addr.checked_add(PAGE_SIZE - 1) else {
        return None;
    };

    Some(sum & PAGE_MASK)

Cheers,
Miguel