Re: [dpdk-dev] [PATCH 1/3] app/testpmd: update Rx offload after setting MTU sccessfully

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 1/21/2020 11:44 AM, Wei Hu (Xavier) wrote:
> From: "Wei Hu (Xavier)" <xavier.huwei@huawei.com>
> 
> Currently, Rx offload capabilities and max_rx_pkt_len in the struct
> variable named rte_port are not updated after setting mtu successfully
> in port_mtu_set function by 'port config mtu <port_id> <value>' command.
> This may lead to reconfig mtu to the initial value in the driver when
> recalling rte_eth_dev_configure API interface.
> 
> This patch updates Rx offload capabilities and max_rx_pkt_len after
> setting mtu successfully when configuring mtu.
> 
> Fixes: ae03d0d18adf ("app/testpmd: command to configure MTU")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Huisong Li <lihuisong@huawei.com>
> Signed-off-by: Wei Hu (Xavier) <xavier.huwei@huawei.com>
> ---
>  app/test-pmd/config.c | 18 +++++++++++++++++-
>  1 file changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/app/test-pmd/config.c b/app/test-pmd/config.c
> index 9669cbd4c..09a1579f5 100644
> --- a/app/test-pmd/config.c
> +++ b/app/test-pmd/config.c
> @@ -1216,7 +1216,9 @@ void
>  port_mtu_set(portid_t port_id, uint16_t mtu)
>  {
>  	int diag;
> +	struct rte_port *rte_port = &ports[port_id];
>  	struct rte_eth_dev_info dev_info;
> +	uint16_t eth_overhead;
>  	int ret;
>  
>  	if (port_id_is_invalid(port_id, ENABLED_WARN))
> @@ -1232,8 +1234,22 @@ port_mtu_set(portid_t port_id, uint16_t mtu)
>  		return;
>  	}
>  	diag = rte_eth_dev_set_mtu(port_id, mtu);
> -	if (diag == 0)
> +	if (diag == 0) {
> +		/*
> +		 * Ether overhead in driver is equal to the difference of
> +		 * max_rx_pktlen and max_mtu in rte_eth_dev_info.
> +		 */
> +		eth_overhead = dev_info.max_rx_pktlen - dev_info.max_mtu;
> +		if (mtu > RTE_ETHER_MAX_LEN - eth_overhead)
> +			rte_port->dev_conf.rxmode.offloads |=
> +						DEV_RX_OFFLOAD_JUMBO_FRAME;
> +		else
> +			rte_port->dev_conf.rxmode.offloads &=
> +						~DEV_RX_OFFLOAD_JUMBO_FRAME;

If the jumbo frame capability supported or not should be tested before setting it.

> +		rte_port->dev_conf.rxmode.max_rx_pkt_len = mtu + eth_overhead;

May need to check against 'dev_info.max_rx_pktlen', if the 'max_rx_pkt_len' is
bigger than this, it will fail in next configure.

Also some divers already does this in PMD code, should we clean that code or not
is a question.