net: sched: Identify hardware traffic classes using classid

This patch offloads the classid to hardware and uses the classid
reserved in the range :ffe0 - :ffef to identify hardware traffic
classes reported via dev->num_tc.

tcf_result structure contains the class ID of the class to which
the packet belongs and is offloaded to hardware via flower filter.
A new helper function is introduced to represent HW traffic
classes 0 through 15 using the reserved classid values :ffe0 - :ffef.

Signed-off-by: Amritha Nambiar <amritha.nambiar@intel.com>
Acked-by: Shannon Nelson <shannon.nelson@oracle.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

include/net/pkt_cls.h

@@ -666,6 +666,7 @@ struct tc_cls_flower_offload {
 	struct fl_flow_key *mask;
 	struct fl_flow_key *key;
 	struct tcf_exts *exts;
+	u32 classid;
 };
 
 enum tc_matchall_command {

include/net/sch_generic.h

@@ -411,6 +411,13 @@ qdisc_class_find(const struct Qdisc_class_hash *hash, u32 id)
 	return NULL;
 }
 
+static inline int tc_classid_to_hwtc(struct net_device *dev, u32 classid)
+{
+	u32 hwtc = TC_H_MIN(classid) - TC_H_MIN_PRIORITY;
+
+	return (hwtc < netdev_get_num_tc(dev)) ? hwtc : -EINVAL;
+}
+
 int qdisc_class_hash_init(struct Qdisc_class_hash *);
 void qdisc_class_hash_insert(struct Qdisc_class_hash *,
 			     struct Qdisc_class_common *);

net/sched/cls_flower.c

@@ -241,6 +241,7 @@ static int fl_hw_replace_filter(struct tcf_proto *tp,
 	cls_flower.mask = mask;
 	cls_flower.key = &f->mkey;
 	cls_flower.exts = &f->exts;
+	cls_flower.classid = f->res.classid;
 
 	err = tc_setup_cb_call(block, &f->exts, TC_SETUP_CLSFLOWER,
 			       &cls_flower, skip_sw);
@@ -266,6 +267,7 @@ static void fl_hw_update_stats(struct tcf_proto *tp, struct cls_fl_filter *f)
 	cls_flower.command = TC_CLSFLOWER_STATS;
 	cls_flower.cookie = (unsigned long) f;
 	cls_flower.exts = &f->exts;
+	cls_flower.classid = f->res.classid;
 
 	tc_setup_cb_call(block, &f->exts, TC_SETUP_CLSFLOWER,
 			 &cls_flower, false);