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 55