Re: [RFC PATCH net-next 0/3] flow_offload: Re-add various features that disappeared

[Jiri Pirko <jiri@resnulli.us>]

Fri, May 03, 2019 at 04:59:28PM CEST, ecree@solarflare.com wrote:
>When the flow_offload infrastructure was added, a couple of things that
> were previously possible for drivers to support in TC offload were not
> plumbed through, perhaps because the drivers in the tree did not fully
> or correctly implement them.
>The main issue was with statistics; in TC (and in the previous offload
> API) statistics are per-action, though generally only on 'delivery'
> actions like mirred, ok and shot.  Actions also have an index, which
> may be supplied by the user, which allows the sharing of entities such
> as counters between multiple rules.  The existing driver implementations
> did not support this, however, instead allocating a single counter per
> rule.  The flow_offload API did not support this either, as (a) the
> action index never reached the driver, and (b) the TC_CLSFLOWER_STATS
> callback was only able to return a single set of stats which were added
> to all counters for actions on the rule.  Patch #1 of this series fixes
> (a) by storing tcfa_index in a new action_index member of struct
> flow_action_entry, while patch #2 fixes (b) by adding a new callback,
> TC_CLSFLOWER_STATS_BYINDEX, which retrieves statistics for a specified
> action_index rather than by rule (although the rule cookie is still   
> passed as well).
>Patch #3 adds flow_rule_match_cvlan(), analogous to
> flow_rule_match_vlan() but accessing FLOW_DISSECTOR_KEY_CVLAN instead
> of FLOW_DISSECTOR_KEY_VLAN, to allow offloading inner VLAN matches.
>This patch series does not include any users of these new interfaces;   
> the driver in which I hope to use them does not yet exist upstream as  
> it is for hardware which is still under development.  However I've CCed
> developers of various other drivers that implement TC offload, in case
> any of them want to implement support.  Otherwise I imagine that David
> won't be willing to take this without a user, in which case I'll save
> it to submit alongside the aforementioned unfinished driver (hence the
> RFC tags for now).

We need in-tree users of the API.


>
>Edward Cree (3):
>  flow_offload: copy tcfa_index into flow_action_entry
>  flow_offload: restore ability to collect separate stats per action
>  flow_offload: support CVLAN match
>
> include/net/flow_offload.h |  3 +++
> include/net/pkt_cls.h      |  2 ++
> net/core/flow_offload.c    |  7 +++++++
> net/sched/cls_api.c        |  1 +
> net/sched/cls_flower.c     | 30 ++++++++++++++++++++++++++++++
> 5 files changed, 43 insertions(+)