[dpdk-dev] [PATCH v2 1/4] ethdev: introduce indirect action APIs

[Andrew Rybchenko]

On 4/10/21 5:03 PM, Bing Zhao wrote:
> Right now, rte_flow_shared_action_* APIs are used for some shared
> actions, like RSS, count. The shared action should be created before
> using it inside a flow. These shared actions sometimes are not
> really shared but just some indirect actions decoupled from a flow.
>
> The new functions rte_flow_action_handle_* are added to replace
> the current shared functions rte_flow_shared_action_*.
>
> There are two types of flow actions:
> 1. the direct (normal) actions that could be created and stored
>    within a flow rule. Such action is tied to its flow rule and
>    cannot be reused.
> 2. the indirect action, in the past, named shared_action. It is
>    created from a direct actioni, like count or rss, and then used
>    in the flow rules with an object handle. The PMD will take care
>    of the retrieve from indirect action to the direct action
>    when it is referenced.
>
> The indirect action is accessed (update / query) w/o any flow rule,
> just via the action object handle. For example, when querying or
> resetting a counter, it could be done out of any flow using this
> counter, but only the handle of the counter action object is
> required.
> The indirect action object could be shared by different flows or
> used by a single flow, depending on the direct action type and
> the real-life requirements.
> The handle of an indirect action object is opaque and defined in
> each driver and possibly different per direct action type.
>
> The old name "shared" is improper in a sense and should be replaced.
>
> All the command lines in testpmd application with "shared_action*"
> are replaced with "indirect_action*".
>
> The parameter of "update" interface is also changed. A general
> pointer will replace the rte_flow_action struct pointer due to the
> facts:
> 1. Some action may not support fields updating. In the example of a
>    counter, the only "update" supported should be the reset. So
>    passing a rte_flow_action struct pointer is meaningless and
>    there is even no such corresponding action struct. What's more,
>    if more than one operations should be supported, for some other
>    action, such pointer parameter may not meet the need.
> 2. Some action may need conditional or partial update, the current
>    parameter will not provide the ability to indicate which part(s)
>    to update.
>    For different types of indirect action objects, the pointer could
>    either be the same of rte_flow_action* struct - in order not to
>    break the current driver implementation, or some wrapper
>    structures with bits as masks to indicate which part to be
>    updated, depending on real needs of the corresponding direct
>    action. For different direct actions, the structures of indirect
>    action objects updating will be different.
>
> All the underlayer PMD callbacks will be moved to these new APIs.
>
> The RTE_FLOW_ACTION_TYPE_SHARED is kept for now in order not to
> break the ABI. All the implementations are changed by using
> RTE_FLOW_ACTION_TYPE_INDIRECT.
>
> Signed-off-by: Bing Zhao <bingz at nvidia.com>

Just for the record. I still dislike renaming since "shared" highlights
purpose (what is definitely better), but "indirect" is just a technical
detail on how it is done.