[PATCH AUTOSEL for 4.9 46/52] xen-netfront: enable device after manual module load

[Sasha Levin]

From: Eduardo Otubo <otubo@xxxxxxxxxx>

[ Upstream commit b707fda2df4070785d0fa8a278aa13944c5f51f8 ]

When loading the module after unloading it, the network interface would
not be enabled and thus wouldn't have a backend counterpart and unable
to be used by the guest.

The guest would face errors like:

  [root@guest ~]# ethtool -i eth0
  Cannot get driver information: No such device

  [root@guest ~]# ifconfig eth0
  eth0: error fetching interface information: Device not found

This patch initializes the state of the netfront device whenever it is
loaded manually, this state would communicate the netback to create its
device and establish the connection between them.

Signed-off-by: Eduardo Otubo <otubo@xxxxxxxxxx>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
---
 drivers/net/xen-netfront.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 1a9dadf7b3cc..b09c81e882b4 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -1345,6 +1345,7 @@ static struct net_device *xennet_create_dev(struct xenbus_device *dev)
 
 	netif_carrier_off(netdev);
 
+	xenbus_switch_state(dev, XenbusStateInitialising);
 	return netdev;
 
  exit:
-- 
2.11.0