diff options
Diffstat (limited to 'include/linux/rwsem.h')
| -rw-r--r-- | include/linux/rwsem.h | 53 |
1 files changed, 52 insertions, 1 deletions
diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h index efd348fe8ca7..a8afe9cd000c 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -11,6 +11,9 @@ #include <linux/types.h> #include <linux/kernel.h> +#include <linux/list.h> +#include <linux/spinlock.h> + #include <asm/system.h> #include <asm/atomic.h> @@ -19,9 +22,57 @@ struct rw_semaphore; #ifdef CONFIG_RWSEM_GENERIC_SPINLOCK #include <linux/rwsem-spinlock.h> /* use a generic implementation */ #else -#include <asm/rwsem.h> /* use an arch-specific implementation */ +/* All arch specific implementations share the same struct */ +struct rw_semaphore { + long count; + spinlock_t wait_lock; + struct list_head wait_list; +#ifdef CONFIG_DEBUG_LOCK_ALLOC + struct lockdep_map dep_map; +#endif +}; + +extern struct rw_semaphore *rwsem_down_read_failed(struct rw_semaphore *sem); +extern struct rw_semaphore *rwsem_down_write_failed(struct rw_semaphore *sem); +extern struct rw_semaphore *rwsem_wake(struct rw_semaphore *); +extern struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem); + +/* Include the arch specific part */ +#include <asm/rwsem.h> + +/* In all implementations count != 0 means locked */ +static inline int rwsem_is_locked(struct rw_semaphore *sem) +{ + return sem->count != 0; +} + +#endif + +/* Common initializer macros and functions */ + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +# define __RWSEM_DEP_MAP_INIT(lockname) , .dep_map = { .name = #lockname } +#else +# define __RWSEM_DEP_MAP_INIT(lockname) #endif +#define __RWSEM_INITIALIZER(name) \ + { RWSEM_UNLOCKED_VALUE, __SPIN_LOCK_UNLOCKED(name.wait_lock), \ + LIST_HEAD_INIT((name).wait_list) __RWSEM_DEP_MAP_INIT(name) } + +#define DECLARE_RWSEM(name) \ + struct rw_semaphore name = __RWSEM_INITIALIZER(name) + +extern void __init_rwsem(struct rw_semaphore *sem, const char *name, + struct lock_class_key *key); + +#define init_rwsem(sem) \ +do { \ + static struct lock_class_key __key; \ + \ + __init_rwsem((sem), #sem, &__key); \ +} while (0) + /* * lock for reading */ |