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>

1 files changed, 17 insertions, 23 deletions

diff --git a/drivers/net/8139too.c b/drivers/net/8139too.c
index 35ad5cff18e6..99304b2aa86e 100644
--- 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));