net: sched: taprio: Fix taprio_dequeue()

In case we don't have 'guard' or 'budget' to transmit the skb, we should
continue traversing the qdisc list since the remaining guard/budget
might be enough to transmit a skb from other children qdiscs.

Fixes: 5a781ccb (“tc: Add support for configuring the taprio scheduler”)
Signed-off-by: Andre Guedes <andre.guedes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/sch_taprio.c

@@ -188,12 +188,12 @@ static struct sk_buff *taprio_dequeue(struct Qdisc *sch)
 		 */
 		if (gate_mask != TAPRIO_ALL_GATES_OPEN &&
 		    ktime_after(guard, entry->close_time))
-			return NULL;
+			continue;
 
 		/* ... and no budget. */
 		if (gate_mask != TAPRIO_ALL_GATES_OPEN &&
 		    atomic_sub_return(len, &entry->budget) < 0)
-			return NULL;
+			continue;
 
 		skb = child->ops->dequeue(child);
 		if (unlikely(!skb))