Improve the performance of F2FS on zoned UFS

Hi Jens,

This patch series improves small write IOPS by a factor of four (+300%) for
zoned UFS devices on my test setup with a UFSHCI 3.0 controller. Please
consider this patch series for the next merge window.

Thank you,

Bart.

Changes compared to v3:
 - Restored the patch that introduces QUEUE_FLAG_NO_ZONE_WRITE_LOCK. That patch
   had accidentally been left out from v2.
 - In patch "block: Introduce the flag REQ_NO_ZONE_WRITE_LOCK", improved the
   patch description and added the function blk_no_zone_write_lock().
 - In patch "block/mq-deadline: Only use zone locking if necessary", moved the
   blk_queue_is_zoned() call into dd_use_write_locking().
 - In patch "fs/f2fs: Disable zone write locking", set REQ_NO_ZONE_WRITE_LOCK
   from inside __bio_alloc() instead of in f2fs_submit_write_bio().

Changes compared to v2:
 - Renamed the request queue flag for disabling zone write locking.
 - Introduced a new request flag for disabling zone write locking.
 - Modified the mq-deadline scheduler such that zone write locking is only
   disabled if both flags are set.
 - Added an F2FS patch that sets the request flag for disabling zone write
   locking.
 - Only disable zone write locking in the UFS driver if auto-hibernation is
   disabled.

Changes compared to v1:
 - Left out the patches that are already upstream.
 - Switched the approach in patch "scsi: Retry unaligned zoned writes" from
   retrying immediately to sending unaligned write commands to the SCSI error
   handler.


Bart Van Assche (7):
  block: Introduce the flag QUEUE_FLAG_NO_ZONE_WRITE_LOCK
  block: Introduce the flag REQ_NO_ZONE_WRITE_LOCK
  block/mq-deadline: Only use zone locking if necessary
  block/null_blk: Support disabling zone write locking
  scsi: Retry unaligned zoned writes
  scsi: ufs: Disable zone write locking
  fs/f2fs: Disable zone write locking

 block/blk-flush.c                 |  3 ++-
 block/mq-deadline.c               | 25 ++++++++++++-----
 drivers/block/null_blk/main.c     |  2 ++
 drivers/block/null_blk/null_blk.h |  1 +
 drivers/block/null_blk/zoned.c    |  3 +++
 drivers/scsi/scsi_error.c         | 38 ++++++++++++++++++++++++++
 drivers/scsi/scsi_lib.c           |  1 +
 drivers/scsi/sd.c                 |  2 ++
 drivers/ufs/core/ufshcd.c         | 45 ++++++++++++++++++++++++++++---
 fs/f2fs/data.c                    |  4 +--
 include/linux/blk-mq.h            | 11 ++++++++
 include/linux/blk_types.h         |  8 ++++++
 include/linux/blkdev.h            | 10 +++++++
 include/scsi/scsi.h               |  1 +
 14 files changed, 142 insertions(+), 12 deletions(-)