diff options
Diffstat (limited to 'lib/rwsem-spinlock.c')
| -rw-r--r-- | lib/rwsem-spinlock.c | 23 |
1 files changed, 14 insertions, 9 deletions
diff --git a/lib/rwsem-spinlock.c b/lib/rwsem-spinlock.c index 9df3ca56db11..ccf95bff7984 100644 --- a/lib/rwsem-spinlock.c +++ b/lib/rwsem-spinlock.c @@ -17,6 +17,19 @@ struct rwsem_waiter { #define RWSEM_WAITING_FOR_WRITE 0x00000002 }; +int rwsem_is_locked(struct rw_semaphore *sem) +{ + int ret = 1; + unsigned long flags; + + if (spin_trylock_irqsave(&sem->wait_lock, flags)) { + ret = (sem->activity != 0); + spin_unlock_irqrestore(&sem->wait_lock, flags); + } + return ret; +} +EXPORT_SYMBOL(rwsem_is_locked); + /* * initialise the semaphore */ @@ -34,6 +47,7 @@ void __init_rwsem(struct rw_semaphore *sem, const char *name, spin_lock_init(&sem->wait_lock); INIT_LIST_HEAD(&sem->wait_list); } +EXPORT_SYMBOL(__init_rwsem); /* * handle the lock release when processes blocked on it that can now run @@ -305,12 +319,3 @@ void __downgrade_write(struct rw_semaphore *sem) spin_unlock_irqrestore(&sem->wait_lock, flags); } -EXPORT_SYMBOL(__init_rwsem); -EXPORT_SYMBOL(__down_read); -EXPORT_SYMBOL(__down_read_trylock); -EXPORT_SYMBOL(__down_write_nested); -EXPORT_SYMBOL(__down_write); -EXPORT_SYMBOL(__down_write_trylock); -EXPORT_SYMBOL(__up_read); -EXPORT_SYMBOL(__up_write); -EXPORT_SYMBOL(__downgrade_write); |