Merge branch 'net-phy-add-device-managed-devm_mdiobus_register'

Heiner Kallweit says:

====================
net: phy: add device-managed devm_mdiobus_register

If there's no special ordering requirement for mdiobus_unregister(),
then driver code can be simplified by using a device-managed version
of mdiobus_register(). Prerequisite is that bus allocation has been
done device-managed too. Else mdiobus_free() may be called whilst
bus is still registered, resulting in a BUG_ON(). Therefore let
devm_mdiobus_register() return -EPERM if bus was allocated
non-managed.

First user of the new functionality is r8169 driver.
====================

Signed-off-by: David S. Miller <[email protected]>

Author: davem330

drivers/net/ethernet/realtek/r8169_main.c

@@ -5185,20 +5185,18 @@ static int r8169_mdio_register(struct rtl8169_private *tp)
 	new_bus->read = r8169_mdio_read_reg;
 	new_bus->write = r8169_mdio_write_reg;
 
-	ret = mdiobus_register(new_bus);
+	ret = devm_mdiobus_register(new_bus);
 	if (ret)
 		return ret;
 
 	tp->phydev = mdiobus_get_phy(new_bus, 0);
 	if (!tp->phydev) {
-		mdiobus_unregister(new_bus);
 		return -ENODEV;
 	} else if (!tp->phydev->drv) {
 		/* Most chip versions fail with the genphy driver.
 		 * Therefore ensure that the dedicated PHY driver is loaded.
 		 */
 		dev_err(&pdev->dev, "realtek.ko not loaded, maybe it needs to be added to initramfs?\n");
-		mdiobus_unregister(new_bus);
 		return -EUNATCH;
 	}
 
@@ -5523,7 +5521,7 @@ static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	rc = register_netdev(dev);
 	if (rc)
-		goto err_mdio_unregister;
+		return rc;
 
 	netif_info(tp, probe, dev, "%s, %pM, XID %03x, IRQ %d\n",
 		   rtl_chip_infos[chipset].name, dev->dev_addr, xid,
@@ -5542,10 +5540,6 @@ static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 		pm_runtime_put_sync(&pdev->dev);
 
 	return 0;
-
-err_mdio_unregister:
-	mdiobus_unregister(tp->phydev->mdio.bus);
-	return rc;
 }
 
 static struct pci_driver rtl8169_pci_driver = {

drivers/net/phy/mdio_bus.c

@@ -170,7 +170,12 @@ EXPORT_SYMBOL(mdiobus_alloc_size);
 
 static void _devm_mdiobus_free(struct device *dev, void *res)
 {
-	mdiobus_free(*(struct mii_bus **)res);
+	struct mii_bus *bus = *(struct mii_bus **)res;
+
+	if (bus->is_managed_registered && bus->state == MDIOBUS_REGISTERED)
+		mdiobus_unregister(bus);
+
+	mdiobus_free(bus);
 }
 
 static int devm_mdiobus_match(struct device *dev, void *res, void *data)
@@ -210,6 +215,7 @@ struct mii_bus *devm_mdiobus_alloc_size(struct device *dev, int sizeof_priv)
 	if (bus) {
 		*ptr = bus;
 		devres_add(dev, ptr);
+		bus->is_managed = 1;
 	} else {
 		devres_free(ptr);
 	}

include/linux/phy.h

@@ -241,6 +241,9 @@ struct mii_bus {
 	int (*reset)(struct mii_bus *bus);
 	struct mdio_bus_stats stats[PHY_MAX_ADDR];
 
+	unsigned int is_managed:1;	/* is device-managed */
+	unsigned int is_managed_registered:1;
+
 	/*
 	 * A lock to ensure that only one thing can read/write
 	 * the MDIO bus at a time
@@ -286,6 +289,20 @@ static inline struct mii_bus *mdiobus_alloc(void)
 
 int __mdiobus_register(struct mii_bus *bus, struct module *owner);
 #define mdiobus_register(bus) __mdiobus_register(bus, THIS_MODULE)
+static inline int devm_mdiobus_register(struct mii_bus *bus)
+{
+	int ret;
+
+	if (!bus->is_managed)
+		return -EPERM;
+
+	ret = mdiobus_register(bus);
+	if (!ret)
+		bus->is_managed_registered = 1;
+
+	return ret;
+}
+
 void mdiobus_unregister(struct mii_bus *bus);
 void mdiobus_free(struct mii_bus *bus);
 struct mii_bus *devm_mdiobus_alloc_size(struct device *dev, int sizeof_priv);