[TG3]: Flush tg3_reset_task()

Make sure tg3_reset_task() is flushed in the close and suspend paths
as noted by Jeff Garzik.

In the close path, calling flush_scheduled_work() may cause deadlock
if linkwatch_event() is on the workqueue. linkwatch_event() will try
to get the rtnl_lock() which is already held by tg3_close(). So
instead, we set a flag in tg3_reset_task() and tg3_close() polls
the flag until it is cleared.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 24 insertions, 2 deletions

diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c
index f2d1dafde087..6fb29ca3fd30 100644
--- a/drivers/net/tg3.c
+++ b/drivers/net/tg3.c
@@ -3482,6 +3482,17 @@ static void tg3_reset_task(void *_data)
         struct tg3 *tp = _data;
         unsigned int restart_timer;
 
+        tg3_full_lock(tp, 0);
+        tp->tg3_flags |= TG3_FLAG_IN_RESET_TASK;
+
+        if (!netif_running(tp->dev)) {
+                tp->tg3_flags &= ~TG3_FLAG_IN_RESET_TASK;
+                tg3_full_unlock(tp);
+                return;
+        }
+
+        tg3_full_unlock(tp);
+
         tg3_netif_stop(tp);
 
         tg3_full_lock(tp, 1);
@@ -3494,10 +3505,12 @@ static void tg3_reset_task(void *_data)
 
         tg3_netif_start(tp);
 
-        tg3_full_unlock(tp);
-
         if (restart_timer)
                 mod_timer(&tp->timer, jiffies + 1);
+
+        tp->tg3_flags &= ~TG3_FLAG_IN_RESET_TASK;
+
+        tg3_full_unlock(tp);
 }
 
 static void tg3_tx_timeout(struct net_device *dev)
@@ -6786,6 +6799,13 @@ static int tg3_close(struct net_device *dev)
 {
         struct tg3 *tp = netdev_priv(dev);
 
+        /* Calling flush_scheduled_work() may deadlock because
+         * linkwatch_event() may be on the workqueue and it will try to get
+         * the rtnl_lock which we are holding.
+         */
+        while (tp->tg3_flags & TG3_FLAG_IN_RESET_TASK)
+                msleep(1);
+
         netif_stop_queue(dev);
 
         del_timer_sync(&tp->timer);
@@ -10880,6 +10900,7 @@ static void __devexit tg3_remove_one(struct pci_dev *pdev)
         if (dev) {
                 struct tg3 *tp = netdev_priv(dev);
 
+                flush_scheduled_work();
                 unregister_netdev(dev);
                 if (tp->regs) {
                         iounmap(tp->regs);
@@ -10901,6 +10922,7 @@ static int tg3_suspend(struct pci_dev *pdev, pm_message_t state)
         if (!netif_running(dev))
                 return 0;
 
+        flush_scheduled_work();
         tg3_netif_stop(tp);
 
         del_timer_sync(&tp->timer);