[PATCH 09/24] rust: usb: implement Sync for Device

Danilo Krummrich
2026-04-27T22:13:05Z

Device<Bound> uses the same underlying struct usb_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 usb::Device<Bound> in their HRT
private data while remaining Send.

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

diff --git a/rust/kernel/usb.rs b/rust/kernel/usb.rs
index 9b9d3ae41087..442e456fd2d3 100644
--- a/rust/kernel/usb.rs
+++ b/rust/kernel/usb.rs
@@ -467,6 +467,10 @@ unsafe impl Send for Device {}
// allow any mutation through a shared reference.
unsafe impl Sync for Device {}

+// SAFETY: Same as `Device<Normal>` -- the underlying `struct usb_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> {}
+
/// Declares a kernel module that exposes a single USB driver.
///
/// # Examples
--
2.54.0