staging: rtl8192u: fix rmmod warn when device is renamed

This driver creates 4 debug files under [devname] folder. The devname
could be wlan0 initially, however it could be renamed later to e.g.
enx00e04c00000. This will cause problem during debug file teardown since
it uses netdev->name, which is no longer wlan0. To solve this problem,
add a notifier to handle device renaming. Also note that we cannot
simply do debugfs_lookup to find out old dentry since by the time the
notifier is called, netdev->name is already changed to new name.

Reported-by: Zheyu Ma <zheyuma97@gmail.com>
Tested-by: Zheyu Ma <zheyuma97@gmail.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Tong Zhang <ztong0001@gmail.com>
Link: https://lore.kernel.org/r/20220730033335.74153-5-ztong0001@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/rtl8192u/r8192U.h b/drivers/staging/rtl8192u/r8192U.h
index 75f312e41a9265c0ea8b5260426a2080121b8ab0..ff0ada00bf4142ab81851f909edbf09c01654d40 100644 (file)
--- a/drivers/staging/rtl8192u/r8192U.h
+++ b/drivers/staging/rtl8192u/r8192U.h
@@ -1122,6 +1122,7 @@ void setKey(struct net_device *dev, u8 EntryNo, u8 KeyIndex, u16 KeyType,
 
 void rtl8192_debugfs_init_one(struct net_device *dev);
 void rtl8192_debugfs_exit_one(struct net_device *dev);
+void rtl8192_debugfs_rename_one(struct net_device *dev);
 void rtl8192_debugfs_init(void);
 void rtl8192_debugfs_exit(void);
 

diff --git a/drivers/staging/rtl8192u/r8192U_core.c b/drivers/staging/rtl8192u/r8192U_core.c
index 865bc0dc7c71bd7ffcb192b5c151473297ba8db8..0a60ef20107c4301d4b5e8e6ba37fe3178195752 100644 (file)
--- a/drivers/staging/rtl8192u/r8192U_core.c
+++ b/drivers/staging/rtl8192u/r8192U_core.c
@@ -4606,6 +4606,30 @@ static void rtl8192_usb_disconnect(struct usb_interface *intf)
        RT_TRACE(COMP_DOWN, "wlan driver removed\n");
 }
 
+static int rtl8192_usb_netdev_event(struct notifier_block *nb, unsigned long event,
+                                   void *data)
+{
+       struct net_device *netdev = netdev_notifier_info_to_dev(data);
+
+       if (netdev->netdev_ops != &rtl8192_netdev_ops)
+               goto out;
+
+       switch (event) {
+       case NETDEV_CHANGENAME:
+               rtl8192_debugfs_rename_one(netdev);
+               break;
+       default:
+               break;
+       }
+
+out:
+       return NOTIFY_DONE;
+}
+
+static struct notifier_block rtl8192_usb_netdev_notifier = {
+       .notifier_call = rtl8192_usb_netdev_event,
+};
+
 static int __init rtl8192_usb_module_init(void)
 {
        int ret;
@@ -4615,6 +4639,12 @@ static int __init rtl8192_usb_module_init(void)
        RT_TRACE(COMP_INIT, "Initializing module");
        RT_TRACE(COMP_INIT, "Wireless extensions version %d", WIRELESS_EXT);
 
+       ret = register_netdevice_notifier(&rtl8192_usb_netdev_notifier);
+       if (ret) {
+               pr_err("register_netdevice_notifier failed %d\n", ret);
+               return ret;
+       }
+
        rtl8192_debugfs_init();
        ret = ieee80211_debug_init();
        if (ret) {
@@ -4663,6 +4693,7 @@ debug_exit:
        ieee80211_debug_exit();
 debugfs_exit:
        rtl8192_debugfs_exit();
+       unregister_netdevice_notifier(&rtl8192_usb_netdev_notifier);
        return ret;
 }
 
@@ -4675,6 +4706,7 @@ static void __exit rtl8192_usb_module_exit(void)
        ieee80211_crypto_deinit();
        ieee80211_debug_exit();
        rtl8192_debugfs_exit();
+       unregister_netdevice_notifier(&rtl8192_usb_netdev_notifier);
        RT_TRACE(COMP_DOWN, "Exiting");
 }
 

diff --git a/drivers/staging/rtl8192u/r8192U_debugfs.c b/drivers/staging/rtl8192u/r8192U_debugfs.c
index c645043466578d0a39059ac3328e021cd6d96f36..fe8ef72506ee1c11ac4d1afeee7b31ee774bc13e 100644 (file)
--- a/drivers/staging/rtl8192u/r8192U_debugfs.c
+++ b/drivers/staging/rtl8192u/r8192U_debugfs.c
@@ -169,6 +169,14 @@ void rtl8192_debugfs_exit_one(struct net_device *dev)
        debugfs_remove_recursive(priv->debugfs_dir);
 }
 
+void rtl8192_debugfs_rename_one(struct net_device *dev)
+{
+       struct r8192_priv *priv = ieee80211_priv(dev);
+       struct dentry *parent_dir = debugfs_lookup(KBUILD_MODNAME, NULL);
+
+       debugfs_rename(parent_dir, priv->debugfs_dir, parent_dir, dev->name);
+}
+
 void rtl8192_debugfs_init(void)
 {
        debugfs_create_dir(KBUILD_MODNAME, NULL);