> I don't think that's necessarily correct.  In the disksort_cylinder()
> case you want both cylinder and rawblkno (maybe rawblkno in this case
> would be sector-relative-to-cylinder ?).

Is it still meaningful?  I think we cannot use actual cylinder number since
zone bit recording makes the physical layout unknown to us.

Anyway, I just use b_cylinder to store raw blkno and call disksort_cylinder(),
and find my notebook extremely improves its performance.

Atsushi