patches/locking-rtmutex--Make-inner-working-of-rt_spin_slow_lock---accessible.patch

Subject: locking/rtmutex: Make inner working of rt_spin_slow_lock() accessible
From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 12 Jul 2017 10:24:49 +0200

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/locking/rtmutex.c        |   40 ++++++++++++++++++++++------------------
 kernel/locking/rtmutex_common.h |    4 ++++
 2 files changed, 26 insertions(+), 18 deletions(-)

--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1045,21 +1045,16 @@ static int task_blocks_on_rt_mutex(struc
  * We store the current state under p->pi_lock in p->saved_state and
  * the try_to_wake_up() code handles this accordingly.
  */
-static void  noinline __sched rt_spin_lock_slowlock(struct rt_mutex *lock)
+void __sched rt_spin_lock_slowlock_locked(struct rt_mutex *lock,
+					  struct rt_mutex_waiter *waiter,
+					  unsigned long flags)
 {
 	struct task_struct *lock_owner, *self = current;
-	struct rt_mutex_waiter waiter, *top_waiter;
-	unsigned long flags;
+	struct rt_mutex_waiter *top_waiter;
 	int ret;
 
-	rt_mutex_init_waiter(&waiter, true);
-
-	raw_spin_lock_irqsave(&lock->wait_lock, flags);
-
-	if (__try_to_take_rt_mutex(lock, self, NULL, STEAL_LATERAL)) {
-		raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+	if (__try_to_take_rt_mutex(lock, self, NULL, STEAL_LATERAL))
 		return;
-	}
 
 	BUG_ON(rt_mutex_owner(lock) == self);
 
@@ -1074,12 +1069,12 @@ static void  noinline __sched rt_spin_lo
 	__set_current_state_no_track(TASK_UNINTERRUPTIBLE);
 	raw_spin_unlock(&self->pi_lock);
 
-	ret = task_blocks_on_rt_mutex(lock, &waiter, self, RT_MUTEX_MIN_CHAINWALK);
+	ret = task_blocks_on_rt_mutex(lock, waiter, self, RT_MUTEX_MIN_CHAINWALK);
 	BUG_ON(ret);
 
 	for (;;) {
 		/* Try to acquire the lock again. */
-		if (__try_to_take_rt_mutex(lock, self, &waiter, STEAL_LATERAL))
+		if (__try_to_take_rt_mutex(lock, self, waiter, STEAL_LATERAL))
 			break;
 
 		top_waiter = rt_mutex_top_waiter(lock);
@@ -1087,9 +1082,9 @@ static void  noinline __sched rt_spin_lo
 
 		raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 
-		debug_rt_mutex_print_deadlock(&waiter);
+		debug_rt_mutex_print_deadlock(waiter);
 
-		if (top_waiter != &waiter || adaptive_wait(lock, lock_owner))
+		if (top_waiter != waiter || adaptive_wait(lock, lock_owner))
 			schedule();
 
 		raw_spin_lock_irqsave(&lock->wait_lock, flags);
@@ -1117,11 +1112,20 @@ static void  noinline __sched rt_spin_lo
 	 */
 	fixup_rt_mutex_waiters(lock);
 
-	BUG_ON(rt_mutex_has_waiters(lock) && &waiter == rt_mutex_top_waiter(lock));
-	BUG_ON(!RB_EMPTY_NODE(&waiter.tree_entry));
+	BUG_ON(rt_mutex_has_waiters(lock) && waiter == rt_mutex_top_waiter(lock));
+	BUG_ON(!RB_EMPTY_NODE(&waiter->tree_entry));
+}
 
-	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+static void noinline __sched rt_spin_lock_slowlock(struct rt_mutex *lock)
+{
+	struct rt_mutex_waiter waiter;
+	unsigned long flags;
 
+	rt_mutex_init_waiter(&waiter, true);
+
+	raw_spin_lock_irqsave(&lock->wait_lock, flags);
+	rt_spin_lock_slowlock_locked(lock, &waiter, flags);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 	debug_rt_mutex_free_waiter(&waiter);
 }
 
@@ -1131,7 +1135,7 @@ static bool __sched __rt_mutex_unlock_co
 /*
  * Slow path to release a rt_mutex spin_lock style
  */
-static void  noinline __sched rt_spin_lock_slowunlock(struct rt_mutex *lock)
+void __sched rt_spin_lock_slowunlock(struct rt_mutex *lock)
 {
 	unsigned long flags;
 	DEFINE_WAKE_Q(wake_q);
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -139,6 +139,10 @@ int __sched rt_mutex_slowlock_locked(str
 				     enum rtmutex_chainwalk chwalk,
 				     struct ww_acquire_ctx *ww_ctx,
 				     struct rt_mutex_waiter *waiter);
+void __sched rt_spin_lock_slowlock_locked(struct rt_mutex *lock,
+					  struct rt_mutex_waiter *waiter,
+					  unsigned long flags);
+void __sched rt_spin_lock_slowunlock(struct rt_mutex *lock);
 
 #ifdef CONFIG_DEBUG_RT_MUTEXES
 # include "rtmutex-debug.h"