r8169: use RTNL to protect critical sections

Most relevant ops (open, close, ethtool ops) are protected with RTNL
lock by net core. Make sure that such ops can't be interrupted by
e.g. (runtime-)suspending by taking the RTNL lock in suspend ops
and the PCI error handler.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/realtek/r8169_main.c

@@ -4524,6 +4524,7 @@ static void rtl_task(struct work_struct *work)
 	struct rtl8169_private *tp =
 		container_of(work, struct rtl8169_private, wk.work);
 
+	rtnl_lock();
 	rtl_lock_work(tp);
 
 	if (!netif_running(tp->dev) ||
@@ -4536,6 +4537,7 @@ static void rtl_task(struct work_struct *work)
 	}
 out_unlock:
 	rtl_unlock_work(tp);
+	rtnl_unlock();
 }
 
 static int rtl8169_poll(struct napi_struct *napi, int budget)
@@ -4788,7 +4790,9 @@ static int __maybe_unused rtl8169_suspend(struct device *device)
 {
 	struct rtl8169_private *tp = dev_get_drvdata(device);
 
+	rtnl_lock();
 	rtl8169_net_suspend(tp);
+	rtnl_unlock();
 
 	return 0;
 }
@@ -4816,11 +4820,13 @@ static int rtl8169_runtime_suspend(struct device *device)
 		return 0;
 	}
 
+	rtnl_lock();
 	rtl_lock_work(tp);
 	__rtl8169_set_wol(tp, WAKE_PHY);
 	rtl_unlock_work(tp);
 
 	rtl8169_net_suspend(tp);
+	rtnl_unlock();
 
 	return 0;
 }
@@ -4882,7 +4888,9 @@ static void rtl_shutdown(struct pci_dev *pdev)
 {
 	struct rtl8169_private *tp = pci_get_drvdata(pdev);
 
+	rtnl_lock();
 	rtl8169_net_suspend(tp);
+	rtnl_unlock();
 
 	/* Restore original MAC address */
 	rtl_rar_set(tp, tp->dev->perm_addr);