Re: [PATCH v7 9/9] rust: sync: atomic: Add Atomic<{usize,isize}>

["Benno Lossin" <lossin@kernel.org>]

On Mon Jul 14, 2025 at 7:36 AM CEST, Boqun Feng wrote:
> +// Defines an internal type that always maps to the integer type which has the same size alignment
> +// as `isize` and `usize`, and `isize` and `usize` are always bi-directional transmutable to
> +// `isize_atomic_repr`, which also always implements `AtomicImpl`.
> +#[allow(non_camel_case_types)]
> +#[cfg(not(CONFIG_64BIT))]
> +type isize_atomic_repr = i32;
> +#[allow(non_camel_case_types)]
> +#[cfg(CONFIG_64BIT)]
> +type isize_atomic_repr = i64;
> +
> +// Ensure size and alignment requirements are checked.
> +crate::static_assert!(core::mem::size_of::<isize>() == core::mem::size_of::<isize_atomic_repr>());
> +crate::static_assert!(core::mem::align_of::<isize>() == core::mem::align_of::<isize_atomic_repr>());
> +crate::static_assert!(core::mem::size_of::<usize>() == core::mem::size_of::<isize_atomic_repr>());
> +crate::static_assert!(core::mem::align_of::<usize>() == core::mem::align_of::<isize_atomic_repr>());

This is fine for now, but I would prefer for this to go into an
`assumptions` module like Miguel proposed some time ago.

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Cheers,
Benno