Re: [RFC net-next 1/8] pkt_cls: make tc_can_offload_extack() check chain index

[Jiri Pirko <jiri@resnulli.us>]

Tue, Jan 23, 2018 at 10:33:33PM CET, jakub.kicinski@netronome.com wrote:
>No upstream drivers seem to allow offload of chains other than 0.

mlxsw does. And I know that Intel was talking about adding the support
to i40e iirc.


>Save driver developers typing and make tc_can_offload_extack()
>check for that condition as well.  Rename the function to
>tc_can_offload_cls() to better represent its application.
>
>Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
>---

[...]


>--- a/include/net/pkt_cls.h
>+++ b/include/net/pkt_cls.h
>@@ -645,15 +645,21 @@ static inline bool tc_can_offload(const struct net_device *dev)
> 	return dev->features & NETIF_F_HW_TC;
> }
> 
>-static inline bool tc_can_offload_extack(const struct net_device *dev,
>-					 struct netlink_ext_ack *extack)
>+static inline bool tc_can_offload_cls(const struct net_device *dev,
>+				      struct tc_cls_common_offload *common)
> {
>-	bool can = tc_can_offload(dev);
>-
>-	if (!can)
>-		NL_SET_ERR_MSG(extack, "TC offload is disabled on net device");
>+	if (common->chain_index) {

This check here is wrong. It is up to the driver if it supports
multichain offload or not, should not be checked in a generic code along
with tc_can_offload.


>+		NL_SET_ERR_MSG(common->extack,
>+			       "Driver supports only offload of chain 0");
>+		return false;
>+	}
>+	if (!tc_can_offload(dev)) {
>+		NL_SET_ERR_MSG(common->extack,
>+			       "TC offload is disabled on net device");
>+		return false;
>+	}
> 
>-	return can;
>+	return true;
> }
> 
> static inline bool tc_skip_hw(u32 flags)
>-- 
>2.15.1
>