phylib: Fix deadlock on resume

[firefly-linux-kernel-4.4.55.git] / drivers / net / phy / mdio_bus.c

diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index bd4e8d72dc08fa7e5a14822ef9d577cabdf3a185..49252d390903c1335f4d3c32ca45a66d108cc00d 100644 (file)
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -303,8 +303,18 @@ static int mdio_bus_suspend(struct device * dev, pm_message_t state)
        struct phy_driver *phydrv = to_phy_driver(dev->driver);
        struct phy_device *phydev = to_phy_device(dev);
 
+       /*
+        * We must stop the state machine manually, otherwise it stops out of
+        * control, possibly with the phydev->lock held. Upon resume, netdev
+        * may call phy routines that try to grab the same lock, and that may
+        * lead to a deadlock.
+        */
+       if (phydev->attached_dev)
+               phy_stop_machine(phydev);
+
        if (!mdio_bus_phy_may_suspend(phydev))
                return 0;
+
        return phydrv->suspend(phydev);
 }
 
@@ -312,10 +322,20 @@ static int mdio_bus_resume(struct device * dev)
 {
        struct phy_driver *phydrv = to_phy_driver(dev->driver);
        struct phy_device *phydev = to_phy_device(dev);
+       int ret;
 
        if (!mdio_bus_phy_may_suspend(phydev))
-               return 0;
-       return phydrv->resume(phydev);
+               goto no_resume;
+
+       ret = phydrv->resume(phydev);
+       if (ret < 0)
+               return ret;
+
+no_resume:
+       if (phydev->attached_dev)
+               phy_start_machine(phydev, NULL);
+
+       return 0;
 }
 
 struct bus_type mdio_bus_type = {