[PATCH v3] app/testpmd: support specify TCs when DCB forward

[fengchengwen]

On 11/7/2025 3:24 AM, Stephen Hemminger wrote:
> On Thu, 6 Nov 2025 20:49:59 +0800
> Chengwen Feng <fengchengwen at huawei.com> wrote:
> 
>> +static void
>> +dcb_forward_tc_update_dcb_info(struct rte_eth_dcb_info *org_dcb_info)
>> +{
>> +	struct rte_eth_dcb_info dcb_info = {0};
>> +	uint32_t i, vmdq_idx;
>> +	uint32_t tc = 0;
>> +
>> +	if (dcb_fwd_tc_mask == DEFAULT_DCB_FWD_TC_MASK)
>> +		return;
>> +
>> +	/*
>> +	 * Use compress scheme to update dcb-info.
>> +	 * E.g. If org_dcb_info->nb_tcs is 4 and dcb_fwd_tc_mask is 0x8, it
>> +	 *      means only enable TC3, then the new dcb-info's nb_tcs is set to
>> +	 *      1, and also move corresponding tc_rxq and tc_txq info to new
>> +	 *      index.
>> +	 */
>> +	for (i = 0; i < org_dcb_info->nb_tcs; i++) {
>> +		if (!(dcb_fwd_tc_mask & (1u << i)))
>> +			continue;
>> +		for (vmdq_idx = 0; vmdq_idx < RTE_ETH_MAX_VMDQ_POOL; vmdq_idx++) {
>> +			dcb_info.tc_queue.tc_rxq[vmdq_idx][tc].base =
>> +				org_dcb_info->tc_queue.tc_rxq[vmdq_idx][i].base;
>> +			dcb_info.tc_queue.tc_rxq[vmdq_idx][tc].nb_queue =
>> +				org_dcb_info->tc_queue.tc_rxq[vmdq_idx][i].nb_queue;
>> +			dcb_info.tc_queue.tc_txq[vmdq_idx][tc].base =
>> +				org_dcb_info->tc_queue.tc_txq[vmdq_idx][i].base;
>> +			dcb_info.tc_queue.tc_txq[vmdq_idx][tc].nb_queue =
>> +				org_dcb_info->tc_queue.tc_txq[vmdq_idx][i].nb_queue;
>> +		}
>> +		tc++;
>> +	}
>> +	dcb_info.nb_tcs = tc;
>> +	memcpy(org_dcb_info, &dcb_info, sizeof(struct rte_eth_dcb_info));
> 
> Prefer direct structure assignment over memcpy() here.
> 	*org_dcb_info = dcb_info;
> 
> This makes sure types are the same, and compiler generates same code.

Thanks Stephen, the V4 already sent to fix it.