83 строки
1.6 KiB
C
83 строки
1.6 KiB
C
/* Based on M68K version, Lineo Inc. May 2001 */
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#ifndef _BFIN_SEMAPHORE_HELPER_H
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#define _BFIN_SEMAPHORE_HELPER_H
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/*
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* SMP- and interrupt-safe semaphores helper functions.
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*
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* (C) Copyright 1996 Linus Torvalds
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*
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*/
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#include <asm/errno.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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atomic_inc(&sem->waking);
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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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int ret;
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unsigned long flags = 0;
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spin_lock_irqsave(&semaphore_wake_lock, flags);
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ret = 0;
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if (atomic_read(&sem->waking) > 0) {
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atomic_dec(&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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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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int ret = 0;
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unsigned long flags = 0;
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spin_lock_irqsave(&semaphore_wake_lock, flags);
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if (atomic_read(&sem->waking) > 0) {
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atomic_dec(&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_trylock:
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* 1 failed to lock
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* 0 got the lock
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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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int ret = 1;
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unsigned long flags = 0;
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spin_lock_irqsave(&semaphore_wake_lock, flags);
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if (atomic_read(&sem->waking) > 0) {
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atomic_dec(&sem->waking);
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ret = 0;
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} else
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atomic_inc(&sem->count);
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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 /* _BFIN_SEMAPHORE_HELPER_H */
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