Re: [PATCH v2] rust: workqueue: replace SAFETY TODO for `WorkItemPointer` impl on `Pin<KBox<T>>`

[Alice Ryhl <aliceryhl@google.com>]

On Thu, Apr 30, 2026 at 12:49:28PM +0530, Sagar Taunk wrote:
> The original implementation left a `SAFETY: TODO` comment on the
> `WorkItemPointer` implementation for `Pin<KBox<T>>`. This patch documents
> the safety requirements that make this implementation sound.
> 
> The safety argument follows the same structure as the `Arc<T>`
> implementation and relies on three guarantees:
>  `__enqueue` strips the `Pin` wrapper via `Pin::into_inner_unchecked`
> and leaks the box via `KBox::into_raw`, producing `*mut T` whose
> allocation remains live for the duration of the queued work;
> `work_container_of` safely reverses the `raw_get_work` offset arithmetic to
> recover the exact `*mut T` that `__enqueue` produced; and the workqueue
> guarantees `run` is called exactly once, making `KBox::from_raw` sound.
> 
> Signed-off-by: Sagar Taunk <sagartaunk2@gmail.com>

Thanks

Reviewed-by: Alice Ryhl <aliceryhl@google.com>