[PATCH 3.16.y-ckt 077/170] hyperv: Fix the total_data_buflen in send path

[Luis Henriques]

3.16.7-ckt1 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Haiyang Zhang <haiyangz at microsoft.com>

commit 942396b01989d54977120f3625e5ba31afe7a75c upstream.

total_data_buflen is used by netvsc_send() to decide if a packet can be put
into send buffer. It should also include the size of RNDIS message before the
Ethernet frame. Otherwise, a messge with total size bigger than send_section_size
may be copied into the send buffer, and cause data corruption.

[Request to include this patch to the Stable branches]

Signed-off-by: Haiyang Zhang <haiyangz at microsoft.com>
Reviewed-by: K. Y. Srinivasan <kys at microsoft.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/net/hyperv/netvsc_drv.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index f15297201777..7e3331821200 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -556,6 +556,7 @@ do_lso:
 do_send:
 	/* Start filling in the page buffers with the rndis hdr */
 	rndis_msg->msg_len += rndis_msg_size;
+	packet->total_data_buflen = rndis_msg->msg_len;
 	packet->page_buf_cnt = init_page_array(rndis_msg, rndis_msg_size,
 					skb, &packet->page_buf[0]);
 
-- 
2.1.0