Re: [PATCH] powerpc: xive: ensure active irqd when setting affinity

From	Benjamin Herrenschmidt <benh@kernel.crashing.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH] powerpc: xive: ensure active irqd when setting affinity
Date	2017-08-09 09:40 +0200
Message-ID	<uctKW-3Wi-17@gated-at.bofh.it> (permalink)
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On Wed, 2017-08-09 at 16:15 +1000, Michael Ellerman wrote:
> I'm not sure I'm convinced. We can't handle every possible case of the
> higher level code calling us in situations we don't expect.
> 
> For example irq_data could be NULL, but we trust the higher level code
> not to do that to us.
> 
> Also I don't see any other driver doing this check.
> 
>   $ git grep irqd_is_started
>   include/linux/irq.h:static inline bool irqd_is_started(struct irq_data *d)
>   kernel/irq/chip.c:      if (irqd_is_started(d)) {
>   kernel/irq/chip.c:      if (irqd_is_started(&desc->irq_data)) {
>   kernel/irq/cpuhotplug.c:        if (irqd_is_per_cpu(d) || !irqd_is_started(d) || !irq_needs_fixup(d)) {

irqd_is_started is brand new so you won't find any :-)

For most cases the problem is a non-issue. Due to how xive works, it's
more of a problem for us because a non-started interrupt has no
targetting information at all.

So this is *somewhat* related to xive internal and I'd rather have
that sanity check in there.

Cheers,
Ben.

Thread

[PATCH] powerpc: xive: ensure active irqd when setting affinity Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> - 2017-08-03 03:40 +0200
  Re: [PATCH] powerpc: xive: ensure active irqd when setting affinity Michael Ellerman <mpe@ellerman.id.au> - 2017-08-08 12:50 +0200
    Re: [PATCH] powerpc: xive: ensure active irqd when setting affinity Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> - 2017-08-09 02:10 +0200
      Re: [PATCH] powerpc: xive: ensure active irqd when setting affinity Michael Ellerman <mpe@ellerman.id.au> - 2017-08-09 08:20 +0200
        Re: [PATCH] powerpc: xive: ensure active irqd when setting affinity Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2017-08-09 09:40 +0200
  Re: powerpc: xive: ensure active irqd when setting affinity Michael Ellerman <patch-notifications@ellerman.id.au> - 2017-08-11 14:30 +0200

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