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staging: vchiq_core: Use killable wait completions for bulk transfers

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commit f27e47bc6b ("staging: vchiq: use completions instead of
semaphores") introduced completions for events in vchiq interface.
It introduced _interruptible() version of completions for waiting
on events. However, it missed a subtle down_interruptible() macro
override in vchiq_killable.h, which used to mask most of the signals
and only interrupt on fatal ones.

The above issue was fixed in commit a772f11670 ("staging: vchiq: switch
to wait_for_completion_killable"). Given the override logic of
down_interruptible() that existed in vchiq_killable.h, that commit
fixed the completions with the correct variation i.e. killable() family
of functions.

However, commit a772f11670 ("staging: vchiq: switch to
wait_for_completion_killable") later got reverted [1] due to high CPU
load noticed by various downstream and upstream distributions [2].
Reverting the commit solved this problem but the root cause was never
diagonsed and the entire commit was reverted.

This patch brings back killable version of wait events but only for
bulk transfers and queue_message() transfer code paths.

The idea is to bring back killable versions for various event
completions in a phased manner so that we do not re-regress again as
noticed in [2]. Hence, no other wait events are converted from
interruptible -> killable in this patch.

Since the bulk transfers are no longer interruptible (but killable),
drop the "_interruptible" suffix from all vchiq_bulk_xfer_* functions.

[1]: commit 086efbabdc ("staging: vchiq: revert "switch to wait_for_completion_killable"")
[2]: https://patchwork.kernel.org/project/linux-arm-kernel/cover/20190509143137.31254-1-nsaenzjulienne@suse.de/

Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Link: https://lore.kernel.org/r/20240918163100.870596-2-umang.jain@ideasonboard.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Umang Jain 2024-09-18 22:00:55 +05:30 • committed by Greg Kroah-Hartman
commit 36022f3ee8
4 changed files with 46 additions and 49 deletions
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