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
11 struct 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
19 extern void percpu_down_read(struct percpu_rw_semaphore *);
20 extern int percpu_down_read_trylock(struct percpu_rw_semaphore *);
21 extern void percpu_up_read(struct percpu_rw_semaphore *);
22
23 extern void percpu_down_write(struct percpu_rw_semaphore *);
24 extern void percpu_up_write(struct percpu_rw_semaphore *);
25
26 extern int __percpu_init_rwsem(struct percpu_rw_semaphore *,
27 const char *, struct lock_class_key *);
28 extern 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
percpu_rwsem_release(struct percpu_rw_semaphore * sem,bool read,unsigned long ip)39 static 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
percpu_rwsem_acquire(struct percpu_rw_semaphore * sem,bool read,unsigned long ip)49 static 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