Re: [PATCH] rust: workqueue: fix SAFETY comment Arc refs in Pin>

Onur Özkan
2026-04-28T10:57:56Z

On Sat, 25 Apr 2026 19:27:01 +0530
Sagar Taunk <sagartaunk2@gmail.com> wrote:

> The `WorkItemPointer` implementation for `Pin<KBox<T>>` contained SAFETY
> comments that incorrectly referenced `Arc::into_raw` instead of
> `KBox::into_raw`. This implementation uses `KBox`, not `Arc`, so update
> the comments to accurately reflect the actual ownership transfer.
>
> Suggested-by: Onur Özkan <contact@onurozkan.dev>
> Link: https://github.com/Rust-for-Linux/linux/issues/1233
> Signed-off-by: Sagar Taunk <sagartaunk2@gmail.com>
> ---
> rust/kernel/workqueue.rs | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/rust/kernel/workqueue.rs b/rust/kernel/workqueue.rs
> index 7e253b6f299c..74c59f2b1c09 100644
> --- a/rust/kernel/workqueue.rs
> +++ b/rust/kernel/workqueue.rs
> @@ -890,9 +890,10 @@ unsafe impl<T, const ID: u64> WorkItemPointer<ID> for Pin<KBox<T>>
> unsafe extern "C" fn run(ptr: *mut bindings::work_struct) {
> // The `__enqueue` method always uses a `work_struct` stored in a `Work<T, ID>`.
> let ptr = ptr.cast::<Work<T, ID>>();
> - // SAFETY: This computes the pointer that `__enqueue` got from `Arc::into_raw`.
> + // SAFETY: This computes the pointer that `__enqueue` got from `KBox::into_raw`.
> let ptr = unsafe { T::work_container_of(ptr) };
> - // SAFETY: This pointer comes from `Arc::into_raw` and we've been given back ownership.
> + // SAFETY: This pointer comes from `KBox::into_raw` and we have been given back ownership,
> + // as the workqueue guarantees `run` is called exactly once.
> let boxed = unsafe { KBox::from_raw(ptr) };
> // SAFETY: The box was already pinned when it was enqueued.
> let pinned = unsafe { Pin::new_unchecked(boxed) };
> --
> 2.54.0
>

Thank you!

Reviewed-by: Onur Özkan <work@onurozkan.dev>