Re: [PATCH 1/9] block: fix default IO priority handling again

On Thu, 23 Jun 2022 09:48:26 +0200, Jan Kara wrote:

Commit e70344c05995 ("block: fix default IO priority handling")
introduced an inconsistency in get_current_ioprio() that tasks without
IO context return IOPRIO_DEFAULT priority while tasks with freshly
allocated IO context will return 0 (IOPRIO_CLASS_NONE/0) IO priority.
Tasks without IO context used to be rare before 5a9d041ba2f6 ("block:
move io_context creation into where it's needed") but after this commit
they became common because now only BFQ IO scheduler setups task's IO
context. Similar inconsistency is there for get_task_ioprio() so this
inconsistency is now exposed to userspace and userspace will see
different IO priority for tasks operating on devices with BFQ compared
to devices without BFQ. Furthemore the changes done by commit
e70344c05995 change the behavior when no IO priority is set for BFQ IO
scheduler which is also documented in ioprio_set(2) manpage:

[...]

Applied, thanks!

[1/9] block: fix default IO priority handling again
      commit: f0f5a5e24fa5412f187f429232334ad6832d1a66
[2/9] block: Return effective IO priority from get_current_ioprio()
      commit: 93fd10125cd702d86f1c4005349b54eeb3c02af3
[3/9] block: Generalize get_current_ioprio() for any task
      commit: 86f80bd5f639921c59afb113fa3ebb3ccb46be84
[4/9] block: Make ioprio_best() static
      commit: c85fb98c51a66ff7346f2e12f6c20fb4f60de812
[5/9] block: Fix handling of tasks without ioprio in ioprio_get(2)
      commit: caf2c269be20c536009ccd815a4e493d0c6c6634
[6/9] blk-ioprio: Remove unneeded field
      commit: d2adb01a5bcbe36bc05fbb383028da755f7a919b
[7/9] blk-ioprio: Convert from rqos policy to direct call
      commit: 8f3d8d7f56aba4c6171e48b107b9167255044653
[8/9] block: Initialize bio priority earlier
      commit: 92c3dfe1cfce7dd7cf6cd32b78b05885d824656e
[9/9] block: Always initialize bio IO priority on submit
      commit: 71ad7aabb8968164b1963fff7216b225fdd80f84

Best regards,
-- 
Jens Axboe