85 lines
1.9 KiB
C
85 lines
1.9 KiB
C
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#ifndef ASMARM_SEMAPHORE_HELPER_H
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#define ASMARM_SEMAPHORE_HELPER_H
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/*
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* These two _must_ execute atomically wrt each other.
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*/
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static inline void wake_one_more(struct semaphore * sem)
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{
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unsigned long flags;
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spin_lock_irqsave(&semaphore_wake_lock, flags);
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if (atomic_read(&sem->count) <= 0)
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sem->waking++;
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spin_unlock_irqrestore(&semaphore_wake_lock, flags);
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}
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static inline int waking_non_zero(struct semaphore *sem)
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{
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unsigned long flags;
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int ret = 0;
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spin_lock_irqsave(&semaphore_wake_lock, flags);
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if (sem->waking > 0) {
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sem->waking--;
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ret = 1;
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}
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spin_unlock_irqrestore(&semaphore_wake_lock, flags);
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return ret;
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}
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/*
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* waking non zero interruptible
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* 1 got the lock
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* 0 go to sleep
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* -EINTR interrupted
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*
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* We must undo the sem->count down_interruptible() increment while we are
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* protected by the spinlock in order to make this atomic_inc() with the
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* atomic_read() in wake_one_more(), otherwise we can race. -arca
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*/
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static inline int waking_non_zero_interruptible(struct semaphore *sem,
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struct task_struct *tsk)
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{
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unsigned long flags;
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int ret = 0;
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spin_lock_irqsave(&semaphore_wake_lock, flags);
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if (sem->waking > 0) {
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sem->waking--;
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ret = 1;
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} else if (signal_pending(tsk)) {
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atomic_inc(&sem->count);
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ret = -EINTR;
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}
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spin_unlock_irqrestore(&semaphore_wake_lock, flags);
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return ret;
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}
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/*
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* waking_non_zero_try_lock:
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* 1 failed to lock
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* 0 got the lock
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*
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* We must undo the sem->count down_interruptible() increment while we are
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* protected by the spinlock in order to make this atomic_inc() with the
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* atomic_read() in wake_one_more(), otherwise we can race. -arca
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*/
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static inline int waking_non_zero_trylock(struct semaphore *sem)
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{
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unsigned long flags;
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int ret = 1;
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spin_lock_irqsave(&semaphore_wake_lock, flags);
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if (sem->waking <= 0)
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atomic_inc(&sem->count);
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else {
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sem->waking--;
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ret = 0;
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}
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spin_unlock_irqrestore(&semaphore_wake_lock, flags);
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return ret;
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}
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#endif
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