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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@savoirfairelinux.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <alexander.levin@verizon.com>
Subject: [PATCH 4.14 125/159] net: dsa: mv88e6xxx: Unregister MDIO bus on error path
Date:   Fri, 23 Feb 2018 19:27:13 +0100
Message-Id: <20180223170758.323061227@linuxfoundation.org>
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4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Andrew Lunn <andrew@lunn.ch>


[ Upstream commit 3126aeec5313565bfa19e2dd8fd7e3c3390514cb ]

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>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/dsa/mv88e6xxx/chip.c |   30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -2153,6 +2153,19 @@ static const struct of_device_id mv88e6x
 	{ },
 };
 
+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)
 {
@@ -2177,27 +2190,16 @@ static int mv88e6xxx_mdios_register(stru
 		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;