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    Subject[RFC PATCH 02/10] mn10300: smp: remove call to ipi_call_lock()/ipi_call_unlock()
    From: Yong Zhang <>

    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 <>
    Cc: David Howells <>
    Cc: Koichi Yasutake <>
    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)


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


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