bio_mergeable 850 block/blk-merge.c if (!rq_mergeable(rq) || !bio_mergeable(bio)) bio_mergeable 38 block/blk-mq-sched.h if (blk_queue_nomerges(q) || !bio_mergeable(bio)) bio_mergeable 316 block/elevator.c if (blk_queue_nomerges(q) || !bio_mergeable(bio))