irq_work: Allow irq_work_sync() to sleep if irq_work() no IRQ support.

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irq_work() triggers instantly an interrupt if supported by the
architecture. Otherwise the work will be processed on the next timer
tick. In worst case irq_work_sync() could spin up to a jiffy.

irq_work_sync() is usually used in tear down context which is fully
preemptible. Based on review irq_work_sync() is invoked from preemptible
context and there is one waiter at a time. This qualifies it to use
rcuwait for synchronisation.

Let irq_work_sync() synchronize with rcuwait if the architecture
processes irqwork via the timer tick.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20211006111852.1514359-3-bigeasy@linutronix.de

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Sebastian Andrzej Siewior 2021-10-06 13:18:50 +02:00 • committed by Peter Zijlstra

parent da6ff09943

commit 810979682c

2 changed files with 13 additions and 0 deletions

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3

include/linux/irq_work.h

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10

kernel/irq_work.c

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