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- /* $Id: semaphore-helper.h,v 1.3 2001/03/26 15:00:33 orjanf Exp $
- *
- * SMP- and interrupt-safe semaphores helper functions. Generic versions, no
- * optimizations whatsoever...
- *
- */
-
- #ifndef _ASM_SEMAPHORE_HELPER_H
- #define _ASM_SEMAPHORE_HELPER_H
-
- #include <asm/atomic.h>
- #include <linux/errno.h>
-
- #define read(a) ((a)->counter)
- #define inc(a) (((a)->counter)++)
- #define dec(a) (((a)->counter)--)
-
- #define count_inc(a) ((*(a))++)
-
- /*
- * These two _must_ execute atomically wrt each other.
- */
- extern inline void wake_one_more(struct semaphore * sem)
- {
- atomic_inc(&sem->waking);
- }
-
- extern inline int waking_non_zero(struct semaphore *sem)
- {
- unsigned long flags;
- int ret = 0;
-
- local_save_flags(flags);
- local_irq_disable();
- if (read(&sem->waking) > 0) {
- dec(&sem->waking);
- ret = 1;
- }
- local_irq_restore(flags);
- return ret;
- }
-
- extern inline int waking_non_zero_interruptible(struct semaphore *sem,
- struct task_struct *tsk)
- {
- int ret = 0;
- unsigned long flags;
-
- local_save_flags(flags);
- local_irq_disable();
- if (read(&sem->waking) > 0) {
- dec(&sem->waking);
- ret = 1;
- } else if (signal_pending(tsk)) {
- inc(&sem->count);
- ret = -EINTR;
- }
- local_irq_restore(flags);
- return ret;
- }
-
- extern inline int waking_non_zero_trylock(struct semaphore *sem)
- {
- int ret = 1;
- unsigned long flags;
-
- local_save_flags(flags);
- local_irq_disable();
- if (read(&sem->waking) <= 0)
- inc(&sem->count);
- else {
- dec(&sem->waking);
- ret = 0;
- }
- local_irq_restore(flags);
- return ret;
- }
-
- #endif /* _ASM_SEMAPHORE_HELPER_H */
-
-
-