From: Yong Zhang <yong.zhang@windriver.com>
Date: Mon, 28 May 2012 21:16:04 +0000 (+0000)
Subject: powerpc/smp: remove call to ipi_call_lock()/ipi_call_unlock()
X-Git-Tag: v3.6-rc1~132^2~65
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e250d4bca6cb91471e0757179a152c0943ecce4a;p=pandora-kernel.git

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>
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