1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
84 lines
1.9 KiB
C
84 lines
1.9 KiB
C
#ifndef ASMARM_SEMAPHORE_HELPER_H
|
|
#define ASMARM_SEMAPHORE_HELPER_H
|
|
|
|
/*
|
|
* These two _must_ execute atomically wrt each other.
|
|
*/
|
|
static inline void wake_one_more(struct semaphore * sem)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&semaphore_wake_lock, flags);
|
|
if (atomic_read(&sem->count) <= 0)
|
|
sem->waking++;
|
|
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
|
|
}
|
|
|
|
static inline int waking_non_zero(struct semaphore *sem)
|
|
{
|
|
unsigned long flags;
|
|
int ret = 0;
|
|
|
|
spin_lock_irqsave(&semaphore_wake_lock, flags);
|
|
if (sem->waking > 0) {
|
|
sem->waking--;
|
|
ret = 1;
|
|
}
|
|
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* waking non zero interruptible
|
|
* 1 got the lock
|
|
* 0 go to sleep
|
|
* -EINTR interrupted
|
|
*
|
|
* We must undo the sem->count down_interruptible() increment while we are
|
|
* protected by the spinlock in order to make this atomic_inc() with the
|
|
* atomic_read() in wake_one_more(), otherwise we can race. -arca
|
|
*/
|
|
static inline int waking_non_zero_interruptible(struct semaphore *sem,
|
|
struct task_struct *tsk)
|
|
{
|
|
unsigned long flags;
|
|
int ret = 0;
|
|
|
|
spin_lock_irqsave(&semaphore_wake_lock, flags);
|
|
if (sem->waking > 0) {
|
|
sem->waking--;
|
|
ret = 1;
|
|
} else if (signal_pending(tsk)) {
|
|
atomic_inc(&sem->count);
|
|
ret = -EINTR;
|
|
}
|
|
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* waking_non_zero_try_lock:
|
|
* 1 failed to lock
|
|
* 0 got the lock
|
|
*
|
|
* We must undo the sem->count down_interruptible() increment while we are
|
|
* protected by the spinlock in order to make this atomic_inc() with the
|
|
* atomic_read() in wake_one_more(), otherwise we can race. -arca
|
|
*/
|
|
static inline int waking_non_zero_trylock(struct semaphore *sem)
|
|
{
|
|
unsigned long flags;
|
|
int ret = 1;
|
|
|
|
spin_lock_irqsave(&semaphore_wake_lock, flags);
|
|
if (sem->waking <= 0)
|
|
atomic_inc(&sem->count);
|
|
else {
|
|
sem->waking--;
|
|
ret = 0;
|
|
}
|
|
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
|
|
return ret;
|
|
}
|
|
|
|
#endif
|