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Subject[RFC PATCH 02/10] mn10300: smp: remove call to ipi_call_lock()/ipi_call_unlock()
Date
From: Yong Zhang <yong.zhang@windriver.com>

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>
Cc: David Howells <dhowells@redhat.com>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: linux-am33-list@redhat.com
---
arch/mn10300/kernel/smp.c | 2 --
1 files changed, 0 insertions(+), 2 deletions(-)
diff --git a/arch/mn10300/kernel/smp.c b/arch/mn10300/kernel/smp.c
index 090d35d..e62c223 100644
--- a/arch/mn10300/kernel/smp.c
+++ b/arch/mn10300/kernel/smp.c
@@ -876,9 +876,7 @@ static void __init smp_online(void)

notify_cpu_starting(cpu);

- ipi_call_lock();
set_cpu_online(cpu, true);
- ipi_call_unlock();

local_irq_enable();
}
--
1.7.5.4


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