e1000: Prevent reset task killing itself.

Killing reset task while adapter is resetting causes deadlock.
Only kill reset task if adapter is not resetting.
Ref bug #43132 on bugzilla.kernel.org

CC: stable@vger.kernel.org
Signed-off-by: Tushar Dave <tushar.n.dave@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/intel/e1000/e1000_main.c

@@ -493,7 +493,11 @@ out:
 static void e1000_down_and_stop(struct e1000_adapter *adapter)
 {
 	set_bit(__E1000_DOWN, &adapter->flags);
-	cancel_work_sync(&adapter->reset_task);
+
+	/* Only kill reset task if adapter is not resetting */
+	if (!test_bit(__E1000_RESETTING, &adapter->flags))
+		cancel_work_sync(&adapter->reset_task);
+
 	cancel_delayed_work_sync(&adapter->watchdog_task);
 	cancel_delayed_work_sync(&adapter->phy_info_task);
 	cancel_delayed_work_sync(&adapter->fifo_stall_task);