bonding: move slave MTU handling from sysfs V2

V1->V2: corrected res/ret use

For some reason, MTU handling (storing, and restoring) is taking  place in
bond_sysfs. The correct place for this code is in bond_enslave, bond_release.
So move it there.

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 5e12462..2c3f9db 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1533,6 +1533,14 @@
 	 */
 	new_slave->original_flags = slave_dev->flags;
 
+	/* Save slave's original mtu and then set it to match the bond */
+	new_slave->original_mtu = slave_dev->mtu;
+	res = dev_set_mtu(slave_dev, bond->dev->mtu);
+	if (res) {
+		pr_debug("Error %d calling dev_set_mtu\n", res);
+		goto err_free;
+	}
+
 	/*
 	 * Save slave's original ("permanent") mac address for modes
 	 * that need it, and for restoring it upon release, and then
@@ -1550,7 +1558,7 @@
 		res = dev_set_mac_address(slave_dev, &addr);
 		if (res) {
 			pr_debug("Error %d calling set_mac_address\n", res);
-			goto err_free;
+			goto err_restore_mtu;
 		}
 	}
 
@@ -1785,6 +1793,9 @@
 		dev_set_mac_address(slave_dev, &addr);
 	}
 
+err_restore_mtu:
+	dev_set_mtu(slave_dev, new_slave->original_mtu);
+
 err_free:
 	kfree(new_slave);
 
@@ -1969,6 +1980,8 @@
 		dev_set_mac_address(slave_dev, &addr);
 	}
 
+	dev_set_mtu(slave_dev, slave->original_mtu);
+
 	slave_dev->priv_flags &= ~(IFF_MASTER_8023AD | IFF_MASTER_ALB |
 				   IFF_SLAVE_INACTIVE | IFF_BONDING |
 				   IFF_SLAVE_NEEDARP);