rust: platform: implement Sync for Device<Bound>

Implement Sync for Device<Bound> in addition to Device<Normal>.

Device<Bound> uses the same underlying struct platform_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 &'bound platform::Device<Bound> in
their private data while remaining Send.

Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Uwe Kleine-König <ukleinek@kernel.org>
Tested-by: Dirk Behme <dirk.behme@de.bosch.com>
Link: https://patch.msgid.link/20260525202921.124698-8-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs
index 975b22ffe5dbf68196d56379c0776af431572266..106a5ed57ea62c4b3ce0c8bf4473c0ac267b4627 100644 (file)
--- a/rust/kernel/platform.rs
+++ b/rust/kernel/platform.rs
@@ -565,3 +565,7 @@ unsafe impl Send for Device {}
 // SAFETY: `Device` can be shared among threads because all methods of `Device`
 // (i.e. `Device<Normal>) are thread safe.
 unsafe impl Sync for Device {}
+
+// SAFETY: Same as `Device<Normal>` -- the underlying `struct platform_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> {}