dm_kvfree
dm_kvfree(s->stat_percpu[cpu][0].histogram, s->histogram_alloc_size);
dm_kvfree(s->stat_percpu[cpu], s->percpu_alloc_size);
dm_kvfree(s->stat_shared[0].tmp.histogram, s->histogram_alloc_size);
dm_kvfree(s, s->shared_alloc_size);