net: dsa: Ensure that port array elements are initialized before being used

A network device notifier can be called for one or more of the created
slave devices before all slave devices have been registered. This can
result in a mismatch between ds->phys_port_mask and the registered devices
by the time the call is made, and it can result in a slave device being
added to a bridge before its entry in ds->ports[] has been initialized.

Rework the initialization code to initialize entries in ds->ports[] in
dsa_slave_create. With this change, dsa_slave_create no longer needs
to return slave_dev but can return an error code instead.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 7 deletions

diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
index 2173402d87e0..fc1813140be6 100644
--- a/net/dsa/dsa.c
+++ b/net/dsa/dsa.c
@@ -314,19 +314,15 @@ dsa_switch_setup(struct dsa_switch_tree *dst, int index,
          * Create network devices for physical switch ports.
          */
         for (i = 0; i < DSA_MAX_PORTS; i++) {
-                struct net_device *slave_dev;
-
                 if (!(ds->phys_port_mask & (1 << i)))
                         continue;
 
-                slave_dev = dsa_slave_create(ds, parent, i, pd->port_names[i]);
-                if (slave_dev == NULL) {
+                ret = dsa_slave_create(ds, parent, i, pd->port_names[i]);
+                if (ret < 0) {
                         netdev_err(dst->master_netdev, "[%d]: can't create dsa slave device for port %d(%s)\n",
                                    index, i, pd->port_names[i]);
-                        continue;
+                        ret = 0;
                 }
-
-                ds->ports[i] = slave_dev;
         }
 
 #ifdef CONFIG_NET_DSA_HWMON