linux-kernel - Re: [PATCH 1/2] gpio: em: remove the gpiochip before removing the irq domain

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Message-ID: <510f14c9-fc3b-734c-53ff-cbf4a7579e32@electromag.com.au>
Date:   Wed, 10 Jul 2019 17:37:24 +0800
From:   Phil Reid <preid@...ctromag.com.au>
To:     Bartosz Golaszewski <brgl@...ev.pl>,
        Linus Walleij <linus.walleij@...aro.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:     linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        stable@...r.kernel.org
Subject: Re: [PATCH 1/2] gpio: em: remove the gpiochip before removing the irq
 domain

G'day Bartosz,

One comment below

On 10/07/2019 17:08, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bgolaszewski@...libre.com>
> 
> In commit 8764c4ca5049 ("gpio: em: use the managed version of
> gpiochip_add_data()") we implicitly altered the ordering of resource
> freeing: since gpiochip_remove() calls gpiochip_irqchip_remove()
> internally, we now can potentially use the irq_domain after it was
> destroyed in the remove() callback (as devm resources are freed after
> remove() has returned).
> 
> Use devm_add_action() to keep the ordering right and entirely kill
> the remove() callback in the driver.
> 
> Reported-by: Geert Uytterhoeven <geert@...ux-m68k.org>
> Fixes: 8764c4ca5049 ("gpio: em: use the managed version of gpiochip_add_data()")
> Cc: stable@...r.kernel.org
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>
> ---
>   drivers/gpio/gpio-em.c | 35 +++++++++++++++++------------------
>   1 file changed, 17 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/gpio/gpio-em.c b/drivers/gpio/gpio-em.c
> index b6af705a4e5f..c88028ac66f2 100644
> --- a/drivers/gpio/gpio-em.c
> +++ b/drivers/gpio/gpio-em.c
> @@ -259,6 +259,13 @@ static const struct irq_domain_ops em_gio_irq_domain_ops = {
>   	.xlate	= irq_domain_xlate_twocell,
>   };
>   
> +static void em_gio_irq_domain_remove(void *data)
> +{
> +	struct irq_domain *domain = data;
> +
> +	irq_domain_remove(domain);
> +}
> +
>   static int em_gio_probe(struct platform_device *pdev)
>   {
>   	struct em_gio_priv *p;
> @@ -333,39 +340,32 @@ static int em_gio_probe(struct platform_device *pdev)
>   		return -ENXIO;
>   	}
>   
> +	ret = devm_add_action(&pdev->dev,
> +			      em_gio_irq_domain_remove, p->irq_domain);

Could devm_add_action_or_reset be used?

> +	if (ret) {
> +		irq_domain_remove(p->irq_domain);
> +		return ret;
> +	}
> +
>   	if (devm_request_irq(&pdev->dev, irq[0]->start,
>   			     em_gio_irq_handler, 0, name, p)) {
>   		dev_err(&pdev->dev, "failed to request low IRQ\n");
> -		ret = -ENOENT;
> -		goto err1;
> +		return -ENOENT;
>   	}
>   
>   	if (devm_request_irq(&pdev->dev, irq[1]->start,
>   			     em_gio_irq_handler, 0, name, p)) {
>   		dev_err(&pdev->dev, "failed to request high IRQ\n");
> -		ret = -ENOENT;
> -		goto err1;
> +		return -ENOENT;
>   	}
>   
>   	ret = devm_gpiochip_add_data(&pdev->dev, gpio_chip, p);
>   	if (ret) {
>   		dev_err(&pdev->dev, "failed to add GPIO controller\n");
> -		goto err1;
> +		return ret;
>   	}
>   
>   	return 0;
> -
> -err1:
> -	irq_domain_remove(p->irq_domain);
> -	return ret;
> -}
> -
> -static int em_gio_remove(struct platform_device *pdev)
> -{
> -	struct em_gio_priv *p = platform_get_drvdata(pdev);
> -
> -	irq_domain_remove(p->irq_domain);
> -	return 0;
>   }
>   
>   static const struct of_device_id em_gio_dt_ids[] = {
> @@ -376,7 +376,6 @@ MODULE_DEVICE_TABLE(of, em_gio_dt_ids);
>   
>   static struct platform_driver em_gio_device_driver = {
>   	.probe		= em_gio_probe,
> -	.remove		= em_gio_remove,
>   	.driver		= {
>   		.name	= "em_gio",
>   		.of_match_table = em_gio_dt_ids,
> 


-- 
Regards
Phil Reid