Re: [PATCH 1/2] drm/panic: use `div_ceil` to clean Clippy warning

From: Alice Ryhl
Date: Mon Mar 03 2025 - 03:06:10 EST


On Sun, Mar 2, 2025 at 12:17 AM Miguel Ojeda <ojeda@xxxxxxxxxx> wrote:
>
> Starting with the upcoming Rust 1.86.0 (to be released 2025-04-03),
> Clippy warns:
>
> error: manually reimplementing `div_ceil`
> --> drivers/gpu/drm/drm_panic_qr.rs:548:26
> |
> 548 | let pad_offset = (offset + 7) / 8;
> | ^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `offset.div_ceil(8)`
> |
> = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#manual_div_ceil
>
> And similarly for `stride`. Thus apply the suggestion to both.
>
> The behavior (and thus codegen) is not exactly equivalent [1][2], since
> `div_ceil()` returns the right value for the values that currently
> would overflow.
>
> Link: https://github.com/rust-lang/rust-clippy/issues/14333 [1]
> Link: https://godbolt.org/z/dPq6nGnv3 [2]
> Signed-off-by: Miguel Ojeda <ojeda@xxxxxxxxxx>

Reviewed-by: Alice Ryhl <aliceryhl@xxxxxxxxxx>