linux-kernel - Re: [PATCH] drivers/i2c/busses/i2c-imx.c: Use with resource management to register interrupts

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Message-ID: <0e71319e-226f-286a-cfd9-b6b94ffba2d8@pengutronix.de>
Date:   Fri, 10 Dec 2021 06:54:17 +0100
From:   Ahmad Fatoum <a.fatoum@...gutronix.de>
To:     lizhe <sensor1010@....com>, linux@...pel-privat.de,
        kernel@...gutronix.de, shawnguo@...nel.org, s.hauer@...gutronix.de,
        festevam@...il.com, linux-imx@....com
Cc:     linux-i2c@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drivers/i2c/busses/i2c-imx.c: Use with resource
 management to register interrupts

Hello lizhe,

On 10.12.21 03:57, lizhe wrote:
> In the probe function, used devm_request_threaded_irq instead of
> request_threaded_irq, make full use of the resource management
> function provided by the kernel

See e50e4f0b85be ("i2c: imx: Fix external abort on interrupt in exit paths")
for why this isn't a safe thing to do here. Given that this is the third time,
I think, this was suggested, you may want to instead patch in a comment
explaining why we _don't_ use devm_request_threaded_irq here..

Cheers,
Ahmad

> 
> Signed-off-by: lizhe <sensor1010@....com>
> ---
>  drivers/i2c/busses/i2c-imx.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index 3576b63a6c03..3e99827b2720 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -1426,7 +1426,7 @@ static int i2c_imx_probe(struct platform_device *pdev)
>  		goto rpm_disable;
>  
>  	/* Request IRQ */
> -	ret = request_threaded_irq(irq, i2c_imx_isr, NULL, IRQF_SHARED,
> +	ret = devm_request_threaded_irq(irq, i2c_imx_isr, NULL, IRQF_SHARED,
>  				   pdev->name, i2c_imx);
>  	if (ret) {
>  		dev_err(&pdev->dev, "can't claim irq %d\n", irq);
> @@ -1472,7 +1472,6 @@ static int i2c_imx_probe(struct platform_device *pdev)
>  
>  clk_notifier_unregister:
>  	clk_notifier_unregister(i2c_imx->clk, &i2c_imx->clk_change_nb);
> -	free_irq(irq, i2c_imx);
>  rpm_disable:
>  	pm_runtime_put_noidle(&pdev->dev);
>  	pm_runtime_disable(&pdev->dev);
> 


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