ioctl() for io_uring

Make some nullblk devices and use fio with the io_uring engine where the target device(s) is one or more nullblk devices. Then you can do the measurements yourself. You will be measuring the fio, io_uring, block layer and null_blk overhead with the latter being pretty small unless a lot of data is being moved.

I do similar measurements with scsi_debug devices in place of nullblk devices.