Linux Device Drivers Development

Acquire and release

• Lock:

void mutex_lock(struct mutex *lock); 
int  mutex_lock_interruptible(struct mutex *lock); 
int  mutex_lock_killable(struct mutex *lock); 

• Unlock:

void mutex_unlock(struct mutex *lock); 

Sometimes, you may only need to check whether a mutex is locked or not. For that purpose, you can use the int mutex_is_locked(struct mutex *lock) function:

int mutex_is_locked(struct mutex *lock); 

What this function does is just check whether the mutex's owner is empty (NULL) or not. There is also mutex_trylock, which acquires the mutex if it is not already locked and returns 1; otherwise, it returns 0:

int mutex_trylock(struct mutex *lock); 

As with the wait queue's interruptible family function, mutex_lock_interruptible(), which ...