[PATCH v4 0/5] Fix I/O priority lost in device-mapper

[Hongyu Jin]

From: Hongyu Jin <hongyu.jin@xxxxxxxxxx>

A high-priority task obtains data from the dm-verity device using the
RT IO priority, during the verification, the IO reading FEC and hash
by kworker loses the RT priority and is blocked by the low-priority IO.
dm-crypt has the same problem in the process of writing data.

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.

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                         | 36 ++++++++++---------
 drivers/md/dm-crypt.c                         |  1 +
 drivers/md/dm-ebs-target.c                    |  8 ++---
 drivers/md/dm-integrity.c                     |  7 +++-
 drivers/md/dm-io.c                            |  1 +
 drivers/md/dm-log.c                           |  1 +
 drivers/md/dm-raid1.c                         |  2 ++
 drivers/md/dm-snap-persistent.c               |  5 +--
 drivers/md/dm-verity-fec.c                    |  5 +--
 drivers/md/dm-verity-target.c                 |  8 +++--
 drivers/md/dm-writecache.c                    |  4 +++
 drivers/md/persistent-data/dm-block-manager.c |  6 ++--
 include/linux/dm-bufio.h                      |  6 ++--
 include/linux/dm-io.h                         |  2 ++
 16 files changed, 69 insertions(+), 44 deletions(-)

-- 
2.34.1