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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()
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commit
e7241d7714
@ -150,5 +150,6 @@ extern int __must_check mutex_lock_killable(struct mutex *lock);
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*/
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extern int mutex_trylock(struct mutex *lock);
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extern void mutex_unlock(struct mutex *lock);
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extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock);
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#endif
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@ -60,6 +60,7 @@ static inline void __raw_spin_unlock(raw_spinlock_t *lock)
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#define __raw_spin_is_locked(lock) ((void)(lock), 0)
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/* for sched.c and kernel_lock.c: */
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# define __raw_spin_lock(lock) do { (void)(lock); } while (0)
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# define __raw_spin_lock_flags(lock, flags) do { (void)(lock); } while (0)
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# define __raw_spin_unlock(lock) do { (void)(lock); } while (0)
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# define __raw_spin_trylock(lock) ({ (void)(lock); 1; })
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#endif /* DEBUG_SPINLOCK */
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@ -473,5 +473,28 @@ int __sched mutex_trylock(struct mutex *lock)
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return ret;
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}
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EXPORT_SYMBOL(mutex_trylock);
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/**
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* atomic_dec_and_mutex_lock - return holding mutex if we dec to 0
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* @cnt: the atomic which we are to dec
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* @lock: the mutex to return holding if we dec to 0
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*
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* return true and hold lock if we dec to 0, return false otherwise
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*/
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int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock)
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{
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/* dec if we can't possibly hit 0 */
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if (atomic_add_unless(cnt, -1, 1))
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return 0;
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/* we might hit 0, so take the lock */
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mutex_lock(lock);
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if (!atomic_dec_and_test(cnt)) {
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/* when we actually did the dec, we didn't hit 0 */
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mutex_unlock(lock);
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return 0;
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}
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/* we hit 0, and we hold the lock */
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return 1;
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}
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EXPORT_SYMBOL(atomic_dec_and_mutex_lock);
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@ -891,9 +891,9 @@ int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock,
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EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible);
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/**
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* rt_mutex_lock_interruptible_ktime - lock a rt_mutex interruptible
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* the timeout structure is provided
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* by the caller
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* rt_mutex_timed_lock - lock a rt_mutex interruptible
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* the timeout structure is provided
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* by the caller
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*
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* @lock: the rt_mutex to be locked
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* @timeout: timeout structure or NULL (no timeout)
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@ -940,7 +940,7 @@ void __sched rt_mutex_unlock(struct rt_mutex *lock)
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}
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EXPORT_SYMBOL_GPL(rt_mutex_unlock);
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/***
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/**
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* rt_mutex_destroy - mark a mutex unusable
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* @lock: the mutex to be destroyed
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*
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