Re: [PATCH v2 5/6] flow: Add queue pair tracking to flow management

[Laurent Vivier <lvivier@redhat.com>]

On 11/26/25 04:41, David Gibson wrote:
>> +/**
>> + * flow_qp() - Get the queue pair for a flow
>> + * @f:		Flow to query (may be NULL)
>> + *
>> + * Return: queue pair number for the flow, or 0 if flow is NULL or has no
>> + *         valid queue pair assignment
>> + */
>> +unsigned int flow_qp(const struct flow_common *f)
>> +{
>> +	if (f == NULL || f->qpair == FLOW_QPAIR_INVALID)
> Are there any instances where you actually want to pass a NULL flow to
> this?
> 
> If you're going to return 0 anyway, why not just set f->qpair to 0 by
> default, rather than using FLOW_QPAIR_INVALID?
> 

In fact, in the multithread part I need to know if the queue pair has been set or not.
I agree that we should avoid this if possible because it takes one slot in the array. And 
as we have 16 qpairs we must use 5 bit (we need 17 values) rather than 4 bit. I'm 
reworking the multithread part, I will see if I can remove this.

Thanks,
Laurent