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/* $Id: rwsem.h,v 1.5 2001/11/18 00:12:56 davem Exp $
* rwsem.h: R/W semaphores implemented using CAS
*
* Written by David S. Miller (davem@redhat.com), 2001.
* Derived from asm-i386/rwsem.h
*/
#ifndef _SPARC64_RWSEM_H
#define _SPARC64_RWSEM_H
#ifndef _LINUX_RWSEM_H
#error "please don't include asm/rwsem.h directly, use linux/rwsem.h instead"
#endif
#ifdef __KERNEL__
#include <linux/list.h>
#include <linux/spinlock.h>
#include <asm/rwsem-const.h>
struct rwsem_waiter;
struct rw_semaphore {
signed int count;
spinlock_t wait_lock;
struct list_head wait_list;
};
#define __RWSEM_INITIALIZER(name) \
{ RWSEM_UNLOCKED_VALUE, SPIN_LOCK_UNLOCKED, LIST_HEAD_INIT((name).wait_list) }
#define DECLARE_RWSEM(name) \
struct rw_semaphore name = __RWSEM_INITIALIZER(name)
static __inline__ void init_rwsem(struct rw_semaphore *sem)
{
sem->count = RWSEM_UNLOCKED_VALUE;
spin_lock_init(&sem->wait_lock);
INIT_LIST_HEAD(&sem->wait_list);
}
extern void __down_read(struct rw_semaphore *sem);
extern int __down_read_trylock(struct rw_semaphore *sem);
extern void __down_write(struct rw_semaphore *sem);
extern int __down_write_trylock(struct rw_semaphore *sem);
extern void __up_read(struct rw_semaphore *sem);
extern void __up_write(struct rw_semaphore *sem);
extern void __downgrade_write(struct rw_semaphore *sem);
static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem)
{
return atomic_add_return(delta, (atomic_t *)(&sem->count));
}
static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem)
{
atomic_add(delta, (atomic_t *)(&sem->count));
}
static inline int rwsem_is_locked(struct rw_semaphore *sem)
{
return (sem->count != 0);
}
#endif /* __KERNEL__ */
#endif /* _SPARC64_RWSEM_H */
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