hyperv: Add processing of MTU reduced by the host
If the host uses packet encapsulation feature, the MTU may be reduced by the
host due to headroom reservation for encapsulation. This patch handles this
new MTU value.
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 3295e4e..15d82ed 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -699,9 +699,10 @@
return -ENODEV;
if (nvdev->nvsp_version >= NVSP_PROTOCOL_VERSION_2)
- limit = NETVSC_MTU;
+ limit = NETVSC_MTU - ETH_HLEN;
- if (mtu < 68 || mtu > limit)
+ /* Hyper-V hosts don't support MTU < ETH_DATA_LEN (1500) */
+ if (mtu < ETH_DATA_LEN || mtu > limit)
return -EINVAL;
nvdev->start_remove = true;
