klist_node_attached
if (klist_node_attached(&dev->p->knode_bus))
return dev->p && klist_node_attached(&dev->p->knode_driver);
extern int klist_node_attached(struct klist_node *n);
EXPORT_SYMBOL_GPL(klist_node_attached);
KUNIT_EXPECT_TRUE(test, klist_node_attached(&c));
KUNIT_EXPECT_FALSE(test, klist_node_attached(&a));
KUNIT_EXPECT_TRUE(test, klist_node_attached(&a));
KUNIT_EXPECT_FALSE(test, klist_node_attached(&a));