Commit f018ae7a authored by Russell King's avatar Russell King Committed by David S. Miller
Browse files

of_mdio: fix MDIO phy device refcounting 



bus_find_device() is defined as:

 * This is similar to the bus_for_each_dev() function above, but it
 * returns a reference to a device that is 'found' for later use, as
 * determined by the @match callback.

and it does indeed return a reference-counted pointer to the device:

        while ((dev = next_device(&i)))
                if (match(dev, data) && get_device(dev))
                                        ^^^^^^^^^^^^^^^
                        break;
        klist_iter_exit(&i);
        return dev;

What that means is that when we're done with the struct device, we must
drop that reference.  Neither of_phy_connect() nor of_phy_attach() did
this when phy_connect_direct() or phy_attach_direct() failed.

With our previous patch, phy_connect_direct() and phy_attach_direct()
take a new refcount on the phy device when successful, so we can drop
our local reference immediatley after these functions, whether or not
they succeeded.

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7322967b

drivers/of/of_mdio.c

+23 −4
Original line number Diff line number Diff line
@@ -197,7 +197,8 @@ static int of_phy_match(struct device *dev, void *phy_np) 
 * of_phy_find_device - Give a PHY node, find the phy_device

 * @phy_np: Pointer to the phy's device tree node

 *

 * Returns a pointer to the phy_device.

 * If successful, returns a pointer to the phy_device with the embedded

 * struct device refcount incremented by one, or NULL on failure.

 */

struct phy_device *of_phy_find_device(struct device_node *phy_np)

{
@@ -217,7 +218,9 @@ EXPORT_SYMBOL(of_phy_find_device); 
 * @hndlr: Link state callback for the network device

 * @iface: PHY data interface type

 *

 * Returns a pointer to the phy_device if successful.  NULL otherwise

 * If successful, returns a pointer to the phy_device with the embedded

 * struct device refcount incremented by one, or NULL on failure. The

 * refcount must be dropped by calling phy_disconnect() or phy_detach().

 */

struct phy_device *of_phy_connect(struct net_device *dev,

				  struct device_node *phy_np,
@@ -225,13 +228,19 @@ struct phy_device *of_phy_connect(struct net_device *dev, 
				  phy_interface_t iface)

{

	struct phy_device *phy = of_phy_find_device(phy_np);

	int ret;



	if (!phy)

		return NULL;



	phy->dev_flags = flags;



	return phy_connect_direct(dev, phy, hndlr, iface) ? NULL : phy;

	ret = phy_connect_direct(dev, phy, hndlr, iface);



	/* refcount is held by phy_connect_direct() on success */

	put_device(&phy->dev);



	return ret ? NULL : phy;

}

EXPORT_SYMBOL(of_phy_connect);
@@ -241,17 +250,27 @@ EXPORT_SYMBOL(of_phy_connect); 
 * @phy_np: Node pointer for the PHY

 * @flags: flags to pass to the PHY

 * @iface: PHY data interface type

 *

 * If successful, returns a pointer to the phy_device with the embedded

 * struct device refcount incremented by one, or NULL on failure. The

 * refcount must be dropped by calling phy_disconnect() or phy_detach().

 */

struct phy_device *of_phy_attach(struct net_device *dev,

				 struct device_node *phy_np, u32 flags,

				 phy_interface_t iface)

{

	struct phy_device *phy = of_phy_find_device(phy_np);

	int ret;



	if (!phy)

		return NULL;



	return phy_attach_direct(dev, phy, flags, iface) ? NULL : phy;

	ret = phy_attach_direct(dev, phy, flags, iface);



	/* refcount is held by phy_attach_direct() on success */

	put_device(&phy->dev);



	return ret ? NULL : phy;

}

EXPORT_SYMBOL(of_phy_attach);

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