Re: [PATCH v11 2/2] rust: clist: Add support to interface with C linked lists

[Alexandre Courbot]

On Wed Feb 25, 2026 at 7:27 AM JST, Joel Fernandes wrote:
> Add a new module `clist` for working with C's doubly circular linked
> lists. Provide low-level iteration over list nodes.
>
> Typed iteration over actual items is provided with a `clist_create`
> macro to assist in creation of the `CList` type.
>
> Cc: Nikola Djukic <ndjukic@xxxxxxxxxx>
> Reviewed-by: Daniel Almeida <daniel.almeida@xxxxxxxxxxxxx>
> Acked-by: Gary Guo <gary@xxxxxxxxxxx>
> Signed-off-by: Joel Fernandes <joelagnelf@xxxxxxxxxx>

Reviewed-by: Alexandre Courbot <acourbot@xxxxxxxxxx>

(with one small comment below)

> ---
>  MAINTAINERS              |   8 +
>  rust/helpers/helpers.c   |   1 +
>  rust/helpers/list.c      |  17 ++
>  rust/kernel/ffi/clist.rs | 338 +++++++++++++++++++++++++++++++++++++++
>  rust/kernel/ffi/mod.rs   |   2 +
>  rust/kernel/lib.rs       |   1 +
>  6 files changed, 367 insertions(+)
>  create mode 100644 rust/helpers/list.c
>  create mode 100644 rust/kernel/ffi/clist.rs
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index dc82a6bd1a61..0dc318c94c99 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -23181,6 +23181,14 @@ T:	git https://github.com/Rust-for-Linux/linux.git alloc-next
>  F:	rust/kernel/alloc.rs
>  F:	rust/kernel/alloc/
>  
> +RUST [FFI HELPER]
> +M:	Joel Fernandes <joelagnelf@xxxxxxxxxx> (CLIST)
> +M:	Alexandre Courbot <acourbot@xxxxxxxxxx> (CLIST)
> +L:	rust-for-linux@xxxxxxxxxxxxxxx
> +S:	Maintained
> +T:	git https://github.com/Rust-for-Linux/linux.git ffi-next
> +F:	rust/kernel/ffi/

Acked-by: Alexandre Courbot <acourbot@xxxxxxxxxx>

<snip>
> +impl<'a, T, const OFFSET: usize> Iterator for CListIter<'a, T, OFFSET> {
> +    type Item = &'a T;
> +
> +    #[inline]
> +    fn next(&mut self) -> Option<Self::Item> {
> +        let head = self.head_iter.next()?;
> +
> +        // Convert to item using OFFSET.
> +        // SAFETY: `item_ptr` calculation from `OFFSET` (calculated using offset_of!)

`item_ptr` does not exist.