8139too: RTNL and flush_scheduled_work deadlock

Your usual dont-flush_scheduled_work-with-RTNL-held stuff.

It is a bit different here since the thread runs permanently
or is only occasionally kicked for recovery depending on the
hardware revision.

Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

diff --git a/drivers/net/8139too.c b/drivers/net/8139too.c
index 35ad5cff18e65936862c20276de4468189a12568..99304b2aa86e3d70d40520a9332e9a57930d4350 100644 (file)
--- a/drivers/net/8139too.c
+++ b/drivers/net/8139too.c
@@ -1109,6 +1109,8 @@ static void __devexit rtl8139_remove_one (struct pci_dev *pdev)
 
        assert (dev != NULL);
 
+       flush_scheduled_work();
+
        unregister_netdev (dev);
 
        __rtl8139_cleanup_dev (dev);
@@ -1603,18 +1605,21 @@ static void rtl8139_thread (struct work_struct *work)
        struct net_device *dev = tp->mii.dev;
        unsigned long thr_delay = next_tick;
 
+       rtnl_lock();
+
+       if (!netif_running(dev))
+               goto out_unlock;
+
        if (tp->watchdog_fired) {
                tp->watchdog_fired = 0;
                rtl8139_tx_timeout_task(work);
-       } else if (rtnl_trylock()) {
-               rtl8139_thread_iter (dev, tp, tp->mmio_addr);
-               rtnl_unlock ();
-       } else {
-               /* unlikely race.  mitigate with fast poll. */
-               thr_delay = HZ / 2;
-       }
+       } else
+               rtl8139_thread_iter(dev, tp, tp->mmio_addr);
 
-       schedule_delayed_work(&tp->thread, thr_delay);
+       if (tp->have_thread)
+               schedule_delayed_work(&tp->thread, thr_delay);
+out_unlock:
+       rtnl_unlock ();
 }
 
 static void rtl8139_start_thread(struct rtl8139_private *tp)
@@ -1626,19 +1631,11 @@ static void rtl8139_start_thread(struct rtl8139_private *tp)
                return;
 
        tp->have_thread = 1;
+       tp->watchdog_fired = 0;
 
        schedule_delayed_work(&tp->thread, next_tick);
 }
 
-static void rtl8139_stop_thread(struct rtl8139_private *tp)
-{
-       if (tp->have_thread) {
-               cancel_rearming_delayed_work(&tp->thread);
-               tp->have_thread = 0;
-       } else
-               flush_scheduled_work();
-}
-
 static inline void rtl8139_tx_clear (struct rtl8139_private *tp)
 {
        tp->cur_tx = 0;
@@ -1696,12 +1693,11 @@ static void rtl8139_tx_timeout (struct net_device *dev)
 {
        struct rtl8139_private *tp = netdev_priv(dev);
 
+       tp->watchdog_fired = 1;
        if (!tp->have_thread) {
-               INIT_DELAYED_WORK(&tp->thread, rtl8139_tx_timeout_task);
+               INIT_DELAYED_WORK(&tp->thread, rtl8139_thread);
                schedule_delayed_work(&tp->thread, next_tick);
-       } else
-               tp->watchdog_fired = 1;
-
+       }
 }
 
 static int rtl8139_start_xmit (struct sk_buff *skb, struct net_device *dev)
@@ -2233,8 +2229,6 @@ static int rtl8139_close (struct net_device *dev)
 
        netif_stop_queue (dev);
 
-       rtl8139_stop_thread(tp);
-
        if (netif_msg_ifdown(tp))
                printk(KERN_DEBUG "%s: Shutting down ethercard, status was 0x%4.4x.\n",
                        dev->name, RTL_R16 (IntrStatus));