Merge branches 'pm-cpufreq', 'pm-cpuidle', 'pm-devfreq', 'pm-opp' and 'pm-tools'

[linux-drm-fsl-dcu.git] / kernel / locking / rwsem-xadd.c

diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c
index d6203faf2eb1f15522b720605bab13f6008fab4d..2f7cc4076f50aa0c534c22e527ab3d1f11ce9a66 100644 (file)
--- a/kernel/locking/rwsem-xadd.c
+++ b/kernel/locking/rwsem-xadd.c
@@ -242,23 +242,25 @@ struct rw_semaphore __sched *rwsem_down_read_failed(struct rw_semaphore *sem)
                schedule();
        }
 
-       tsk->state = TASK_RUNNING;
-
+       __set_task_state(tsk, TASK_RUNNING);
        return sem;
 }
+EXPORT_SYMBOL(rwsem_down_read_failed);
 
 static inline bool rwsem_try_write_lock(long count, struct rw_semaphore *sem)
 {
-       if (!(count & RWSEM_ACTIVE_MASK)) {
-               /* try acquiring the write lock */
-               if (sem->count == RWSEM_WAITING_BIAS &&
-                   cmpxchg(&sem->count, RWSEM_WAITING_BIAS,
-                           RWSEM_ACTIVE_WRITE_BIAS) == RWSEM_WAITING_BIAS) {
-                       if (!list_is_singular(&sem->wait_list))
-                               rwsem_atomic_update(RWSEM_WAITING_BIAS, sem);
-                       return true;
-               }
+       /*
+        * Try acquiring the write lock. Check count first in order
+        * to reduce unnecessary expensive cmpxchg() operations.
+        */
+       if (count == RWSEM_WAITING_BIAS &&
+           cmpxchg(&sem->count, RWSEM_WAITING_BIAS,
+                   RWSEM_ACTIVE_WRITE_BIAS) == RWSEM_WAITING_BIAS) {
+               if (!list_is_singular(&sem->wait_list))
+                       rwsem_atomic_update(RWSEM_WAITING_BIAS, sem);
+               return true;
        }
+
        return false;
 }
 
@@ -465,6 +467,7 @@ struct rw_semaphore __sched *rwsem_down_write_failed(struct rw_semaphore *sem)
 
        return sem;
 }
+EXPORT_SYMBOL(rwsem_down_write_failed);
 
 /*
  * handle waking up a waiter on the semaphore
@@ -485,6 +488,7 @@ struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem)
 
        return sem;
 }
+EXPORT_SYMBOL(rwsem_wake);
 
 /*
  * downgrade a write lock into a read lock
@@ -506,8 +510,4 @@ struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem)
 
        return sem;
 }
-
-EXPORT_SYMBOL(rwsem_down_read_failed);
-EXPORT_SYMBOL(rwsem_down_write_failed);
-EXPORT_SYMBOL(rwsem_wake);
 EXPORT_SYMBOL(rwsem_downgrade_wake);