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

On Mon, Jul 14, 2025 at 01:06:08PM +0200, Benno Lossin wrote:
> 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.
> 

Well, sure. Also if `assumptions` or other core kernel mod can provide
a definition similar to `isize_atomic_repr`, I'm happy to use it.

Regards,
Boqun

> ---
> Cheers,
> Benno