Re: [PATCH net] net: flow_offload: skip hw stats check for FLOW_ACTION_HW_STATS_DISABLED

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

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On Mon, Apr 20, 2020 at 04:14:22PM +0200, Jiri Pirko wrote:
> Mon, Apr 20, 2020 at 03:57:54PM CEST, fw@strlen.de wrote:
[...]
> >I mean, the user is forced to use SW datapath just because HW can't turn
> >off stats?!  Same for a config change, why do i need to change my rules
> 
> By default, they are on. That is what user should do in most of the
> cases.

Fair enough, I can workaround this problem by using
FLOW_ACTION_HW_STATS_ANY. However, I still don't need counters and
there is no way to say "I don't care" to the drivers.

Note that the flow_offload infrastructure is used by ethtool,
netfilter, flowtable and tc these days.

* ethtool's default behaviour is no counters.
* netfilter's default behaviour is no counters.
* flowtable's default behaviour is no counters.


I understand FLOW_ACTION_HW_STATS_DISABLED means disabled, strictly.
But would you allow me to introduce FLOW_ACTION_HW_STATS_DONT_CARE to
fix ethtool, netfilter and flowtable? :-)

FLOW_ACTION_HW_STATS_DONT_CARE means "this front-end doesn't need
counters, let driver decide what it is best".

Thank you.

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diff --git a/include/net/flow_offload.h b/include/net/flow_offload.h
index 3619c6acf60f..ae09d1911912 100644
--- a/include/net/flow_offload.h
+++ b/include/net/flow_offload.h
@@ -164,17 +164,21 @@ enum flow_action_mangle_base {
 };
 
 enum flow_action_hw_stats_bit {
+	FLOW_ACTION_HW_STATS_DONT_CARE_BIT,
 	FLOW_ACTION_HW_STATS_IMMEDIATE_BIT,
 	FLOW_ACTION_HW_STATS_DELAYED_BIT,
 };
 
 enum flow_action_hw_stats {
 	FLOW_ACTION_HW_STATS_DISABLED = 0,
+	FLOW_ACTION_HW_STATS_DONT_CARE =
+		BIT(FLOW_ACTION_HW_STATS_DONT_CARE_BIT),
 	FLOW_ACTION_HW_STATS_IMMEDIATE =
 		BIT(FLOW_ACTION_HW_STATS_IMMEDIATE_BIT),
 	FLOW_ACTION_HW_STATS_DELAYED = BIT(FLOW_ACTION_HW_STATS_DELAYED_BIT),
 	FLOW_ACTION_HW_STATS_ANY = FLOW_ACTION_HW_STATS_IMMEDIATE |
-				   FLOW_ACTION_HW_STATS_DELAYED,
+				   FLOW_ACTION_HW_STATS_DELAYED |
+				   FLOW_ACTION_HW_STATS_DONT_CARE,
 };
 
 typedef void (*action_destr)(void *priv);