void ipv6_mc_unmap(struct inet6_dev *idev)
{
	struct ifmcaddr6 *i;

	/* Install multicast list, except for all-nodes (already installed) */

	mutex_lock(&idev->mc_lock);
	for_each_mc_mclock(idev, i)
		igmp6_group_dropped(i);
	mutex_unlock(&idev->mc_lock);
}
void ipv6_mc_unmap(struct inet6_dev *idev)
{
	struct ifmcaddr6 *i;

	 

	mutex_lock(&idev->mc_lock);
	for_each_mc_mclock(idev, i)
		igmp6_group_dropped(i);
	mutex_unlock(&idev->mc_lock);
}