net: dsa: destroy the phylink instance on any error in dsa_slave_phy_setup

DSA supports connecting to a phy-handle, and has a fallback to a non-OF
based method of connecting to an internal PHY on the switch's own MDIO
bus, if no phy-handle and no fixed-link nodes were present.

The -ENODEV error code from the first attempt (phylink_of_phy_connect)
is what triggers the second attempt (phylink_connect_phy).

However, when the first attempt returns a different error code than
-ENODEV, this results in an unbalance of calls to phylink_create and
phylink_destroy by the time we exit the function. The phylink instance
has leaked.

There are many other error codes that can be returned by
phylink_of_phy_connect. For example, phylink_validate returns -EINVAL.
So this is a practical issue too.

Fixes: a81bccb0d343 ("net: dsa: Plug in PHYLINK support")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://lore.kernel.org/r/20210914134331.2303380-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 662ff531d4e29874f9d64e6b91d96a1e7e0e959c..a2bf2d8ac65b7db8bc27ebbe1114f94a8da94149 100644 (file)
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -1854,13 +1854,11 @@ static int dsa_slave_phy_setup(struct net_device *slave_dev)
                 * use the switch internal MDIO bus instead
                 */
                ret = dsa_slave_phy_connect(slave_dev, dp->index, phy_flags);
-               if (ret) {
-                       netdev_err(slave_dev,
-                                  "failed to connect to port %d: %d\n",
-                                  dp->index, ret);
-                       phylink_destroy(dp->pl);
-                       return ret;
-               }
+       }
+       if (ret) {
+               netdev_err(slave_dev, "failed to connect to PHY: %pe\n",
+                          ERR_PTR(ret));
+               phylink_destroy(dp->pl);
        }
 
        return ret;