add down_write_killable_nested()

 */

extern void down_read_nested(struct rw_semaphore *sem, int subclass);

extern void down_write_nested(struct rw_semaphore *sem, int subclass);

extern int down_write_killable_nested(struct rw_semaphore *sem, int subclass);

extern void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest_lock);

# define down_write_nest_lock(sem, nest_lock)			\

# define down_read_nested(sem, subclass)		down_read(sem)

# define down_write_nest_lock(sem, nest_lock)	down_write(sem)

# define down_write_nested(sem, subclass)	down_write(sem)

# define down_write_killable_nested(sem, subclass)	down_write_killable(sem)

# define down_read_non_owner(sem)		down_read(sem)

# define up_read_non_owner(sem)			up_read(sem)

#endif

EXPORT_SYMBOL(down_write_nested);

int __sched down_write_killable_nested(struct rw_semaphore *sem, int subclass)

{

	might_sleep();

	rwsem_acquire(&sem->dep_map, subclass, 0, _RET_IP_);

	if (LOCK_CONTENDED_RETURN(sem, __down_write_trylock, __down_write_killable)) {

		rwsem_release(&sem->dep_map, 1, _RET_IP_);

		return -EINTR;

	}

	rwsem_set_owner(sem);

	return 0;

}

EXPORT_SYMBOL(down_write_killable_nested);

void up_read_non_owner(struct rw_semaphore *sem)

{

	__up_read(sem);