#ifndef _ASM_POWERPC_SEMAPHORE_H
#define _ASM_POWERPC_SEMAPHORE_H
/*
* Remove spinlock-based RW semaphores; RW semaphore definitions are
* now in rwsem.h and we use the generic lib/rwsem.c implementation.
* Rework semaphores to use atomic_dec_if_positive.
* -- Paul Mackerras (paulus@samba.org)
*/
#ifdef __KERNEL__
#include <asm/atomic.h>
#include <asm/system.h>
#include <linux/wait.h>
#include <linux/rwsem.h>
struct semaphore {
* Note that any negative value of count is equivalent to 0,
* but additionally indicates that some process(es) might be
* sleeping on `wait'.
atomic_t count;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name, n) \
{ \
.count = ATOMIC_INIT(n), \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
}
#define __DECLARE_SEMAPHORE_GENERIC(name, count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name, 1)
#define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name, 0)
static inline void sema_init (struct semaphore *sem, int val)
{
atomic_set(&sem->count, val);
init_waitqueue_head(&sem->wait);
static inline void init_MUTEX (struct semaphore *sem)
sema_init(sem, 1);
static inline void init_MUTEX_LOCKED (struct semaphore *sem)
sema_init(sem, 0);
extern void __down(struct semaphore * sem);
extern int __down_interruptible(struct semaphore * sem);
extern void __up(struct semaphore * sem);
static inline void down(struct semaphore * sem)
might_sleep();
* Try to get the semaphore, take the slow path if we fail.
if (unlikely(atomic_dec_return(&sem->count) < 0))
__down(sem);
static inline int down_interruptible(struct semaphore * sem)
int ret = 0;
ret = __down_interruptible(sem);
return ret;
static inline int down_trylock(struct semaphore * sem)
return atomic_dec_if_positive(&sem->count) < 0;
static inline void up(struct semaphore * sem)
if (unlikely(atomic_inc_return(&sem->count) <= 0))
__up(sem);
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_SEMAPHORE_H */