Unlocking API

The full unlocking API is:

void spin_unlock(spinlock_t *lock);
void spin_unlock_irqrestore(spinlock_t *lock, 
                            unsigned long flags);
void spin_unlock_irq(spinlock_t *lock);
void spin_unlock_bh(spinlock_t *lock);

Use the one which matches the locking function

There is also a reader/writer spinlock type
rwlock_t
See LDD3 for details