Priority of a merged request is computed by ioprio_best(). If one of the
requests has undefined priority (IOPRIO_CLASS_NONE) and another request
has priority from IOPRIO_CLASS_BE, the function will return the
undefined priority which is wrong. Fix the function to properly return
priority of a request with the defined priority.
Signed-off-by: Jan Kara <firstname.lastname@example.org>
Reviewed-by: Jeff Moyer <email@example.com>
Signed-off-by: Jens Axboe <firstname.lastname@example.org>