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/net/8021q/vlan.c b/net/8021q/vlan.c
index a2ad15250575..2c6c2bd6e4a9 100644
--- a/net/8021q/vlan.c
+++ b/net/8021q/vlan.c
@@ -525,6 +525,10 @@ static int vlan_device_event(struct notifier_block *unused, unsigned long event,
                 break;
 
         case NETDEV_UNREGISTER:
+                /* twiddle thumbs on netns device moves */
+                if (dev->reg_state != NETREG_UNREGISTERING)
+                        break;
+
                 /* Delete all VLANs for this dev. */
                 grp->killall = 1;