bit_spin_unlock
bit_spin_unlock(bit ^ be_to_le, iv->bitlock);
bit_spin_unlock(BH_JournalHead, &bh->b_state);
bit_spin_unlock(0, (unsigned long *)bkt);
bit_spin_unlock(3, &d->bits);
bit_spin_unlock(3, &d->bits);
bit_spin_unlock(SL_locked, &slab->flags.f);