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Date: Sat, 29 Apr 2006 01:51:16 -0700
From: Andrew Morton <akpm@osdl.org>
To: Arjan van de Ven <arjan@linux.intel.com>
Cc: greg@kroah.com, linux-pci@atrey.karlin.mff.cuni.cz,
       linux-kernel@vger.kernel.org, airlied@linux.ie, pjones@redhat.com
Subject: Re: Add a "enable" sysfs attribute to the pci devices to allow
 userspace (Xorg) to enable devices without doing foul direct access
Message-Id: <20060429015116.2c3d964b.akpm@osdl.org>
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Arjan van de Ven <arjan@linux.intel.com> wrote:
>
> +static ssize_t
> +is_enabled_store(struct device *dev, struct device_attribute *attr,
> +		const char *buf, size_t count)
> +{
> +        struct pci_dev *pdev = to_pci_dev(dev);

whitespace broke

> +	if (!pdev)
> +		return 1;

Can this happen?

> +	/* this can crash the machine when done on the "wrong" device */
> +	if (!capable(CAP_SYS_ADMIN))
> +		return 1;

Don't the file's permissions suffice?

> +	if (*buf == '0')
> +		pci_disable_device(pdev);
> +
> +	if (*buf == '1')
> +		pci_enable_device(pdev);
> +
> +	return 1;

	return count;

> +}
> +
>  
>  struct device_attribute pci_dev_attrs[] = {
>  	__ATTR_RO(resource),
> @@ -101,6 +124,7 @@ struct device_attribute pci_dev_attrs[] 
>  	__ATTR_RO(irq),
>  	__ATTR_RO(local_cpus),
>  	__ATTR_RO(modalias),
> +	__ATTR(enable, 0600, is_enabled_show, is_enabled_store),
>  	__ATTR_NULL,
>  };
>