3.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: "Eric W. Biederman" <redacted>

commit d2237d35748e7f448a9c2d9dc6a85ef637466e24 upstream.

Renato Westphal noticed that since commit a2835763e130c343ace5320c20d33c281e7097b7
"rtnetlink: handle rtnl_link netlink notifications manually" was merged
we no longer send a netlink message when a networking device is moved
from one network namespace to another.

Fix this by adding the missing manual notification in dev_change_net_namespaces.

Since all network devices that are processed by dev_change_net_namspaces are
in the initialized state the complicated tests that guard the manual
rtmsg_ifinfo calls in rollback_registered and register_netdevice are
unnecessary and we can just perform a plain notification.

Tested-by: Renato Westphal <redacted>
Signed-off-by: Eric W. Biederman <redacted>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 net/core/dev.c |    1 +
 1 file changed, 1 insertion(+)

--- a/net/core/dev.c
+++ b/net/core/dev.c

@@ -6115,6 +6115,7 @@ int dev_change_net_namespace(struct net_
 	*/
 	call_netdevice_notifiers(NETDEV_UNREGISTER, dev);
 	call_netdevice_notifiers(NETDEV_UNREGISTER_BATCH, dev);
+	rtmsg_ifinfo(RTM_DELLINK, dev, ~0U);
 
 	/*
 	 *	Flush the unicast and multicast chains