Re: [dpdk-dev] [PATCH] ethdev: check for Rx RSS distribution and RSS hash

[Andrew Rybchenko <arybchenko@solarflare.com>]

On 4/27/20 3:34 PM, Lijun Ou wrote:
> When rte api checks the Rx RSS distribution is enable but the RSS
> hash is disabled, it will return an error.
>
> Signed-off-by: Lijun Ou <oulijun@huawei.com>
> ---
>  lib/librte_ethdev/rte_ethdev.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>
> diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
> index 0854ef8..07734c4 100644
> --- a/lib/librte_ethdev/rte_ethdev.c
> +++ b/lib/librte_ethdev/rte_ethdev.c
> @@ -1411,6 +1411,17 @@ rte_eth_dev_configure(uint16_t port_id, uint16_t nb_rx_q, uint16_t nb_tx_q,
>  		goto rollback;
>  	}
>  
> +	/* Check if Rx RSS distribution is enable but RSS hash is disabled. */
> +	if (((dev_conf->rxmode.mq_mode & ETH_MQ_RX_RSS_FLAG) != 0) &&
> +	    !(dev_conf->rxmode.offloads & DEV_RX_OFFLOAD_RSS_HASH)) {
> +		RTE_ETHDEV_LOG(ERR,
> +			"Ethdev port_id=%u config valid Rx mq_mode with RSS but %s offload is no-requested\n",
> +			port_id,
> +			rte_eth_dev_rx_offload_name(DEV_RX_OFFLOAD_RSS_HASH));
> +		ret = -EINVAL;
> +		goto rollback;
> +	}
> +
>  	/*
>  	 * Setup new number of RX/TX queues and reconfigure device.
>  	 */

NACK. It is perfectly fine to do distribution, but do not need RSS hash
information.
 - ETH_MQ_RX_RSS_FLAG controls RSS hash calculation and distribution
 - DEV_RX_OFFLOAD_RSS_HASH controls delivery of the hash value
   itself from HW to SW