1 #ifndef _LINUX_PERCPU_RWSEM_H
2 #define _LINUX_PERCPU_RWSEM_H
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>
10 struct percpu_rw_semaphore {
11 unsigned int __percpu *fast_read_ctr;
13 struct rw_semaphore rw_sem;
14 atomic_t slow_read_ctr;
15 wait_queue_head_t write_waitq;
18 extern void percpu_down_read(struct percpu_rw_semaphore *);
19 extern void percpu_up_read(struct percpu_rw_semaphore *);
21 extern void percpu_down_write(struct percpu_rw_semaphore *);
22 extern void percpu_up_write(struct percpu_rw_semaphore *);
24 extern int __percpu_init_rwsem(struct percpu_rw_semaphore *,
25 const char *, struct lock_class_key *);
26 extern void percpu_free_rwsem(struct percpu_rw_semaphore *);
28 #define percpu_init_rwsem(brw) \
30 static struct lock_class_key rwsem_key; \
31 __percpu_init_rwsem(brw, #brw, &rwsem_key); \