list_add_tail_rcu(&mqp->list, &mcast->qp_list);
atomic_inc(&mcast->refcount);
rb_link_node(&mcast->rb_node, pn, n);
rb_insert_color(&mcast->rb_node, &mcast_tree);
list_add_tail_rcu(&mqp->list, &mcast->qp_list);
atomic_inc(&mcast->refcount);
rb_link_node(&mcast->rb_node, pn, n);
rb_insert_color(&mcast->rb_node, &mcast_tree);