Merge tag 'locking-core-2025-01-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking updates from Ingo Molnar:
 "Lockdep:

   - Improve and fix lockdep bitsize limits, clarify the Kconfig
     documentation (Carlos Llamas)

   - Fix lockdep build warning on Clang related to
     chain_hlock_class_idx() inlining (Andy Shevchenko)

   - Relax the requirements of PROVE_RAW_LOCK_NESTING arch support by
     not tying it to ARCH_SUPPORTS_RT unnecessarily (Waiman Long)

  Rust integration:

   - Support lock pointers managed by the C side (Lyude Paul)

   - Support guard types (Lyude Paul)

   - Update MAINTAINERS file filters to include the Rust locking code
     (Boqun Feng)

  Wake-queues:

   - Add raw_spin_*wake() helpers to simplify locking code (John Stultz)

  SMP cross-calls:

   - Fix potential data update race by evaluating the local cond_func()
     before IPI side-effects (Mathieu Desnoyers)

  Guard primitives:

   - Ease [c]tags based searches by including the cleanup/guard type
     primitives (Peter Zijlstra)

  ww_mutexes:

   - Simplify the ww_mutex self-test code via swap() (Thorsten Blum)

  Static calls:

   - Update the static calls MAINTAINERS file-pattern (Jiri Slaby)"

* tag 'locking-core-2025-01-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  MAINTAINERS: Add static_call_inline.c to STATIC BRANCH/CALL
  cleanup, tags: Create tags for the cleanup primitives
  sched/wake_q: Add helper to call wake_up_q after unlock with preemption disabled
  rust: sync: Add lock::Backend::assert_is_held()
  rust: sync: Add SpinLockGuard type alias
  rust: sync: Add MutexGuard type alias
  rust: sync: Make Guard::new() public
  rust: sync: Add Lock::from_raw() for Lock<(), B>
  locking: MAINTAINERS: Start watching Rust locking primitives
  lockdep: Move lockdep_assert_locked() under #ifdef CONFIG_PROVE_LOCKING
  lockdep: Mark chain_hlock_class_idx() with __maybe_unused
  lockdep: Document MAX_LOCKDEP_CHAIN_HLOCKS calculation
  lockdep: Clarify size for LOCKDEP_*_BITS configs
  lockdep: Fix upper limit for LOCKDEP_*_BITS configs
  locking/ww_mutex/test: Use swap() macro
  smp/scf: Evaluate local cond_func() before IPI side-effects
  locking/lockdep: Enforce PROVE_RAW_LOCK_NESTING only if ARCH_SUPPORTS_RT

1 files changed, 13 insertions, 0 deletions

diff --git a/rust/kernel/sync/lock/mutex.rs b/rust/kernel/sync/lock/mutex.rs
index 0e946ebefce1..70cadbc2e8e2 100644
--- a/rust/kernel/sync/lock/mutex.rs
+++ b/rust/kernel/sync/lock/mutex.rs
@@ -86,6 +86,14 @@ pub use new_mutex;
 /// [`struct mutex`]: srctree/include/linux/mutex.h
 pub type Mutex<T> = super::Lock<T, MutexBackend>;
 
+/// A [`Guard`] acquired from locking a [`Mutex`].
+///
+/// This is simply a type alias for a [`Guard`] returned from locking a [`Mutex`]. It will unlock
+/// the [`Mutex`] upon being dropped.
+///
+/// [`Guard`]: super::Guard
+pub type MutexGuard<'a, T> = super::Guard<'a, T, MutexBackend>;
+
 /// A kernel `struct mutex` lock backend.
 pub struct MutexBackend;
 
@@ -126,4 +134,9 @@ unsafe impl super::Backend for MutexBackend {
             None
         }
     }
+
+    unsafe fn assert_is_held(ptr: *mut Self::State) {
+        // SAFETY: The `ptr` pointer is guaranteed to be valid and initialized before use.
+        unsafe { bindings::mutex_assert_is_held(ptr) }
+    }
 }