blk_mq_sched_allow_merge
if (!sched_allow_merge || blk_mq_sched_allow_merge(q, rq, bio))
if (!sched_allow_merge || blk_mq_sched_allow_merge(q, rq, bio))
if (!blk_mq_sched_allow_merge(q, rq, bio))
if (!blk_mq_sched_allow_merge(q, rq, bio))