locking/rtmutex: Split API from implementation

Prepare for reusing the inner functions of rtmutex for RT lock
substitutions: introduce kernel/locking/rtmutex_api.c and move
them there.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211302.726560996@linutronix.de

kernel/locking/Makefile

@@ -24,7 +24,7 @@ obj-$(CONFIG_SMP) += spinlock.o
 obj-$(CONFIG_LOCK_SPIN_ON_OWNER) += osq_lock.o
 obj-$(CONFIG_PROVE_LOCKING) += spinlock.o
 obj-$(CONFIG_QUEUED_SPINLOCKS) += qspinlock.o
-obj-$(CONFIG_RT_MUTEXES) += rtmutex.o
+obj-$(CONFIG_RT_MUTEXES) += rtmutex_api.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
 obj-$(CONFIG_QUEUED_RWLOCKS) += qrwlock.o

kernel/locking/rtmutex_common.h

@@ -37,6 +37,33 @@ struct rt_mutex_waiter {
 	u64			deadline;
 };
 
+/*
+ * PI-futex support (proxy locking functions, etc.):
+ */
+extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
+				       struct task_struct *proxy_owner);
+extern void rt_mutex_proxy_unlock(struct rt_mutex *lock);
+extern int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
+				     struct rt_mutex_waiter *waiter,
+				     struct task_struct *task);
+extern int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
+				     struct rt_mutex_waiter *waiter,
+				     struct task_struct *task);
+extern int rt_mutex_wait_proxy_lock(struct rt_mutex *lock,
+			       struct hrtimer_sleeper *to,
+			       struct rt_mutex_waiter *waiter);
+extern bool rt_mutex_cleanup_proxy_lock(struct rt_mutex *lock,
+				 struct rt_mutex_waiter *waiter);
+
+extern int rt_mutex_futex_trylock(struct rt_mutex *l);
+extern int __rt_mutex_futex_trylock(struct rt_mutex *l);
+
+extern void rt_mutex_futex_unlock(struct rt_mutex *lock);
+extern bool __rt_mutex_futex_unlock(struct rt_mutex *lock,
+				struct wake_q_head *wake_q);
+
+extern void rt_mutex_postunlock(struct wake_q_head *wake_q);
+
 /*
  * Must be guarded because this header is included from rcu/tree_plugin.h
  * unconditionally.
@@ -78,13 +105,6 @@ static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)
 
 	return (struct task_struct *) (owner & ~RT_MUTEX_HAS_WAITERS);
 }
-#else /* CONFIG_RT_MUTEXES */
-/* Used in rcu/tree_plugin.h */
-static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)
-{
-	return NULL;
-}
-#endif  /* !CONFIG_RT_MUTEXES */
 
 /*
  * Constants for rt mutex functions which have a selectable deadlock
@@ -108,34 +128,6 @@ static inline void __rt_mutex_basic_init(struct rt_mutex *lock)
 	lock->waiters = RB_ROOT_CACHED;
 }
 
-/*
- * PI-futex support (proxy locking functions, etc.):
- */
-extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
-				       struct task_struct *proxy_owner);
-extern void rt_mutex_proxy_unlock(struct rt_mutex *lock);
-extern void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter);
-extern int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
-				     struct rt_mutex_waiter *waiter,
-				     struct task_struct *task);
-extern int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
-				     struct rt_mutex_waiter *waiter,
-				     struct task_struct *task);
-extern int rt_mutex_wait_proxy_lock(struct rt_mutex *lock,
-			       struct hrtimer_sleeper *to,
-			       struct rt_mutex_waiter *waiter);
-extern bool rt_mutex_cleanup_proxy_lock(struct rt_mutex *lock,
-				 struct rt_mutex_waiter *waiter);
-
-extern int rt_mutex_futex_trylock(struct rt_mutex *l);
-extern int __rt_mutex_futex_trylock(struct rt_mutex *l);
-
-extern void rt_mutex_futex_unlock(struct rt_mutex *lock);
-extern bool __rt_mutex_futex_unlock(struct rt_mutex *lock,
-				 struct wake_q_head *wqh);
-
-extern void rt_mutex_postunlock(struct wake_q_head *wake_q);
-
 /* Debug functions */
 static inline void debug_rt_mutex_unlock(struct rt_mutex *lock)
 {
@@ -161,4 +153,20 @@ static inline void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)
 		memset(waiter, 0x22, sizeof(*waiter));
 }
 
+static inline void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
+{
+	debug_rt_mutex_init_waiter(waiter);
+	RB_CLEAR_NODE(&waiter->pi_tree_entry);
+	RB_CLEAR_NODE(&waiter->tree_entry);
+	waiter->task = NULL;
+}
+
+#else /* CONFIG_RT_MUTEXES */
+/* Used in rcu/tree_plugin.h */
+static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)
+{
+	return NULL;
+}
+#endif  /* !CONFIG_RT_MUTEXES */
+
 #endif