sch_direct_xmit
bool sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
if (sch_direct_xmit(skb, q, dev, txq, NULL, true) &&
if (sch_direct_xmit(skb, q, dev, txq, root_lock, true))
return sch_direct_xmit(skb, q, dev, txq, root_lock, validate);