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Merge branch 'core/locking' into perfcounters/core

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Merge reason: we moved a mutex.h commit that originated from the
              perfcounters tree into core/locking - but now merge
	      back that branch to solve a merge artifact and to
	      pick up cleanups of this commit that happened in
	      core/locking.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2009-05-06 08:46:27 +02:00
commit 3611dfb8ed
3 changed files with 29 additions and 28 deletions
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24
include/linux/mutex.h
View File

@ -150,28 +150,6 @@ extern int __must_check mutex_lock_killable(struct mutex *lock);
*/
extern int mutex_trylock(struct mutex *lock);
extern void mutex_unlock(struct mutex *lock);
/**
* atomic_dec_and_mutex_lock - return holding mutex if we dec to 0
* @cnt: the atomic which we are to dec
* @lock: the mutex to return holding if we dec to 0
*
* return true and hold lock if we dec to 0, return false otherwise
*/
static inline int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock)
{
/* dec if we can't possibly hit 0 */
if (atomic_add_unless(cnt, -1, 1))
return 0;
/* we might hit 0, so take the lock */
mutex_lock(lock);
if (!atomic_dec_and_test(cnt)) {
/* when we actually did the dec, we didn't hit 0 */
mutex_unlock(lock);
return 0;
}
/* we hit 0, and we hold the lock */
return 1;
}
extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock);
#endif

25
kernel/mutex.c
View File

@ -471,5 +471,28 @@ int __sched mutex_trylock(struct mutex *lock)
return ret;
}
EXPORT_SYMBOL(mutex_trylock);
/**
* atomic_dec_and_mutex_lock - return holding mutex if we dec to 0
* @cnt: the atomic which we are to dec
* @lock: the mutex to return holding if we dec to 0
*
* return true and hold lock if we dec to 0, return false otherwise
*/
int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock)
{
/* dec if we can't possibly hit 0 */
if (atomic_add_unless(cnt, -1, 1))
return 0;
/* we might hit 0, so take the lock */
mutex_lock(lock);
if (!atomic_dec_and_test(cnt)) {
/* when we actually did the dec, we didn't hit 0 */
mutex_unlock(lock);
return 0;
}
/* we hit 0, and we hold the lock */
return 1;
}
EXPORT_SYMBOL(atomic_dec_and_mutex_lock);

8
kernel/rtmutex.c
View File

@ -864,9 +864,9 @@ int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock,
EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible);
/**
* rt_mutex_lock_interruptible_ktime - lock a rt_mutex interruptible
* the timeout structure is provided
* by the caller
* rt_mutex_timed_lock - lock a rt_mutex interruptible
* the timeout structure is provided
* by the caller
*
* @lock: the rt_mutex to be locked
* @timeout: timeout structure or NULL (no timeout)
@ -913,7 +913,7 @@ void __sched rt_mutex_unlock(struct rt_mutex *lock)
}
EXPORT_SYMBOL_GPL(rt_mutex_unlock);
/***
/**
* rt_mutex_destroy - mark a mutex unusable
* @lock: the mutex to be destroyed
*