Commit e7241d77 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  spinlock: Add missing __raw_spin_lock_flags() stub for UP
  mutex: add atomic_dec_and_mutex_lock(), fix
  locking, rtmutex.c: Documentation cleanup
  mutex: add atomic_dec_and_mutex_lock()
parents 3f6280dd 04dce7d9
......@@ -150,5 +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);
extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock);
#endif
......@@ -60,6 +60,7 @@ static inline void __raw_spin_unlock(raw_spinlock_t *lock)
#define __raw_spin_is_locked(lock) ((void)(lock), 0)
/* for sched.c and kernel_lock.c: */
# define __raw_spin_lock(lock) do { (void)(lock); } while (0)
# define __raw_spin_lock_flags(lock, flags) do { (void)(lock); } while (0)
# define __raw_spin_unlock(lock) do { (void)(lock); } while (0)
# define __raw_spin_trylock(lock) ({ (void)(lock); 1; })
#endif /* DEBUG_SPINLOCK */
......
......@@ -473,5 +473,28 @@ 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);
......@@ -891,9 +891,9 @@ 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)
......@@ -940,7 +940,7 @@ 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
*
......
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