net: sched: shrink struct qdisc_skb_cb to 28 bytes
We cannot make struct qdisc_skb_cb bigger without impacting IPoIB,
or increasing skb->cb[] size.
Commit e0f31d849867 ("flow_keys: Record IP layer protocol in
skb_flow_dissect()") broke IPoIB.
Only current offender is sch_choke, and this one do not need an
absolutely precise flow key.
If we store 17 bytes of flow key, its more than enough. (Its the actual
size of flow_keys if it was a packed structure, but we might add new
fields at the end of it later)
Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: e0f31d849867 ("flow_keys: Record IP layer protocol in skb_flow_dissect()")
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_choke.c b/net/sched/sch_choke.c
index ed30e43..fb666d1 100644
--- a/net/sched/sch_choke.c
+++ b/net/sched/sch_choke.c
@@ -133,10 +133,16 @@
--sch->q.qlen;
}
+/* private part of skb->cb[] that a qdisc is allowed to use
+ * is limited to QDISC_CB_PRIV_LEN bytes.
+ * As a flow key might be too large, we store a part of it only.
+ */
+#define CHOKE_K_LEN min_t(u32, sizeof(struct flow_keys), QDISC_CB_PRIV_LEN - 3)
+
struct choke_skb_cb {
u16 classid;
u8 keys_valid;
- struct flow_keys keys;
+ u8 keys[QDISC_CB_PRIV_LEN - 3];
};
static inline struct choke_skb_cb *choke_skb_cb(const struct sk_buff *skb)
@@ -163,22 +169,26 @@
static bool choke_match_flow(struct sk_buff *skb1,
struct sk_buff *skb2)
{
+ struct flow_keys temp;
+
if (skb1->protocol != skb2->protocol)
return false;
if (!choke_skb_cb(skb1)->keys_valid) {
choke_skb_cb(skb1)->keys_valid = 1;
- skb_flow_dissect(skb1, &choke_skb_cb(skb1)->keys);
+ skb_flow_dissect(skb1, &temp);
+ memcpy(&choke_skb_cb(skb1)->keys, &temp, CHOKE_K_LEN);
}
if (!choke_skb_cb(skb2)->keys_valid) {
choke_skb_cb(skb2)->keys_valid = 1;
- skb_flow_dissect(skb2, &choke_skb_cb(skb2)->keys);
+ skb_flow_dissect(skb2, &temp);
+ memcpy(&choke_skb_cb(skb2)->keys, &temp, CHOKE_K_LEN);
}
return !memcmp(&choke_skb_cb(skb1)->keys,
&choke_skb_cb(skb2)->keys,
- sizeof(struct flow_keys));
+ CHOKE_K_LEN);
}
/*