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Date:   Tue, 13 Sep 2022 08:39:30 +0100
From:   "Russell King (Oracle)" <linux@armlinux.org.uk>
To:     Tang Bin <tangbin@cmss.chinamobile.com>
Cc:     shawnguo@kernel.org, s.hauer@pengutronix.de, kernel@pengutronix.de,
        festevam@gmail.com, linux-imx@nxp.com,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] soc: imx: fix error check in imx8mp_blk_ctrl_probe()
Message-ID: <YyAzsl72LzMTdoDF@shell.armlinux.org.uk>
References: <20220913073434.7252-1-tangbin@cmss.chinamobile.com>
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Sender: Russell King (Oracle) <linux@armlinux.org.uk>
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On Tue, Sep 13, 2022 at 03:34:34PM +0800, Tang Bin wrote:
> In the function imx8mp_blk_ctrl_probe(),
> dev_pm_domain_attach_by_name() may return NULL in some cases,
> so IS_ERR() doesn't meet the requirements. Thus fix it.
> 
> Fixes: 556f5cf9568a ("soc: imx: add i.MX8MP HSIO blk-ctrl")
> Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
> ---
>  drivers/soc/imx/imx8mp-blk-ctrl.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/soc/imx/imx8mp-blk-ctrl.c b/drivers/soc/imx/imx8mp-blk-ctrl.c
> index ccb30c6cd..ed8557eaf 100644
> --- a/drivers/soc/imx/imx8mp-blk-ctrl.c
> +++ b/drivers/soc/imx/imx8mp-blk-ctrl.c
> @@ -597,11 +597,11 @@ static int imx8mp_blk_ctrl_probe(struct platform_device *pdev)
>  
>  		domain->power_dev =
>  			dev_pm_domain_attach_by_name(dev, data->gpc_name);
> -		if (IS_ERR(domain->power_dev)) {
> +		if (IS_ERR_OR_NULL(domain->power_dev)) {
>  			dev_err_probe(dev, PTR_ERR(domain->power_dev),
>  				      "failed to attach power domain %s\n",
>  				      data->gpc_name);
> -			ret = PTR_ERR(domain->power_dev);
> +			ret = PTR_ERR(domain->power_dev) ? : -ENODATA;
>  			goto cleanup_pds;
>  		}
>  		dev_set_name(domain->power_dev, "%s", data->name);

Checking for NULL in this case is likely a good idea, as if
domain->power_dev is NULL, then dev_set_name() will probably oops the
kernel. Whether returning -ENODATA and causing a failure, or whether
moving on to the next domain is a question that the maintainers of
this code need to answer, bearing in mind that NULL here means that
the device doesn't need a power domain.

-- 
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