[PATCH v7 1/9] ethdev: overwrite some comment related to RSS

[lihuisong (C)]

在 2023/10/28 9:46, Jie Hai 写道:
> 1. overwrite the comments of fields of 'rte_eth_rss_conf'.
> 2. Add comments for RTE_ETH_HASH_FUNCTION_DEFAULT.
>
> Signed-off-by: Jie Hai <haijie1 at huawei.com>
> ---
>   lib/ethdev/rte_ethdev.h | 33 ++++++++++++++++++---------------
>   lib/ethdev/rte_flow.h   |  1 +
>   2 files changed, 19 insertions(+), 15 deletions(-)
>
> diff --git a/lib/ethdev/rte_ethdev.h b/lib/ethdev/rte_ethdev.h
> index 2fd3cd808dbf..37fd5afef48a 100644
> --- a/lib/ethdev/rte_ethdev.h
> +++ b/lib/ethdev/rte_ethdev.h
> @@ -448,24 +448,27 @@ struct rte_vlan_filter_conf {
>   /**
>    * A structure used to configure the Receive Side Scaling (RSS) feature
>    * of an Ethernet port.
> - * If not NULL, the *rss_key* pointer of the *rss_conf* structure points
> - * to an array holding the RSS key to use for hashing specific header
> - * fields of received packets. The length of this array should be indicated
> - * by *rss_key_len* below. Otherwise, a default random hash key is used by
> - * the device driver.
> - *
> - * The *rss_key_len* field of the *rss_conf* structure indicates the length
> - * in bytes of the array pointed by *rss_key*. To be compatible, this length
> - * will be checked in i40e only. Others assume 40 bytes to be used as before.
> - *
> - * The *rss_hf* field of the *rss_conf* structure indicates the different
> - * types of IPv4/IPv6 packets to which the RSS hashing must be applied.
> - * Supplying an *rss_hf* equal to zero disables the RSS feature.
>    */
>   struct rte_eth_rss_conf {
> -	uint8_t *rss_key;    /**< If not NULL, 40-byte hash key. */
> +	/**
> +	 * In rte_eth_dev_rss_hash_conf_get(), the *rss_key_len* should be
> +	 * greater than or equal to the hash_key_size which get from
Is this added the new comment?
Suggest that the "rss_key_len" field should be equal to the 
hash_key_size from dev_info_get().
Because many PMDs, like, hns3, i40e, ice and mlx5, check it in driver 
based on the condition that the rss_key_len field must be equal to the 
hash_key_size when the rss_key is not NULL.
IMO, it is better that this check should be added in ethdev layer.
> +	 * rte_eth_dev_info_get() API. And the *rss_key* should contain at least
> +	 * *rss_key_len* bytes. If not meet these requirements, the query result

here "rss_key_len" should be "hash_key_size", right?

> +	 * is unreliable even the operation returns success.
s/even/even if
> +	 *
> +	 * In rte_eth_dev_rss_hash_update() or rte_eth_dev_configure(), the
> +	 * *rss_key_len* indicates the length of the *rss_key* in bytes of
> +	 * the array pointed by *rss_key*. Drivers are free to ignore the
> +	 * *rss_key_len* and assume key length is 40 bytes.
please modify the comment: "Drivers are free to ignore the *rss_key_len* 
and assume key length is 40 bytes. "
Actually, most of PMDs, like, hns3, i40e, mlx, do not configure RSS hash 
key if rss_key is NULL and treat it as not updating the hash key.
> +	 */
> +	uint8_t *rss_key;
>   	uint8_t rss_key_len; /**< hash key length in bytes. */
> -	uint64_t rss_hf;     /**< Hash functions to apply - see below. */
> +	/**
> +	 * Indicates the type of packets or the specific part of packets to
> +	 * which RSS hashing is to be applied.
> +	 */
> +	uint64_t rss_hf;
>   };
>   
>   /*
> diff --git a/lib/ethdev/rte_flow.h b/lib/ethdev/rte_flow.h
> index edefa34c10da..25f1dffd1f30 100644
> --- a/lib/ethdev/rte_flow.h
> +++ b/lib/ethdev/rte_flow.h
> @@ -3226,6 +3226,7 @@ struct rte_flow_query_count {
>    * Hash function types.
>    */
>   enum rte_eth_hash_function {
> +	/** DEFAULT means driver decides which hash algorithm to pick. */
>   	RTE_ETH_HASH_FUNCTION_DEFAULT = 0,
>   	RTE_ETH_HASH_FUNCTION_TOEPLITZ, /**< Toeplitz */
>   	RTE_ETH_HASH_FUNCTION_SIMPLE_XOR, /**< Simple XOR */