Merge branch 'for-5.9/block' into for-5.9/block-merge

* for-5.9/block: (124 commits)
  blk-cgroup: show global disk stats in root cgroup io.stat
  blk-cgroup: make iostat functions visible to stat printing
  block: improve discard bio alignment in __blkdev_issue_discard()
  block: change REQ_OP_ZONE_RESET and REQ_OP_ZONE_RESET_ALL to be odd numbers
  block: defer flush request no matter whether we have elevator
  block: make blk_timeout_init() static
  block: remove retry loop in ioc_release_fn()
  block: remove unnecessary ioc nested locking
  block: integrate bd_start_claiming into __blkdev_get
  block: use bd_prepare_to_claim directly in the loop driver
  block: refactor bd_start_claiming
  block: simplify the restart case in __blkdev_get
  Revert "blk-rq-qos: remove redundant finish_wait to rq_qos_wait."
  block: always remove partitions from blk_drop_partitions()
  block: relax jiffies rounding for timeouts
  blk-mq: remove redundant validation in __blk_mq_end_request()
  blk-mq: Remove unnecessary local variable
  writeback: remove bdi->congested_fn
  writeback: remove struct bdi_writeback_congested
  writeback: remove {set,clear}_wb_congested
  ...

diff --cc Documentation/admin-guide/cgroup-v2.rst
Simple merge

diff --cc block/blk-mq-debugfs.c
Simple merge

diff --cc block/blk-mq.c
Simple merge

diff --cc drivers/block/nbd.c
Simple merge

diff --cc drivers/block/virtio_blk.c
Simple merge

diff --cc drivers/block/zram/zram_drv.c
Simple merge

diff --cc drivers/md/dm-rq.c
Simple merge

diff --cc drivers/md/dm-writecache.c
Simple merge

diff --cc drivers/md/dm-zoned-target.c
Simple merge

diff --cc drivers/md/dm.c
Simple merge

diff --cc drivers/nvme/host/core.c
Simple merge

diff --cc drivers/nvme/host/multipath.c
Simple merge

diff --cc drivers/nvme/host/nvme.h
Simple merge

diff --cc drivers/nvme/host/pci.c
Simple merge

diff --cc drivers/nvme/host/rdma.c
Simple merge

diff --cc drivers/nvme/host/tcp.c
Simple merge

diff --cc drivers/nvme/target/loop.c
Simple merge

diff --cc fs/btrfs/disk-io.c
Simple merge

diff --cc include/linux/blkdev.h
Simple merge

diff --cc include/linux/fs.h
Simple merge