Re: [PATCH v2] rust: alloc: Add doctest for `ArrayLayout`

[Jimmy Ostler <jtostler1@gmail.com>]

On Thu, Dec 5, 2024 at 3:35 AM Danilo Krummrich <dakr@kernel.org> wrote:

> Hi Jimmy,
>
> Thanks for the patch!
>
> On Thu, Dec 05, 2024 at 02:56:27AM -0800, Jimmy Ostler wrote:
> > Add a rustdoc example and Kunit test to the `ArrayLayout` struct's
> > `ArrayLayout::new()` function.
> >
> > Add an implementation of `From<LayoutError> for Error` for the
> > `kernel::alloc::LayoutError`. This is necessary for the new test to
> > compile.
>
> Please split this into a separate patch.

Got it, the next version will be split into separate patches.

> > diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs
> > index 52c502432447..ac8526140d7a 100644
> > --- a/rust/kernel/error.rs
> > +++ b/rust/kernel/error.rs
> > @@ -4,9 +4,10 @@
> >  //!
> >  //! C header: [`include/uapi/asm-generic/errno-base.h`](srctree/include/uapi/asm-generic/errno-base.h)
> > 
> > -use crate::{alloc::AllocError, str::CStr};
> > -
> > -use core::alloc::LayoutError;
> > +use crate::{
> > +    alloc::{layout::LayoutError, AllocError},
> > +    str::CStr,
> > +};
>
> I think this part of the change would be enough, since we don't make use of the
> `From` implementation of `core::alloc::LayoutError` anywhere.
>
> I think we can add it (again), once it's needed.

Okay, that makes sense. It is still used in the documentation for the
macro `stack_try_pin_init`, and it is hidden and not used as a test, but
it would probably be prudent to change that for consistency, as
`Box::new` no longer returns `core::alloc::AllocError`.
I can add that into the v3 patchset, unless there's some reason we
should leave it.

> > 
> >  use core::fmt;
> >  use core::num::NonZeroI32;
> > @@ -223,6 +224,12 @@ fn from(_: LayoutError) -> Error {
> >      }
> >  }
> > 
> > +impl From<core::alloc::LayoutError> for Error {
> > +    fn from(_: core::alloc::LayoutError) -> Error {
> > +        code::ENOMEM
> > +    }
> > +}
> > +
> >  impl From<core::fmt::Error> for Error {
> >      fn from(_: core::fmt::Error) -> Error {
> >          code::EINVAL
> >
> > base-commit: 1dc707e647bc919834eff9636c8d00b78c782545
> > --
> > 2.47.1
> >

Thanks!

Jimmy Ostler