[dpdk-dev] [PATCH] net/i40e: consider QinQ when setting MTU

Lu, Wenzhuo wenzhuo.lu at intel.com
Fri Apr 28 10:30:21 CEST 2017


Hi Ferruh,

> -----Original Message-----
> From: Wu, Jingjing
> Sent: Friday, April 28, 2017 4:27 PM
> To: Yigit, Ferruh; Lu, Wenzhuo; dev at dpdk.org
> Subject: RE: [dpdk-dev] [PATCH] net/i40e: consider QinQ when setting MTU
> 
> 
> 
> > -----Original Message-----
> > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Ferruh Yigit
> > Sent: Friday, April 28, 2017 1:55 PM
> > To: Lu, Wenzhuo <wenzhuo.lu at intel.com>; dev at dpdk.org
> > Subject: Re: [dpdk-dev] [PATCH] net/i40e: consider QinQ when setting
> > MTU
> >
> > On 4/28/2017 2:55 AM, Wenzhuo Lu wrote:
> > > When counting max packet length from MTU, count VLAN tag length
> > > twice for QinQ packets.
> > >
> > > Signed-off-by: Wenzhuo Lu <wenzhuo.lu at intel.com>
> > > ---
> > >  drivers/net/i40e/i40e_ethdev.c    | 2 +-
> > >  drivers/net/i40e/i40e_ethdev_vf.c | 2 +-
> > >  2 files changed, 2 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/net/i40e/i40e_ethdev.c
> > > b/drivers/net/i40e/i40e_ethdev.c index 3fa25dc..74041ae 100644
> > > --- a/drivers/net/i40e/i40e_ethdev.c
> > > +++ b/drivers/net/i40e/i40e_ethdev.c
> > > @@ -10593,7 +10593,7 @@ static void i40e_set_default_mac_addr(struct
> > rte_eth_dev *dev,
> > >  	struct i40e_pf *pf = I40E_DEV_PRIVATE_TO_PF(dev->data-
> > >dev_private);
> > >  	struct rte_eth_dev_data *dev_data = pf->dev_data;
> > >  	uint32_t frame_size = mtu + ETHER_HDR_LEN
> > > -			      + ETHER_CRC_LEN + I40E_VLAN_TAG_SIZE;
> > > +			      + ETHER_CRC_LEN + I40E_VLAN_TAG_SIZE * 2;
> >
> > Hi Wenzhuo,
> >
> > Shouldn't we check if QinQ enabled before taking size account?
> 
> Hi, Ferruh
> 
> Checking QinQ enabled here makes no sense, because we don't know If the
> packets is carry single vlan or double vlan.
> 
> Acked-by: Jingjing Wu <jingjing.wu at intel.com>
BTW, the patch aligned the behavior of kernel driver and DPDK.



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