[PATCH 10/24] rust: device: implement Sync for Device

Danilo Krummrich
2026-04-27T22:13:11Z

The underlying `struct device` is the same for all device contexts;
`Bound` is a zero-sized type-state marker that does not affect thread
safety. Implement `Sync` for `Device<Bound>` with the same safety
argument as the existing `Device<Normal>` implementation.

This is needed for types that hold `&'a Device<Bound>`, such as
`io::mem::IoMem`, to be `Send`.

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

diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs
index 09cbe8a438a9..b330b87178d3 100644
--- a/rust/kernel/device.rs
+++ b/rust/kernel/device.rs
@@ -503,6 +503,10 @@ unsafe impl Send for Device {}
// synchronization in `struct device`.
unsafe impl Sync for Device {}

+// SAFETY: Same as `Device<Normal>` -- the underlying `struct device` is the same; `Bound` is a
+// zero-sized type-state marker that does not affect thread safety.
+unsafe impl Sync for Device<Bound> {}
+
/// Marker trait for the context or scope of a bus specific device.
///
/// [`DeviceContext`] is a marker trait for types representing the context of a bus specific
--
2.54.0