percpu-rwsem.h
#ifndef _LINUX_PERCPU_RWSEM_H
#define _LINUX_PERCPU_RWSEM_H
#include <linux/atomic.h>
#include <linux/rwsem.h>
#include <linux/percpu.h>
#include <linux/wait.h>
#include <linux/lockdep.h>
struct percpu_rw_semaphore {
unsigned int __percpu *fast_read_ctr;
atomic_t write_ctr;
struct rw_semaphore rw_sem;
atomic_t slow_read_ctr;
wait_queue_head_t write_waitq;
};
extern void percpu_down_read(struct percpu_rw_semaphore *);
extern void percpu_up_read(struct percpu_rw_semaphore *);
extern void percpu_down_write(struct percpu_rw_semaphore *);
extern void percpu_up_write(struct percpu_rw_semaphore *);
extern int __percpu_init_rwsem(struct percpu_rw_semaphore *,
const char *, struct lock_class_key *);
extern void percpu_free_rwsem(struct percpu_rw_semaphore *);
#define percpu_init_rwsem(brw) \
({ \
static struct lock_class_key rwsem_key; \
__percpu_init_rwsem(brw, #brw, &rwsem_key); \
})
#endif