net: stmmac: fix notifier registration

commit 474a31e13a4e9749fb3ee55794d69d0f17ee0998 upstream.

We cannot register the same netdev notifier multiple times when probing
stmmac devices. Register the notifier only once in module init, and also
make debugfs creation/deletion safe against simultaneous notifier call.

Fixes: 481a7d154cbb ("stmmac: debugfs entry name is not be changed when udev rename device name.")
Signed-off-by: Aaro Koskinen <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Hugo SIMELIERE <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -4067,6 +4067,8 @@ static void stmmac_init_fs(struct net_device *dev)
 {
 	struct stmmac_priv *priv = netdev_priv(dev);
 
+	rtnl_lock();
+
 	/* Create per netdev entries */
 	priv->dbgfs_dir = debugfs_create_dir(dev->name, stmmac_fs_dir);
 
@@ -4078,14 +4080,13 @@ static void stmmac_init_fs(struct net_device *dev)
 	debugfs_create_file("dma_cap", 0444, priv->dbgfs_dir, dev,
 			    &stmmac_dma_cap_fops);
 
-	register_netdevice_notifier(&stmmac_notifier);
+	rtnl_unlock();
 }
 
 static void stmmac_exit_fs(struct net_device *dev)
 {
 	struct stmmac_priv *priv = netdev_priv(dev);
 
-	unregister_netdevice_notifier(&stmmac_notifier);
 	debugfs_remove_recursive(priv->dbgfs_dir);
 }
 #endif /* CONFIG_DEBUG_FS */
@@ -4455,14 +4456,14 @@ int stmmac_dvr_remove(struct device *dev)
 
 	netdev_info(priv->dev, "%s: removing driver", __func__);
 
-#ifdef CONFIG_DEBUG_FS
-	stmmac_exit_fs(ndev);
-#endif
 	stmmac_stop_all_dma(priv);
 
 	stmmac_mac_set(priv, priv->ioaddr, false);
 	netif_carrier_off(ndev);
 	unregister_netdev(ndev);
+#ifdef CONFIG_DEBUG_FS
+	stmmac_exit_fs(ndev);
+#endif
 	if (priv->plat->stmmac_rst)
 		reset_control_assert(priv->plat->stmmac_rst);
 	clk_disable_unprepare(priv->plat->pclk);
@@ -4679,6 +4680,7 @@ static int __init stmmac_init(void)
 	/* Create debugfs main directory if it doesn't exist yet */
 	if (!stmmac_fs_dir)
 		stmmac_fs_dir = debugfs_create_dir(STMMAC_RESOURCE_NAME, NULL);
+	register_netdevice_notifier(&stmmac_notifier);
 #endif
 
 	return 0;
@@ -4687,6 +4689,7 @@ static int __init stmmac_init(void)
 static void __exit stmmac_exit(void)
 {
 #ifdef CONFIG_DEBUG_FS
+	unregister_netdevice_notifier(&stmmac_notifier);
 	debugfs_remove_recursive(stmmac_fs_dir);
 #endif
 }