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authorHerbert Xu <herbert@gondor.apana.org.au>2009-01-29 14:19:50 +0000
committerDavid S. Miller <davem@davemloft.net>2009-01-29 16:33:03 -0800
commit86911732d3996a9da07914b280621450111bb6da (patch)
treee787240d5ba869ddf4d0adfc3f9c69e0372e96ef /net/ipv6/af_inet6.c
parent5d0d9be8ef456afc6c3fb5f8aad06ef19b704b05 (diff)
downloadlinux-2.6.38-lt-ux500-86911732d3996a9da07914b280621450111bb6da.tar.gz
gro: Avoid copying headers of unmerged packets
Unfortunately simplicity isn't always the best. The fraginfo interface turned out to be suboptimal. The problem was quite obvious. For every packet, we have to copy the headers from the frags structure into skb->head, even though for 99% of the packets this part is immediately thrown away after the merge. LRO didn't have this problem because it directly read the headers from the frags structure. This patch attempts to address this by creating an interface that allows GRO to access the headers in the first frag without having to copy it. Because all drivers that use frags place the headers in the first frag this optimisation should be enough. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/af_inet6.c')
-rw-r--r--net/ipv6/af_inet6.c30
1 files changed, 20 insertions, 10 deletions
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index c802bc1658a..bd91eadcbe3 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -799,24 +799,34 @@ static struct sk_buff **ipv6_gro_receive(struct sk_buff **head,
int proto;
__wsum csum;
- if (unlikely(!pskb_may_pull(skb, sizeof(*iph))))
+ iph = skb_gro_header(skb, sizeof(*iph));
+ if (unlikely(!iph))
goto out;
- iph = ipv6_hdr(skb);
- __skb_pull(skb, sizeof(*iph));
+ skb_gro_pull(skb, sizeof(*iph));
+ skb_set_transport_header(skb, skb_gro_offset(skb));
- flush += ntohs(iph->payload_len) != skb->len;
+ flush += ntohs(iph->payload_len) != skb_gro_len(skb);
rcu_read_lock();
- proto = ipv6_gso_pull_exthdrs(skb, iph->nexthdr);
- iph = ipv6_hdr(skb);
- IPV6_GRO_CB(skb)->proto = proto;
+ proto = iph->nexthdr;
ops = rcu_dereference(inet6_protos[proto]);
- if (!ops || !ops->gro_receive)
- goto out_unlock;
+ if (!ops || !ops->gro_receive) {
+ __pskb_pull(skb, skb_gro_offset(skb));
+ proto = ipv6_gso_pull_exthdrs(skb, proto);
+ skb_gro_pull(skb, -skb_transport_offset(skb));
+ skb_reset_transport_header(skb);
+ __skb_push(skb, skb_gro_offset(skb));
+
+ if (!ops || !ops->gro_receive)
+ goto out_unlock;
+
+ iph = ipv6_hdr(skb);
+ }
+
+ IPV6_GRO_CB(skb)->proto = proto;
flush--;
- skb_reset_transport_header(skb);
nlen = skb_network_header_len(skb);
for (p = *head; p; p = p->next) {