Re: [PATCH net,v2] net: flow_offload: skip hw stats check for FLOW_ACTION_HW_STATS_DONT_CARE

[Pablo Neira Ayuso <pablo@netfilter.org>]

On Tue, May 05, 2020 at 11:46:16AM -0700, Jakub Kicinski wrote:
> On Tue, 5 May 2020 20:36:43 +0200 Jiri Pirko wrote:
> > Tue, May 05, 2020 at 07:47:36PM CEST, pablo@netfilter.org wrote:
> > >This patch adds FLOW_ACTION_HW_STATS_DONT_CARE which tells the driver
> > >that the frontend does not need counters, this hw stats type request
> > >never fails. The FLOW_ACTION_HW_STATS_DISABLED type explicitly requests
> > >the driver to disable the stats, however, if the driver cannot disable
> > >counters, it bails out.
> > >
> > >TCA_ACT_HW_STATS_* maintains the 1:1 mapping with FLOW_ACTION_HW_STATS_*
> > >except by disabled which is mapped to FLOW_ACTION_HW_STATS_DISABLED
> > >(this is 0 in tc). Add tc_act_hw_stats() to perform the mapping between
> > >TCA_ACT_HW_STATS_* and FLOW_ACTION_HW_STATS_*.
> > >
> > >Fixes: 319a1d19471e ("flow_offload: check for basic action hw stats type")
> > >Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>  
> > 
> > Looks great. Thanks!
> > 
> > Reviewed-by: Jiri Pirko <jiri@mellanox.com>
> 
> Is this going to "just work" for mlxsw?
> 
>         act = flow_action_first_entry_get(flow_action);                         
>         if (act->hw_stats == FLOW_ACTION_HW_STATS_ANY ||                        
>             act->hw_stats == FLOW_ACTION_HW_STATS_IMMEDIATE) {                  
>                 /* Count action is inserted first */                            
>                 err = mlxsw_sp_acl_rulei_act_count(mlxsw_sp, rulei, extack);    
>                 if (err)                                                        
>                         return err;                                             
>         } else if (act->hw_stats != FLOW_ACTION_HW_STATS_DISABLED) {            
>                 NL_SET_ERR_MSG_MOD(extack, "Unsupported action HW stats type"); 
>                 return -EOPNOTSUPP;                                             
>         }
> 
> if hw_stats is 0 we'll get into the else and bail.
> 
> That doesn't deliver on the "don't care" promise, no?

I can send a v3 to handle the _DONT_CARE type from the mlxsw.

Thank you.