Merge branch 'hyperv'

K. Y. Srinivasan says:

====================
Fix issues with Heper-V network offload code

WS2008 R2 does not support udp checksum offload. Furthermore, ws2012 and
ws2012 r2 have issues offloading udp checksum from Linux guests.
This patch-set addresses these issues as well as other bug fixes.
Please apply.

In this version, I have addressed the comment from David Miller with reagards
to COWing the skb prior to modifying the header (patch 3/3).
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 28 insertions, 2 deletions

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 4e4cf9e0c8d7..31e55fba7cad 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -319,7 +319,9 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
         packet = kzalloc(sizeof(struct hv_netvsc_packet) +
                          (num_data_pgs * sizeof(struct hv_page_buffer)) +
                          sizeof(struct rndis_message) +
-                         NDIS_VLAN_PPI_SIZE, GFP_ATOMIC);
+                         NDIS_VLAN_PPI_SIZE +
+                         NDIS_CSUM_PPI_SIZE +
+                         NDIS_LSO_PPI_SIZE, GFP_ATOMIC);
         if (!packet) {
                 /* out of memory, drop packet */
                 netdev_err(net, "unable to allocate hv_netvsc_packet\n");
@@ -396,7 +398,30 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
                 csum_info->transmit.tcp_checksum = 1;
                 csum_info->transmit.tcp_header_offset = hdr_offset;
         } else if (net_trans_info & INFO_UDP) {
-                csum_info->transmit.udp_checksum = 1;
+                /* UDP checksum offload is not supported on ws2008r2.
+                 * Furthermore, on ws2012 and ws2012r2, there are some
+                 * issues with udp checksum offload from Linux guests.
+                 * (these are host issues).
+                 * For now compute the checksum here.
+                 */
+                struct udphdr *uh;
+                u16 udp_len;
+
+                ret = skb_cow_head(skb, 0);
+                if (ret)
+                        goto drop;
+
+                uh = udp_hdr(skb);
+                udp_len = ntohs(uh->len);
+                uh->check = 0;
+                uh->check = csum_tcpudp_magic(ip_hdr(skb)->saddr,
+                                              ip_hdr(skb)->daddr,
+                                              udp_len, IPPROTO_UDP,
+                                              csum_partial(uh, udp_len, 0));
+                if (uh->check == 0)
+                        uh->check = CSUM_MANGLED_0;
+
+                csum_info->transmit.udp_checksum = 0;
         }
         goto do_send;
 
@@ -436,6 +461,7 @@ do_send:
 
         ret = netvsc_send(net_device_ctx->device_ctx, packet);
 
+drop:
         if (ret == 0) {
                 net->stats.tx_bytes += skb->len;
                 net->stats.tx_packets++;