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,