From: stephen hemminger <stephen@networkplumber.org>
Date: Tue, 6 Dec 2016 21:43:54 +0000 (-0800)
Subject: netvsc: reduce maximum GSO size
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=33c7b0f74c57d1a3c0a623ce794d7f61e097d09c;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git

netvsc: reduce maximum GSO size

[ Upstream commit a50af86dd49ee1851d1ccf06dd0019c05b95e297 ]

Hyper-V (and Azure) support using NVGRE which requires some extra space
for encapsulation headers. Because of this the largest allowed TSO
packet is reduced.

For older releases, hard code a fixed reduced value.  For next release,
there is a better solution which uses result of host offload
negotiation.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 409b48e1e589..7a601d8c615e 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -40,6 +40,8 @@
 
 #include "hyperv_net.h"
 
+/* Restrict GSO size to account for NVGRE */
+#define NETVSC_GSO_MAX_SIZE	62768
 
 #define RING_SIZE_MIN 64
 static int ring_size = 128;
@@ -852,6 +854,7 @@ static int netvsc_set_channels(struct net_device *net,
 		}
 		goto recover;
 	}
+	netif_set_gso_max_size(net, NETVSC_GSO_MAX_SIZE);
 
  out:
 	netvsc_open(net);