Re: [PATCH 2/5] rust: error: Add Error::from_kernel_errno()

[Gary Guo <gary@garyguo.net>]

On Fri, 24 Feb 2023 17:50:20 +0900
Asahi Lina <lina@asahilina.net> wrote:

> From: Miguel Ojeda <ojeda@kernel.org>
> 
> Add a function to create `Error` values out of a kernel error return,
> which safely upholds the invariant that the error code is well-formed
> (negative and greater than -MAX_ERRNO). If a malformed code is passed
> in, it will be converted to EINVAL.
> 
> Lina: Imported from rust-for-linux/rust as authored by Miguel and Fox
> with refactoring from Wedson.
> 
> Co-developed-by: Fox Chen <foxhlchen@gmail.com>
> Signed-off-by: Fox Chen <foxhlchen@gmail.com>
> Co-developed-by: Wedson Almeida Filho <wedsonaf@gmail.com>
> Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> Signed-off-by: Asahi Lina <lina@asahilina.net>
> ---
>  rust/kernel/error.rs | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs
> index 8611758e27f4..3b439fdb405c 100644
> --- a/rust/kernel/error.rs
> +++ b/rust/kernel/error.rs
> @@ -72,6 +72,25 @@ pub mod code {
>  pub struct Error(core::ffi::c_int);
>  
>  impl Error {
> +    /// Creates an [`Error`] from a kernel error code.
> +    ///
> +    /// It is a bug to pass an out-of-range `errno`. `EINVAL` would
> +    /// be returned in such a case.
> +    pub(crate) fn from_kernel_errno(errno: core::ffi::c_int) -> Error {

Maybe just `from_errno`? I don't know why `kernel` would need to be
emphasised here.

Best,
Gary