[dpdk-dev] [PATCH v4 3/5] net/ice: fix max mtu size packets with vlan tag cannot be received by default

Zhang, Qi Z qi.z.zhang at intel.com
Wed Sep 30 02:34:32 CEST 2020



> -----Original Message-----
> From: Ananyev, Konstantin <konstantin.ananyev at intel.com>
> Sent: Wednesday, September 30, 2020 7:02 AM
> To: Zhang, Qi Z <qi.z.zhang at intel.com>; Yang, SteveX
> <stevex.yang at intel.com>; dev at dpdk.org
> Cc: Zhao1, Wei <wei.zhao1 at intel.com>; Guo, Jia <jia.guo at intel.com>; Yang,
> Qiming <qiming.yang at intel.com>; Wu, Jingjing <jingjing.wu at intel.com>; Xing,
> Beilei <beilei.xing at intel.com>
> Subject: RE: [PATCH v4 3/5] net/ice: fix max mtu size packets with vlan tag
> cannot be received by default
> 
> >
> > > -----Original Message-----
> > > From: Yang, SteveX <stevex.yang at intel.com>
> > > Sent: Monday, September 28, 2020 2:56 PM
> > > To: dev at dpdk.org
> > > Cc: Zhao1, Wei <wei.zhao1 at intel.com>; Guo, Jia <jia.guo at intel.com>;
> > > Yang, Qiming <qiming.yang at intel.com>; Zhang, Qi Z
> > > <qi.z.zhang at intel.com>; Wu, Jingjing <jingjing.wu at intel.com>; Xing,
> > > Beilei <beilei.xing at intel.com>; Ananyev, Konstantin
> > > <konstantin.ananyev at intel.com>; Yang, SteveX <stevex.yang at intel.com>
> > > Subject: [PATCH v4 3/5] net/ice: fix max mtu size packets with vlan
> > > tag cannot be received by default
> > >
> > > testpmd will initialize default max packet length to 1518 which
> > > doesn't include vlan tag size in ether overheader. Once, send the
> > > max mtu length packet with vlan tag, the max packet length will
> > > exceed 1518 that will cause packets dropped directly from NIC hw side.
> > >
> > > ice can support dual vlan tags that need more 8 bytes for max packet
> > > size, so, configures the correct max packet size in dev_config ops.
> > >
> > > Fixes: 50cc9d2a6e9d ("net/ice: fix max frame size")
> > >
> > > Signed-off-by: SteveX Yang <stevex.yang at intel.com>
> > > ---
> > >  drivers/net/ice/ice_ethdev.c | 11 +++++++++++
> > >  1 file changed, 11 insertions(+)
> > >
> > > diff --git a/drivers/net/ice/ice_ethdev.c
> > > b/drivers/net/ice/ice_ethdev.c index
> > > cfd357b05..6b7098444 100644
> > > --- a/drivers/net/ice/ice_ethdev.c
> > > +++ b/drivers/net/ice/ice_ethdev.c
> > > @@ -3146,6 +3146,7 @@ ice_dev_configure(struct rte_eth_dev *dev)
> > > struct ice_adapter *ad =
> > > ICE_DEV_PRIVATE_TO_ADAPTER(dev->data->dev_private);
> > >  struct ice_pf *pf = ICE_DEV_PRIVATE_TO_PF(dev->data->dev_private);
> > > +uint32_t frame_size = dev->data->mtu + ICE_ETH_OVERHEAD;
> > >  int ret;
> > >
> > >  /* Initialize to TRUE. If any of Rx queues doesn't meet the @@
> > > -3157,6
> > > +3158,16 @@ ice_dev_configure(struct rte_eth_dev *dev)
> > >  if (dev->data->dev_conf.rxmode.mq_mode & ETH_MQ_RX_RSS_FLAG)
> > > dev->data->dev_conf.rxmode.offloads |= DEV_RX_OFFLOAD_RSS_HASH;
> > >
> > > +/**
> > > + * Considering QinQ packet, max frame size should be equal or
> > > + * larger than total size of MTU and Ether overhead.
> > > + */
> >
> > > +if (frame_size > dev->data->dev_conf.rxmode.max_rx_pkt_len) {
> >
> >
> > Why we need this check?
> > Can we just call ice_mtu_set directly
> 
> I think that without that check we can silently overwrite provided by user
> dev_conf.rxmode.max_rx_pkt_len value.

OK, I see

But still have one question
dev->data->mtu is initialized to 1518 as default , but if application set dev_conf.rxmode.max_rx_pkt_len = 1000 in dev_configure.
does that mean we will still will set mtu to 1518, is this expected?

Should we just call ice_mtu_set(dev, dev_conf.rxmode.max_rx_pkt_len) here?



> 
> > And please remove above comment, since ether overhead is already
> considered in ice_mtu_set.
> >
> >
> > > +ret = ice_mtu_set(dev, dev->data->mtu); if (ret != 0) return ret; }
> > > +
> > >  ret = ice_init_rss(pf);
> > >  if (ret) {
> > >  PMD_DRV_LOG(ERR, "Failed to enable rss for PF");
> > > --
> > > 2.17.1
> >
> 



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