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/rcu_sync.h>
9#include <linux/lockdep.h>
10
11struct percpu_rw_semaphore {
12	struct rcu_sync		rss;
13	unsigned int __percpu	*fast_read_ctr;
14	struct rw_semaphore	rw_sem;
15	atomic_t		slow_read_ctr;
16	wait_queue_head_t	write_waitq;
17};
18
19extern void percpu_down_read(struct percpu_rw_semaphore *);
20extern int  percpu_down_read_trylock(struct percpu_rw_semaphore *);
21extern void percpu_up_read(struct percpu_rw_semaphore *);
22
23extern void percpu_down_write(struct percpu_rw_semaphore *);
24extern void percpu_up_write(struct percpu_rw_semaphore *);
25
26extern int __percpu_init_rwsem(struct percpu_rw_semaphore *,
27				const char *, struct lock_class_key *);
28extern void percpu_free_rwsem(struct percpu_rw_semaphore *);
29
30#define percpu_init_rwsem(brw)	\
31({								\
32	static struct lock_class_key rwsem_key;			\
33	__percpu_init_rwsem(brw, #brw, &rwsem_key);		\
34})
35
36
37#define percpu_rwsem_is_held(sem) lockdep_is_held(&(sem)->rw_sem)
38
39static inline void percpu_rwsem_release(struct percpu_rw_semaphore *sem,
40					bool read, unsigned long ip)
41{
42	lock_release(&sem->rw_sem.dep_map, 1, ip);
43#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
44	if (!read)
45		sem->rw_sem.owner = NULL;
46#endif
47}
48
49static inline void percpu_rwsem_acquire(struct percpu_rw_semaphore *sem,
50					bool read, unsigned long ip)
51{
52	lock_acquire(&sem->rw_sem.dep_map, 0, 1, read, 1, NULL, ip);
53}
54
55#endif
56