[PATCH 08/24] rust: auxiliary: implement Sync for Device

Danilo Krummrich
2026-04-27T22:12:58Z

Device<Bound> uses the same underlying struct auxiliary_device as
Device<Normal>; Bound is a zero-sized type-state marker that does not
affect thread safety.

This is needed for drivers to store &'a auxiliary::Device<Bound> in
their HRT private data while remaining Send.

Signed-off-by: Danilo Krummrich <dakr@kernel.org>
---
rust/kernel/auxiliary.rs | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/rust/kernel/auxiliary.rs b/rust/kernel/auxiliary.rs
index 5cd10b254baf..8a278ddb5b95 100644
--- a/rust/kernel/auxiliary.rs
+++ b/rust/kernel/auxiliary.rs
@@ -366,6 +366,10 @@ unsafe impl Send for Device {}
// (i.e. `Device<Normal>) are thread safe.
unsafe impl Sync for Device {}

+// SAFETY: Same as `Device<Normal>` -- the underlying `struct auxiliary_device` is the same;
+// `Bound` is a zero-sized type-state marker that does not affect thread safety.
+unsafe impl Sync for Device<device::Bound> {}
+
/// Wrapper that stores a [`TypeId`] alongside the registration data for runtime type checking.
#[repr(C)]
#[pin_data]
--
2.54.0