Use rb_first() to get first entry in rb tree.
Signed-off-by: Akinbou Mita <akinobu.mita@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
        for (i = 0; i < 500; i++) {
                struct htb_class *cl;
                long diff;
-               struct rb_node *p = q->wait_pq[level].rb_node;
+               struct rb_node *p = rb_first(&q->wait_pq[level]);
+
                if (!p)
                        return 0;
-               while (p->rb_left)
-                       p = p->rb_left;
 
                cl = rb_entry(p, struct htb_class, pq_node);
                if (time_after(cl->pq_key, q->jiffies)) {