net: sched: fix tc_should_offload for specific clsact classes

When offloading classifiers such as u32 or flower to hardware, and the
qdisc is clsact (TC_H_CLSACT), then we need to differentiate its classes,
since not all of them handle ingress, therefore we must leave those in
software path. Add a .tcf_cl_offload() callback, so we can generically
handle them, tested on ixgbe.

Fixes: 10cbc68434 ("net/sched: cls_flower: Hardware offloaded filters statistics support")
Fixes: 5b33f48842 ("net/flower: Introduce hardware offload support")
Fixes: a1b7c5fd7f ("net: sched: add cls_u32 offload hooks for netdevs")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/pkt_cls.h

@@ -392,16 +392,20 @@ struct tc_cls_u32_offload {
 	};
 };
 
-static inline bool tc_should_offload(struct net_device *dev, u32 flags)
+static inline bool tc_should_offload(const struct net_device *dev,
+				     const struct tcf_proto *tp, u32 flags)
 {
+	const struct Qdisc *sch = tp->q;
+	const struct Qdisc_class_ops *cops = sch->ops->cl_ops;
+
 	if (!(dev->features & NETIF_F_HW_TC))
 		return false;
-
 	if (flags & TCA_CLS_FLAGS_SKIP_HW)
 		return false;
-
 	if (!dev->netdev_ops->ndo_setup_tc)
 		return false;
+	if (cops && cops->tcf_cl_offload)
+		return cops->tcf_cl_offload(tp->classid);
 
 	return true;
 }

include/net/sch_generic.h

@@ -168,6 +168,7 @@ struct Qdisc_class_ops {
 
 	/* Filter manipulation */
 	struct tcf_proto __rcu ** (*tcf_chain)(struct Qdisc *, unsigned long);
+	bool			(*tcf_cl_offload)(u32 classid);
 	unsigned long		(*bind_tcf)(struct Qdisc *, unsigned long,
 					u32 classid);
 	void			(*unbind_tcf)(struct Qdisc *, unsigned long);