86 строки
1.6 KiB
C
86 строки
1.6 KiB
C
#ifndef _H8300_SEMAPHORE_HELPER_H
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#define _H8300_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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* based on
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* m68k version by Andreas Schwab
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*/
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#include <linux/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((atomic_t *)&sem->sleepers);
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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;
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spin_lock_irqsave(&semaphore_wake_lock, flags);
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ret = 0;
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if (sem->sleepers > 0) {
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sem->sleepers--;
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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;
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unsigned long flags;
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spin_lock_irqsave(&semaphore_wake_lock, flags);
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ret = 0;
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if (sem->sleepers > 0) {
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sem->sleepers--;
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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;
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unsigned long flags;
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spin_lock_irqsave(&semaphore_wake_lock, flags);
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ret = 1;
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if (sem->sleepers <= 0)
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atomic_inc(&sem->count);
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else {
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sem->sleepers--;
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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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