[dpdk-dev] [PATCH v8 1/2] app/testpmd: fix max rx packet length for VLAN packets

[Thomas Monjalon]

04/11/2020 18:07, Ferruh Yigit:
> On 11/4/2020 4:51 PM, Thomas Monjalon wrote:
> > 03/11/2020 14:29, Ferruh Yigit:
> >> On 11/2/2020 11:48 AM, Ferruh Yigit wrote:
> >>> On 11/2/2020 8:52 AM, SteveX Yang wrote:
> >>>> When the max rx packet length is smaller than the sum of mtu size and
> >>>> ether overhead size, it should be enlarged, otherwise the VLAN packets
> >>>> will be dropped.
> >>>>
> >>>> Fixes: 35b2d13fd6fd ("net: add rte prefix to ether defines")
> >>>>
> >>>> Signed-off-by: SteveX Yang <stevex.yang at intel.com>
> >>>
> >>> Reviewed-by: Ferruh Yigit <ferruh.yigit at intel.com>
> >>
> >> Applied to dpdk-next-net/main, thanks.
> >>
> >> only 1/2 applied since discussion is going on for 2/2.
> > 
> > I'm not sure this testpmd change is good.
> > 
> > Reminder: testpmd is for testing the PMDs.
> > Don't we want to see VLAN packets dropped in the case described above?
> > 
> 
> The patch set 'max_rx_pkt_len' in a way to make MTU 1500 for all PMDs,
> otherwise testpmd set hard-coded 'RTE_ETHER_MAX_LEN' value, which makes MTU 
> between 1492-1500 depending on PMD.
> 
> It is application responsibility to provide correct 'max_rx_pkt_len'.
> I guess the original intention was to set MTU as 1500 but was not correct for 
> all PMDs and this patch is fixing it.
> 
> The same problem in the ethdev, (assuming 'RTE_ETHER_MAX_LEN' will give MTU 
> 1500), the other patch in the set is to fix it later.

OK but the testpmd patch is just hiding the issue, isn't it?