[RFC dlm/next 08/12] kobject: add kset_type_create_and_add() helper

[Alexander Aring <aahringo@redhat.com>]

Currently there exists the kset_create_and_add() helper that does not
allow to have a different ktype for the created kset kobject. To allow
a different ktype this patch will introduce the function
kset_type_create_and_add() that allows to set a different ktype instead
of using the global default kset_ktype variable.

In my example I need to separate the created kobject inside the kset by
net-namespaces. This patch allows me to do that by providing a user
defined kobj_type structure that implements the necessary namespace
functionality.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
---
 include/linux/kobject.h |  8 +++++--
 lib/kobject.c           | 49 +++++++++++++++++++++++++----------------
 2 files changed, 36 insertions(+), 21 deletions(-)

diff --git a/include/linux/kobject.h b/include/linux/kobject.h
index c8219505a79f..7504b7547ed2 100644
--- a/include/linux/kobject.h
+++ b/include/linux/kobject.h
@@ -175,8 +175,12 @@ struct kset {
 void kset_init(struct kset *kset);
 int __must_check kset_register(struct kset *kset);
 void kset_unregister(struct kset *kset);
-struct kset * __must_check kset_create_and_add(const char *name, const struct kset_uevent_ops *u,
-					       struct kobject *parent_kobj);
+struct kset * __must_check
+kset_type_create_and_add(const char *name, const struct kset_uevent_ops *u,
+			 struct kobject *parent_kobj, const struct kobj_type *ktype);
+struct kset * __must_check
+kset_create_and_add(const char *name, const struct kset_uevent_ops *u,
+		    struct kobject *parent_kobj);
 
 static inline struct kset *to_kset(struct kobject *kobj)
 {
diff --git a/lib/kobject.c b/lib/kobject.c
index 72fa20f405f1..fbae94ea9bb5 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -957,7 +957,8 @@ static const struct kobj_type kset_ktype = {
  */
 static struct kset *kset_create(const char *name,
 				const struct kset_uevent_ops *uevent_ops,
-				struct kobject *parent_kobj)
+				struct kobject *parent_kobj,
+				const struct kobj_type *ktype)
 {
 	struct kset *kset;
 	int retval;
@@ -973,17 +974,32 @@ static struct kset *kset_create(const char *name,
 	kset->uevent_ops = uevent_ops;
 	kset->kobj.parent = parent_kobj;
 
-	/*
-	 * The kobject of this kset will have a type of kset_ktype and belong to
-	 * no kset itself.  That way we can properly free it when it is
-	 * finished being used.
-	 */
-	kset->kobj.ktype = &kset_ktype;
+	kset->kobj.ktype = ktype;
 	kset->kobj.kset = NULL;
 
 	return kset;
 }
 
+struct kset *kset_type_create_and_add(const char *name,
+				      const struct kset_uevent_ops *uevent_ops,
+				      struct kobject *parent_kobj,
+				      const struct kobj_type *ktype)
+{
+	struct kset *kset;
+	int error;
+
+	kset = kset_create(name, uevent_ops, parent_kobj, ktype);
+	if (!kset)
+		return NULL;
+	error = kset_register(kset);
+	if (error) {
+		kfree(kset);
+		return NULL;
+	}
+	return kset;
+}
+EXPORT_SYMBOL_GPL(kset_type_create_and_add);
+
 /**
  * kset_create_and_add() - Create a struct kset dynamically and add it to sysfs.
  *
@@ -1002,18 +1018,13 @@ struct kset *kset_create_and_add(const char *name,
 				 const struct kset_uevent_ops *uevent_ops,
 				 struct kobject *parent_kobj)
 {
-	struct kset *kset;
-	int error;
-
-	kset = kset_create(name, uevent_ops, parent_kobj);
-	if (!kset)
-		return NULL;
-	error = kset_register(kset);
-	if (error) {
-		kfree(kset);
-		return NULL;
-	}
-	return kset;
+	/*
+	 * The kobject of this kset will have a type of kset_ktype and belong to
+	 * no kset itself.  That way we can properly free it when it is
+	 * finished being used.
+	 */
+	return kset_type_create_and_add(name, uevent_ops, parent_kobj,
+					&kset_ktype);
 }
 EXPORT_SYMBOL_GPL(kset_create_and_add);
 
-- 
2.43.0