From: Jakub Kicinski <jakub.kicinski@netronome.com>
Date: Thu, 25 Jan 2018 14:00:43 -0800
Subject: pkt_cls: add new tc cls helper to check offload flag and chain index
Patch-mainline: v4.16-rc1
Git-commit: 878db9f0f26df7674f6fc46f1c1c9390c99880ec
References: bsc#1109837

Very few (mlxsw) upstream drivers seem to allow offload of chains
other than 0.  Save driver developers typing and add a helper for
checking both if ethtool's TC offload flag is on and if chain is 0.
This helper will set the extack appropriately in both error cases.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 include/net/pkt_cls.h |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

--- a/include/net/pkt_cls.h
+++ b/include/net/pkt_cls.h
@@ -656,6 +656,20 @@ static inline bool tc_can_offload_extack
 	return can;
 }
 
+static inline bool
+tc_cls_can_offload_and_chain0(const struct net_device *dev,
+			      struct tc_cls_common_offload *common)
+{
+	if (!tc_can_offload_extack(dev, common->extack))
+		return false;
+	if (common->chain_index) {
+		NL_SET_ERR_MSG(common->extack,
+			       "Driver supports only offload of chain 0");
+		return false;
+	}
+	return true;
+}
+
 static inline bool tc_skip_hw(u32 flags)
 {
 	return (flags & TCA_CLS_FLAGS_SKIP_HW) ? true : false;