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

From: Florian Fainelli
Date: Mon Sep 25 2017 - 18:56:03 EST


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.fainelli@xxxxxxxxx>
---
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