1 files changed, 32 insertions, 3 deletions
diff --git a/rust/kernel/sync/lock.rs b/rust/kernel/sync/lock.rs
index eb80048e0110..360a10a9216d 100644
--- a/rust/kernel/sync/lock.rs
+++ b/rust/kernel/sync/lock.rs
@@ -12,7 +12,7 @@ use crate::{
     str::CStr,
     types::{NotThreadSafe, Opaque, ScopeGuard},
 };
-use core::{cell::UnsafeCell, marker::PhantomPinned};
+use core::{cell::UnsafeCell, marker::PhantomPinned, pin::Pin};
 use macros::pin_data;
 
 pub mod mutex;
@@ -129,7 +129,7 @@ unsafe impl<T: ?Sized + Send, B: Backend> Sync for Lock<T, B> {}
 
 impl<T, B: Backend> Lock<T, B> {
     /// Constructs a new lock initialiser.
-    pub fn new(t: T, name: &'static CStr, key: &'static LockClassKey) -> impl PinInit<Self> {
+    pub fn new(t: T, name: &'static CStr, key: Pin<&'static LockClassKey>) -> impl PinInit<Self> {
         pin_init!(Self {
             data: UnsafeCell::new(t),
             _pin: PhantomPinned,
@@ -199,7 +199,36 @@ pub struct Guard<'a, T: ?Sized, B: Backend> {
 // SAFETY: `Guard` is sync when the data protected by the lock is also sync.
 unsafe impl<T: Sync + ?Sized, B: Backend> Sync for Guard<'_, T, B> {}
 
-impl<T: ?Sized, B: Backend> Guard<'_, T, B> {
+impl<'a, T: ?Sized, B: Backend> Guard<'a, T, B> {
+    /// Returns the lock that this guard originates from.
+    ///
+    /// # Examples
+    ///
+    /// The following example shows how to use [`Guard::lock_ref()`] to assert the corresponding
+    /// lock is held.
+    ///
+    /// ```
+    /// # use kernel::{new_spinlock, stack_pin_init, sync::lock::{Backend, Guard, Lock}};
+    ///
+    /// fn assert_held<T, B: Backend>(guard: &Guard<'_, T, B>, lock: &Lock<T, B>) {
+    ///     // Address-equal means the same lock.
+    ///     assert!(core::ptr::eq(guard.lock_ref(), lock));
+    /// }
+    ///
+    /// // Creates a new lock on the stack.
+    /// stack_pin_init!{
+    ///     let l = new_spinlock!(42)
+    /// }
+    ///
+    /// let g = l.lock();
+    ///
+    /// // `g` originates from `l`.
+    /// assert_held(&g, &l);
+    /// ```
+    pub fn lock_ref(&self) -> &'a Lock<T, B> {
+        self.lock
+    }
+
     pub(crate) fn do_unlocked<U>(&mut self, cb: impl FnOnce() -> U) -> U {
         // SAFETY: The caller owns the lock, so it is safe to unlock it.
         unsafe { B::unlock(self.lock.state.get(), &self.state) };