Re: [dpdk-dev] [PATCH 1/8] net/bnxt: remove assert for zero data len in Tx path

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

On 6/15/2022 3:56 PM, Kalesh A P wrote:
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> 
> 
> From: Somnath Kotur <somnath.kotur@broadcom.com>
> 
> Currently the PMD tries to detect a potential 0 byte DMA by
> using RTE_VERIFY.
> But since RTE_VERIFY internally calls rte_panic() it is fatal to
> the application and some applications want to avoid that.
> So return an error from the bnxt xmit handler if such a bad pkt is
> encountered by logging an error message, dumping the pkt header and
> dump the current stack as well
> 
> Signed-off-by: Somnath Kotur <somnath.kotur@broadcom.com>
> Reviewed-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
> ---
>   drivers/net/bnxt/bnxt_txr.c | 29 ++++++++++++++++++++++++++---
>   1 file changed, 26 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/bnxt/bnxt_txr.c b/drivers/net/bnxt/bnxt_txr.c
> index 7a7196a..67e0167 100644
> --- a/drivers/net/bnxt/bnxt_txr.c
> +++ b/drivers/net/bnxt/bnxt_txr.c
> @@ -123,6 +123,26 @@ bnxt_xmit_need_long_bd(struct rte_mbuf *tx_pkt, struct bnxt_tx_queue *txq)
>          return false;
>   }
> 
> +static bool
> +bnxt_zero_data_len_tso_segsz(struct rte_mbuf *tx_pkt, uint8_t data_len_chk)
> +{
> +       const char *type_str = "Data len";
> +       uint16_t len_to_check = tx_pkt->data_len;
> +
> +       if (data_len_chk == 0) {
> +               type_str = "TSO Seg size";
> +               len_to_check = tx_pkt->tso_segsz;
> +       }
> +
> +       if (len_to_check == 0) {
> +               PMD_DRV_LOG(ERR, "Error! Tx pkt %s == 0\n", type_str);
> +               rte_pktmbuf_dump(stdout, tx_pkt, 64);
> +               rte_dump_stack();
> +               return true;
> +       }
> +       return false;
> +}
> +
>   static uint16_t bnxt_start_xmit(struct rte_mbuf *tx_pkt,
>                                  struct bnxt_tx_queue *txq,
>                                  uint16_t *coal_pkts,
> @@ -179,7 +199,8 @@ static uint16_t bnxt_start_xmit(struct rte_mbuf *tx_pkt,
>          }
> 
>          /* Check non zero data_len */
> -       RTE_VERIFY(tx_pkt->data_len);
> +       if (unlikely(bnxt_zero_data_len_tso_segsz(tx_pkt, 1)))
> +               return -EIO;
> 

Some PMDs does the similar verification in the 'rte_eth_tx_prepare()' 
API (tx_pkt_prepare() dev_ops), this helps to separate the checks and Tx 
data path code, do you want to do the same?