Re: [PATCH v8 1/3] rust: io: add resource abstraction

[Danilo Krummrich <dakr@kernel.org>]

On Fri, May 09, 2025 at 05:29:46PM -0300, Daniel Almeida wrote:
> +#[cfg(CONFIG_HAS_IOPORT)]
> +/// Returns a reference to the global `ioport_resource` variable.
> +pub fn ioport_resource() -> &'static Resource {
> +    // SAFETY: `bindings::ioport_resoure` has global lifetime and is of type Resource.
> +    unsafe { Resource::from_ptr(core::ptr::addr_of_mut!(bindings::ioport_resource)) }

Should be possible to use `&raw mut`.

> +}
> +
> +#[cfg(CONFIG_HAS_IOMEM)]
> +/// Returns a reference to the global `iomem_resource` variable.
> +pub fn iomem_resource() -> &'static Resource {
> +    // SAFETY: `bindings::iomem_resoure` has global lifetime and is of type Resource.
> +    unsafe { Resource::from_ptr(core::ptr::addr_of_mut!(bindings::iomem_resource)) }

Same here.

> +/// A resource abstraction.
> +///
> +/// # Invariants
> +///
> +/// `Resource` is a transparent wrapper around a valid `bindings::resource`.
> +#[repr(transparent)]
> +pub struct Resource(Opaque<bindings::resource>);
> +
> +impl Resource {
> +    /// Creates a reference to a [`Resource`] from a valid pointer.
> +    ///
> +    /// # Safety
> +    ///
> +    /// The caller must ensure that for the duration of 'a, the pointer will
> +    /// point at a valid `bindings::resource`
> +    ///
> +    /// The caller must also ensure that the `Resource` is only accessed via the
> +    /// returned reference for the duration of 'a.
> +    pub(crate) const unsafe fn from_ptr<'a>(ptr: *mut bindings::resource) -> &'a Self {

Throughout the tree, functions with this signature are usually called as_ref().