enqueue_to_backlog
ret = enqueue_to_backlog(skb, cpu, &rflow->last_qtail);
ret = enqueue_to_backlog(skb, smp_processor_id(), &qtail);
ret = enqueue_to_backlog(skb, cpu, &rflow->last_qtail);
enqueue_to_backlog(skb, cpu, &rflow->last_qtail);