[PATCH v6 0/5] Fix I/O priority lost in device-mapper

[Hongyu Jin <hongyu.jin.cn@gmail.com>]

From: Hongyu Jin <hongyu.jin@unisoc.com>

High-priority tasks get data from dm-verity devices via RT IO priority,
I/O will lose RT priority when reading FEC and hash values via kworker
submission IO during verification, and the verification phase may be
blocked by low-priority IO.

Dm-crypt has the same problem in the data writing process.

This is because io_context and blkcg are missing.

Move bio_set_ioprio() into submit_bio():
1. Only call bio_set_ioprio() once to set the priority of original bio,
   the bio that cloned and splited from original bio will auto inherit
   the priority of original bio in clone process.

2. Make the IO priority of the original bio to be passed to dm,
   and the dm target inherits the IO priority as needed.

All changes are based on master branch commit 2cf4f94d8e86 ("Merge tag
'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi")

Changes in v6:
  - Rebase patch and resolve conflict for patch 1, 3, 4
  - Modify patch 4: fec_read_parity() follow the priority of original
    bio
  - Update commit message
Changes in v5:
  - Rewrite patch 2, add ioprio parameter in dm_io();
  - Modify dm_io() in patch 3 
Changes in v4:
  - Modify commit message by Suggestion
  - Modify patch for dm-crypt
Changes in v3:
  - Split patch for device-mapper
  - Add patch to fix dm-crypy I/O priority question
  - Add block patch to review together
  - Fix some error in v2 patch
Changes in v2:
  - Add ioprio field in struct dm_io_region
  - Initial struct dm_io_region::ioprio to IOPRIO_DEFAULT
  - Add two interface

Hongyu Jin (5):
  block: Fix bio IO priority setting
  dm: Support I/O priority for dm_io()
  dm-bufio: Support I/O priority
  dm verity: Fix I/O priority lost when read FEC and hash
  dm-crypt: Fix lost ioprio when queuing write bios

 block/blk-core.c                              | 10 +++++
 block/blk-mq.c                                | 11 -----
 drivers/md/dm-bufio.c                         | 43 +++++++++++--------
 drivers/md/dm-crypt.c                         |  1 +
 drivers/md/dm-ebs-target.c                    |  8 ++--
 drivers/md/dm-integrity.c                     | 12 +++---
 drivers/md/dm-io.c                            | 23 +++++-----
 drivers/md/dm-kcopyd.c                        |  4 +-
 drivers/md/dm-log.c                           |  4 +-
 drivers/md/dm-raid1.c                         |  6 +--
 drivers/md/dm-snap-persistent.c               |  8 ++--
 drivers/md/dm-verity-fec.c                    | 20 ++++++---
 drivers/md/dm-verity-target.c                 | 13 ++++--
 drivers/md/dm-writecache.c                    |  8 ++--
 drivers/md/persistent-data/dm-block-manager.c |  6 +--
 include/linux/dm-bufio.h                      |  5 ++-
 include/linux/dm-io.h                         |  3 +-
 17 files changed, 105 insertions(+), 80 deletions(-)


base-commit: 2cf4f94d8e8646803f8fb0facf134b0cd7fb691a
-- 
2.34.1