Re: [PATCH v2] rust: check type of `$ptr` in `container_of!`

[Tamir Duberstein]

On Sat, Apr 12, 2025 at 2:16 PM Tamir Duberstein <tamird@xxxxxxxxx> wrote:
>
> [...]
>
> diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
> index 1df11156302a..6fbd4cc5afff 100644
> --- a/rust/kernel/lib.rs
> +++ b/rust/kernel/lib.rs
> @@ -198,9 +198,14 @@ fn panic(info: &core::panic::PanicInfo<'_>) -> ! {
>  /// ```
>  #[macro_export]
>  macro_rules! container_of {
> -    ($ptr:expr, $type:ty, $($f:tt)*) => {{
> -        let offset: usize = ::core::mem::offset_of!($type, $($f)*);
> -        $ptr.byte_sub(offset).cast::<$type>()
> +    ($field_ptr:expr, $Container:ty, $($fields:tt)*) => {{
> +        let offset: usize = ::core::mem::offset_of!($Container, $($fields)*);
> +        let container_ptr = $field_ptr.byte_sub(offset).cast::<$Container>();
> +        if false {
> +            let field_ptr = ::core::ptr::addr_of!((*container_ptr).$($fields)*).cast_mut();
> +            [$field_ptr, field_ptr]; // typeof(`$ptr_to_field`) == typeof(`$Container.$($fields)*`)

The comment here should be s/ptr_to_field/field_ptr/. I missed this
when renaming this placeholder for clarity.

> +        }
> +        container_ptr
>      }}
>  }