Re: [PATCH v3 02/12] rust: error: improve unsafe code in example

[Trevor Gross]

On Wed, Jan 31, 2024 at 3:24 PM Valentin Obst via B4 Relay
<devnull+kernel.valentinobst.de@xxxxxxxxxx> wrote:
>
> From: Valentin Obst <kernel@xxxxxxxxxxxxxxx>
>
> The `from_err_ptr` function is safe. There is no need for the call to it
> to be inside the unsafe block.
>
> Reword the SAFETY comment to provide a better justification of why the
> FFI call is safe.
>
> Signed-off-by: Valentin Obst <kernel@xxxxxxxxxxxxxxx>
> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@xxxxxxxxx>
> Reviewed-by: Alice Ryhl <aliceryhl@xxxxxxxxxx>

Reviewed-by: Trevor Gross <tmgross@xxxxxxxxx>

> ---
>  rust/kernel/error.rs | 10 +++-------
>  1 file changed, 3 insertions(+), 7 deletions(-)
>
> diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs
> index 4f0c1edd63b7..4786d3ee1e92 100644
> --- a/rust/kernel/error.rs
> +++ b/rust/kernel/error.rs
> @@ -264,13 +264,9 @@ pub fn to_result(err: core::ffi::c_int) -> Result {
>  ///     pdev: &mut PlatformDevice,
>  ///     index: u32,
>  /// ) -> Result<*mut core::ffi::c_void> {
> -///     // SAFETY: FFI call.
> -///     unsafe {
> -///         from_err_ptr(bindings::devm_platform_ioremap_resource(
> -///             pdev.to_ptr(),
> -///             index,
> -///         ))
> -///     }
> +///     // SAFETY: `pdev` points to a valid platform device. There are no safety requirements
> +///     // on `index`.
> +///     from_err_ptr(unsafe { bindings::devm_platform_ioremap_resource(pdev.to_ptr(), index) })
>  /// }
>  /// ```
>  // TODO: Remove `dead_code` marker once an in-kernel client is available.
>
> --
> 2.43.0
>
>