tree c953c271057033b5fbc47b8ddb77c78d926c221e
parent 1a0c3298d6c6bfc357c38772e7f32d193c60c77d
author Jiri Kosina <jkosina@suse.cz> 1256743559 +0900
committer Tejun Heo <tj@kernel.org> 1256743559 +0900

percpu: allow pcpu_alloc() to be called with IRQs off

pcpu_alloc() and pcpu_extend_area_map() perform a series of
spin_lock_irq()/spin_unlock_irq() calls, which make them unsafe
with respect to being called from contexts which have IRQs off.

This patch converts the code to perform save/restore of flags instead,
making pcpu_alloc() (or __alloc_percpu() respectively) to be called
from early kernel startup stage, where IRQs are off.

This is needed for proper initialization of per-cpu rq_weight data from
sched_init().

tj: added comment explaining why irqsave/restore is used in alloc path.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Tejun Heo <tj@kernel.org>