[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>

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);

drivers/net/tg3.h

@@ -2162,6 +2162,7 @@ struct tg3 {
 #define TG3_FLAG_JUMBO_RING_ENABLE	0x00800000
 #define TG3_FLAG_10_100_ONLY		0x01000000
 #define TG3_FLAG_PAUSE_AUTONEG		0x02000000
+#define TG3_FLAG_IN_RESET_TASK		0x04000000
 #define TG3_FLAG_BROKEN_CHECKSUMS	0x10000000
 #define TG3_FLAG_GOT_SERDES_FLOWCTL	0x20000000
 #define TG3_FLAG_SPLIT_MODE		0x40000000