Re: [PATCH v17 03/10] rust: implement `ForeignOwnable` for `Owned`

"Gary Guo" [off-list ref] writes:

On Thu Jun 4, 2026 at 9:11 PM BST, Andreas Hindborg wrote:

quoted

Implement `ForeignOwnable` for `Owned<T>`. This allows use of `Owned<T>` in
places such as the `XArray`.

Note that `T` does not need to implement `ForeignOwnable` for `Owned<T>` to
implement `ForeignOwnable`.

Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
 rust/kernel/owned.rs | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/rust/kernel/owned.rs b/rust/kernel/owned.rs
index 456e239e906e..5eacdf327d12 100644
--- a/rust/kernel/owned.rs
+++ b/rust/kernel/owned.rs

@@ -15,6 +15,8 @@
     ptr::NonNull, //
 };
 
+use kernel::types::ForeignOwnable;
+
 /// Types that specify their own way of performing allocation and destruction. Typically, this trait
 /// is implemented on types from the C side.
 ///

@@ -108,6 +110,7 @@ pub trait Ownable {
 ///
 /// - Until `T::release` is called, this `Owned<T>` exclusively owns the underlying `T`.
 /// - The `T` value is pinned.
+#[repr(transparent)]

AFAIT this `#[repr(transparent)]` isn't actually needed.

I'll drop it.

quoted

 pub struct Owned<T: Ownable> {
     ptr: NonNull<T>,
 }

@@ -185,3 +188,46 @@ fn drop(&mut self) {
         unsafe { T::release(self.ptr.as_mut()) };
     }
 }
+
+// SAFETY: We derive the pointer to `T` from a valid `T`, so the returned
+// pointer satisfy alignment requirements of `T`.
+unsafe impl<T: Ownable + 'static> ForeignOwnable for Owned<T> {

You should drop the `'static` bound and put where bound on the GAT below
instead. See how `Box` is doing it.

I will take a look.


Best regards,
Andreas Hindborg