On 05/10/2017 08:20 AM, Jon Mason wrote:
> There is a potential unnecessary refcount decriment on error path of
> put_device(&pb->mii_bus->dev), as it is possible to avoid the
> of_mdio_find_bus() call if mux_bus is specified by the calling function.
>
> The same put_device() is not called in the error path if the
> devm_kzalloc of pb fails. This caused the variable used in the
> put_device() to be changed, as the pb pointer was obviously not set up.
>
> There is an unnecessary of_node_get() on child_bus_node if the
> of_mdiobus_register() is successful, as the
> for_each_available_child_of_node() automatically increments this.
> Thus the refcount on this node will always be +1 more than it should be.
>
> There is no of_node_put() on child_bus_node if the of_mdiobus_register()
> call fails.
>
> Finally, it is lacking devm_kfree() of pb in the error path. While this
> might not be technically necessary, it was present in other parts of the
> function. So, I am adding it where necessary to make it uniform.
>
> Signed-off-by: Jon Mason <jon.ma...@broadcom.com>
> Fixes: f20e6657a875 ("mdio: mux: Enhanced MDIO mux framework for integrated
> multiplexers")
> Fixes: 0ca2997d1452 ("netdev/of/phy: Add MDIO bus multiplexer support.")
Reviewed-by: Florian Fainelli <f.faine...@gmail.com>
Please include "net" in the subject for future submissions, thanks!
> ---
> drivers/net/phy/mdio-mux.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/phy/mdio-mux.c b/drivers/net/phy/mdio-mux.c
> index 963838d4fac1..6943c5ece44a 100644
> --- a/drivers/net/phy/mdio-mux.c
> +++ b/drivers/net/phy/mdio-mux.c
> @@ -122,10 +122,9 @@ int mdio_mux_init(struct device *dev,
> pb = devm_kzalloc(dev, sizeof(*pb), GFP_KERNEL);
> if (pb == NULL) {
> ret_val = -ENOMEM;
> - goto err_parent_bus;
> + goto err_pb_kz;
> }
>
> -
> pb->switch_data = data;
> pb->switch_fn = switch_fn;
> pb->current_child = -1;
> @@ -154,6 +153,7 @@ int mdio_mux_init(struct device *dev,
> cb->mii_bus = mdiobus_alloc();
> if (!cb->mii_bus) {
> ret_val = -ENOMEM;
> + devm_kfree(dev, cb);
> of_node_put(child_bus_node);
> break;
> }
> @@ -169,8 +169,8 @@ int mdio_mux_init(struct device *dev,
> if (r) {
> mdiobus_free(cb->mii_bus);
> devm_kfree(dev, cb);
> + of_node_put(child_bus_node);
> } else {
> - of_node_get(child_bus_node);
> cb->next = pb->children;
> pb->children = cb;
> }
> @@ -181,9 +181,11 @@ int mdio_mux_init(struct device *dev,
> return 0;
> }
>
> + devm_kfree(dev, pb);
> +err_pb_kz:
> /* balance the reference of_mdio_find_bus() took */
> - put_device(&pb->mii_bus->dev);
> -
> + if (!mux_bus)
> + put_device(&parent_bus->dev);
> err_parent_bus:
> of_node_put(parent_bus_node);
> return ret_val;
>
--
Florian
