kobject: Remove redundant checks for whether ktype is NULL

When adding koject or kset, we have made sure that ktype cannot be NULL.
Therefore, after adding koject or kset, there is no need to worry about
ktype being NULL. Clear all ktype-related redundancy checks.
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20230805084114.1298-3-thunder.leizhen@huaweicloud.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

lib/kobject.c

@@ -74,13 +74,11 @@ static int create_dir(struct kobject *kobj)
 	if (error)
 		return error;
 
-	if (ktype) {
 	error = sysfs_create_groups(kobj, ktype->default_groups);
 	if (error) {
 		sysfs_remove_dir(kobj);
 		return error;
 	}
-	}
 
 	/*
 	 * @kobj->sd may be deleted by an ancestor going away.  Hold an
@@ -591,7 +589,6 @@ static void __kobject_del(struct kobject *kobj)
 	sd = kobj->sd;
 	ktype = get_ktype(kobj);
 
-	if (ktype)
 	sysfs_remove_groups(kobj, ktype->default_groups);
 
 	/* send "remove" if the caller did not do it but sent "add" */
@@ -669,10 +666,6 @@ static void kobject_cleanup(struct kobject *kobj)
 	pr_debug("'%s' (%p): %s, parent %p\n",
 		 kobject_name(kobj), kobj, __func__, kobj->parent);
 
-	if (t && !t->release)
-		pr_debug("'%s' (%p): does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.\n",
-			 kobject_name(kobj), kobj);
-
 	/* remove from sysfs if the caller did not do it */
 	if (kobj->state_in_sysfs) {
 		pr_debug("'%s' (%p): auto cleanup kobject_del\n",
@@ -683,10 +676,13 @@ static void kobject_cleanup(struct kobject *kobj)
 		parent = NULL;
 	}
 
-	if (t && t->release) {
+	if (t->release) {
 		pr_debug("'%s' (%p): calling ktype release\n",
 			 kobject_name(kobj), kobj);
 		t->release(kobj);
+	} else {
+		pr_debug("'%s' (%p): does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.\n",
+			 kobject_name(kobj), kobj);
 	}
 
 	/* free name if we allocated it */
@@ -1060,7 +1056,7 @@ const struct kobj_ns_type_operations *kobj_child_ns_ops(const struct kobject *pa
 {
 	const struct kobj_ns_type_operations *ops = NULL;
 
-	if (parent && parent->ktype && parent->ktype->child_ns_type)
+	if (parent && parent->ktype->child_ns_type)
 		ops = parent->ktype->child_ns_type(parent);
 
 	return ops;