`GenDisk` is a pointer to a `struct gendisk`. It is safe to reference this
struct from multiple threads.

Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
 rust/kernel/block/mq/gen_disk.rs | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/rust/kernel/block/mq/gen_disk.rs b/rust/kernel/block/mq/gen_disk.rs
index 2b204b0ed49a..94af85fe1716 100644
--- a/rust/kernel/block/mq/gen_disk.rs
+++ b/rust/kernel/block/mq/gen_disk.rs
@@ -234,6 +234,17 @@ unsafe impl<T> Send for GenDisk<T>
 {
 }
 
+// SAFETY: `GenDisk` is an owned pointer to a `struct gendisk` and an `Arc` to a `TagSet`. It is
+// safe to reference these from multiple threads if the `Arc` and the `gendisk` private data is
+// `Sync`.
+unsafe impl<T> Sync for GenDisk<T>
+where
+    T: Operations,
+    T::QueueData: Sync,
+    Arc<TagSet<T>>: Sync,
+{
+}
+
 impl<T: Operations> Drop for GenDisk<T> {
     fn drop(&mut self) {
         // SAFETY: By type invariant of `Self`, `self.gendisk` points to a valid

-- 
2.51.2