[dpdk-users] To enable offloading DEV_TX_OFFLOAD_MULTI_SEGS per port and per queue

[Anupama Laxmi <anupamalaxmi4@gmail.com>]

I would like to enable per port offloading to set TX offloading for
multiple segments using DEV_TX_OFFLOAD_MULTI_SEGS. UDP packets were getting
dropped with error Bad UDP length > IP payload length as seen in the
wireshark capture. This issue is seen after I upgraded to DPDK 18.08. Hence
I would like to set the offload DEV_TX_OFFLOAD_MULTI_SEGS per port to allow
segmenation of big packets.

I am getting the below error when I try to set the above offload.

Ethdev port_id=0 tx_queue_id=0, new added offloads 0x9f3e55 must be within
pre-queue offload capabilities 0x0 in rte_eth_tx_queue_setup()

Please let me know where I am going wrong and how do I set the offload
DEV_TX_OFFLOAD_MULTI_SEGS correctly.

static const struct rte_eth_txconf tx_conf = {
    .tx_thresh = {
        .pthresh = TX_PTHRESH,
        .hthresh = TX_HTHRESH,
        .wthresh = TX_WTHRESH,
    },
    .tx_free_thresh = 0,
    .tx_rs_thresh = 0,
};


static struct rte_eth_conf port_conf = {
        .rxmode = {
                .mq_mode = ETH_MQ_RX_RSS,
                .max_rx_pkt_len = JUMBO_FRAME_MAX_SIZE,
                .split_hdr_size = 0,
                .offloads = (DEV_RX_OFFLOAD_CHECKSUM |
                             DEV_RX_OFFLOAD_CRC_STRIP),
        },
        .rx_adv_conf = {
                .rss_conf = {
                        .rss_key = NULL,
                        .rss_hf = ETH_RSS_TCP| ETH_RSS_UDP |
                             ETH_RSS_TCP | ETH_RSS_SCTP,
                },
        },
        .txmode = {
                .mq_mode = ETH_MQ_TX_NONE,
        },
};


struct rte_eth_txconf *tx_conf;
struct rte_eth_conf local_port_conf = port_conf;
if(dev_info.tx_offload_capa & DEV_TX_OFFLOAD_MULTI_SEGS)
        {

           local_port_conf.txmode.offloads |= DEV_TX_OFFLOAD_MULTI_SEGS;
        }
ret = rte_eth_dev_configure(port, nbqueue, nbqueue, &local_port_conf);
rte_eth_dev_info_get(port, &dev_info);
        tx_conf = &dev_info.default_txconf;
        tx_conf->offloads = local_port_conf.txmode.offloads;

        ret = rte_eth_tx_queue_setup(port, queue, RTE_TEST_TX_DESC_DEFAULT,
master_socket_id, &tx_conf);