Re: [PATCH 04/13] Kbuild: Rust support

[Miguel Ojeda]

On Fri, Apr 16, 2021 at 7:05 PM Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> Typical Rust error handling should match the regular kernel
> IS_ERR/ERR_PTR/PTR_ERR model fairly well, although the syntax is
> fairly different (and it's not limited to pointers).

Yeah, exactly. We already have a `KernelResult<T>` type which is a
`Result<T, Error>`, where `Error` is a wrapper for the usual kernel
int errors.

So, for instance, a function that can either fail or return `Data`
would have a declaration like:

    pub fn foo() -> KernelResult<Data>

A caller that needs to handle the error can use pattern matching or
one of the methods in `Result`. And if they only need to bubble the
error up, they can use the ? operator:

    pub fn bar() -> KernelResult<Data> {
        let data = foo()?;

        // `data` is already a `Data` here, not a `KernelResult<Data>`
    }

Cheers,
Miguel