From: stephen hemminger <stephen@networkplumber.org>
Date: Wed, 19 Jul 2017 11:53:12 -0700
Patch-mainline: v4.14-rc1
Subject: netvsc: force link update after MTU change
Git-commit: 1b01994aa6f9bad60d2b162c17dca530c21e2687
References: fate#323887

If two MTU changes are in less than update interval (2 seconds),
then the netvsc network device may get stuck with no carrier.

The netvsc driver debounces link status events which is fine
for unsolicited updates, but blocks getting the update after
down/up from MTU reinitialization.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Olaf Hering <ohering@suse.de>
---
 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
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -783,6 +783,7 @@ static int netvsc_set_channels(struct net_device *net,
 		ret = netvsc_open(net);
 
 	/* We may have missed link change notifications */
+	net_device_ctx->last_reconfig = 0;
 	schedule_delayed_work(&net_device_ctx->dwork, 0);
 
 	return ret;