[PATCH 4.4 01/27] netvsc: reduce maximum GSO size
From: Greg Kroah-Hartman
Date: Fri Jan 13 2017 - 06:38:42 EST
4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: stephen hemminger <stephen@xxxxxxxxxxxxxxxxxx>
[ 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@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/hyperv/netvsc_drv.c | 3 +++
1 file changed, 3 insertions(+)
--- 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 ne
}
goto recover;
}
+ netif_set_gso_max_size(net, NETVSC_GSO_MAX_SIZE);
out:
netvsc_open(net);