net: free_netdev: exit earlier if dummy

For dummy devices, exit earlier at free_netdev() instead of executing
the whole function. This is necessary, because dummy devices are
special, and shouldn't have the second part of the function executed.

Otherwise reg_state, which is NETREG_DUMMY, will be overwritten and
there will be no way to identify that this is a dummy device. Also, this
device do not need the final put_device(), since dummy devices are not
registered (through register_netdevice()), where the device reference is
increased (at netdev_register_kobject()/device_add()).

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/dev.c b/net/core/dev.c
index 44c2d698fd1b4411f5bf351c0f513c798a5939f3..62b39d6b1d8f44f18923a2cb301fd4efbf1485c9 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -11066,7 +11066,8 @@ void free_netdev(struct net_device *dev)
        phy_link_topo_destroy(dev->link_topo);
 
        /*  Compatibility with error handling in drivers */
-       if (dev->reg_state == NETREG_UNINITIALIZED) {
+       if (dev->reg_state == NETREG_UNINITIALIZED ||
+           dev->reg_state == NETREG_DUMMY) {
                netdev_freemem(dev);
                return;
        }