Re: [PATCH 0/5] use custom FFI integer types

[Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>]

On Fri, Sep 13, 2024 at 11:32 PM Gary Guo <gary@garyguo.net> wrote:
>
> This patch series aim to reduce the unnecessary type casts needed in
> Rust code doing FFI calls.
>
> With this series, we can ensure:
>
> * `size_t` is mapped to usize. Currently this is mostly true except for
>   C builtin functions, which gets translated by bindgen to c_ulong/c_uint.
>
> * `__kernel_size_t` is mapped to usize. Currently this is mapped to
>   c_ulong/c_uint.
>
> * `unsigned long` is mapped to usize. Currently this is mapped by Rust
>   libcore to either u32 or u64.
>
> * `char` is mapped to `u8`. Currently this is mapped by Rust libcore to
>   either i8 or u8.
>
> After this series, FFI code needs to use `kernel::ffi` types instead of
> `core::ffi`.

Applied to `rust-next` -- thanks everyone!

Gary: please double-check if you have time!

    [ Trevor asked: "I wonder how reliable this behavior is. Maybe bindgen
      could do a better job controlling this, is there an open issue?".

      Gary replied: ..."apparently this is indeed the suggested approach in
      https://github.com/rust-lang/rust-bindgen/issues/1770". - Miguel ]

    [ Formatted comment. - Miguel ]

    [ Formatted comment. - Miguel ]

    [ Added `rustdoc`, `rusttest` and KUnit tests support. Rebased on top of
      `rust-next` (e.g. migrated more `core::ffi` cases). Reworded crate
      docs slightly and formatted. - Miguel ]

    [ Moved `uaccess` changes from the next commit, since they were
      irrefutable patterns that Rust >= 1.82.0 warns about. Reworded
      slightly and reformatted a few documentation comments. Rebased on
      top of `rust-next`. - Miguel ]

    [ Moved `uaccess` changes to the previous commit, since they were
      irrefutable patterns that Rust >= 1.82.0 warns about. Removed a
      couple casts that now use `c""` literals. Rebased on top of
      `rust-next`. - Miguel ]

Cheers,
Miguel