tcp6: Add GRO support

This patch adds GRO support for TCP over IPv6.  The code is exactly
the same as the IPv4 version except for the pseudo-header checksum
computation.

Note that I've removed the unused tcphdr argument from tcp_v6_check
rather than invent a bogus value for GRO.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 35bcddf..bd6ff90 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2542,6 +2542,7 @@
 
 	return pp;
 }
+EXPORT_SYMBOL(tcp_gro_receive);
 
 int tcp_gro_complete(struct sk_buff *skb)
 {
@@ -2558,6 +2559,7 @@
 
 	return 0;
 }
+EXPORT_SYMBOL(tcp_gro_complete);
 
 #ifdef CONFIG_TCP_MD5SIG
 static unsigned long tcp_md5sig_users;