Add test loop_08, which creates a ublk device with UBLK_F_IO_DESC_SIZE
enabled and io_desc_size set to 64. The test issues verified I/O to the
device using fio.
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Link: https://patch.msgid.link/20260803211441.2538144-8-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>