net: usb: lan78xx: don't modify phy_device state concurrently

Currently phy_device state could be left in inconsistent state shown
by following alert message[1]. This is because phy_read_status could
be called concurrently from lan78xx_delayedwork, phy_state_machine and
__ethtool_get_link. Fix this by making sure that phy_device state is
updated atomically.

[1] lan78xx 1-1.1.1:1.0 eth0: No phy led trigger registered for speed(-1)

Signed-off-by: Ivan T. Ivanov <iivanov@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 2548938..6d092d7 100644 (file)
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -1154,7 +1154,7 @@ static int lan78xx_link_reset(struct lan78xx_net *dev)
 {
        struct phy_device *phydev = dev->net->phydev;
        struct ethtool_link_ksettings ecmd;
-       int ladv, radv, ret;
+       int ladv, radv, ret, link;
        u32 buf;
 
        /* clear LAN78xx interrupt status */
@@ -1162,9 +1162,12 @@ static int lan78xx_link_reset(struct lan78xx_net *dev)
        if (unlikely(ret < 0))
                return -EIO;
 
+       mutex_lock(&phydev->lock);
        phy_read_status(phydev);
+       link = phydev->link;
+       mutex_unlock(&phydev->lock);
 
-       if (!phydev->link && dev->link_on) {
+       if (!link && dev->link_on) {
                dev->link_on = false;
 
                /* reset MAC */
@@ -1177,7 +1180,7 @@ static int lan78xx_link_reset(struct lan78xx_net *dev)
                        return -EIO;
 
                del_timer(&dev->stat_monitor);
-       } else if (phydev->link && !dev->link_on) {
+       } else if (link && !dev->link_on) {
                dev->link_on = true;
 
                phy_ethtool_ksettings_get(phydev, &ecmd);
@@ -1466,9 +1469,14 @@ static int lan78xx_set_eee(struct net_device *net, struct ethtool_eee *edata)
 
 static u32 lan78xx_get_link(struct net_device *net)
 {
+       u32 link;
+
+       mutex_lock(&net->phydev->lock);
        phy_read_status(net->phydev);
+       link = net->phydev->link;
+       mutex_unlock(&net->phydev->lock);
 
-       return net->phydev->link;
+       return link;
 }
 
 static void lan78xx_get_drvinfo(struct net_device *net,