linux-kernel - Re: [PATCH 03/11] genirq: Export irq_set_affinity

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Message-ID: <87r1dccp5z.ffs@tglx>
Date:   Sat, 25 Sep 2021 23:37:28 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Marc Zyngier <maz@...nel.org>,
        Florian Fainelli <f.fainelli@...il.com>
Cc:     linux-kernel@...r.kernel.org, Russell King <linux@...linux.org.uk>,
        Ray Jui <rjui@...adcom.com>,
        Scott Branden <sbranden@...adcom.com>,
        "maintainer:BROADCOM BCM281XX/BCM11XXX/BCM216XX ARM ARCHITE..." 
        <bcm-kernel-feedback-list@...adcom.com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        Rich Felker <dalias@...c.org>,
        Rob Herring <robh+dt@...nel.org>,
        Frank Rowand <frowand.list@...il.com>,
        Ard Biesheuvel <ardb@...nel.org>,
        Mike Rapoport <rppt@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Arnd Bergmann <arnd@...db.de>,
        Guenter Roeck <linux@...ck-us.net>,
        Kefeng Wang <wangkefeng.wang@...wei.com>,
        Mark Rutland <mark.rutland@....com>,
        Andrey Konovalov <andreyknvl@...il.com>,
        Anshuman Khandual <anshuman.khandual@....com>,
        Valentin Schneider <valentin.schneider@....com>,
        Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        "moderated list:ARM PORT" <linux-arm-kernel@...ts.infradead.org>,
        "open list:SUPERH" <linux-sh@...r.kernel.org>,
        "open list:BROADCOM BMIPS MIPS ARCHITECTURE" 
        <linux-mips@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE" 
        <devicetree@...r.kernel.org>
Subject: Re: [PATCH 03/11] genirq: Export irq_set_affinity_locked()

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@...il.com> 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.

Thanks,

        tglx