gro: Only use skb_gro_header for completely non-linear packets
Currently skb_gro_header is used for packets which put the hardware
header in skb->data with the rest in frags. Since the drivers that
need this optimisation all provide completely non-linear packets,
we can gain extra optimisations by only performing the frag0
optimisation for completely non-linear packets.
In particular, we can simply test frag0 (instead of skb_headlen)
to see whether the optimisation is in force.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 61890ed..d1afc3b 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1135,22 +1135,23 @@
hlen += offset;
if (!NAPI_GRO_CB(skb)->frag0 ||
- unlikely(skb_shinfo(skb)->frags[0].size + skb_headlen(skb) < hlen))
+ unlikely(skb_shinfo(skb)->frags[0].size < hlen)) {
+ NAPI_GRO_CB(skb)->frag0 = NULL;
return pskb_may_pull(skb, hlen) ? skb->data + offset : NULL;
+ }
return NAPI_GRO_CB(skb)->frag0 + offset;
}
static inline void *skb_gro_mac_header(struct sk_buff *skb)
{
- return skb_headlen(skb) ? skb_mac_header(skb) :
- NAPI_GRO_CB(skb)->frag0;
+ return NAPI_GRO_CB(skb)->frag0 ?: skb_mac_header(skb);
}
static inline void *skb_gro_network_header(struct sk_buff *skb)
{
- return skb_headlen(skb) ? skb_network_header(skb) :
- NAPI_GRO_CB(skb)->frag0 + skb_network_offset(skb);
+ return (NAPI_GRO_CB(skb)->frag0 ?: skb->data) +
+ skb_network_offset(skb);
}
static inline int dev_hard_header(struct sk_buff *skb, struct net_device *dev,
diff --git a/net/core/dev.c b/net/core/dev.c
index bdb1a73..f9d90c5 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2510,7 +2510,8 @@
NAPI_GRO_CB(skb)->data_offset = 0;
NAPI_GRO_CB(skb)->frag0 = NULL;
- if (!skb_headlen(skb) && !PageHighMem(skb_shinfo(skb)->frags[0].page))
+ if (skb->mac_header == skb->tail &&
+ !PageHighMem(skb_shinfo(skb)->frags[0].page))
NAPI_GRO_CB(skb)->frag0 =
page_address(skb_shinfo(skb)->frags[0].page) +
skb_shinfo(skb)->frags[0].page_offset;