net: phy: Guard against the presence of a netdev

A prerequisite for PHYLIB to work in the absence of a struct net_device
is to not access pointers to it.

Changes are needed in the following areas:

 - Printing: In some places netdev_err was replaced with phydev_err.

 - Incrementing reference count to the parent MDIO bus driver: If there
   is no net device, then the reference count should definitely be
   incremented since there is no chance that it was an Ethernet driver
   who registered the MDIO bus.

 - Sysfs links are not created in case there is no attached_dev.

 - No netif_carrier_off is done if there is no attached_dev.

Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 8fd1bf37718bf475b1e9b5773f687d3e30d99fd8..da3bf3f70d63171b45dba195caec9e0fa2bacd12 100644 (file)
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -1138,6 +1138,9 @@ static void phy_sysfs_create_links(struct phy_device *phydev)
        struct net_device *dev = phydev->attached_dev;
        int err;
 
+       if (!dev)
+               return;
+
        err = sysfs_create_link(&phydev->mdio.dev.kobj, &dev->dev.kobj,
                                "attached_dev");
        if (err)
@@ -1176,9 +1179,9 @@ static void phy_sysfs_create_links(struct phy_device *phydev)
 int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
                      u32 flags, phy_interface_t interface)
 {
-       struct module *ndev_owner = dev->dev.parent->driver->owner;
        struct mii_bus *bus = phydev->mdio.bus;
        struct device *d = &phydev->mdio.dev;
+       struct module *ndev_owner = NULL;
        bool using_genphy = false;
        int err;
 
@@ -1187,8 +1190,10 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
         * our own module->refcnt here, otherwise we would not be able to
         * unload later on.
         */
+       if (dev)
+               ndev_owner = dev->dev.parent->driver->owner;
        if (ndev_owner != bus->owner && !try_module_get(bus->owner)) {
-               dev_err(&dev->dev, "failed to get the bus module\n");
+               phydev_err(phydev, "failed to get the bus module\n");
                return -EIO;
        }
 
@@ -1207,7 +1212,7 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
        }
 
        if (!try_module_get(d->driver->owner)) {
-               dev_err(&dev->dev, "failed to get the device driver module\n");
+               phydev_err(phydev, "failed to get the device driver module\n");
                err = -EIO;
                goto error_put_device;
        }
@@ -1228,8 +1233,10 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
        }
 
        phydev->phy_link_change = phy_link_change;
-       phydev->attached_dev = dev;
-       dev->phydev = phydev;
+       if (dev) {
+               phydev->attached_dev = dev;
+               dev->phydev = phydev;
+       }
 
        /* Some Ethernet drivers try to connect to a PHY device before
         * calling register_netdevice() -> netdev_register_kobject() and
@@ -1252,7 +1259,8 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
        /* Initial carrier state is off as the phy is about to be
         * (re)initialized.
         */
-       netif_carrier_off(phydev->attached_dev);
+       if (dev)
+               netif_carrier_off(phydev->attached_dev);
 
        /* Do initial configuration here, now that
         * we have certain key parameters
@@ -1358,16 +1366,19 @@ EXPORT_SYMBOL_GPL(phy_driver_is_genphy_10g);
 void phy_detach(struct phy_device *phydev)
 {
        struct net_device *dev = phydev->attached_dev;
-       struct module *ndev_owner = dev->dev.parent->driver->owner;
+       struct module *ndev_owner = NULL;
        struct mii_bus *bus;
 
        if (phydev->sysfs_links) {
-               sysfs_remove_link(&dev->dev.kobj, "phydev");
+               if (dev)
+                       sysfs_remove_link(&dev->dev.kobj, "phydev");
                sysfs_remove_link(&phydev->mdio.dev.kobj, "attached_dev");
        }
        phy_suspend(phydev);
-       phydev->attached_dev->phydev = NULL;
-       phydev->attached_dev = NULL;
+       if (dev) {
+               phydev->attached_dev->phydev = NULL;
+               phydev->attached_dev = NULL;
+       }
        phydev->phylink = NULL;
 
        phy_led_triggers_unregister(phydev);
@@ -1390,6 +1401,8 @@ void phy_detach(struct phy_device *phydev)
        bus = phydev->mdio.bus;
 
        put_device(&phydev->mdio.dev);
+       if (dev)
+               ndev_owner = dev->dev.parent->driver->owner;
        if (ndev_owner != bus->owner)
                module_put(bus->owner);