Re: [PATCH v11 06/10] genirq/msi-doorbell: msi_doorbell_safe

From: Auger Eric
Date: Fri Jul 22 2016 - 10:09:13 EST


Hi Thomas,
On 22/07/2016 14:44, Thomas Gleixner wrote:
> On Thu, 21 Jul 2016, Auger Eric wrote:
>> On 20/07/2016 10:12, Thomas Gleixner wrote:
>>> On Tue, 19 Jul 2016, Eric Auger wrote:
>>>> +bool msi_doorbell_safe(void)
>>>> +{
>>>> + struct irqchip_doorbell *db;
>>>> + bool irq_remapping = true;
>>>> +
>>>> + mutex_lock(&irqchip_doorbell_mutex);
>>>> + list_for_each_entry(db, &irqchip_doorbell_list, next) {
>>>> + irq_remapping &= db->info.irq_remapping;
>>>
>>> db->info.irq_remapping is set in msi_doorbell_register(). So you can keep book
>>> about that there. No need to iterate here.
>> Yes makes sense to store the info at registration time. Currently this
>> function is not in any fast path but that's cleaner from a general
>> perspective. I will need to do such iteration at un-registration though.
>
> Two simple counter should be sufficient.
>
> nr_registered_bells;
> nr_remapped_bells;

Yes definitively smarter to use counters! mental viscosity.

Thanks

Eric
>
> ....
>
> Thanks,
>
> tglx
>