6lowpan: add debugfs support

This patch will introduce a 6lowpan entry into the debugfs if enabled.
Inside this 6lowpan directory we create a subdirectories of all 6lowpan
interfaces to offer a per interface debugfs support.

Reviewed-by: Stefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/6lowpan/core.c

@@ -15,9 +15,13 @@
 
 #include <net/6lowpan.h>
 
+#include "6lowpan_i.h"
+
 int lowpan_register_netdevice(struct net_device *dev,
 			      enum lowpan_lltypes lltype)
 {
+	int ret;
+
 	dev->addr_len = EUI64_ADDR_LEN;
 	dev->type = ARPHRD_6LOWPAN;
 	dev->mtu = IPV6_MIN_MTU;
@@ -25,7 +29,15 @@ int lowpan_register_netdevice(struct net_device *dev,
 
 	lowpan_priv(dev)->lltype = lltype;
 
-	return register_netdevice(dev);
+	ret = lowpan_dev_debugfs_init(dev);
+	if (ret < 0)
+		return ret;
+
+	ret = register_netdevice(dev);
+	if (ret < 0)
+		lowpan_dev_debugfs_exit(dev);
+
+	return ret;
 }
 EXPORT_SYMBOL(lowpan_register_netdevice);
 
@@ -44,6 +56,7 @@ EXPORT_SYMBOL(lowpan_register_netdev);
 void lowpan_unregister_netdevice(struct net_device *dev)
 {
 	unregister_netdevice(dev);
+	lowpan_dev_debugfs_exit(dev);
 }
 EXPORT_SYMBOL(lowpan_unregister_netdevice);
 
@@ -57,6 +70,12 @@ EXPORT_SYMBOL(lowpan_unregister_netdev);
 
 static int __init lowpan_module_init(void)
 {
+	int ret;
+
+	ret = lowpan_debugfs_init();
+	if (ret < 0)
+		return ret;
+
 	request_module_nowait("ipv6");
 
 	request_module_nowait("nhc_dest");
@@ -69,6 +88,13 @@ static int __init lowpan_module_init(void)
 
 	return 0;
 }
+
+static void __exit lowpan_module_exit(void)
+{
+	lowpan_debugfs_exit();
+}
+
 module_init(lowpan_module_init);
+module_exit(lowpan_module_exit);
 
 MODULE_LICENSE("GPL");