[PATCH 4.19] stmmac: debugfs entry name is not be changed when udev rename device name.

[gouhao@xxxxxxxxxxxxx]

From: Jiping Ma <jiping.ma2@xxxxxxxxxxxxx>

commit 481a7d154cbbd5ca355cc01cc8969876b240eded upstream.

Add one notifier for udev changes net device name.

Fixes: 466c5ac8bdf2 ("net: stmmac: create one debugfs dir per net-device")
Signed-off-by: Jiping Ma <jiping.ma2@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Gou Hao <gouhao@xxxxxxxxxxxxx>
---
 .../net/ethernet/stmicro/stmmac/stmmac_main.c | 32 +++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 0a4d093adfc9..3e35cdf0d2b7 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -114,6 +114,7 @@ MODULE_PARM_DESC(chain_mode, "To use chain instead of ring mode");
 static irqreturn_t stmmac_interrupt(int irq, void *dev_id);
 
 #ifdef CONFIG_DEBUG_FS
+static const struct net_device_ops stmmac_netdev_ops;
 static int stmmac_init_fs(struct net_device *dev);
 static void stmmac_exit_fs(struct net_device *dev);
 #endif
@@ -4034,6 +4035,34 @@ static const struct file_operations stmmac_dma_cap_fops = {
 	.release = single_release,
 };
 
+/* Use network device events to rename debugfs file entries.
+ */
+static int stmmac_device_event(struct notifier_block *unused,
+			       unsigned long event, void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+	struct stmmac_priv *priv = netdev_priv(dev);
+
+	if (dev->netdev_ops != &stmmac_netdev_ops)
+		goto done;
+
+	switch (event) {
+	case NETDEV_CHANGENAME:
+		if (priv->dbgfs_dir)
+			priv->dbgfs_dir = debugfs_rename(stmmac_fs_dir,
+							 priv->dbgfs_dir,
+							 stmmac_fs_dir,
+							 dev->name);
+		break;
+	}
+done:
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block stmmac_notifier = {
+	.notifier_call = stmmac_device_event,
+};
+
 static int stmmac_init_fs(struct net_device *dev)
 {
 	struct stmmac_priv *priv = netdev_priv(dev);
@@ -4072,6 +4101,8 @@ static int stmmac_init_fs(struct net_device *dev)
 		return -ENOMEM;
 	}
 
+	register_netdevice_notifier(&stmmac_notifier);
+
 	return 0;
 }
 
@@ -4079,6 +4110,7 @@ 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 */
-- 
2.20.1