gre: Call gso_make_checksum

Call gso_make_checksum. This should have the benefit of using a
checksum that may have been previously computed for the packet.

This also adds NETIF_F_GSO_GRE_CSUM to differentiate devices that
offload GRE GSO with and without the GRE checksum offloaed.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/netdev_features.h b/include/linux/netdev_features.h
index f1338e0f9866..e5a589435e2b 100644
--- a/include/linux/netdev_features.h
+++ b/include/linux/netdev_features.h
@@ -42,6 +42,7 @@ enum {
         NETIF_F_TSO6_BIT,               /* ... TCPv6 segmentation */
         NETIF_F_FSO_BIT,                /* ... FCoE segmentation */
         NETIF_F_GSO_GRE_BIT,            /* ... GRE with TSO */
+        NETIF_F_GSO_GRE_CSUM_BIT,       /* ... GRE with csum with TSO */
         NETIF_F_GSO_IPIP_BIT,           /* ... IPIP tunnel with TSO */
         NETIF_F_GSO_SIT_BIT,            /* ... SIT tunnel with TSO */
         NETIF_F_GSO_UDP_TUNNEL_BIT,     /* ... UDP TUNNEL with TSO */
@@ -112,6 +113,7 @@ enum {
 #define NETIF_F_RXFCS           __NETIF_F(RXFCS)
 #define NETIF_F_RXALL           __NETIF_F(RXALL)
 #define NETIF_F_GSO_GRE         __NETIF_F(GSO_GRE)
+#define NETIF_F_GSO_GRE_CSUM    __NETIF_F(GSO_GRE_CSUM)
 #define NETIF_F_GSO_IPIP        __NETIF_F(GSO_IPIP)
 #define NETIF_F_GSO_SIT         __NETIF_F(GSO_SIT)
 #define NETIF_F_GSO_UDP_TUNNEL  __NETIF_F(GSO_UDP_TUNNEL)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 5a6d10a538f5..c705808bef9c 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -347,6 +347,8 @@ enum {
         SKB_GSO_MPLS = 1 << 10,
 
         SKB_GSO_UDP_TUNNEL_CSUM = 1 << 11,
+
+        SKB_GSO_GRE_CSUM = 1 << 12,
 };
 
 #if BITS_PER_LONG > 32