linux-kernel - Re: [PATCH] spi: fsl-qspi: use devm function instead of driver remove

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Message-ID: <Z+VylBMSnQVHFSV5@lizhi-Precision-Tower-5810>
Date: Thu, 27 Mar 2025 11:45:24 -0400
From: Frank Li <Frank.li@....com>
To: Han Xu <han.xu@....com>
Cc: Mark Brown <broonie@...nel.org>,
	John Ogness <john.ogness@...utronix.de>,
	Volker Haspel <volker.haspel@...utronix.de>, stable@...r.kernel.org,
	Kevin Hao <haokexin@...il.com>, linux-spi@...r.kernel.org,
	imx@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] spi: fsl-qspi: use devm function instead of driver remove

On Wed, Mar 26, 2025 at 05:41:51PM -0500, Han Xu wrote:
> Driver use devm APIs to manage clk/irq/resources and register the spi
> controller, but the legacy remove function will be called first during
> device detach and trigger kernel panic. Drop the remove function and use
> devm_add_action_or_reset() for driver cleanup to ensure the release
> sequence.
>
> Trigger kernel panic on i.MX8MQ by
> echo 30bb0000.spi >/sys/bus/platform/drivers/fsl-quadspi/unbind
>
> Cc: stable@...r.kernel.org
> Fixes: 8fcb830a00f0 ("spi: spi-fsl-qspi: use devm_spi_register_controller")
> Reported-by: Kevin Hao <haokexin@...il.com>
> Signed-off-by: Han Xu <han.xu@....com>

Reviewed-by: Frank Li <Frank.Li@....com>

> ---
>  drivers/spi/spi-fsl-qspi.c | 31 +++++++++++++++++--------------
>  1 file changed, 17 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/spi/spi-fsl-qspi.c b/drivers/spi/spi-fsl-qspi.c
> index 355e6a39fb418..5c59fddb32c1b 100644
> --- a/drivers/spi/spi-fsl-qspi.c
> +++ b/drivers/spi/spi-fsl-qspi.c
> @@ -844,6 +844,19 @@ static const struct spi_controller_mem_caps fsl_qspi_mem_caps = {
>  	.per_op_freq = true,
>  };
>
> +static void fsl_qspi_cleanup(void *data)
> +{
> +	struct fsl_qspi *q = data;
> +
> +	/* disable the hardware */
> +	qspi_writel(q, QUADSPI_MCR_MDIS_MASK, q->iobase + QUADSPI_MCR);
> +	qspi_writel(q, 0x0, q->iobase + QUADSPI_RSER);
> +
> +	fsl_qspi_clk_disable_unprep(q);
> +
> +	mutex_destroy(&q->lock);
> +}
> +
>  static int fsl_qspi_probe(struct platform_device *pdev)
>  {
>  	struct spi_controller *ctlr;
> @@ -934,6 +947,10 @@ static int fsl_qspi_probe(struct platform_device *pdev)
>
>  	ctlr->dev.of_node = np;
>
> +	ret = devm_add_action_or_reset(dev, fsl_qspi_cleanup, q);
> +	if (ret)
> +		goto err_destroy_mutex;
> +

Look like needn't goto err_destroy_mutex. it should be enough

	if (ret)
		return ret;

Orginal error path:

err_destroy_mutex:
        mutex_destroy(&q->lock);    // already in fsl_qspi_cleanup()

err_disable_clk:
        fsl_qspi_clk_disable_unprep(q); // already in fsl_qspi_cleanup()

err_put_ctrl:
        spi_controller_put(ctlr); // suppose it is wrong, devm_spi_register_controller()
should consider it.


Frank

>  	ret = devm_spi_register_controller(dev, ctlr);
>  	if (ret)
>  		goto err_destroy_mutex;
> @@ -953,19 +970,6 @@ static int fsl_qspi_probe(struct platform_device *pdev)
>  	return ret;
>  }
>
> -static void fsl_qspi_remove(struct platform_device *pdev)
> -{
> -	struct fsl_qspi *q = platform_get_drvdata(pdev);
> -
> -	/* disable the hardware */
> -	qspi_writel(q, QUADSPI_MCR_MDIS_MASK, q->iobase + QUADSPI_MCR);
> -	qspi_writel(q, 0x0, q->iobase + QUADSPI_RSER);
> -
> -	fsl_qspi_clk_disable_unprep(q);
> -
> -	mutex_destroy(&q->lock);
> -}
> -
>  static int fsl_qspi_suspend(struct device *dev)
>  {
>  	return 0;
> @@ -1003,7 +1007,6 @@ static struct platform_driver fsl_qspi_driver = {
>  		.pm =   &fsl_qspi_pm_ops,
>  	},
>  	.probe          = fsl_qspi_probe,
> -	.remove		= fsl_qspi_remove,
>  };
>  module_platform_driver(fsl_qspi_driver);
>
> --
> 2.34.1
>