crush_hash32_3
extern __u32 crush_hash32_3(int type, __u32 a, __u32 b, __u32 c);
i = crush_hash32_3(bucket->hash, x, bucket->id, p) %
draw = crush_hash32_3(bucket->h.hash, x, bucket->h.items[i], r);
u = crush_hash32_3(bucket->h.hash, x, ids[i], r);
s = crush_hash32_3(bucket->hash, x, bucket->id, 0) %