[dpdk-dev] [PATCH] ethdev: remove deprecated shared counter attribute

[Stephen Hemminger]

On Tue, 28 Sep 2021 18:23:00 +0300
Andrew Rybchenko <andrew.rybchenko at oktetlabs.ru> wrote:

> @@ -2498,24 +2498,11 @@ struct rte_flow_query_age {
>   * Counters can be retrieved and reset through ``rte_flow_query()``, see
>   * ``struct rte_flow_query_count``.
>   *
> - * @deprecated Shared attribute is deprecated, use generic
> - * RTE_FLOW_ACTION_TYPE_INDIRECT action.
> - *
> - * The shared flag indicates whether the counter is unique to the flow rule the
> - * action is specified with, or whether it is a shared counter.
> - *
> - * For a count action with the shared flag set, then then a global device
> - * namespace is assumed for the counter id, so that any matched flow rules using
> - * a count action with the same counter id on the same port will contribute to
> - * that counter.
> - *
>   * For ports within the same switch domain then the counter id namespace extends
>   * to all ports within that switch domain.
>   */
>  struct rte_flow_action_count {
> -	/** @deprecated Share counter ID with other flow rules. */
> -	uint32_t shared:1;
> -	uint32_t reserved:31; /**< Reserved, must be zero. */
> +	uint32_t reserved; /**< Reserved, must be zero. */
>  	uint32_t id; /**< Counter ID. */

Reserved fields are often source of future problems.
You should change each driver to check that reserved field
return -ENOTSUP if non-zero.  That way if reserved field is ever
used in future it won't break API/ABI.

The other option is to just remove the reserved field and take the API/ABI
hit now.