Re: [PATCH v2 05/11] pci: use helper for safer setting of driver_override

[Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>]

On 23/02/2022 22:51, Bjorn Helgaas wrote:
> In subject, to match drivers/pci/ convention, do something like:
> 
>   PCI: Use driver_set_override() instead of open-coding
> 
> On Wed, Feb 23, 2022 at 08:13:04PM +0100, Krzysztof Kozlowski wrote:
>> Use a helper for seting driver_override to reduce amount of duplicated
>> code.
> 
> s/seting/setting/
> 
>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
>> ---
>>  drivers/pci/pci-sysfs.c | 24 ++++--------------------
>>  1 file changed, 4 insertions(+), 20 deletions(-)
>>
>> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
>> index 602f0fb0b007..16a163d4623e 100644
>> --- a/drivers/pci/pci-sysfs.c
>> +++ b/drivers/pci/pci-sysfs.c
>> @@ -567,31 +567,15 @@ static ssize_t driver_override_store(struct device *dev,
>>  				     const char *buf, size_t count)
>>  {
>>  	struct pci_dev *pdev = to_pci_dev(dev);
>> -	char *driver_override, *old, *cp;
>> +	int ret;
>>  
>>  	/* We need to keep extra room for a newline */
>>  	if (count >= (PAGE_SIZE - 1))
>>  		return -EINVAL;
> 
> This check makes no sense in the new function.  Michael alluded to
> this as well.

I am not sure if I got your comment properly. You mean here:
1. Move this check to driver_set_override()?
2. Remove the check entirely?

> 
>> -	driver_override = kstrndup(buf, count, GFP_KERNEL);
>> -	if (!driver_override)
>> -		return -ENOMEM;
>> -
>> -	cp = strchr(driver_override, '\n');
>> -	if (cp)
>> -		*cp = '\0';
>> -
>> -	device_lock(dev);
>> -	old = pdev->driver_override;
>> -	if (strlen(driver_override)) {
>> -		pdev->driver_override = driver_override;
>> -	} else {
>> -		kfree(driver_override);
>> -		pdev->driver_override = NULL;
>> -	}
>> -	device_unlock(dev);
>> -
>> -	kfree(old);
>> +	ret = driver_set_override(dev, &pdev->driver_override, buf);
>> +	if (ret)
>> +		return ret;
>>  
>>  	return count;
>>  }
>> -- 
>> 2.32.0
>>
>>
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Best regards,
Krzysztof