futex,rt_mutex: Introduce rt_mutex_init_waiter()

Since there's already two copies of this code, introduce a helper now
before adding a third one.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: juri.lelli@arm.com
Cc: bigeasy@linutronix.de
Cc: xlpang@redhat.com
Cc: rostedt@goodmis.org
Cc: mathieu.desnoyers@efficios.com
Cc: jdesfossez@efficios.com
Cc: dvhart@infradead.org
Cc: bristot@redhat.com
Link: http://lkml.kernel.org/r/20170322104151.950039479@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

3 files changed, 11 insertions, 7 deletions

diff --git a/kernel/futex.c b/kernel/futex.c
index 3b0aace334a8..f03ff63326d7 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2956,10 +2956,7 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
          * The waiter is allocated on our stack, manipulated by the requeue
          * code while we sleep on uaddr.
          */
-        debug_rt_mutex_init_waiter(&rt_waiter);
-        RB_CLEAR_NODE(&rt_waiter.pi_tree_entry);
-        RB_CLEAR_NODE(&rt_waiter.tree_entry);
-        rt_waiter.task = NULL;
+        rt_mutex_init_waiter(&rt_waiter);
 
         ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, VERIFY_WRITE);
         if (unlikely(ret != 0))
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 7d63bc5dd9b2..d2fe4b472b13 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1153,6 +1153,14 @@ void rt_mutex_adjust_pi(struct task_struct *task)
                                    next_lock, NULL, task);
 }
 
+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;
+}
+
 /**
  * __rt_mutex_slowlock() - Perform the wait-wake-try-to-take loop
  * @lock:                the rt_mutex to take
@@ -1235,9 +1243,7 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
         unsigned long flags;
         int ret = 0;
 
-        debug_rt_mutex_init_waiter(&waiter);
-        RB_CLEAR_NODE(&waiter.pi_tree_entry);
-        RB_CLEAR_NODE(&waiter.tree_entry);
+        rt_mutex_init_waiter(&waiter);
 
         /*
          * Technically we could use raw_spin_[un]lock_irq() here, but this can
diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
index af667f61ebcb..10f57d688f17 100644
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -103,6 +103,7 @@ 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,
                                   struct task_struct *proxy_owner);
+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);