Patch "net: dsa: Fix network device registration order" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

net: dsa: Fix network device registration order

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
net-dsa-fix-network-device-registration-order.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Florian Fainelli <[email protected]>
Date: Mon, 25 Sep 2017 15:55:53 -0700
Subject: net: dsa: Fix network device registration order

From: Florian Fainelli <[email protected]>

[ 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.

---
 net/dsa/slave.c |   28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

@@ -1269,26 +1269,32 @@ int dsa_slave_create(struct dsa_switch *
 	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(ds->ports[port].dn))
+		of_phy_deregister_fixed_link(ds->ports[port].dn);
+out_free:
+	free_netdev(slave_dev);
+	ds->ports[port].netdev = NULL;
+	return ret;
 }
 
 void dsa_slave_destroy(struct net_device *slave_dev)

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/net-dsa-fix-network-device-registration-order.patch