Re: [PATCH] net: apm: xgene: force XGene enet driver to re-balance IRQ usage

[Eric Dumazet <eric.dumazet@gmail.com>]

On 09/18/2018 04:15 PM, Al Stone wrote:
> On 09/18/2018 05:09 PM, Lendacky, Thomas wrote:
>>
>>
>> On 09/17/2018 09:35 PM, David Miller wrote:
>>> From: Al Stone <ahs3@redhat.com>
>>> Date: Mon, 17 Sep 2018 17:35:33 -0600
>>>
>>>> @@ -866,8 +866,11 @@ static int xgene_enet_napi(struct napi_struct *napi, const int budget)
>>>>  	processed = xgene_enet_process_ring(ring, budget);
>>>>  
>>>>  	if (processed != budget) {
>>>> +		struct irq_desc *desc = irq_to_desc(ring->irq);
>>>> +
>>>>  		napi_complete_done(napi, processed);
>>
>> The problem could be that the driver isn't checking the
>> napi_complete_done() return code.  It was changed to return a bool and
>> the check should be more like:
>>
>>   if ((processed != budget) && napi_complete_done(napi, processed)) {
>>
>> If it returns false, then the driver will get called for polling again
>> after having issued enable_irq() and it well then issue the enable_irq()
>> a second (or more) time without having the matching diable_irq().
>>
>> Thanks,
>> Tom
> 
> Aha, that might be.  My apologies -- I play in ACPI but seldom in the network
> drivers, so was not fully aware of that change.  I can give that a try.
> 
> Thanks for the pointer.
> 

Yes, please look at commit d7aba644ffdebf756e51e26a2229055211838e89
("amd-xgbe: Enable IRQs only if napi_complete_done() is true")