rt_mutex: Add lockdep annotations

Now that (PI) futexes have their own private RT-mutex interface and
implementation we can easily add lockdep annotations to the existing
RT-mutex interface.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
index 1abba5c..44fd002 100644
--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -37,6 +37,9 @@ struct rt_mutex {
 	int			line;
 	void			*magic;
 #endif
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	struct lockdep_map	dep_map;
+#endif
 };
 
 struct rt_mutex_waiter;
@@ -58,19 +61,33 @@ struct hrtimer_sleeper;
 #ifdef CONFIG_DEBUG_RT_MUTEXES
 # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
 	, .name = #mutexname, .file = __FILE__, .line = __LINE__
-# define rt_mutex_init(mutex)			__rt_mutex_init(mutex, __func__)
+
+# define rt_mutex_init(mutex) \
+do { \
+	static struct lock_class_key __key; \
+	__rt_mutex_init(mutex, __func__, &__key); \
+} while (0)
+
  extern void rt_mutex_debug_task_free(struct task_struct *tsk);
 #else
 # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname)
-# define rt_mutex_init(mutex)			__rt_mutex_init(mutex, NULL)
+# define rt_mutex_init(mutex)			__rt_mutex_init(mutex, NULL, NULL)
 # define rt_mutex_debug_task_free(t)			do { } while (0)
 #endif
 
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+#define __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname) \
+	, .dep_map = { .name = #mutexname }
+#else
+#define __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)
+#endif
+
 #define __RT_MUTEX_INITIALIZER(mutexname) \
 	{ .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
 	, .waiters = RB_ROOT \
 	, .owner = NULL \
-	__DEBUG_RT_MUTEX_INITIALIZER(mutexname)}
+	__DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
+	__DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)}
 
 #define DEFINE_RT_MUTEX(mutexname) \
 	struct rt_mutex mutexname = __RT_MUTEX_INITIALIZER(mutexname)
@@ -86,7 +103,7 @@ static inline int rt_mutex_is_locked(struct rt_mutex *lock)
 	return lock->owner != NULL;
 }
 
-extern void __rt_mutex_init(struct rt_mutex *lock, const char *name);
+extern void __rt_mutex_init(struct rt_mutex *lock, const char *name, struct lock_class_key *key);
 extern void rt_mutex_destroy(struct rt_mutex *lock);
 
 extern void rt_mutex_lock(struct rt_mutex *lock);