Merge branch 'for-4.21/block' into for-4.21/aio

Merge branch 'for-4.21/block' into for-4.21/aio

* for-4.21/block: (351 commits)
  blk-mq: enable IO poll if .nr_queues of type poll > 0
  blk-mq: change blk_mq_queue_busy() to blk_mq_queue_inflight()
  blk-mq: skip zero-queue maps in blk_mq_map_swqueue
  block: fix blk-iolatency accounting underflow
  blk-mq: fix dispatch from sw queue
  block: mq-deadline: Fix write completion handling
  nvme-pci: don't share queue maps
  blk-mq: only dispatch to non-defauly queue maps if they have queues
  blk-mq: export hctx->type in debugfs instead of sysfs
  blk-mq: fix allocation for queue mapping table
  blk-wbt: export internal state via debugfs
  blk-mq-debugfs: support rq_qos
  block: update sysfs documentation
  block: loop: check error using IS_ERR instead of IS_ERR_OR_NULL in loop_add()
  aoe: add __exit annotation
  block: clear REQ_HIPRI if polling is not supported
  blk-mq: replace and kill blk_mq_request_issue_directly
  blk-mq: issue directly with bypass 'false' in blk_mq_sched_insert_requests
  blk-mq: refactor the code of issue request directly
  block: remove the bio_integrity_advance export
  ...