On 05/29/2012 12:46 PM, Yong Zhang wrote: > From: Yong Zhang <yong.zhang@xxxxxxxxxxxxx> > > 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@xxxxxxxxx> > Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> > Cc: sparclinux@xxxxxxxxxxxxxxx > --- > arch/sparc/kernel/smp_64.c | 6 ++---- > 1 files changed, 2 insertions(+), 4 deletions(-) > > diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c > index f591598..60e745c 100644 > --- a/arch/sparc/kernel/smp_64.c > +++ b/arch/sparc/kernel/smp_64.c > @@ -124,9 +124,9 @@ void __cpuinit smp_callin(void) > while (!cpumask_test_cpu(cpuid, &smp_commenced_mask)) > rmb(); > > - ipi_call_lock_irq(); > + local_irq_disable(); This looks odd. IRQs must not have been enabled at this point. Just remove the call to local_irq_enable() that is found a few lines above this line and then you won't have to add this call to local_irq_disable(). > set_cpu_online(cpuid, true); > - ipi_call_unlock_irq(); > + local_irq_enable(); > > /* idle thread is expected to have preempt disabled */ > preempt_disable(); > @@ -1308,9 +1308,7 @@ int __cpu_disable(void) > mdelay(1); > local_irq_disable(); > > - ipi_call_lock(); > set_cpu_online(cpu, false); > - ipi_call_unlock(); > > cpu_map_rebuild(); > Regards, Srivatsa S. Bhat -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
