Re: [PATCH v4 4/4] rust: add abstraction for `struct page`

[Alice Ryhl]

On Mon, Apr 8, 2024 at 11:19 AM Miguel Ojeda
<miguel.ojeda.sandonis@xxxxxxxxx> wrote:
>
> On Mon, Apr 8, 2024 at 9:54 AM Alice Ryhl <aliceryhl@xxxxxxxxxx> wrote:
> >
> > From bindgen's point of view, this constant is just an integer literal
> > with no type information. So I don't see how we can expect it to
> > always be generated as a usize?
>
> In the case of `PAGE_SIZE`, there is type information (`size_t`),
> since it comes from the constant helper:
>
>     const size_t RUST_CONST_HELPER_PAGE_SIZE = PAGE_SIZE;
>
> For the other one, `PAGE_SHIFT`, there is also type information
> (`int`), but bindgen currently picks a type based on the value for
> those (but ideally/eventually bindgen should respect it instead).
>
> So for the former, the allow and the cast are not needed since we are
> already handling it explicitly. And for the latter, if we want to have
> it as `usize`, we should have the cast but not the allow, because now
> it does `u32`, but if it respected the type, it would be `c_int` or
> `i32`. So either way we would need the cast.

Good point. Will fix this for next version.

Alice