> + /* > + * For devices using a BIO-based driver, we need zone resources only > + * if zone append emulation is required. > + */ > + if (!queue_is_mq(disk->queue) && > + !queue_emulates_zone_append(disk->queue)) > + return 0; > + This code and the comment is duplicated in two places. It also fails to capture why bio drivers don't need zoned resources - that is that we can't enforce QD=1 per zone for them. Maybe add a little helper to encapsulate this check and expand the comment a little? Otherwise looks good: Reviewed-by: Christoph Hellwig <hch@xxxxxx>