bonding: permit enslaving interfaces without set_mac support

Currently we exit if the slave isn't the first slave, doesn't support mac
address setting and fail_over_mac isn't FOM_ACTIVE. It's wrong because we
only require ndo_set_mac_address in case bonding is in active-backup mode
and FOM isn't FOM_ACTIVE.

To fix this - only exit with an error if we're in a/b mode and have
fail_over_mac != FOM_ACTIVE.

Also, maintain current behaviour on the first slave (forcibly change fom to
FOM_ACTIVE) to not break anyone's configuration.

CC: Jay Vosburgh <j.vosburgh@gmail.com>
CC: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: Veaceslav Falico <vfalico@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 9 deletions

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 6d3b8db882a1..d643807a8e6a 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1302,19 +1302,20 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
         }
 
         if (slave_ops->ndo_set_mac_address == NULL) {
-                if (!bond_has_slaves(bond)) {
-                        pr_warn("%s: Warning: The first slave device specified does not support setting the MAC address\n",
-                                bond_dev->name);
-                        if (BOND_MODE(bond) == BOND_MODE_ACTIVEBACKUP) {
+                pr_warn("%s: Warning: The slave device specified does not support setting the MAC address\n",
+                        bond_dev->name);
+                if (BOND_MODE(bond) == BOND_MODE_ACTIVEBACKUP &&
+                    bond->params.fail_over_mac != BOND_FOM_ACTIVE) {
+                        if (!bond_has_slaves(bond)) {
                                 bond->params.fail_over_mac = BOND_FOM_ACTIVE;
                                 pr_warn("%s: Setting fail_over_mac to active for active-backup mode\n",
                                         bond_dev->name);
+                        } else {
+                                pr_err("%s: Error: The slave device specified does not support setting the MAC address, but fail_over_mac is not set to active\n",
+                                       bond_dev->name);
+                                res = -EOPNOTSUPP;
+                                goto err_undo_flags;
                         }
-                } else if (bond->params.fail_over_mac != BOND_FOM_ACTIVE) {
-                        pr_err("%s: Error: The slave device specified does not support setting the MAC address, but fail_over_mac is not set to active\n",
-                               bond_dev->name);
-                        res = -EOPNOTSUPP;
-                        goto err_undo_flags;
                 }
         }