g_valid_obj
int g_valid_obj(void const *ptr);
KASSERT(g_valid_obj(foo) == 1, ("%p is not a g_class", foo))
KASSERT(g_valid_obj(foo) == 2, ("%p is not a g_geom", foo))
KASSERT(g_valid_obj(foo) == 3, ("%p is not a g_consumer", foo))
KASSERT(g_valid_obj(foo) == 4, ("%p is not a g_provider", foo))
KASSERT(g_valid_obj(ptr) == 0,
g_valid_obj(ptr)));
switch (g_valid_obj((void *)addr)) {