net: mdio-mux: fix unbalanced put_device

mdio_mux_uninit() call put_device (unconditionally) because of
of_mdio_find_bus() in mdio_mux_init.
But of_mdio_find_bus is only called if mux_bus is empty.
If mux_bus is set, mdio_mux_uninit will print a "refcount_t: underflow"
trace.

This patch add a get_device in the other branch of "if (mux_bus)".

Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/phy/mdio-mux.c b/drivers/net/phy/mdio-mux.c
index 282828551bdd45c6614077536dc5d096dce130c6..6f75e9f27fed26f7a74ef28044b158906fb85b51 100644 (file)
--- a/drivers/net/phy/mdio-mux.c
+++ b/drivers/net/phy/mdio-mux.c
@@ -116,6 +116,7 @@ int mdio_mux_init(struct device *dev,
        } else {
                parent_bus_node = NULL;
                parent_bus = mux_bus;
+               get_device(&parent_bus->dev);
        }
 
        pb = devm_kzalloc(dev, sizeof(*pb), GFP_KERNEL);
@@ -184,9 +185,7 @@ int mdio_mux_init(struct device *dev,
        dev_err(dev, "Error: No acceptable child buses found\n");
        devm_kfree(dev, pb);
 err_pb_kz:
-       /* balance the reference of_mdio_find_bus() took */
-       if (!mux_bus)
-               put_device(&parent_bus->dev);
+       put_device(&parent_bus->dev);
 err_parent_bus:
        of_node_put(parent_bus_node);
        return ret_val;
@@ -204,7 +203,6 @@ void mdio_mux_uninit(void *mux_handle)
                cb = cb->next;
        }
 
-       /* balance the reference of_mdio_find_bus() in mdio_mux_init() took */
        put_device(&pb->mii_bus->dev);
 }
 EXPORT_SYMBOL_GPL(mdio_mux_uninit);