Re: [PATCH 4/7] platform/x86: hp-bioscfg: Use wmi_instance_count()

[Armin Wolf <W_Armin@gmx.de>]

Am 04.02.25 um 11:37 schrieb Ilpo Järvinen:

> On Mon, 3 Feb 2025, Armin Wolf wrote:
>
>> The WMI core already knows the instance count of a WMI guid.
>> Use this information instead of querying all possible instances
>> which is slow and might be unreliable.
>>
>> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
>> ---
>>   drivers/platform/x86/hp/hp-bioscfg/bioscfg.c | 13 +++++--------
>>   1 file changed, 5 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/platform/x86/hp/hp-bioscfg/bioscfg.c b/drivers/platform/x86/hp/hp-bioscfg/bioscfg.c
>> index 0b277b7e37dd..63c78b4d8258 100644
>> --- a/drivers/platform/x86/hp/hp-bioscfg/bioscfg.c
>> +++ b/drivers/platform/x86/hp/hp-bioscfg/bioscfg.c
>> @@ -388,16 +388,13 @@ union acpi_object *hp_get_wmiobj_pointer(int instance_id, const char *guid_strin
>>    */
>>   int hp_get_instance_count(const char *guid_string)
>>   {
>> -	union acpi_object *wmi_obj = NULL;
>> -	int i = 0;
>> +	int ret;
>>
>> -	do {
>> -		kfree(wmi_obj);
>> -		wmi_obj = hp_get_wmiobj_pointer(i, guid_string);
>> -		i++;
>> -	} while (wmi_obj);
>> +	ret = wmi_instance_count(guid_string);
>> +	if (ret < 0)
>> +		return 0;
>>
>> -	return i - 1;
>> +	return ret;
>>   }
> Hi Armin,
>
> While it is the existing way of doing things, I don't like how the error
> is not properly passed on here. And if the error handling is pushed
> upwards to the calling sites, then this entire function becomes useless
> and wmi_instance_count() could be used directly in the callers.
>
The thing is that for the hp-bioscfg driver, a missing WMI GUID is not an error.
In this case 0 instances are available.

I would keep this function for now.

Thanks,
Armin Wolf