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 56