[NET_SCHED]: Fix requeueing in HFSC scheduler.

Requeued packets are kept in a high-priority queue
which is always dequeued first.

net/sched/sch_hfsc.c

@@ -181,12 +181,11 @@ struct hfsc_sched
 {
 	u16	defcls;				/* default class id */
 	struct hfsc_class root;			/* root class */
-	struct hfsc_class *last_xmit;		/* class that transmitted last
-						   packet (for requeueing) */
 	struct list_head clhash[HFSC_HSIZE];	/* class hash */
 	struct list_head eligible;		/* eligible list */
 	struct list_head droplist;		/* active leaf class list (for
 						   dropping) */
+	struct sk_buff_head requeue;		/* requeued packet */
 	struct timer_list wd_timer;		/* watchdog timer */
 };
 
@@ -1228,9 +1227,6 @@ hfsc_delete_class(struct Qdisc *sch, unsigned long arg)
 	list_del(&cl->siblings);
 	hfsc_adjust_levels(cl->cl_parent);
 	hfsc_purge_queue(sch, cl);
-	if (q->last_xmit == cl)
-		q->last_xmit = NULL;
-
 	if (--cl->refcnt == 0)
 		hfsc_destroy_class(sch, cl);
 
@@ -1538,6 +1534,7 @@ hfsc_init_qdisc(struct Qdisc *sch, struct rtattr *opt)
 		INIT_LIST_HEAD(&q->clhash[i]);
 	INIT_LIST_HEAD(&q->eligible);
 	INIT_LIST_HEAD(&q->droplist);
+	skb_queue_head_init(&q->requeue);
 
 	q->root.refcnt  = 1;
 	q->root.classid = sch->handle;
@@ -1616,10 +1613,9 @@ hfsc_reset_qdisc(struct Qdisc *sch)
 		list_for_each_entry(cl, &q->clhash[i], hlist)
 			hfsc_reset_class(cl);
 	}
-
+	__skb_queue_purge(&q->requeue);
 	INIT_LIST_HEAD(&q->eligible);
 	INIT_LIST_HEAD(&q->droplist);
-	q->last_xmit = NULL;
 	del_timer(&q->wd_timer);
 	sch->flags &= ~TCQ_F_THROTTLED;
 	sch->q.qlen = 0;
@@ -1636,7 +1632,7 @@ hfsc_destroy_qdisc(struct Qdisc *sch)
 		list_for_each_entry_safe(cl, next, &q->clhash[i], hlist)
 			hfsc_destroy_class(sch, cl);
 	}
-
+	__skb_queue_purge(&q->requeue);
 	del_timer(&q->wd_timer);
 }
 
@@ -1705,6 +1701,8 @@ hfsc_dequeue(struct Qdisc *sch)
 
 	if (sch->q.qlen == 0)
 		return NULL;
+	if ((skb = __skb_dequeue(&q->requeue)))
+		goto out;
 
 	PSCHED_GET_TIME(cur_time);
 
@@ -1754,7 +1752,7 @@ hfsc_dequeue(struct Qdisc *sch)
 		set_passive(cl);
 	}
 
-	q->last_xmit = cl;
+ out:
 	sch->flags &= ~TCQ_F_THROTTLED;
 	sch->q.qlen--;
 
@@ -1765,28 +1763,10 @@ static int
 hfsc_requeue(struct sk_buff *skb, struct Qdisc *sch)
 {
 	struct hfsc_sched *q = (struct hfsc_sched *)sch->data;
-	struct hfsc_class *cl = q->last_xmit;
-	unsigned int len = skb->len;
-	int ret;
 
-	if (cl == NULL) {
-		kfree_skb(skb);
-		sch->stats.drops++;
-		return NET_XMIT_DROP;
-	}
-
-	ret = cl->qdisc->ops->requeue(skb, cl->qdisc);
-	if (ret == NET_XMIT_SUCCESS) {
-		if (cl->qdisc->q.qlen == 1)
-			set_active(cl, len);
-		sch->q.qlen++;
-	} else {
-		cl->stats.drops++;
-		sch->stats.drops++;
-	}
-	q->last_xmit = NULL;
-
-	return ret;
+	__skb_queue_head(&q->requeue, skb);
+	sch->q.qlen++;
+	return NET_XMIT_SUCCESS;
 }
 
 static unsigned int