linux-kernel - Re: [PATCH v3 1/3] genirq: enhance error recovery code in free irq

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Message-ID: <alpine.DEB.2.21.1908151617150.1908@nanos.tec.linutronix.de>
Date:   Thu, 15 Aug 2019 16:20:52 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Ben Luo <luoben@...ux.alibaba.com>
cc:     alex.williamson@...hat.com, linux-kernel@...r.kernel.org,
        tao.ma@...ux.alibaba.com, gerry@...ux.alibaba.com,
        nanhai.zou@...ux.alibaba.com, linyunsheng@...wei.com
Subject: Re: [PATCH v3 1/3] genirq: enhance error recovery code in free irq

On Thu, 15 Aug 2019, Ben Luo wrote:

> Per Thomas Gleixner's comments:
> 1) free_irq/free_percpu_irq returns if called from IRQ context
> 2) move WARN out of the locked region and print out dev_id

Please do not describe WHAT the patch is doing, please describe WHY.
 
> Signed-off-by: Ben Luo <luoben@...ux.alibaba.com>
> ---
>  kernel/irq/manage.c | 32 ++++++++++++++++++++------------
>  1 file changed, 20 insertions(+), 12 deletions(-)
> 
> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
> index e8f7f17..6f9b20f 100644
> --- a/kernel/irq/manage.c
> +++ b/kernel/irq/manage.c
> @@ -1690,7 +1690,11 @@ static struct irqaction *__free_irq(struct irq_desc *desc, void *dev_id)
>  	struct irqaction *action, **action_ptr;
>  	unsigned long flags;
>  
> -	WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
> +	if (in_interrupt()) {
> +		WARN(1, "Trying to free IRQ %d (dev_id %p) from IRQ context!\n",
> +		     irq, dev_id);
> +		return NULL;
> +	}

	if (WARN(in_interrupt(), ."Tr...."))
		return NULL;

Thanks,

	tglx