pkt_sched: Remove qdisc->ops->requeue() etc.

After implementing qdisc->ops->peek() and changing sch_netem into
classless qdisc there are no more qdisc->ops->requeue() users. This
patch removes this method with its wrappers (qdisc_requeue()), and
also unused qdisc->requeue structure. There are a few minor fixes of
warnings (htb_enqueue()) and comments btw.

The idea to kill ->requeue() and a similar patch were first developed
by David S. Miller.

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_multiq.c b/net/sched/sch_multiq.c
index 155648d..f645ac5 100644
--- a/net/sched/sch_multiq.c
+++ b/net/sched/sch_multiq.c
@@ -92,40 +92,6 @@
 	return ret;
 }
 
-
-static int
-multiq_requeue(struct sk_buff *skb, struct Qdisc *sch)
-{
-	struct Qdisc *qdisc;
-	struct multiq_sched_data *q = qdisc_priv(sch);
-	int ret;
-
-	qdisc = multiq_classify(skb, sch, &ret);
-#ifdef CONFIG_NET_CLS_ACT
-	if (qdisc == NULL) {
-		if (ret & __NET_XMIT_BYPASS)
-			sch->qstats.drops++;
-		kfree_skb(skb);
-		return ret;
-	}
-#endif
-
-	ret = qdisc->ops->requeue(skb, qdisc);
-	if (ret == NET_XMIT_SUCCESS) {
-		sch->q.qlen++;
-		sch->qstats.requeues++;
-		if (q->curband)
-			q->curband--;
-		else
-			q->curband = q->bands - 1;
-		return NET_XMIT_SUCCESS;
-	}
-	if (net_xmit_drop_count(ret))
-		sch->qstats.drops++;
-	return ret;
-}
-
-
 static struct sk_buff *multiq_dequeue(struct Qdisc *sch)
 {
 	struct multiq_sched_data *q = qdisc_priv(sch);
@@ -140,7 +106,7 @@
 			q->curband = 0;
 
 		/* Check that target subqueue is available before
-		 * pulling an skb to avoid excessive requeues
+		 * pulling an skb to avoid head-of-line blocking.
 		 */
 		if (!__netif_subqueue_stopped(qdisc_dev(sch), q->curband)) {
 			qdisc = q->queues[q->curband];
@@ -170,7 +136,7 @@
 			curband = 0;
 
 		/* Check that target subqueue is available before
-		 * pulling an skb to avoid excessive requeues
+		 * pulling an skb to avoid head-of-line blocking.
 		 */
 		if (!__netif_subqueue_stopped(qdisc_dev(sch), curband)) {
 			qdisc = q->queues[curband];
@@ -480,7 +446,6 @@
 	.enqueue	=	multiq_enqueue,
 	.dequeue	=	multiq_dequeue,
 	.peek		=	multiq_peek,
-	.requeue	=	multiq_requeue,
 	.drop		=	multiq_drop,
 	.init		=	multiq_init,
 	.reset		=	multiq_reset,