ceph_stable_mod
last_pgid.seed = ceph_stable_mod(pgid.seed, t->pg_num, t->pg_num_mask);
s = ceph_stable_mod(s, old_pg_num, old_mask);
pgid->seed = ceph_stable_mod(raw_pgid->seed, pi->pg_num,
ceph_stable_mod(raw_pgid->seed,
return ceph_stable_mod(raw_pgid->seed, pi->pgp_num,