bonding: add the debugfs facility to the bonding driver

This patch provides the debugfs facility to the bonding driver.
The "bonding" directory is created in the debugfs root and directories of
each bonding interface (like bond0, bond1...) are created in that.

 # mount -t debugfs none /sys/kernel/debug

 # ls /sys/kernel/debug/bonding
 bond0  bond1
Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/Makefile

@@ -4,7 +4,7 @@
 
 obj-$(CONFIG_BONDING) += bonding.o
 
-bonding-objs := bond_main.o bond_3ad.o bond_alb.o bond_sysfs.o
+bonding-objs := bond_main.o bond_3ad.o bond_alb.o bond_sysfs.o bond_debugfs.o
 
 ipv6-$(subst m,y,$(CONFIG_IPV6)) += bond_ipv6.o
 bonding-objs += $(ipv6-y)

drivers/net/bonding/bond_debugfs.c

+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/netdevice.h>
+
+#include "bonding.h"
+
+#ifdef CONFIG_DEBUG_FS
+
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+
+static struct dentry *bonding_debug_root;
+
+void bond_debug_register(struct bonding *bond)
+{
+	if (!bonding_debug_root)
+		return;
+
+	bond->debug_dir =
+		debugfs_create_dir(bond->dev->name, bonding_debug_root);
+
+	if (!bond->debug_dir) {
+		pr_warning("%s: Warning: failed to register to debugfs\n",
+			bond->dev->name);
+		return;
+	}
+}
+
+void bond_debug_unregister(struct bonding *bond)
+{
+	if (!bonding_debug_root)
+		return;
+
+	debugfs_remove_recursive(bond->debug_dir);
+}
+
+void bond_debug_reregister(struct bonding *bond)
+{
+	struct dentry *d;
+
+	if (!bonding_debug_root)
+		return;
+
+	d = debugfs_rename(bonding_debug_root, bond->debug_dir,
+			   bonding_debug_root, bond->dev->name);
+	if (d) {
+		bond->debug_dir = d;
+	} else {
+		pr_warning("%s: Warning: failed to reregister, "
+				"so just unregister old one\n",
+				bond->dev->name);
+		bond_debug_unregister(bond);
+	}
+}
+
+void bond_create_debugfs(void)
+{
+	bonding_debug_root = debugfs_create_dir("bonding", NULL);
+
+	if (!bonding_debug_root) {
+		pr_warning("Warning: Cannot create bonding directory"
+				" in debugfs\n");
+	}
+}
+
+void bond_destroy_debugfs(void)
+{
+	debugfs_remove_recursive(bonding_debug_root);
+	bonding_debug_root = NULL;
+}
+
+
+#else /* !CONFIG_DEBUG_FS */
+
+void bond_debug_register(struct bonding *bond)
+{
+}
+
+void bond_debug_unregister(struct bonding *bond)
+{
+}
+
+void bond_debug_reregister(struct bonding *bond)
+{
+}
+
+void bond_create_debugfs(void)
+{
+}
+
+void bond_destroy_debugfs(void)
+{
+}
+
+#endif /* CONFIG_DEBUG_FS */

drivers/net/bonding/bond_main.c

@@ -3503,6 +3503,8 @@ static int bond_event_changename(struct bonding *bond)
 	bond_remove_proc_entry(bond);
 	bond_create_proc_entry(bond);
 
+	bond_debug_reregister(bond);
+
 	return NOTIFY_DONE;
 }
 
@@ -4785,6 +4787,8 @@ static void bond_uninit(struct net_device *bond_dev)
 
 	bond_remove_proc_entry(bond);
 
+	bond_debug_unregister(bond);
+
 	__hw_addr_flush(&bond->mc_list);
 
 	list_for_each_entry_safe(vlan, tmp, &bond->vlan_list, vlan_list) {
@@ -5187,6 +5191,8 @@ static int bond_init(struct net_device *bond_dev)
 
 	bond_prepare_sysfs_group(bond);
 
+	bond_debug_register(bond);
+
 	__hw_addr_init(&bond->mc_list);
 	return 0;
 }
@@ -5308,6 +5314,8 @@ static int __init bonding_init(void)
 	if (res)
 		goto err_link;
 
+	bond_create_debugfs();
+
 	for (i = 0; i < max_bonds; i++) {
 		res = bond_create(&init_net, NULL);
 		if (res)
@@ -5318,7 +5326,6 @@ static int __init bonding_init(void)
 	if (res)
 		goto err;
 
-
 	register_netdevice_notifier(&bond_netdev_notifier);
 	register_inetaddr_notifier(&bond_inetaddr_notifier);
 	bond_register_ipv6_notifier();
@@ -5342,6 +5349,7 @@ static void __exit bonding_exit(void)
 	bond_unregister_ipv6_notifier();
 
 	bond_destroy_sysfs();
+	bond_destroy_debugfs();
 
 	rtnl_link_unregister(&bond_link_ops);
 	unregister_pernet_subsys(&bond_net_ops);

drivers/net/bonding/bonding.h

@@ -259,6 +259,10 @@ struct bonding {
 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 	struct   in6_addr master_ipv6;
 #endif
+#ifdef CONFIG_DEBUG_FS
+	/* debugging suport via debugfs */
+	struct	 dentry *debug_dir;
+#endif /* CONFIG_DEBUG_FS */
 };
 
 /**
@@ -380,6 +384,11 @@ void bond_select_active_slave(struct bonding *bond);
 void bond_change_active_slave(struct bonding *bond, struct slave *new_active);
 void bond_register_arp(struct bonding *);
 void bond_unregister_arp(struct bonding *);
+void bond_create_debugfs(void);
+void bond_destroy_debugfs(void);
+void bond_debug_register(struct bonding *bond);
+void bond_debug_unregister(struct bonding *bond);
+void bond_debug_reregister(struct bonding *bond);
 
 struct bond_net {
 	struct net *		net;	/* Associated network namespace */