[PATCH 1/3] driver core: class: add class_pseudo_register

[Heiner Kallweit <hkallweit1@xxxxxxxxx>]

In preparation of removing class_compat support, add a helper for
creating a pseudo class in sysfs. This way we can keep class_kset
private to driver core. This helper will be used by vfio/mdev,
replacing the call to class_compat_create().

Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
---
 drivers/base/class.c         | 14 ++++++++++++++
 include/linux/device/class.h |  1 +
 2 files changed, 15 insertions(+)

diff --git a/drivers/base/class.c b/drivers/base/class.c
index 582b5a02a..f812236e2 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -578,6 +578,20 @@ struct class_compat *class_compat_register(const char *name)
 }
 EXPORT_SYMBOL_GPL(class_compat_register);
 
+/**
+ * class_pseudo_register - create a pseudo class entry in sysfs
+ * @name: the name of the child
+ *
+ * Helper for creating a pseudo class in sysfs, keeps class_kset private
+ *
+ * Returns: the created kobject
+ */
+struct kobject *class_pseudo_register(const char *name)
+{
+	return kobject_create_and_add(name, &class_kset->kobj);
+}
+EXPORT_SYMBOL_GPL(class_pseudo_register);
+
 /**
  * class_compat_unregister - unregister a compatibility class
  * @cls: the class to unregister
diff --git a/include/linux/device/class.h b/include/linux/device/class.h
index 518c9c83d..8b6e890c7 100644
--- a/include/linux/device/class.h
+++ b/include/linux/device/class.h
@@ -86,6 +86,7 @@ int class_compat_create_link(struct class_compat *cls, struct device *dev,
 			     struct device *device_link);
 void class_compat_remove_link(struct class_compat *cls, struct device *dev,
 			      struct device *device_link);
+struct kobject *class_pseudo_register(const char *name);
 
 void class_dev_iter_init(struct class_dev_iter *iter, const struct class *class,
 			 const struct device *start, const struct device_type *type);
-- 
2.47.1