l2arc_data_free_t
l2arc_data_free_t *df = kmem_alloc(sizeof (*df), KM_SLEEP);
l2arc_data_free_t *df, *df_prev;
kmem_free(df, sizeof (l2arc_data_free_t));
list_create(l2arc_free_on_write, sizeof (l2arc_data_free_t),
offsetof(l2arc_data_free_t, l2df_list_node));