diff options
Diffstat (limited to 'include/linux/rwsem.h')
-rw-r--r-- | include/linux/rwsem.h | 96 |
1 files changed, 38 insertions, 58 deletions
diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h index f99fe90732a..7b524b4109a 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -9,8 +9,6 @@ #include <linux/linkage.h> -#define RWSEM_DEBUG 0 - #ifdef __KERNEL__ #include <linux/types.h> @@ -26,89 +24,71 @@ struct rw_semaphore; #include <asm/rwsem.h> /* use an arch-specific implementation */ #endif -#ifndef rwsemtrace -#if RWSEM_DEBUG -extern void FASTCALL(rwsemtrace(struct rw_semaphore *sem, const char *str)); -#else -#define rwsemtrace(SEM,FMT) -#endif -#endif - /* * lock for reading */ -static inline void down_read(struct rw_semaphore *sem) -{ - might_sleep(); - rwsemtrace(sem,"Entering down_read"); - __down_read(sem); - rwsemtrace(sem,"Leaving down_read"); -} +extern void down_read(struct rw_semaphore *sem); /* * trylock for reading -- returns 1 if successful, 0 if contention */ -static inline int down_read_trylock(struct rw_semaphore *sem) -{ - int ret; - rwsemtrace(sem,"Entering down_read_trylock"); - ret = __down_read_trylock(sem); - rwsemtrace(sem,"Leaving down_read_trylock"); - return ret; -} +extern int down_read_trylock(struct rw_semaphore *sem); /* * lock for writing */ -static inline void down_write(struct rw_semaphore *sem) -{ - might_sleep(); - rwsemtrace(sem,"Entering down_write"); - __down_write(sem); - rwsemtrace(sem,"Leaving down_write"); -} +extern void down_write(struct rw_semaphore *sem); /* * trylock for writing -- returns 1 if successful, 0 if contention */ -static inline int down_write_trylock(struct rw_semaphore *sem) -{ - int ret; - rwsemtrace(sem,"Entering down_write_trylock"); - ret = __down_write_trylock(sem); - rwsemtrace(sem,"Leaving down_write_trylock"); - return ret; -} +extern int down_write_trylock(struct rw_semaphore *sem); /* * release a read lock */ -static inline void up_read(struct rw_semaphore *sem) -{ - rwsemtrace(sem,"Entering up_read"); - __up_read(sem); - rwsemtrace(sem,"Leaving up_read"); -} +extern void up_read(struct rw_semaphore *sem); /* * release a write lock */ -static inline void up_write(struct rw_semaphore *sem) -{ - rwsemtrace(sem,"Entering up_write"); - __up_write(sem); - rwsemtrace(sem,"Leaving up_write"); -} +extern void up_write(struct rw_semaphore *sem); /* * downgrade write lock to read lock */ -static inline void downgrade_write(struct rw_semaphore *sem) -{ - rwsemtrace(sem,"Entering downgrade_write"); - __downgrade_write(sem); - rwsemtrace(sem,"Leaving downgrade_write"); -} +extern void downgrade_write(struct rw_semaphore *sem); + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +/* + * nested locking. NOTE: rwsems are not allowed to recurse + * (which occurs if the same task tries to acquire the same + * lock instance multiple times), but multiple locks of the + * same lock class might be taken, if the order of the locks + * is always the same. This ordering rule can be expressed + * to lockdep via the _nested() APIs, but enumerating the + * subclasses that are used. (If the nesting relationship is + * static then another method for expressing nested locking is + * the explicit definition of lock class keys and the use of + * lockdep_set_class() at lock initialization time. + * See Documentation/lockdep-design.txt for more details.) + */ +extern void down_read_nested(struct rw_semaphore *sem, int subclass); +extern void down_write_nested(struct rw_semaphore *sem, int subclass); +/* + * Take/release a lock when not the owner will release it. + * + * [ This API should be avoided as much as possible - the + * proper abstraction for this case is completions. ] + */ +extern void down_read_non_owner(struct rw_semaphore *sem); +extern void up_read_non_owner(struct rw_semaphore *sem); +#else +# define down_read_nested(sem, subclass) down_read(sem) +# define down_write_nested(sem, subclass) down_write(sem) +# define down_read_non_owner(sem) down_read(sem) +# define up_read_non_owner(sem) up_read(sem) +#endif #endif /* __KERNEL__ */ #endif /* _LINUX_RWSEM_H */ |