[IPV6]: Added GSO support for TCPv6

This patch adds GSO support for IPv6 and TCPv6.  This is based on a patch
by Ananda Raju <Ananda.Raju@neterion.com>.  His original description is:

	This patch enables TSO over IPv6. Currently Linux network stacks
	restricts TSO over IPv6 by clearing of the NETIF_F_TSO bit from
	"dev->features". This patch will remove this restriction.

	This patch will introduce a new flag NETIF_F_TSO6 which will be used
	to check whether device supports TSO over IPv6. If device support TSO
	over IPv6 then we don't clear of NETIF_F_TSO and which will make the
	TCP layer to create TSO packets. Any device supporting TSO over IPv6
	will set NETIF_F_TSO6 flag in "dev->features" along with NETIF_F_TSO.

	In case when user disables TSO using ethtool, NETIF_F_TSO will get
	cleared from "dev->features". So even if we have NETIF_F_TSO6 we don't
	get TSO packets created by TCP layer.

	SKB_GSO_TCPV4 renamed to SKB_GSO_TCP to make it generic GSO packet.
	SKB_GSO_UDPV4 renamed to SKB_GSO_UDP as UFO is not a IPv4 feature.
	UFO is supported over IPv6 also

	The following table shows there is significant improvement in
	throughput with normal frames and CPU usage for both normal and jumbo.

	--------------------------------------------------
	|          |     1500        |      9600         |
	|          ------------------|-------------------|
	|          | thru     CPU    |  thru     CPU     |
	--------------------------------------------------
	| TSO OFF  | 2.00   5.5% id  |  5.66   20.0% id  |
	--------------------------------------------------
	| TSO ON   | 2.63   78.0 id  |  5.67   39.0% id  |
	--------------------------------------------------

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

1 files changed, 2 insertions, 4 deletions

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index bf7f8c26c488..7ea5bea49aa9 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -270,9 +270,8 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
         ipv6_addr_copy(&np->saddr, saddr);
         inet->rcv_saddr = LOOPBACK4_IPV6;
 
+        sk->sk_gso_type = SKB_GSO_TCPV6;
         ip6_dst_store(sk, dst, NULL);
-        sk->sk_route_caps = dst->dev->features &
-                ~(NETIF_F_IP_CSUM | NETIF_F_TSO);
 
         icsk->icsk_ext_hdr_len = 0;
         if (np->opt)
@@ -930,9 +929,8 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
          * comment in that function for the gory details. -acme
          */
 
+        sk->sk_gso_type = SKB_GSO_TCPV6;
         ip6_dst_store(newsk, dst, NULL);
-        newsk->sk_route_caps = dst->dev->features &
-                ~(NETIF_F_IP_CSUM | NETIF_F_TSO);
 
         newtcp6sk = (struct tcp6_sock *)newsk;
         inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;