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 void percpu_up_read(struct percpu_rw_semaphore *);
  20
  21 extern void percpu_down_write(struct percpu_rw_semaphore *);
  22 extern void percpu_up_write(struct percpu_rw_semaphore *);
  23
  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 *);
  27
  28 #define percpu_init_rwsem(brw)  \
  29 ({                                                              \
  30         static struct lock_class_key rwsem_key;                 \
  31         __percpu_init_rwsem(brw, #brw, &rwsem_key);             \
  32 })
  33
  34 #endif