LXR linux/include/linux/percpu-rwsem.h

   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