Re: [PATCH RFC net-next 05/19] net: dsa: tag_ar9331: add GRO callbacks

[Florian Fainelli]

On 1/13/20 2:28 AM, Vladimir Oltean wrote:
> On Mon, 13 Jan 2020 at 11:46, Alexander Lobakin <alobakin@xxxxxxxx> wrote:
>>
>> Vladimir Oltean wrote 13.01.2020 12:42:
>>> Hi Alexander,
>>>
>>> On Mon, 13 Jan 2020 at 11:22, Alexander Lobakin <alobakin@xxxxxxxx>
>>> wrote:
>>>>
>>>> CPU ports can't be bridged anyway
>>>>
>>>> Regards,
>>>> á á á á á á
>>>
>>> The fact that CPU ports can't be bridged is already not ideal.
>>> One can have a DSA switch with cascaded switches on each port, so it
>>> acts like N DSA masters (not as DSA links, since the taggers are
>>> incompatible), with each switch forming its own tree. It is desirable
>>> that the ports of the DSA switch on top are bridged, so that
>>> forwarding between cascaded switches does not pass through the CPU.
>>
>> Oh, I see. But currently DSA infra forbids the adding DSA masters to
>> bridges IIRC. Can't name it good or bad decision, but was introduced
>> to prevent accidental packet flow breaking on DSA setups.
>>
> 
> I just wanted to point out that some people are going to be looking at
> ways by which the ETH_P_XDSA handler can be made to play nice with the
> master's rx_handler, and that it would be nice to at least not make
> the limitation worse than it is by converting everything to
> rx_handlers (which "currently" can't be stacked, from the comments in
> netdevice.h).

I am not sure this would change the situation much, today we cannot have
anything but switch tags travel on the DSA master network device,
whether we accomplish the RX tap through a special skb->protocol value
or via rx_handler, it probably does not functionally matter, but it
could change the performance.
-- 
Florian