diff options
| -rw-r--r-- | include/linux/rwsem.h | 10 | ||||
| -rw-r--r-- | kernel/rwsem.c | 16 |
2 files changed, 26 insertions, 0 deletions
diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h index 8da67d625e13..0616ffe45702 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -133,10 +133,20 @@ do { \ _down_write_nest_lock(sem, &(nest_lock)->dep_map); \ } while (0); +/* + * 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_nest_lock(sem, nest_lock) down_write(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 /* _LINUX_RWSEM_H */ diff --git a/kernel/rwsem.c b/kernel/rwsem.c index b3c6c3fcd847..cfff1435bdfb 100644 --- a/kernel/rwsem.c +++ b/kernel/rwsem.c @@ -126,6 +126,15 @@ void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest) EXPORT_SYMBOL(_down_write_nest_lock); +void down_read_non_owner(struct rw_semaphore *sem) +{ + might_sleep(); + + __down_read(sem); +} + +EXPORT_SYMBOL(down_read_non_owner); + void down_write_nested(struct rw_semaphore *sem, int subclass) { might_sleep(); @@ -136,6 +145,13 @@ void down_write_nested(struct rw_semaphore *sem, int subclass) EXPORT_SYMBOL(down_write_nested); +void up_read_non_owner(struct rw_semaphore *sem) +{ + __up_read(sem); +} + +EXPORT_SYMBOL(up_read_non_owner); + #endif |