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powerpc/smp: remove call to ipi_call_lock()/ipi_call_unlock()

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1) call_function.lock used in smp_call_function_many() is just to protect
   call_function.queue and &data->refs, cpu_online_mask is outside of the
   lock. And it's not necessary to protect cpu_online_mask,
   because data->cpumask is pre-calculate and even if a cpu is brougt up
   when calling arch_send_call_function_ipi_mask(), it's harmless because
   validation test in generic_smp_call_function_interrupt() will take care
   of it.

2) For cpu down issue, stop_machine() will guarantee that no concurrent
   smp_call_fuction() is processing.

Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Yong Zhang 2012-05-28 21:16:04 +00:00 committed by Benjamin Herrenschmidt
parent 17968fbbd1
commit e250d4bca6
1 changed files with 0 additions and 2 deletions
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2
arch/powerpc/kernel/smp.c
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@ -571,7 +571,6 @@ void __devinit start_secondary(void *unused)
if (system_state == SYSTEM_RUNNING)
vdso_data->processorCount++;
#endif
ipi_call_lock();
notify_cpu_starting(cpu);
set_cpu_online(cpu, true);
/* Update sibling maps */
@ -601,7 +600,6 @@ void __devinit start_secondary(void *unused)
of_node_put(np);
}
of_node_put(l2_cache);
ipi_call_unlock();
local_irq_enable();