/* Routine learns (new) priority of leaf and activates feed chain for the prio. It can be called on already active leaf safely. It also adds leaf into droplist.  */
static void htb_activate(struct htb_sched *q, struct htb_class *cl)
/* Routine learns (new) priority of leaf and activates feed chain for the prio. It can be called on already active leaf safely. It also adds leaf into droplist.  */
static void htb_activate(struct htb_sched *q, struct htb_class *cl)
{
	WARN_ON(cl->level || !cl->un.leaf.q || !cl->un.leaf.q->q.qlen);
	if (!cl->prio_activity) {
		cl->prio_activity = 1 << cl->prio;
		htb_activate_prios(q, cl);
		list_add_tail(&cl->un.leaf.drop_list,
			      q->drops + cl->prio);
	}
}