linux-kernel - Re: [patch 19/55] genirq: Provide irq_fixup_move

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Date:   Tue, 20 Jun 2017 08:58:36 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Dou Liyang <douly.fnst@...fujitsu.com>
cc:     LKML <linux-kernel@...r.kernel.org>,
        Marc Zyngier <marc.zyngier@....com>,
        Christoph Hellwig <hch@....de>, Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Jens Axboe <axboe@...nel.dk>,
        Keith Busch <keith.busch@...el.com>
Subject: Re: [patch 19/55] genirq: Provide irq_fixup_move_pending()

On Tue, 20 Jun 2017, Dou Liyang wrote:
> At 06/20/2017 07:37 AM, Thomas Gleixner wrote:
> [...]
> > 
> > +/**
> > + * irq_fixup_move_pending - Cleanup irq move pending from a dying CPU
> > + * @desc:		Interrupt descpriptor to clean up
> > + * @force_clear:	If set clear the move pending bit unconditionally.
> > + *			If not set, clear it only when the dying CPU is the
> > + *			last one in the pending mask.
> > + *
> > + * Returns true if the pending bit was set and the pending mask contains an
> > + * online CPU other than the dying CPU.
> > + */
> > +bool irq_fixup_move_pending(struct irq_desc *desc, bool force_clear)
> > +{
> > +	struct irq_data *data = irq_desc_get_irq_data(desc);
> > +
> > +	if (!irqd_is_setaffinity_pending(data))
> > +		return false;
> > +
> > +	/*
> > +	 * The outgoing CPU might be the last online target in a pending
> > +	 * interrupt move. If that's the case clear the pending move bit.
> > +	 */
> > +	if (cpumask_any_and(desc->pending_mask, cpu_online_mask) > nr_cpu_ids)
> > {
> 
> Should we consider the case of "=nr_cpu_ids" here, like:
> 
> cpumask_any_and(desc->pending_mask, cpu_online_mask) >= nr_cpu_ids

Yes, indeed. > is wrong. Good catch!

Thanks,

	tglx