team: block mtu change before it happens via NETDEV_PRECHANGEMTU

Now it catches the NETDEV_CHANGEMTU notification, which is signaled after
the actual change happened on the device, and returns NOTIFY_BAD, so that
the change on the device is reverted.

This might be quite costly and messy, so use the new NETDEV_PRECHANGEMTU to
catch the MTU change before the actual change happens and signal that it's
forbidden to do it.

CC: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Acked-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/team/team.c b/drivers/net/team/team.c
index b75ae5b..dff24e3 100644 (file)
--- a/drivers/net/team/team.c
+++ b/drivers/net/team/team.c
@@ -2851,7 +2851,7 @@ static int team_device_event(struct notifier_block *unused,
        case NETDEV_FEAT_CHANGE:
                team_compute_features(port->team);
                break;
-       case NETDEV_CHANGEMTU:
+       case NETDEV_PRECHANGEMTU:
                /* Forbid to change mtu of underlaying device */
                return NOTIFY_BAD;
        case NETDEV_PRE_TYPE_CHANGE: