hyperv: Properly handle checksum offload

Do checksum offload only if the client of the driver wants checksum to be
offloaded.

In V1 version of this patch, I  addressed comments from
Stephen Hemminger <stephen@networkplumber.org> and
Eric Dumazet <eric.dumazet@gmail.com>.

In this version of the patch I have addressed comments from
David Miller.

This patch fixes a bug that is exposed in gateway scenarios.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 31e55fba7cadd03d9e19221139727272b9eeec77..7918d5132c1f14764cda43daf9f98d7f7c01f310 100644 (file)
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -382,6 +382,10 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
        if (skb_is_gso(skb))
                goto do_lso;
 
+       if ((skb->ip_summed == CHECKSUM_NONE) ||
+           (skb->ip_summed == CHECKSUM_UNNECESSARY))
+               goto do_send;
+
        rndis_msg_size += NDIS_CSUM_PPI_SIZE;
        ppi = init_ppi_data(rndis_msg, NDIS_CSUM_PPI_SIZE,
                            TCPIP_CHKSUM_PKTINFO);