Merge Linus master into drm-next

The merge is clean, but the arm build fails afterwards,
due to API changes in the regulator tree.

I've included the patch into the merge to fix the build.

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 21 insertions, 30 deletions

diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index 94674e5919cb..4cccea6b8934 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -25,7 +25,7 @@
 #include <linux/spinlock.h>
 #include <linux/interrupt.h>
 #include <linux/debug_locks.h>
-#include "mcs_spinlock.h"
+#include <linux/osq_lock.h>
 
 /*
  * In the DEBUG case we are using the "NULL fastpath" for mutexes,
@@ -217,44 +217,35 @@ ww_mutex_set_context_slowpath(struct ww_mutex *lock,
 }
 
 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
-static inline bool owner_running(struct mutex *lock, struct task_struct *owner)
-{
-	if (lock->owner != owner)
-		return false;
-
-	/*
-	 * Ensure we emit the owner->on_cpu, dereference _after_ checking
-	 * lock->owner still matches owner, if that fails, owner might
-	 * point to free()d memory, if it still matches, the rcu_read_lock()
-	 * ensures the memory stays valid.
-	 */
-	barrier();
-
-	return owner->on_cpu;
-}
-
 /*
  * Look out! "owner" is an entirely speculative pointer
  * access and not reliable.
  */
 static noinline
-int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner)
+bool mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner)
 {
+	bool ret = true;
+
 	rcu_read_lock();
-	while (owner_running(lock, owner)) {
-		if (need_resched())
+	while (lock->owner == owner) {
+		/*
+		 * Ensure we emit the owner->on_cpu, dereference _after_
+		 * checking lock->owner still matches owner. If that fails,
+		 * owner might point to freed memory. If it still matches,
+		 * the rcu_read_lock() ensures the memory stays valid.
+		 */
+		barrier();
+
+		if (!owner->on_cpu || need_resched()) {
+			ret = false;
 			break;
+		}
 
 		cpu_relax_lowlatency();
 	}
 	rcu_read_unlock();
 
-	/*
-	 * We break out the loop above on need_resched() and when the
-	 * owner changed, which is a sign for heavy contention. Return
-	 * success only when lock->owner is NULL.
-	 */
-	return lock->owner == NULL;
+	return ret;
 }
 
 /*
@@ -269,7 +260,7 @@ static inline int mutex_can_spin_on_owner(struct mutex *lock)
 		return 0;
 
 	rcu_read_lock();
-	owner = ACCESS_ONCE(lock->owner);
+	owner = READ_ONCE(lock->owner);
 	if (owner)
 		retval = owner->on_cpu;
 	rcu_read_unlock();
@@ -343,7 +334,7 @@ static bool mutex_optimistic_spin(struct mutex *lock,
 			 * As such, when deadlock detection needs to be
 			 * performed the optimistic spinning cannot be done.
 			 */
-			if (ACCESS_ONCE(ww->ctx))
+			if (READ_ONCE(ww->ctx))
 				break;
 		}
 
@@ -351,7 +342,7 @@ static bool mutex_optimistic_spin(struct mutex *lock,
 		 * If there's an owner, wait for it to either
 		 * release the lock or go to sleep.
 		 */
-		owner = ACCESS_ONCE(lock->owner);
+		owner = READ_ONCE(lock->owner);
 		if (owner && !mutex_spin_on_owner(lock, owner))
 			break;
 
@@ -490,7 +481,7 @@ static inline int __sched
 __ww_mutex_lock_check_stamp(struct mutex *lock, struct ww_acquire_ctx *ctx)
 {
 	struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
-	struct ww_acquire_ctx *hold_ctx = ACCESS_ONCE(ww->ctx);
+	struct ww_acquire_ctx *hold_ctx = READ_ONCE(ww->ctx);
 
 	if (!hold_ctx)
 		return 0;