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>

1 files changed, 4 insertions, 1 deletions

diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
index bf4ba15fb780..c59fa5d9c22c 100644
--- 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