[PATCH net] net: dsa: Fix network device registration order

[Florian Fainelli]

We cannot be registering the network device first, then setting its
carrier off and finally connecting it to a PHY, doing that leaves a
window during which the carrier is at best inconsistent, and at worse
the device is not usable without a down/up sequence since the network
device is visible to user space with possibly no PHY device attached.

Re-order steps so that they make logical sense. This fixes some devices
where the port was not usable after e.g: an unbind then bind of the
driver.

Fixes: 0071f56e46da ("dsa: Register netdev before phy")
Fixes: 91da11f870f0 ("net: Distributed Switch Architecture protocol support")
Signed-off-by: Florian Fainelli <f.faine...@gmail.com>
---
 net/dsa/slave.c | 31 ++++++++++++++++++-------------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 2afa99506f8b..865e29e62bad 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -1301,28 +1301,33 @@ int dsa_slave_create(struct dsa_port *port, const char 
*name)
        p->old_duplex = -1;
 
        port->netdev = slave_dev;
-       ret = register_netdev(slave_dev);
-       if (ret) {
-               netdev_err(master, "error %d registering interface %s\n",
-                          ret, slave_dev->name);
-               port->netdev = NULL;
-               free_percpu(p->stats64);
-               free_netdev(slave_dev);
-               return ret;
-       }
 
        netif_carrier_off(slave_dev);
 
        ret = dsa_slave_phy_setup(p, slave_dev);
        if (ret) {
                netdev_err(master, "error %d setting up slave phy\n", ret);
-               unregister_netdev(slave_dev);
-               free_percpu(p->stats64);
-               free_netdev(slave_dev);
-               return ret;
+               goto out_free;
+       }
+
+       ret = register_netdev(slave_dev);
+       if (ret) {
+               netdev_err(master, "error %d registering interface %s\n",
+                          ret, slave_dev->name);
+               goto out_phy;
        }
 
        return 0;
+
+out_phy:
+       phy_disconnect(p->phy);
+       if (of_phy_is_fixed_link(p->dp->dn))
+               of_phy_deregister_fixed_link(p->dp->dn);
+out_free:
+       free_percpu(p->stats64);
+       free_netdev(slave_dev);
+       port->netdev = NULL;
+       return ret;
 }
 
 void dsa_slave_destroy(struct net_device *slave_dev)
-- 
2.9.3