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-rw-r--r--include/linux/mutex.h24
-rw-r--r--kernel/mutex.c25
-rw-r--r--kernel/rtmutex.c8
3 files changed, 29 insertions, 28 deletions
diff --git a/include/linux/mutex.h b/include/linux/mutex.h
index 93054fc3635c..878cab4f5fcc 100644
--- a/include/linux/mutex.h
+++ b/include/linux/mutex.h
@@ -150,28 +150,6 @@ extern int __must_check mutex_lock_killable(struct mutex *lock);
150 */ 150 */
151extern int mutex_trylock(struct mutex *lock); 151extern int mutex_trylock(struct mutex *lock);
152extern void mutex_unlock(struct mutex *lock); 152extern void mutex_unlock(struct mutex *lock);
153 153extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock);
154/**
155 * atomic_dec_and_mutex_lock - return holding mutex if we dec to 0
156 * @cnt: the atomic which we are to dec
157 * @lock: the mutex to return holding if we dec to 0
158 *
159 * return true and hold lock if we dec to 0, return false otherwise
160 */
161static inline int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock)
162{
163 /* dec if we can't possibly hit 0 */
164 if (atomic_add_unless(cnt, -1, 1))
165 return 0;
166 /* we might hit 0, so take the lock */
167 mutex_lock(lock);
168 if (!atomic_dec_and_test(cnt)) {
169 /* when we actually did the dec, we didn't hit 0 */
170 mutex_unlock(lock);
171 return 0;
172 }
173 /* we hit 0, and we hold the lock */
174 return 1;
175}
176 154
177#endif 155#endif
diff --git a/kernel/mutex.c b/kernel/mutex.c
index f415e80a9119..f788a5ace24b 100644
--- a/kernel/mutex.c
+++ b/kernel/mutex.c
@@ -471,5 +471,28 @@ int __sched mutex_trylock(struct mutex *lock)
471 471
472 return ret; 472 return ret;
473} 473}
474
475EXPORT_SYMBOL(mutex_trylock); 474EXPORT_SYMBOL(mutex_trylock);
475
476/**
477 * atomic_dec_and_mutex_lock - return holding mutex if we dec to 0
478 * @cnt: the atomic which we are to dec
479 * @lock: the mutex to return holding if we dec to 0
480 *
481 * return true and hold lock if we dec to 0, return false otherwise
482 */
483int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock)
484{
485 /* dec if we can't possibly hit 0 */
486 if (atomic_add_unless(cnt, -1, 1))
487 return 0;
488 /* we might hit 0, so take the lock */
489 mutex_lock(lock);
490 if (!atomic_dec_and_test(cnt)) {
491 /* when we actually did the dec, we didn't hit 0 */
492 mutex_unlock(lock);
493 return 0;
494 }
495 /* we hit 0, and we hold the lock */
496 return 1;
497}
498EXPORT_SYMBOL(atomic_dec_and_mutex_lock);
diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c
index 69d9cb921ffa..013882e83497 100644
--- a/kernel/rtmutex.c
+++ b/kernel/rtmutex.c
@@ -864,9 +864,9 @@ int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock,
864EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible); 864EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible);
865 865
866/** 866/**
867 * rt_mutex_lock_interruptible_ktime - lock a rt_mutex interruptible 867 * rt_mutex_timed_lock - lock a rt_mutex interruptible
868 * the timeout structure is provided 868 * the timeout structure is provided
869 * by the caller 869 * by the caller
870 * 870 *
871 * @lock: the rt_mutex to be locked 871 * @lock: the rt_mutex to be locked
872 * @timeout: timeout structure or NULL (no timeout) 872 * @timeout: timeout structure or NULL (no timeout)
@@ -913,7 +913,7 @@ void __sched rt_mutex_unlock(struct rt_mutex *lock)
913} 913}
914EXPORT_SYMBOL_GPL(rt_mutex_unlock); 914EXPORT_SYMBOL_GPL(rt_mutex_unlock);
915 915
916/*** 916/**
917 * rt_mutex_destroy - mark a mutex unusable 917 * rt_mutex_destroy - mark a mutex unusable
918 * @lock: the mutex to be destroyed 918 * @lock: the mutex to be destroyed
919 * 919 *