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Date:   Mon, 19 Jul 2021 11:41:56 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Ming Lei <ming.lei@redhat.com>
Cc:     Thomas Gleixner <tglx@linutronix.de>, linux-kernel@vger.kernel.org,
        Bjorn Helgaas <helgaas@kernel.org>, linux-pci@vger.kernel.org,
        Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH] genirq/affinity: add helper of irq_affinity_calc_sets
Message-ID: <20210719094156.GB431@lst.de>
References: <20210715111827.569756-1-ming.lei@redhat.com>
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On Thu, Jul 15, 2021 at 07:18:27PM +0800, Ming Lei wrote:
> +				WARN_ON_ONCE(irq_affinity_calc_sets(1, affd));

Hiding actual functionality inside a WARN_ON is nasty.

> +int irq_affinity_calc_sets(unsigned int affvecs, struct irq_affinity *affd)
> +{
> +	/*
> +	 * Simple invocations do not provide a calc_sets() callback. Install
> +	 * the generic one.
> +	 */
> +	if (!affd->calc_sets)
> +		affd->calc_sets = default_calc_sets;
> +
> +	/* Recalculate the sets */
> +	affd->calc_sets(affd, affvecs);

I'm not sure a function like this should have side effects.  Either
we move the assign to an init function with a single caller, or do an
if / else here.