Add Work::disable_sync() as a safe wrapper for disable_work_sync().

Drivers can use this during teardown to stop new queueing and wait for
queued or running work to finish before dropping related resources.

Tested-by: Deborah Brouwer <deborah.brouwer@collabora.com>
Signed-off-by: Onur Özkan <work@onurozkan.dev>
---
 rust/kernel/workqueue.rs | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/rust/kernel/workqueue.rs b/rust/kernel/workqueue.rs
index 706e833e9702..6acc7b5ba31c 100644
--- a/rust/kernel/workqueue.rs
+++ b/rust/kernel/workqueue.rs
@@ -530,6 +530,21 @@ pub unsafe fn raw_get(ptr: *const Self) -> *mut bindings::work_struct {
         // the compiler does not complain that the `work` field is unused.
         unsafe { Opaque::cast_into(core::ptr::addr_of!((*ptr).work)) }
     }
+
+    /// Disables this work item and waits for queued/running executions to finish.
+    ///
+    /// # Safety
+    ///
+    /// Must be called from a sleepable context if the work was last queued on a non-BH
+    /// workqueue.
+    #[inline]
+    pub unsafe fn disable_sync(&self) {
+        let ptr: *const Self = self;
+        // SAFETY: `self` points to a valid initialized work.
+        let raw_work = unsafe { Self::raw_get(ptr) };
+        // SAFETY: `raw_work` is a valid embedded `work_struct`.
+        unsafe { bindings::disable_work_sync(raw_work) };
+    }
 }
 
 /// Declares that a type contains a [`Work<T, ID>`].
-- 
2.51.2