gro: Avoid unnecessary comparison after skb_gro_header
For the overwhelming majority of cases, skb_gro_header's return
value cannot be NULL. Yet we must check it because of its current
form. This patch splits it up into multiple functions in order
to avoid this.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 61f5538..b6215be 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -817,13 +817,20 @@
struct sk_buff *p;
struct ipv6hdr *iph;
unsigned int nlen;
+ unsigned int hlen;
+ unsigned int off;
int flush = 1;
int proto;
__wsum csum;
- iph = skb_gro_header(skb, sizeof(*iph));
- if (unlikely(!iph))
- goto out;
+ off = skb_gro_offset(skb);
+ hlen = off + sizeof(*iph);
+ iph = skb_gro_header_fast(skb, off);
+ if (skb_gro_header_hard(skb, hlen)) {
+ iph = skb_gro_header_slow(skb, hlen, off);
+ if (unlikely(!iph))
+ goto out;
+ }
skb_gro_pull(skb, sizeof(*iph));
skb_set_transport_header(skb, skb_gro_offset(skb));