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

[Zhang, Qi Z]

> -----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 
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