linux-kernel - Re: [PATCH v7 2/5] genirq: Add handle_fasteoi_{level,edge}

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Message-ID: <alpine.DEB.2.20.1708141221440.1865@nanos>
Date:   Mon, 14 Aug 2017 12:25:01 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     David Daney <david.daney@...ium.com>
cc:     Linus Walleij <linus.walleij@...aro.org>,
        Alexandre Courbot <gnurou@...il.com>,
        Mark Rutland <mark.rutland@....com>,
        Marc Zyngier <marc.zyngier@....com>,
        linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v7 2/5] genirq: Add handle_fasteoi_{level,edge}_irq flow
 handlers.

On Wed, 9 Aug 2017, David Daney wrote:
>  #ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY

Can we please make them conditional in order not to bloat all kernels with
it? Like we do for handle_edge_eoi_irq() ?

>  /**
> + *	handle_fasteoi_edge_irq - irq handler for edge hierarchy
> + *	stacked on transparent controllers
> + *
> + *	@desc:	the interrupt description structure for this irq
> + *
> + *	Like handle_fasteoi_irq(), but for use with hierarchy where
> + *	the irq_chip also needs to have its ->irq_ack() function
> + *	called.
> + */
> +void handle_fasteoi_edge_irq(struct irq_desc *desc)
> +{
> +	struct irq_chip *chip = desc->irq_data.chip;
> +
> +	raw_spin_lock(&desc->lock);
> +
> +	if (!irq_may_run(desc))
> +		goto out;
> +
> +	desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
> +
> +	/*
> +	 * If its disabled or no action available
> +	 * then mask it and get out of here:
> +	 */
> +	if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) {
> +		desc->istate |= IRQS_PENDING;
> +		mask_irq(desc);
> +		goto out;
> +	}
> +
> +	kstat_incr_irqs_this_cpu(desc);
> +	if (desc->istate & IRQS_ONESHOT)
> +		mask_irq(desc);
> +
> +	/* Start handling the irq */
> +	desc->irq_data.chip->irq_ack(&desc->irq_data);
> +
> +	preflow_handler(desc);
> +	handle_irq_event(desc);

Hmm. That's quite different to the way we handle edge interrupts
normally. See handle_edge_irq() and handle_edge_eoi_irq().

Thanks,

	tglx