bonding: check return value of nofitier when changing type

This patch adds the possibility to refuse the bonding type change for
other subsystems (such as for example bridge, vlan, etc.)

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 2 deletions

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 7eeb18751d67..cbe9e353d46a 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1480,8 +1480,15 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
                                  bond_dev->name,
                                  bond_dev->type, slave_dev->type);
 
-                        netdev_bonding_change(bond_dev,
-                                              NETDEV_PRE_TYPE_CHANGE);
+                        res = netdev_bonding_change(bond_dev,
+                                                    NETDEV_PRE_TYPE_CHANGE);
+                        res = notifier_to_errno(res);
+                        if (res) {
+                                pr_err("%s: refused to change device type\n",
+                                       bond_dev->name);
+                                res = -EBUSY;
+                                goto err_undo_flags;
+                        }
 
                         if (slave_dev->type != ARPHRD_ETHER)
                                 bond_setup_by_slave(bond_dev, slave_dev);