Re: Schedule affinity_notify work while migrating IRQs during hot plug

From	Thomas Gleixner <tglx@linutronix.de>
Newsgroups	linux.kernel
Subject	Re: Schedule affinity_notify work while migrating IRQs during hot plug
Date	2017-02-27 19:10 +0100
Message-ID	<tfxUf-Oq-19@gated-at.bofh.it> (permalink)
References	<tdpHr-7P4-11@gated-at.bofh.it> <tfxhv-jQ-1@gated-at.bofh.it>
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On Mon, 27 Feb 2017, Sodagudi Prasad wrote:
> So I am thinking that, adding following sched_work() would notify clients.

And break the world and some more.

> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
> index 6b66959..5e4766b 100644
> --- a/kernel/irq/manage.c
> +++ b/kernel/irq/manage.c
> @@ -207,6 +207,7 @@ int irq_do_set_affinity(struct irq_data *data, const
> struct cpumask *mask,
>         case IRQ_SET_MASK_OK_DONE:
>                 cpumask_copy(desc->irq_common_data.affinity, mask);
>         case IRQ_SET_MASK_OK_NOCOPY:
> +               schedule_work(&desc->affinity_notify->work);
>                 irq_set_thread_affinity(desc);
>                 ret = 0;

You cannot do that unconditionally and just slap that schedule_work() call
into the code. Aside of that schedule_work() would be invoked twice for all
calls which come via irq_set_affinity_locked() ....

Thanks,

	tglx

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Schedule affinity_notify work while migrating IRQs during hot plug Sodagudi Prasad <psodagud@codeaurora.org> - 2017-02-21 22:00 +0100
  Re: Schedule affinity_notify work while migrating IRQs during hot  plug Sodagudi Prasad <psodagud@codeaurora.org> - 2017-02-27 18:30 +0100
    Re: Schedule affinity_notify work while migrating IRQs during hot  plug Thomas Gleixner <tglx@linutronix.de> - 2017-02-27 19:10 +0100

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