1#ifndef _LINUX_PERCPU_RWSEM_H
2#define _LINUX_PERCPU_RWSEM_H
3
4#include <linux/atomic.h>
5#include <linux/rwsem.h>
6#include <linux/percpu.h>
7#include <linux/wait.h>
8#include <linux/lockdep.h>
9
10struct percpu_rw_semaphore {
11	unsigned int __percpu	*fast_read_ctr;
12	atomic_t		write_ctr;
13	struct rw_semaphore	rw_sem;
14	atomic_t		slow_read_ctr;
15	wait_queue_head_t	write_waitq;
16};
17
18extern void percpu_down_read(struct percpu_rw_semaphore *);
19extern void percpu_up_read(struct percpu_rw_semaphore *);
20
21extern void percpu_down_write(struct percpu_rw_semaphore *);
22extern void percpu_up_write(struct percpu_rw_semaphore *);
23
24extern int __percpu_init_rwsem(struct percpu_rw_semaphore *,
25				const char *, struct lock_class_key *);
26extern void percpu_free_rwsem(struct percpu_rw_semaphore *);
27
28#define percpu_init_rwsem(brw)	\
29({								\
30	static struct lock_class_key rwsem_key;			\
31	__percpu_init_rwsem(brw, #brw, &rwsem_key);		\
32})
33
34#endif
35