Re: [PATCH] net/hns3: fix Rx packet truncation when KEEP CRC enabled

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

On 2/6/2024 1:10 AM, Jie Hai wrote:
> From: Dengdui Huang <huangdengdui@huawei.com>
> 
> When KEEP_CRC offload is enabled, some packets will be truncated and
> the CRC is still be stripped in following cases:
> 1. For HIP08 hardware, the packet type is TCP and the length
>    is less than or equal to 60B.
> 2. For other hardwares, the packet type is IP and the length
>    is less than or equal to 60B.
> 

If a device doesn't support the offload by some packets, it can be
option to disable offload for that device, instead of calculating it in
software and append it.
Unless you have a specific usecase, or requirement to support the offload.

<...>

> @@ -2492,10 +2544,16 @@ hns3_recv_pkts_simple(void *rx_queue,
>  			goto pkt_err;
>  
>  		rxm->packet_type = hns3_rx_calc_ptype(rxq, l234_info, ol_info);
> -
>  		if (rxm->packet_type == RTE_PTYPE_L2_ETHER_TIMESYNC)
>  			rxm->ol_flags |= RTE_MBUF_F_RX_IEEE1588_PTP;
>  
> +		if (unlikely(rxq->crc_len > 0)) {
> +			if (hns3_need_recalculate_crc(rxq, rxm))
> +				hns3_recalculate_crc(rxq, rxm);
> +			rxm->pkt_len -= rxq->crc_len;
> +			rxm->data_len -= rxq->crc_len;
>

Removing 'crc_len' from 'mbuf->pkt_len' & 'mbuf->data_len' is
practically same as stripping CRC.

We don't count CRC length in the statistics, but it should be accessible
in the payload by the user.