[1/4] kobject: add kset_type_create_and_add() helper

Commit Message

Alexander Aring Oct. 3, 2024, 3:14 p.m. UTC

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.

Acked-by: Greg Kroah-Hartman <[e-mail]>
Signed-off-by: Alexander Aring <[e-mail]>
---
 include/linux/kobject.h |  8 ++++--
 lib/kobject.c           | 59 ++++++++++++++++++++++++++++++-----------
 2 files changed, 50 insertions(+), 17 deletions(-)

Patch

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..09dd3d4c7f56 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -946,6 +946,7 @@  static const struct kobj_type kset_ktype = {
  * @name: the name for the kset
  * @uevent_ops: a struct kset_uevent_ops for the kset
  * @parent_kobj: the parent kobject of this kset, if any.
+ * @ktype: a struct kobj_type for the kset
  *
  * This function creates a kset structure dynamically.  This structure can
  * then be registered with the system and show up in sysfs with a call to
@@ -957,7 +958,8 @@  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;
@@ -973,39 +975,38 @@  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;
 }
 
 /**
- * kset_create_and_add() - Create a struct kset dynamically and add it to sysfs.
+ * kset_type_create_and_add() - Create a struct kset with kobj_type dynamically
+ *                              and add it to sysfs.
  *
  * @name: the name for the kset
  * @uevent_ops: a struct kset_uevent_ops for the kset
  * @parent_kobj: the parent kobject of this kset, if any.
+ * @ktype: a struct kobj_type for the kset
  *
- * This function creates a kset structure dynamically and registers it
- * with sysfs.  When you are finished with this structure, call
+ * This function creates a kset structure with ktype structure dynamically and
+ * registers it with sysfs.  When you are finished with this structure, call
  * kset_unregister() and the structure will be dynamically freed when it
- * is no longer being used.
+ * is no longer being used. Works like kset_create_and_add() just with the
+ * possibility to assign kobj_type to the kset.
  *
  * If the kset was not able to be created, NULL will be returned.
  */
-struct kset *kset_create_and_add(const char *name,
-				 const struct kset_uevent_ops *uevent_ops,
-				 struct kobject *parent_kobj)
+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);
+	kset = kset_create(name, uevent_ops, parent_kobj, ktype);
 	if (!kset)
 		return NULL;
 	error = kset_register(kset);
@@ -1015,6 +1016,34 @@  struct kset *kset_create_and_add(const char *name,
 	}
 	return kset;
 }
+EXPORT_SYMBOL_GPL(kset_type_create_and_add);
+
+/**
+ * kset_create_and_add() - Create a struct kset dynamically and add it to sysfs.
+ *
+ * @name: the name for the kset
+ * @uevent_ops: a struct kset_uevent_ops for the kset
+ * @parent_kobj: the parent kobject of this kset, if any.
+ *
+ * This function creates a kset structure dynamically and registers it
+ * with sysfs.  When you are finished with this structure, call
+ * kset_unregister() and the structure will be dynamically freed when it
+ * is no longer being used.
+ *
+ * If the kset was not able to be created, NULL will be returned.
+ */
+struct kset *kset_create_and_add(const char *name,
+				 const struct kset_uevent_ops *uevent_ops,
+				 struct kobject *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.
+	 */
+	return kset_type_create_and_add(name, uevent_ops, parent_kobj,
+					&kset_ktype);
+}
 EXPORT_SYMBOL_GPL(kset_create_and_add);