net_sched: Add size table for qdiscs

Add size table functions for qdiscs and calculate packet size in
qdisc_enqueue().

Based on patch by Patrick McHardy
 http://marc.info/?l=linux-netdev&m=115201979221729&w=2

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 2 deletions

diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index ae49be00022f..a59085700678 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -84,8 +84,9 @@ struct netem_skb_cb {
 
 static inline struct netem_skb_cb *netem_skb_cb(struct sk_buff *skb)
 {
-        BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct netem_skb_cb));
-        return (struct netem_skb_cb *)skb->cb;
+        BUILD_BUG_ON(sizeof(skb->cb) <
+                sizeof(struct qdisc_skb_cb) + sizeof(struct netem_skb_cb));
+        return (struct netem_skb_cb *)qdisc_skb_cb(skb)->data;
 }
 
 /* init_crandom - initialize correlated random number generator