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 <[email protected]> and Eric Dumazet <[email protected]>.

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

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

---
 drivers/net/hyperv/netvsc_drv.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

index 939e3af..64c7816 100644
@@ -467,6 +467,10 @@ 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);

1.7.4.1

From: "K. Y. Srinivasan" <[email protected]>
Date: Wed, 30 Apr 2014 09:05:21 -0700

It does not make any sense to submit a patch for net-next and also ask for it to be included in -stable.

First of all, -stable submissions are handled by me directly for networking. Therefore you should not CC: stable on such patches, instead you ask me politly to include it in my stable submission queue.

Second of all, if a patch is destined for stable, it should be submitted for 'net' not 'net-next'.