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/lockdep.h>
   9
  10 struct percpu_rw_semaphore {
  11         unsigned int __percpu   *fast_read_ctr;
  12         atomic_t                write_ctr;
  13         struct rw_semaphore     rw_sem;
  14         atomic_t                slow_read_ctr;
  15         wait_queue_head_t       write_waitq;
  16 };
  17
  18 extern void percpu_down_read(struct percpu_rw_semaphore *);
  19 extern int  percpu_down_read_trylock(struct percpu_rw_semaphore *);
  20 extern void percpu_up_read(struct percpu_rw_semaphore *);
  21
  22 extern void percpu_down_write(struct percpu_rw_semaphore *);
  23 extern void percpu_up_write(struct percpu_rw_semaphore *);
  24
  25 extern int __percpu_init_rwsem(struct percpu_rw_semaphore *,
  26                                 const char *, struct lock_class_key *);
  27 extern void percpu_free_rwsem(struct percpu_rw_semaphore *);
  28
  29 #define percpu_init_rwsem(brw)  \
  30 ({                                                              \
  31         static struct lock_class_key rwsem_key;                 \
  32         __percpu_init_rwsem(brw, #brw, &rwsem_key);             \
  33 })
  34
  35
  36 #define percpu_rwsem_is_held(sem) lockdep_is_held(&(sem)->rw_sem)
  37
  38 static inline void percpu_rwsem_release(struct percpu_rw_semaphore *sem,
  39                                         bool read, unsigned long ip)
  40 {
  41         lock_release(&sem->rw_sem.dep_map, 1, ip);
  42 #ifdef CONFIG_RWSEM_SPIN_ON_OWNER
  43         if (!read)
  44                 sem->rw_sem.owner = NULL;
  45 #endif
  46 }
  47
  48 static inline void percpu_rwsem_acquire(struct percpu_rw_semaphore *sem,
  49                                         bool read, unsigned long ip)
  50 {
  51         lock_acquire(&sem->rw_sem.dep_map, 0, 1, read, 1, NULL, ip);
  52 }
  53
  54 #endif