Re: [PATCH 03/11] genirq: Export irq_set_affinity_locked()

From: Florian Fainelli
Date: Mon Sep 27 2021 - 13:51:12 EST

On 9/25/21 2:37 PM, Thomas Gleixner wrote:
> On Sat, Sep 25 2021 at 23:21, Thomas Gleixner wrote:
>> On Sat, Sep 25 2021 at 12:48, Marc Zyngier wrote:
>>> On Fri, 24 Sep 2021 18:05:38 +0100, Florian Fainelli <f.fainelli@xxxxxxxxx> wrote:
>>>> }
>>>> +EXPORT_SYMBOL_GPL(irq_set_affinity_locked);
>>> This doesn't seem right.
>>> This driver seem to try and move interrupts on its own when the CPU
>>> goes down. Why can't it rely on the normal CPU hotplug infrastructure
>>> to do so like all the other drivers (bar some Cavium driver that does
>>> the same thing)?
>>> I'd rather you take this opportunity to move these drivers into the
>>> 21st century, so that we can kill irq_cpu_offline() and co altogether.
>> I wanted to kill these callbacks years ago. Cavium has two variants of
>> those offline/online callbacks:
>> 1) octeon_irq_cpu_offline_ciu() which is doing the same as that BCM
>> driver. These really can go away. Just remove the callback and
>> everything just works.
> For BCM this works today when that chip is used on ARM[64] simply
> because the only architecture which invokes irq_cpu_offline() is MIPS.

That is correct. How would you recommend addressing that? In premise
when this driver is used on ARM[64] it is used as a second level
interrupt controller hanging off the ARM GIC (or another ARM CPU
interrupt controller), so in that case I suppose I could make the
irq_set_cpu_offline be dependent upon CONFIG_SMP and CONFIG_MIPS, would
that be acceptable?