[PATCH 2/2] rust: platform: impl Send + Sync for platform::Device

[Danilo Krummrich <dakr@kernel.org>]

Commit 4d320e30ee04 ("rust: platform: fix unrestricted &mut
platform::Device") changed the definition of platform::Device and
discarded the implicitly derived Send and Sync traits.

This isn't required by upstream code yet, and hence did not cause any
issues. However, it is relied on by upcoming drivers, hence add it back
in.

Signed-off-by: Danilo Krummrich <dakr@kernel.org>
---
 rust/kernel/platform.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs
index c77c9f2e9aea..2811ca53d8b6 100644
--- a/rust/kernel/platform.rs
+++ b/rust/kernel/platform.rs
@@ -233,3 +233,10 @@ fn as_ref(&self) -> &device::Device {
         unsafe { device::Device::as_ref(dev) }
     }
 }
+
+// SAFETY: A `Device` is always reference-counted and can be released from any thread.
+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 {}
-- 
2.48.1