#ifndef _ASM_POWERPC_RWSEM_H#define _ASM_POWERPC_RWSEM_H #ifndef _LINUX_RWSEM_H#error "Please don't include <asm/rwsem.h> directly, use <linux/rwsem.h> instead."#endif #ifdef __KERNEL__ /* * R/W semaphores for PPC using the stuff in lib/rwsem.c. * Adapted largely from include/asm-i386/rwsem.h * by Paul Mackerras <paulus@samba.org>. */ /* * the semaphore definition */#ifdef CONFIG_PPC64# define RWSEM_ACTIVE_MASK		0xffffffffL#else# define RWSEM_ACTIVE_MASK		0x0000ffffL#endif #define RWSEM_UNLOCKED_VALUE		0x00000000L#define RWSEM_ACTIVE_BIAS		0x00000001L#define RWSEM_WAITING_BIAS		(-RWSEM_ACTIVE_MASK-1)#define RWSEM_ACTIVE_READ_BIAS		RWSEM_ACTIVE_BIAS#define RWSEM_ACTIVE_WRITE_BIAS		(RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS) /* * lock for reading */static inline void __down_read(struct rw_semaphore *sem){	if (unlikely(atomic_long_inc_return((atomic_long_t *)&sem->count) <= 0))		rwsem_down_read_failed(sem);} static inline int __down_read_trylock(struct rw_semaphore *sem){	long tmp; 	while ((tmp = sem->count) >= 0) {		if (tmp == cmpxchg(&sem->count, tmp,				   tmp + RWSEM_ACTIVE_READ_BIAS)) {			return 1;		}	}	return 0;} /* * lock for writing */static inline void __down_write_nested(struct rw_semaphore *sem, int subclass){	long tmp; 	tmp = atomic_long_add_return(RWSEM_ACTIVE_WRITE_BIAS,				     (atomic_long_t *)&sem->count);	if (unlikely(tmp != RWSEM_ACTIVE_WRITE_BIAS))		rwsem_down_write_failed(sem);} static inline void __down_write(struct rw_semaphore *sem){	__down_write_nested(sem, 0);} static inline int __down_write_trylock(struct rw_semaphore *sem){	long tmp; 	tmp = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE,		      RWSEM_ACTIVE_WRITE_BIAS);	return tmp == RWSEM_UNLOCKED_VALUE;} /* * unlock after reading */static inline void __up_read(struct rw_semaphore *sem){	long tmp; 	tmp = atomic_long_dec_return((atomic_long_t *)&sem->count);	if (unlikely(tmp < -1 && (tmp & RWSEM_ACTIVE_MASK) == 0))		rwsem_wake(sem);} /* * unlock after writing */static inline void __up_write(struct rw_semaphore *sem){	if (unlikely(atomic_long_sub_return(RWSEM_ACTIVE_WRITE_BIAS,				 (atomic_long_t *)&sem->count) < 0))		rwsem_wake(sem);} /* * implement atomic add functionality */static inline void rwsem_atomic_add(long delta, struct rw_semaphore *sem){	atomic_long_add(delta, (atomic_long_t *)&sem->count);} /* * downgrade write lock to read lock */static inline void __downgrade_write(struct rw_semaphore *sem){	long tmp; 	tmp = atomic_long_add_return(-RWSEM_WAITING_BIAS,				     (atomic_long_t *)&sem->count);	if (tmp < 0)		rwsem_downgrade_wake(sem);} /* * implement exchange and add functionality */static inline long rwsem_atomic_update(long delta, struct rw_semaphore *sem){	return atomic_long_add_return(delta, (atomic_long_t *)&sem->count);} #endif	/* __KERNEL__ */#endif	/* _ASM_POWERPC_RWSEM_H */