Commit e250d4bc authored May 28, 2012 by Yong Zhang Committed by Benjamin Herrenschmidt Jul 03, 2012

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



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>

parent 17968fbb

arch/powerpc/kernel/smp.c

+0 −2

Original line number	Original line	Diff line number	Diff line
	@@ -571,7 +571,6 @@ void __devinit start_secondary(void *unused)
	if (system_state == SYSTEM_RUNNING)		if (system_state == SYSTEM_RUNNING)
	vdso_data->processorCount++;		vdso_data->processorCount++;
	#endif		#endif
	ipi_call_lock();
	notify_cpu_starting(cpu);		notify_cpu_starting(cpu);
	set_cpu_online(cpu, true);		set_cpu_online(cpu, true);
	/* Update sibling maps */		/* Update sibling maps */
	@@ -601,7 +600,6 @@ void __devinit start_secondary(void *unused)
	of_node_put(np);		of_node_put(np);
	}		}
	of_node_put(l2_cache);		of_node_put(l2_cache);
	ipi_call_unlock();

	local_irq_enable();		local_irq_enable();

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