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>

2 files changed, 72 insertions, 14 deletions

diff --git a/drivers/base/class.c b/drivers/base/class.c
index 9c6a0d6408e7..8e231d05b400 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -63,6 +63,14 @@ static void class_release(struct kobject *kobj)
         kfree(cp);
 }
 
+static const struct kobj_ns_type_operations *class_child_ns_type(struct kobject *kobj)
+{
+        struct class_private *cp = to_class(kobj);
+        struct class *class = cp->class;
+
+        return class->ns_type;
+}
+
 static const struct sysfs_ops class_sysfs_ops = {
         .show   = class_attr_show,
         .store  = class_attr_store,
@@ -71,6 +79,7 @@ static const struct sysfs_ops class_sysfs_ops = {
 static struct kobj_type class_ktype = {
         .sysfs_ops      = &class_sysfs_ops,
         .release        = class_release,
+        .child_ns_type  = class_child_ns_type,
 };
 
 /* Hotplug events for classes go to the class class_subsys */
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 356dd011b8f9..f0699918e2f6 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -131,9 +131,21 @@ static void device_release(struct kobject *kobj)
         kfree(p);
 }
 
+static const void *device_namespace(struct kobject *kobj)
+{
+        struct device *dev = to_dev(kobj);
+        const void *ns = NULL;
+
+        if (dev->class && dev->class->ns_type)
+                ns = dev->class->namespace(dev);
+
+        return ns;
+}
+
 static struct kobj_type device_ktype = {
         .release        = device_release,
         .sysfs_ops      = &dev_sysfs_ops,
+        .namespace      = device_namespace,
 };
 
 
@@ -595,11 +607,59 @@ static struct kobject *virtual_device_parent(struct device *dev)
         return virtual_dir;
 }
 
-static struct kobject *get_device_parent(struct device *dev,
-                                         struct device *parent)
+struct class_dir {
+        struct kobject kobj;
+        struct class *class;
+};
+
+#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
+
+static void class_dir_release(struct kobject *kobj)
+{
+        struct class_dir *dir = to_class_dir(kobj);
+        kfree(dir);
+}
+
+static const
+struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
 {
+        struct class_dir *dir = to_class_dir(kobj);
+        return dir->class->ns_type;
+}
+
+static struct kobj_type class_dir_ktype = {
+        .release        = class_dir_release,
+        .sysfs_ops      = &kobj_sysfs_ops,
+        .child_ns_type  = class_dir_child_ns_type
+};
+
+static struct kobject *
+class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
+{
+        struct class_dir *dir;
         int retval;
 
+        dir = kzalloc(sizeof(*dir), GFP_KERNEL);
+        if (!dir)
+                return NULL;
+
+        dir->class = class;
+        kobject_init(&dir->kobj, &class_dir_ktype);
+
+        dir->kobj.kset = &class->p->class_dirs;
+
+        retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
+        if (retval < 0) {
+                kobject_put(&dir->kobj);
+                return NULL;
+        }
+        return &dir->kobj;
+}
+
+
+static struct kobject *get_device_parent(struct device *dev,
+                                         struct device *parent)
+{
         if (dev->class) {
                 static DEFINE_MUTEX(gdp_mutex);
                 struct kobject *kobj = NULL;
@@ -634,18 +694,7 @@ static struct kobject *get_device_parent(struct device *dev,
                 }
 
                 /* or create a new class-directory at the parent device */
-                k = kobject_create();
-                if (!k) {
-                        mutex_unlock(&gdp_mutex);
-                        return NULL;
-                }
-                k->kset = &dev->class->p->class_dirs;
-                retval = kobject_add(k, parent_kobj, "%s", dev->class->name);
-                if (retval < 0) {
-                        mutex_unlock(&gdp_mutex);
-                        kobject_put(k);
-                        return NULL;
-                }
+                k = class_dir_create_and_add(dev->class, parent_kobj);
                 /* do not emit an uevent for this simple "glue" directory */
                 mutex_unlock(&gdp_mutex);
                 return k;