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
  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
  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
  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