1 files changed, 50 insertions, 29 deletions

diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index edc72962ae63..fdd79d3ccd8c 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -17,6 +17,7 @@
 #include <linux/errno.h>
 #include <linux/skbuff.h>
 #include <linux/vmalloc.h>
+#include <linux/prandom.h>
 #include <linux/rtnetlink.h>
 #include <linux/reciprocal_div.h>
 #include <linux/rbtree.h>
@@ -78,6 +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;
 
@@ -382,6 +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)
@@ -411,6 +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++;
 }
 
@@ -446,12 +451,10 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 	struct netem_sched_data *q = qdisc_priv(sch);
 	/* We don't fill cb now as skb_unshare() may invalidate it */
 	struct netem_skb_cb *cb;
-	struct sk_buff *skb2;
+	struct sk_buff *skb2 = NULL;
 	struct sk_buff *segs = NULL;
 	unsigned int prev_len = qdisc_pkt_len(skb);
 	int count = 1;
-	int rc = NET_XMIT_SUCCESS;
-	int rc_drop = NET_XMIT_DROP;
 
 	/* Do not fool qdisc_drop_all() */
 	skb->prev = NULL;
@@ -480,19 +483,11 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 		skb_orphan_partial(skb);
 
 	/*
-	 * If we need to duplicate packet, then re-insert at top of the
-	 * qdisc tree, since parent queuer expects that only one
-	 * skb will be queued.
+	 * If we need to duplicate packet, then clone it before
+	 * original is modified.
 	 */
-	if (count > 1 && (skb2 = skb_clone(skb, GFP_ATOMIC)) != NULL) {
-		struct Qdisc *rootq = qdisc_root_bh(sch);
-		u32 dupsave = q->duplicate; /* prevent duplicating a dup... */
-
-		q->duplicate = 0;
-		rootq->enqueue(skb2, rootq, to_free);
-		q->duplicate = dupsave;
-		rc_drop = NET_XMIT_SUCCESS;
-	}
+	if (count > 1)
+		skb2 = skb_clone(skb, GFP_ATOMIC);
 
 	/*
 	 * Randomized packet corruption.
@@ -504,7 +499,8 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 		if (skb_is_gso(skb)) {
 			skb = netem_segment(skb, sch, to_free);
 			if (!skb)
-				return rc_drop;
+				goto finish_segs;
+
 			segs = skb->next;
 			skb_mark_not_on_list(skb);
 			qdisc_skb_cb(skb)->pkt_len = skb->len;
@@ -526,11 +522,28 @@ 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);
-		return rc_drop;
+		if (skb2)
+			__qdisc_drop(skb2, to_free);
+		return NET_XMIT_DROP;
+	}
+
+	/*
+	 * If doing duplication then re-insert at top of the
+	 * qdisc tree, since parent queuer expects that only one
+	 * skb will be queued.
+	 */
+	if (skb2) {
+		struct Qdisc *rootq = qdisc_root_bh(sch);
+		u32 dupsave = q->duplicate; /* prevent duplicating a dup... */
+
+		q->duplicate = 0;
+		rootq->enqueue(skb2, rootq, to_free);
+		q->duplicate = dupsave;
+		skb2 = NULL;
 	}
 
 	qdisc_qstats_backlog_inc(sch, skb);
@@ -601,9 +614,12 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 	}
 
 finish_segs:
+	if (skb2)
+		__qdisc_drop(skb2, to_free);
+
 	if (segs) {
 		unsigned int len, last_len;
-		int nb;
+		int rc, nb;
 
 		len = skb ? skb->len : 0;
 		nb = skb ? 1 : 0;
@@ -690,8 +706,8 @@ 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;
 	}
@@ -707,8 +723,7 @@ 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,
@@ -731,21 +746,25 @@ deliver:
 
 				err = qdisc_enqueue(skb, q->qdisc, &to_free);
 				kfree_skb_list(to_free);
-				if (err != NET_XMIT_SUCCESS &&
-				    net_xmit_drop_count(err)) {
-					qdisc_qstats_drop(sch);
-					qdisc_tree_reduce_backlog(sch, 1,
-								  pkt_len);
+				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,
@@ -755,8 +774,10 @@ deliver:
 
 	if (q->qdisc) {
 		skb = q->qdisc->ops->dequeue(q->qdisc);
-		if (skb)
+		if (skb) {
+			sch->q.qlen--;
 			goto deliver;
+		}
 	}
 	return NULL;
 }