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

[Ori Kam]

Hi Jei,

> -----Original Message-----
> From: Jie Hai <haijie1 at huawei.com>
> Sent: Friday, October 27, 2023 12:28 PM
> 
> 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
> +	 * 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
> +	 * is unreliable even the operation returns success.
> +	 *
> +	 * 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.

In the original comment, it is stated that if no RSS key is given rss_key = NULL , then the PMD selects a random hash key,
Is this behavior changed?

> +	 */
> +	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 */
> --
> 2.30.0