linux-kernel - Re: [PATCH v3 1/4] genirq/irqdomain: Allow partial trimming of irq

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Date:   Thu, 08 Oct 2020 22:47:29 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Marc Zyngier <maz@...nel.org>
Cc:     linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Dmitry Osipenko <digetx@...il.com>,
        Sowjanya Komatineni <skomatineni@...dia.com>,
        Venkat Reddy Talla <vreddytalla@...dia.com>,
        kernel-team@...roid.com
Subject: Re: [PATCH v3 1/4] genirq/irqdomain: Allow partial trimming of irq_data hierarchy

On Thu, Oct 08 2020 at 14:06, Marc Zyngier wrote:
> On 2020-10-08 12:22, Thomas Gleixner wrote:
> Here's what I have now, with the pmc driver calling
> irq_domain_disconnect_hierarchy() at the right spots.
>
>   static int irq_domain_alloc_irq_data(struct irq_domain *domain,
> @@ -1362,11 +1442,16 @@ int __irq_domain_alloc_irqs(struct irq_domain 
> *domain, int irq_base,
>   		mutex_unlock(&irq_domain_mutex);
>   		goto out_free_irq_data;
>   	}
> -	for (i = 0; i < nr_irqs; i++)
> +	for (i = 0; i < nr_irqs; i++) {
> +		ret = irq_domain_trim_hierarchy(virq + i);
> +		if (ret)
> +			break;
>   		irq_domain_insert_irq(virq + i);

You can't do that in one go because in case of an error you leak the
already inserted irqs. You need two loops.

	for (i = 0; i < nr_irqs; i++) {
		ret = irq_domain_trim_hierarchy(virq + i);
		if (ret) {
                	mutex_unlock(&irq_domain_mutex);
			goto out_free_irq_data;
        }

	for (i = 0; i < nr_irqs; i++)
   		irq_domain_insert_irq(virq + i);

  	mutex_unlock(&irq_domain_mutex);
	return virq;

>   out_free_irq_data:
>   	irq_domain_free_irq_data(virq, nr_irqs);

Thanks,

        tglx