net: Make qdisc_skb_cb upper size bound explicit.

[ Upstream commit 16bda13d90c8d5da243e2cfa1677e62ecce26860 ]

Just like skb->cb[], so that qdisc_skb_cb can be encapsulated inside
of other data structures.

This is intended to be used by IPoIB so that it can remember
addressing information stored at hard_header_ops->create() time that
it can fetch when the packet gets to the transmit routine.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index f6bb08b73ca4c81a923a2d575801c5a38940efa4..55ce96b53b092e3ca04db6eaa7d6888fb9f478bc 100644 (file)
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -220,9 +220,16 @@ struct tcf_proto {
 
 struct qdisc_skb_cb {
        unsigned int            pkt_len;
-       long                    data[];
+       unsigned char           data[24];
 };
 
+static inline void qdisc_cb_private_validate(const struct sk_buff *skb, int sz)
+{
+       struct qdisc_skb_cb *qcb;
+       BUILD_BUG_ON(sizeof(skb->cb) < sizeof(unsigned int) + sz);
+       BUILD_BUG_ON(sizeof(qcb->data) < sz);
+}
+
 static inline int qdisc_qlen(const struct Qdisc *q)
 {
        return q->q.qlen;

diff --git a/net/sched/sch_choke.c b/net/sched/sch_choke.c
index 3422b25df9e46d8149ea0591ddc1625740b64bb6..081ffb9188d5ff565ec529064e42c91ca524f80f 100644 (file)
--- a/net/sched/sch_choke.c
+++ b/net/sched/sch_choke.c
@@ -225,8 +225,7 @@ struct choke_skb_cb {
 
 static inline struct choke_skb_cb *choke_skb_cb(const struct sk_buff *skb)
 {
-       BUILD_BUG_ON(sizeof(skb->cb) <
-               sizeof(struct qdisc_skb_cb) + sizeof(struct choke_skb_cb));
+       qdisc_cb_private_validate(skb, sizeof(struct choke_skb_cb));
        return (struct choke_skb_cb *)qdisc_skb_cb(skb)->data;
 }
 

diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index fd34012a009ba72d0244dce00b6aac13a4bf7565..7801b15b56884f71cbf0ce1bfecf89340018944d 100644 (file)
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -118,8 +118,7 @@ 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 qdisc_skb_cb) + sizeof(struct netem_skb_cb));
+       qdisc_cb_private_validate(skb, sizeof(struct netem_skb_cb));
        return (struct netem_skb_cb *)qdisc_skb_cb(skb)->data;
 }
 

diff --git a/net/sched/sch_sfb.c b/net/sched/sch_sfb.c
index e83c272c0325530edbedb86ac0c16c162e49fff0..17859eabe8d95da2fb5736e79dcc3c2df8cdeced 100644 (file)
--- a/net/sched/sch_sfb.c
+++ b/net/sched/sch_sfb.c
@@ -93,8 +93,7 @@ struct sfb_skb_cb {
 
 static inline struct sfb_skb_cb *sfb_skb_cb(const struct sk_buff *skb)
 {
-       BUILD_BUG_ON(sizeof(skb->cb) <
-               sizeof(struct qdisc_skb_cb) + sizeof(struct sfb_skb_cb));
+       qdisc_cb_private_validate(skb, sizeof(struct sfb_skb_cb));
        return (struct sfb_skb_cb *)qdisc_skb_cb(skb)->data;
 }