netns: keep vlan slaves on master netns move

previously, if a vlan master device was moved from one network namespace
to another, all 802.1q and macvlan slaves were deleted.

we can use dev->reg_state to figure out whether dev_change_net_namespace
is happening, since that won't set dev->reg_state NETREG_UNREGISTERING.
so, this changes 8021q and macvlan to ignore NETDEV_UNREGISTER when
reg_state is not NETREG_UNREGISTERING.

Signed-off-by: David Lamparter <equinox@diac24.net>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Daniel Lezcano <daniel.lezcano@free.fr>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index 0ef0eb0db945..0fc9dc7f20db 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -788,6 +788,10 @@ static int macvlan_device_event(struct notifier_block *unused,
                 }
                 break;
         case NETDEV_UNREGISTER:
+                /* twiddle thumbs on netns device moves */
+                if (dev->reg_state != NETREG_UNREGISTERING)
+                        break;
+
                 list_for_each_entry_safe(vlan, next, &port->vlans, list)
                         vlan->dev->rtnl_link_ops->dellink(vlan->dev, NULL);
                 break;