net: dsa: mv88e6xxx: Unregister MDIO bus on error path

The MDIO busses need to be unregistered before they are freed,
otherwise BUG() is called. Add a call to the unregister code if the
registration fails, since we can have multiple busses, of which some
may correctly register before one fails. This requires moving the code
around a little.

Fixes: a3c53be55c95 ("net: dsa: mv88e6xxx: Support multiple MDIO busses")
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 16 insertions, 14 deletions

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 70004264f60d..66d33e97cbc5 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -2177,6 +2177,19 @@ static const struct of_device_id mv88e6xxx_mdio_external_match[] = {
         { },
 };
 
+static void mv88e6xxx_mdios_unregister(struct mv88e6xxx_chip *chip)
+
+{
+        struct mv88e6xxx_mdio_bus *mdio_bus;
+        struct mii_bus *bus;
+
+        list_for_each_entry(mdio_bus, &chip->mdios, list) {
+                bus = mdio_bus->bus;
+
+                mdiobus_unregister(bus);
+        }
+}
+
 static int mv88e6xxx_mdios_register(struct mv88e6xxx_chip *chip,
                                     struct device_node *np)
 {
@@ -2201,27 +2214,16 @@ static int mv88e6xxx_mdios_register(struct mv88e6xxx_chip *chip,
                 match = of_match_node(mv88e6xxx_mdio_external_match, child);
                 if (match) {
                         err = mv88e6xxx_mdio_register(chip, child, true);
-                        if (err)
+                        if (err) {
+                                mv88e6xxx_mdios_unregister(chip);
                                 return err;
+                        }
                 }
         }
 
         return 0;
 }
 
-static void mv88e6xxx_mdios_unregister(struct mv88e6xxx_chip *chip)
-
-{
-        struct mv88e6xxx_mdio_bus *mdio_bus;
-        struct mii_bus *bus;
-
-        list_for_each_entry(mdio_bus, &chip->mdios, list) {
-                bus = mdio_bus->bus;
-
-                mdiobus_unregister(bus);
-        }
-}
-
 static int mv88e6xxx_get_eeprom_len(struct dsa_switch *ds)
 {
         struct mv88e6xxx_chip *chip = ds->priv;