net: fix net_device refcounting

of_find_net_device_by_node() uses class_find_device() internally to
lookup the corresponding network device.  class_find_device() returns
a reference to the embedded struct device, with its refcount
incremented.

Add a comment to the definition in net/core/net-sysfs.c indicating the
need to drop this refcount, and fix the DSA code to drop this refcount
when the OF-generated platform data is cleaned up and freed.  Also
arrange for the ref to be dropped when handling errors.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index b279077c30894dfeb69e2c21686d702cc809e678..805a95a481076dcc229c881322c2e6ef308692bd 100644 (file)
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -1481,6 +1481,15 @@ static int of_dev_node_match(struct device *dev, const void *data)
        return ret == 0 ? dev->of_node == data : ret;
 }
 
+/*
+ * of_find_net_device_by_node - lookup the net device for the device node
+ * @np: OF device node
+ *
+ * Looks up the net_device structure corresponding with the device node.
+ * If successful, returns a pointer to the net_device with the embedded
+ * struct device refcount incremented by one, or NULL on failure. The
+ * refcount must be dropped when done with the net_device.
+ */
 struct net_device *of_find_net_device_by_node(struct device_node *np)
 {
        struct device *dev;

diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
index bf4ba15fb780e96ed77858c68a5d724a065962d6..c59fa5d9c22c449b4bfa9f058575d44324cfd7f9 100644 (file)
--- a/net/dsa/dsa.c
+++ b/net/dsa/dsa.c
@@ -679,7 +679,7 @@ static int dsa_of_probe(struct device *dev)
        pd = kzalloc(sizeof(*pd), GFP_KERNEL);
        if (!pd) {
                ret = -ENOMEM;
-               goto out_put_mdio;
+               goto out_put_ethernet;
        }
 
        dev->platform_data = pd;
@@ -773,6 +773,8 @@ out_free_chip:
 out_free:
        kfree(pd);
        dev->platform_data = NULL;
+out_put_ethernet:
+       put_device(&ethernet_dev->dev);
 out_put_mdio:
        put_device(&mdio_bus->dev);
        return ret;
@@ -786,6 +788,7 @@ static void dsa_of_remove(struct device *dev)
                return;
 
        dsa_of_free_platform_data(pd);
+       put_device(&pd->of_netdev->dev);
        kfree(pd);
 }
 #else