Subject: [PATCH 33/48] net: dsa: Fix network device registration order

From: Florian Fainelli <[email-masked]>
Date: Mon, 25 Sep 2017 15:55:53 -0700

[ Upstream commit e804441cfe0b60f6c430901946a69c01eac09df1 ]

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 <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 net/dsa/slave.c | 28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 9507bd38cf04..07677540129a 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -1180,26 +1180,32 @@ int dsa_slave_create(struct dsa_switch *ds, struct device *parent,
 	p->old_duplex = -1;
 
 	ds->ports[port].netdev = slave_dev;
-	ret = register_netdev(slave_dev);
-	if (ret) {
-		netdev_err(master, "error %d registering interface %s\n",
-			   ret, slave_dev->name);
-		ds->ports[port].netdev = NULL;
-		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_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_netdev(slave_dev);
+	ds->ports[port].netdev = NULL;
+	return ret;
 }
 
 void dsa_slave_destroy(struct net_device *slave_dev)
-- 
2.13.6