Christophe Leroy's on March 21, 2020 1:33 am:
>
>
> Le 20/03/2020 à 16:24, Nicholas Piggin a écrit :
>> Signed-off-by: Nicholas Piggin <npig...@gmail.com>
>> ---
>> arch/powerpc/platforms/pseries/lpar.c | 10 +++++++++-
>> 1 file changed, 9 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/platforms/pseries/lpar.c
>> b/arch/powerpc/platforms/pseries/lpar.c
>> index 3c3da25b445c..e4ed5317f117 100644
>> --- a/arch/powerpc/platforms/pseries/lpar.c
>> +++ b/arch/powerpc/platforms/pseries/lpar.c
>> @@ -636,8 +636,16 @@ static const struct proc_ops
>> vcpudispatch_stats_freq_proc_ops = {
>>
>> static int __init vcpudispatch_stats_procfs_init(void)
>> {
>> - if (!lppaca_shared_proc(get_lppaca()))
>> + /*
>> + * Avoid smp_processor_id while preemptible. All CPUs should have
>> + * the same value for lppaca_shared_proc.
>> + */
>> + preempt_disable();
>> + if (!lppaca_shared_proc(get_lppaca())) {
>> + preempt_enable();
>> return 0;
>> + }
>> + preempt_enable();
>
> Can we avoid the double preempt_enable() with something like:
>
> preempt_disable();
> is_shared = lppaca_shared_proc(get_lppaca());
> preempt_enable();
> if (!is_shared)
> return 0;
I don't mind too much. Same number of lines.
Thanks,
Nick
