net: dsa: Setup dsa_netdev_ops

Now that we have all the infrastructure in place for calling into the
dsa_ptr->netdev_ops function pointers, install them when we configure
the DSA CPU/management interface and tear them down. The flow is
unchanged from before, but now we preserve equality of tests when
network device drivers do tests like dev->netdev_ops == &foo_ops which
was not the case before since we were allocating an entirely new
structure.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/dsa.h

@@ -230,7 +230,6 @@ struct dsa_port {
 	 * Original copy of the master netdev net_device_ops
 	 */
 	const struct dsa_netdevice_ops *netdev_ops;
-	const struct net_device_ops *orig_ndo_ops;
 
 	bool setup;
 };

net/dsa/master.c

@@ -220,12 +220,17 @@ static int dsa_master_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 		break;
 	}
 
-	if (cpu_dp->orig_ndo_ops && cpu_dp->orig_ndo_ops->ndo_do_ioctl)
-		err = cpu_dp->orig_ndo_ops->ndo_do_ioctl(dev, ifr, cmd);
+	if (dev->netdev_ops->ndo_do_ioctl)
+		err = dev->netdev_ops->ndo_do_ioctl(dev, ifr, cmd);
 
 	return err;
 }
 
+static const struct dsa_netdevice_ops dsa_netdev_ops = {
+	.ndo_do_ioctl = dsa_master_ioctl,
+	.ndo_get_phys_port_name = dsa_master_get_phys_port_name,
+};
+
 static int dsa_master_ethtool_setup(struct net_device *dev)
 {
 	struct dsa_port *cpu_dp = dev->dsa_ptr;
@@ -260,38 +265,10 @@ static void dsa_master_ethtool_teardown(struct net_device *dev)
 	cpu_dp->orig_ethtool_ops = NULL;
 }
 
-static int dsa_master_ndo_setup(struct net_device *dev)
-{
-	struct dsa_port *cpu_dp = dev->dsa_ptr;
-	struct dsa_switch *ds = cpu_dp->ds;
-	struct net_device_ops *ops;
-
-	if (dev->netdev_ops->ndo_get_phys_port_name)
-		return 0;
-
-	ops = devm_kzalloc(ds->dev, sizeof(*ops), GFP_KERNEL);
-	if (!ops)
-		return -ENOMEM;
-
-	cpu_dp->orig_ndo_ops = dev->netdev_ops;
-	if (cpu_dp->orig_ndo_ops)
-		memcpy(ops, cpu_dp->orig_ndo_ops, sizeof(*ops));
-
-	ops->ndo_get_phys_port_name = dsa_master_get_phys_port_name;
-	ops->ndo_do_ioctl = dsa_master_ioctl;
-
-	dev->netdev_ops  = ops;
-
-	return 0;
-}
-
-static void dsa_master_ndo_teardown(struct net_device *dev)
+static void dsa_netdev_ops_set(struct net_device *dev,
+			       const struct dsa_netdevice_ops *ops)
 {
-	struct dsa_port *cpu_dp = dev->dsa_ptr;
-
-	if (cpu_dp->orig_ndo_ops)
-		dev->netdev_ops = cpu_dp->orig_ndo_ops;
-	cpu_dp->orig_ndo_ops = NULL;
+	dev->dsa_ptr->netdev_ops = ops;
 }
 
 static ssize_t tagging_show(struct device *d, struct device_attribute *attr,
@@ -353,9 +330,7 @@ int dsa_master_setup(struct net_device *dev, struct dsa_port *cpu_dp)
 	if (ret)
 		return ret;
 
-	ret = dsa_master_ndo_setup(dev);
-	if (ret)
-		goto out_err_ethtool_teardown;
+	dsa_netdev_ops_set(dev, &dsa_netdev_ops);
 
 	ret = sysfs_create_group(&dev->dev.kobj, &dsa_group);
 	if (ret)
@@ -364,8 +339,7 @@ int dsa_master_setup(struct net_device *dev, struct dsa_port *cpu_dp)
 	return ret;
 
 out_err_ndo_teardown:
-	dsa_master_ndo_teardown(dev);
-out_err_ethtool_teardown:
+	dsa_netdev_ops_set(dev, NULL);
 	dsa_master_ethtool_teardown(dev);
 	return ret;
 }
@@ -373,7 +347,7 @@ int dsa_master_setup(struct net_device *dev, struct dsa_port *cpu_dp)
 void dsa_master_teardown(struct net_device *dev)
 {
 	sysfs_remove_group(&dev->dev.kobj, &dsa_group);
-	dsa_master_ndo_teardown(dev);
+	dsa_netdev_ops_set(dev, NULL);
 	dsa_master_ethtool_teardown(dev);
 	dsa_master_reset_mtu(dev);