Subject: Re: [PATCH net-next 04/13] sunhme: Return an ERR_PTR from quattro_pci_find

From: Sean Anderson <[email-masked]>
Date: Mon, 19 Sep 2022 10:08:55 -0400

On 9/19/22 09:11, Rolf Eike Beer wrote:
> Am Montag, 19. September 2022, 01:26:17 CEST schrieb Sean Anderson:
>> In order to differentiate between a missing bridge and an OOM condition,
>> return ERR_PTRs from quattro_pci_find. This also does some general linting
>> in the area.
>>
>> Signed-off-by: Sean Anderson <[email-masked]>
>> ---
>>
>>   drivers/net/ethernet/sun/sunhme.c | 33 +++++++++++++++++++------------
>>   1 file changed, 20 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/sun/sunhme.c
>> b/drivers/net/ethernet/sun/sunhme.c index 1fc16801f520..52247505d08e 100644
>> --- a/drivers/net/ethernet/sun/sunhme.c
>> +++ b/drivers/net/ethernet/sun/sunhme.c
>> @@ -2569,30 +2569,33 @@ static void quattro_sbus_free_irqs(void)
>>   #ifdef CONFIG_PCI
>>   static struct quattro *quattro_pci_find(struct pci_dev *pdev)
>>   {
>> +	int i;
>>   	struct pci_dev *bdev = pdev->bus->self;
>>   	struct quattro *qp;
>>
>> -	if (!bdev) return NULL;
>> +	if (!bdev)
>> +		return ERR_PTR(-ENODEV);
>> +
>>   	for (qp = qfe_pci_list; qp != NULL; qp = qp->next) {
>>   		struct pci_dev *qpdev = qp->quattro_dev;
>>
>>   		if (qpdev == bdev)
>>   			return qp;
>>   	}
>> +
>>   	qp = kmalloc(sizeof(struct quattro), GFP_KERNEL);
>> -	if (qp != NULL) {
>> -		int i;
>> +	if (!qp)
>> +		return ERR_PTR(-ENOMEM);
>>
>> -		for (i = 0; i < 4; i++)
>> -			qp->happy_meals[i] = NULL;
>> +	for (i = 0; i < 4; i++)
>> +		qp->happy_meals[i] = NULL;
> 
> I know you are only reindenting it, but I dislike moving the variable up to
> the top of the function. Since the kernel is C99 meanwhile the variable could
> be declared just in the for loop. 

Hm, I thought this style was discouraged.

> And when touching this anyway I think we
> could get rid of the magic "4" by using ARRAY_SIZE(qp->happy_meals). Or just
> replace the whole thing with memset(qp->happy_meals, 0, sizeof(qp-
>> happy_meals)).

Yeah, that avoids the whole problem.

--Sean