From: Vijay Subramanian <subramanian.vijay@gmail.com>
Date: Thu, 19 Jan 2012 10:20:59 +0000 (+0000)
Subject: netem: Fix off-by-one bug in reordering
X-Git-Tag: v3.12-rc1~3966^2~33
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=a42b4799c683723e8c464de4026af085b2ebd5fa;p=kernel%2Fkernel-generic.git

netem: Fix off-by-one bug in reordering

With netem reordering, a gap of N is supposed to reorder every Nth packet with
given reorder probability.  However, the code currently skips N packets and
reorders every (N+1)th packet.

Signed-off-by: Vijay Subramanian <subramanian.vijay@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index e7e1d0b..2776012 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -419,7 +419,7 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 
 	cb = netem_skb_cb(skb);
 	if (q->gap == 0 ||		/* not doing reordering */
-	    q->counter < q->gap ||	/* inside last reordering gap */
+	    q->counter < q->gap - 1 ||	/* inside last reordering gap */
 	    q->reorder < get_crandom(&q->reorder_cor)) {
 		psched_time_t now;
 		psched_tdiff_t delay;