1 files changed, 57 insertions, 6 deletions

diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index fe6fed291a7b..32a5f3304046 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -79,6 +79,8 @@ struct netem_sched_data {
 	struct sk_buff	*t_head;
 	struct sk_buff	*t_tail;
 
+	u32 t_len;
+
 	/* optional qdisc for classful handling (NULL at netem init) */
 	struct Qdisc	*qdisc;
 
@@ -383,6 +385,7 @@ static void tfifo_reset(struct Qdisc *sch)
 	rtnl_kfree_skbs(q->t_head, q->t_tail);
 	q->t_head = NULL;
 	q->t_tail = NULL;
+	q->t_len = 0;
 }
 
 static void tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch)
@@ -412,6 +415,7 @@ static void tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch)
 		rb_link_node(&nskb->rbnode, parent, p);
 		rb_insert_color(&nskb->rbnode, &q->t_root);
 	}
+	q->t_len++;
 	sch->q.qlen++;
 }
 
@@ -425,6 +429,7 @@ static struct sk_buff *netem_segment(struct sk_buff *skb, struct Qdisc *sch,
 	struct sk_buff *segs;
 	netdev_features_t features = netif_skb_features(skb);
 
+	qdisc_skb_cb(skb)->pkt_segs = 1;
 	segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
 
 	if (IS_ERR_OR_NULL(segs)) {
@@ -518,7 +523,7 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 			1<<get_random_u32_below(8);
 	}
 
-	if (unlikely(sch->q.qlen >= sch->limit)) {
+	if (unlikely(q->t_len >= sch->limit)) {
 		/* re-link segs, so that qdisc_drop_all() frees them all */
 		skb->next = segs;
 		qdisc_drop_all(skb, sch, to_free);
@@ -702,8 +707,8 @@ static struct sk_buff *netem_dequeue(struct Qdisc *sch)
 tfifo_dequeue:
 	skb = __qdisc_dequeue_head(&sch->q);
 	if (skb) {
-		qdisc_qstats_backlog_dec(sch, skb);
 deliver:
+		qdisc_qstats_backlog_dec(sch, skb);
 		qdisc_bstats_update(sch, skb);
 		return skb;
 	}
@@ -719,8 +724,7 @@ deliver:
 
 		if (time_to_send <= now && q->slot.slot_next <= now) {
 			netem_erase_head(q, skb);
-			sch->q.qlen--;
-			qdisc_qstats_backlog_dec(sch, skb);
+			q->t_len--;
 			skb->next = NULL;
 			skb->prev = NULL;
 			/* skb->dev shares skb->rbnode area,
@@ -746,17 +750,22 @@ deliver:
 				if (err != NET_XMIT_SUCCESS) {
 					if (net_xmit_drop_count(err))
 						qdisc_qstats_drop(sch);
+					sch->qstats.backlog -= pkt_len;
+					sch->q.qlen--;
 					qdisc_tree_reduce_backlog(sch, 1, pkt_len);
 				}
 				goto tfifo_dequeue;
 			}
+			sch->q.qlen--;
 			goto deliver;
 		}
 
 		if (q->qdisc) {
 			skb = q->qdisc->ops->dequeue(q->qdisc);
-			if (skb)
+			if (skb) {
+				sch->q.qlen--;
 				goto deliver;
+			}
 		}
 
 		qdisc_watchdog_schedule_ns(&q->watchdog,
@@ -766,8 +775,10 @@ deliver:
 
 	if (q->qdisc) {
 		skb = q->qdisc->ops->dequeue(q->qdisc);
-		if (skb)
+		if (skb) {
+			sch->q.qlen--;
 			goto deliver;
+		}
 	}
 	return NULL;
 }
@@ -963,6 +974,41 @@ static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla,
 	return 0;
 }
 
+static const struct Qdisc_class_ops netem_class_ops;
+
+static int check_netem_in_tree(struct Qdisc *sch, bool duplicates,
+			       struct netlink_ext_ack *extack)
+{
+	struct Qdisc *root, *q;
+	unsigned int i;
+
+	root = qdisc_root_sleeping(sch);
+
+	if (sch != root && root->ops->cl_ops == &netem_class_ops) {
+		if (duplicates ||
+		    ((struct netem_sched_data *)qdisc_priv(root))->duplicate)
+			goto err;
+	}
+
+	if (!qdisc_dev(root))
+		return 0;
+
+	hash_for_each(qdisc_dev(root)->qdisc_hash, i, q, hash) {
+		if (sch != q && q->ops->cl_ops == &netem_class_ops) {
+			if (duplicates ||
+			    ((struct netem_sched_data *)qdisc_priv(q))->duplicate)
+				goto err;
+		}
+	}
+
+	return 0;
+
+err:
+	NL_SET_ERR_MSG(extack,
+		       "netem: cannot mix duplicating netems with other netems in tree");
+	return -EINVAL;
+}
+
 /* Parse netlink message to set options */
 static int netem_change(struct Qdisc *sch, struct nlattr *opt,
 			struct netlink_ext_ack *extack)
@@ -1021,6 +1067,11 @@ static int netem_change(struct Qdisc *sch, struct nlattr *opt,
 	q->gap = qopt->gap;
 	q->counter = 0;
 	q->loss = qopt->loss;
+
+	ret = check_netem_in_tree(sch, qopt->duplicate, extack);
+	if (ret)
+		goto unlock;
+
 	q->duplicate = qopt->duplicate;
 
 	/* for compatibility with earlier versions.