[IPSEC]: Set skb->data to payload in x->mode->output

This patch changes the calling convention so that on entry from
x->mode->output and before entry into x->type->output skb->data
will point to the payload instead of the IP header.

This is essentially a redistribution of skb_push/skb_pull calls
with the aim of minimising them on the common path of tunnel +
ESP.

It'll also let us use the same calling convention between IPv4
and IPv6 with the next patch.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/net/ipv4/xfrm4_mode_transport.c b/net/ipv4/xfrm4_mode_transport.c
index 601047161ea6..10499d2ec65e 100644
--- a/net/ipv4/xfrm4_mode_transport.c
+++ b/net/ipv4/xfrm4_mode_transport.c
@@ -27,8 +27,8 @@ static int xfrm4_transport_output(struct xfrm_state *x, struct sk_buff *skb)
         int ihl = iph->ihl * 4;
 
         skb->transport_header = skb->network_header + ihl;
-        skb_push(skb, x->props.header_len);
-        skb_reset_network_header(skb);
+        skb_set_network_header(skb, -x->props.header_len);
+        __skb_pull(skb, ihl);
         memmove(skb_network_header(skb), iph, ihl);
         return 0;
 }