From: Mohammed Gamal <mgamal@redhat.com>
Date: Wed, 9 May 2018 10:17:34 +0200
Patch-mainline: v4.17-rc5
Subject: hv_netvsc: Fix net device attach on older Windows hosts
Git-commit: 55be9f25be1ca5bda75c39808fc77e42691bc07f
References: fate#323887

On older windows hosts the net_device instance is returned to
the caller of rndis_filter_device_add() without having the presence
bit set first. This would cause any subsequent calls to network device
operations (e.g. MTU change, channel change) to fail after the device
is detached once, returning -ENODEV.

Instead of returning the device instabce, we take the exit path where
we call netif_device_attach()

Fixes: 7b2ee50c0cd5 ("hv_netvsc: common detach logic")
Signed-off-by: Mohammed Gamal <mgamal@redhat.com>
Reviewed-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/rndis_filter.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -1288,7 +1288,7 @@ struct netvsc_device *rndis_filter_device_add(struct hv_device *dev,
 		   rndis_device->link_state ? "down" : "up");
 
 	if (net_device->nvsp_version < NVSP_PROTOCOL_VERSION_5)
-		return net_device;
+		goto out;
 
 	rndis_filter_query_link_speed(rndis_device, net_device);