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: Russell King <rmk+ker...@arm.linux.org.uk>
---
drivers/of/of_mdio.c | 27 +++++++++++++++++++++++----
1 file changed, 23 insertions(+), 4 deletions(-)
diff --git a/drivers/of/of_mdio.c b/drivers/of/of_mdio.c
index 1350fa25cdb0..a87a868fed64 100644
--- a/drivers/of/of_mdio.c
+++ b/drivers/of/of_mdio.c
@@ -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);
--
2.1.0
_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev
