zipf/pareto: use min of file size and io size for init

It is valid to use size=foo, where foo is larger than the size
of the file or device. For that case, we don't want offsets
larger than the size of the file. So use the minimum of the
real or given size.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
Start of transition from unsigned long long to uint64_t

Signed-off-by: Jens Axboe <axboe@kernel.dk>
Use uintptr_t for engine data

Gets rid of a warning on 32-bit builds on Linux.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
time: convert to uint64_t

Signed-off-by: Jens Axboe <axboe@kernel.dk>