kobj: Add basic infrastructure for dealing with namespaces.

Move complete knowledge of namespaces into the kobject layer
so we can use that information when reporting kobjects to
userspace.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

include/linux/kobject.h

@@ -108,6 +108,8 @@ struct kobj_type {
 	void (*release)(struct kobject *kobj);
 	const struct sysfs_ops *sysfs_ops;
 	struct attribute **default_attrs;
+	const struct kobj_ns_type_operations *(*child_ns_type)(struct kobject *kobj);
+	const void *(*namespace)(struct kobject *kobj);
 };
 
 struct kobj_uevent_env {
@@ -134,6 +136,30 @@ struct kobj_attribute {
 
 extern const struct sysfs_ops kobj_sysfs_ops;
 
+enum kobj_ns_type {
+	KOBJ_NS_TYPE_NONE = 0,
+	KOBJ_NS_TYPES
+};
+
+struct sock;
+struct kobj_ns_type_operations {
+	enum kobj_ns_type type;
+	const void *(*current_ns)(void);
+	const void *(*netlink_ns)(struct sock *sk);
+	const void *(*initial_ns)(void);
+};
+
+int kobj_ns_type_register(const struct kobj_ns_type_operations *ops);
+int kobj_ns_type_registered(enum kobj_ns_type type);
+const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent);
+const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj);
+
+const void *kobj_ns_current(enum kobj_ns_type type);
+const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk);
+const void *kobj_ns_initial(enum kobj_ns_type type);
+void kobj_ns_exit(enum kobj_ns_type type, const void *ns);
+
+
 /**
  * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
  *