macvlan: Propagate lowerdev MTU changes

When the physical MTU changes we should ensure that all existing MACVLAN
dev MTU do not exceed the new lowerdev MTU. This patch adds that
propagation.

Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
Reviewed-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index f0118d1a3e4687573b6d59191842bf222cb5736e..e03707de1eeee4ea1b4efd31ab27e9f7e5c08f20 100644 (file)
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -1091,6 +1091,13 @@ static int macvlan_device_event(struct notifier_block *unused,
                        netdev_update_features(vlan->dev);
                }
                break;
+       case NETDEV_CHANGEMTU:
+               list_for_each_entry(vlan, &port->vlans, list) {
+                       if (vlan->dev->mtu <= dev->mtu)
+                               continue;
+                       dev_set_mtu(vlan->dev, dev->mtu);
+               }
+               break;
        case NETDEV_UNREGISTER:
                /* twiddle thumbs on netns device moves */
                if (dev->reg_state != NETREG_UNREGISTERING)