Seperate ioprio value from setting

Newer kernels allow passing a value of '0' for resetting ioprio,
and our check for if (td->ioprio) doesn't allow passing a value of
0 into sys_ioprio_set(). So seperate the setting from the value by
adding a ->ioprio_set bool.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
3 files changed