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Date:   Thu, 28 Jul 2022 17:59:08 +0200
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Cc:     kah.jing.lee@intel.com, linux-kernel@vger.kernel.org,
        arnd@arndb.de, rafael.j.wysocki@intel.com, tien.sung.ang@intel.com,
        dinh.nguyen@intel.com, Zhou@kroah.com,
        Furong <furong.zhou@intel.com>, Vinod Koul <vkoul@kernel.org>,
        Bard Liao <yung-chuan.liao@linux.intel.com>
Subject: Re: [PATCH v2 1/3] drivers: misc: intel_sysid: Add sysid from arch
 to drivers
Message-ID: <YuKyTKHk3c7DibX3@kroah.com>
References: <20220721123017.416438-1-kah.jing.lee@intel.com>
 <20220721123149.416618-1-kah.jing.lee@intel.com>
 <YuJAll2MEgKF0MVM@kroah.com>
 <be3f189e-c17c-2438-450d-3d84dfcd71da@linux.intel.com>
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On Thu, Jul 28, 2022 at 10:37:37AM -0500, Pierre-Louis Bossart wrote:
> Thanks for the review Greg,
> 
> >> +static int intel_sysid_probe(struct platform_device *pdev)
> >> +{
> >> +	struct intel_sysid *sysid;
> >> +	struct resource	*regs;
> >> +
> >> +	sysid = devm_kzalloc(&pdev->dev, sizeof(struct intel_sysid),
> >> +		GFP_KERNEL);
> >> +	if (!sysid)
> >> +		return -ENOMEM;
> >> +
> >> +	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> >> +	if (!regs)
> >> +		return -ENXIO;
> >> +
> >> +	sysid->regs = devm_ioremap_resource(&pdev->dev, regs);
> >> +	if (IS_ERR(sysid->regs))
> >> +		return PTR_ERR(sysid->regs);
> >> +
> >> +	platform_set_drvdata(pdev, sysid);
> >> +
> >> +	return devm_device_add_group(&pdev->dev, &intel_sysid_attr_group);
> > 
> > You just raced with userspace and lost.  Please use the default group
> > for the platform device.
> > 
> > I need to go remove this function, it should not be used at all as it is
> > broken.
> 
> Can you elaborate on the issue and suggested replacement?
> 
> We used this function for the SoundWire sysfs based on your review
> comments (2 years ago?) that we should not muck with kobj, and that
> function devm_device_add_group() is also used in a probe function.

Use the default_groups pointer in the driver structure.

thanks,

greg k-h