static inline int next_slot(struct b43_dmaring *ring, int slot)
{
	B43_WARN_ON(!(slot >= -1 && slot <= ring->nr_slots - 1));
	if (slot == ring->nr_slots - 1)
		return 0;
	return slot + 1;
}
static inline int next_slot(struct b43_dmaring *ring, int slot)
{
	B43_WARN_ON(!(slot >= -1 && slot <= ring->nr_slots - 1));
	if (slot == ring->nr_slots - 1)
		return 0;
	return slot + 1;
}