net: sched: add an offload dump helper

Qdisc dump operation of offload-capable qdiscs performs a few
extra steps which are identical among all the qdiscs.  Add
a helper to share this code.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/sch_generic.h

@@ -579,6 +579,18 @@ void qdisc_put(struct Qdisc *qdisc);
 void qdisc_put_unlocked(struct Qdisc *qdisc);
 void qdisc_tree_reduce_backlog(struct Qdisc *qdisc, unsigned int n,
 			       unsigned int len);
+#ifdef CONFIG_NET_SCHED
+int qdisc_offload_dump_helper(struct Qdisc *q, enum tc_setup_type type,
+			      void *type_data);
+#else
+static inline int
+qdisc_offload_dump_helper(struct Qdisc *q, enum tc_setup_type type,
+			  void *type_data)
+{
+	q->flags &= ~TCQ_F_OFFLOADED;
+	return 0;
+}
+#endif
 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
 			  const struct Qdisc_ops *ops,
 			  struct netlink_ext_ack *extack);

net/sched/sch_api.c

@@ -810,6 +810,27 @@ void qdisc_tree_reduce_backlog(struct Qdisc *sch, unsigned int n,
 }
 EXPORT_SYMBOL(qdisc_tree_reduce_backlog);
 
+int qdisc_offload_dump_helper(struct Qdisc *sch, enum tc_setup_type type,
+			      void *type_data)
+{
+	struct net_device *dev = qdisc_dev(sch);
+	int err;
+
+	sch->flags &= ~TCQ_F_OFFLOADED;
+	if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
+		return 0;
+
+	err = dev->netdev_ops->ndo_setup_tc(dev, type, type_data);
+	if (err == -EOPNOTSUPP)
+		return 0;
+
+	if (!err)
+		sch->flags |= TCQ_F_OFFLOADED;
+
+	return err;
+}
+EXPORT_SYMBOL(qdisc_offload_dump_helper);
+
 static int tc_fill_qdisc(struct sk_buff *skb, struct Qdisc *q, u32 clid,
 			 u32 portid, u32 seq, u16 flags, int event)
 {

net/sched/sch_prio.c

@@ -251,7 +251,6 @@ static int prio_init(struct Qdisc *sch, struct nlattr *opt,
 
 static int prio_dump_offload(struct Qdisc *sch)
 {
-	struct net_device *dev = qdisc_dev(sch);
 	struct tc_prio_qopt_offload hw_stats = {
 		.command = TC_PRIO_STATS,
 		.handle = sch->handle,
@@ -263,21 +262,8 @@ static int prio_dump_offload(struct Qdisc *sch)
 			},
 		},
 	};
-	int err;
-
-	sch->flags &= ~TCQ_F_OFFLOADED;
-	if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
-		return 0;
 
-	err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_PRIO,
-					    &hw_stats);
-	if (err == -EOPNOTSUPP)
-		return 0;
-
-	if (!err)
-		sch->flags |= TCQ_F_OFFLOADED;
-
-	return err;
+	return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_PRIO, &hw_stats);
 }
 
 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)

net/sched/sch_red.c

@@ -281,7 +281,6 @@ static int red_init(struct Qdisc *sch, struct nlattr *opt,
 
 static int red_dump_offload_stats(struct Qdisc *sch, struct tc_red_qopt *opt)
 {
-	struct net_device *dev = qdisc_dev(sch);
 	struct tc_red_qopt_offload hw_stats = {
 		.command = TC_RED_STATS,
 		.handle = sch->handle,
@@ -291,22 +290,8 @@ static int red_dump_offload_stats(struct Qdisc *sch, struct tc_red_qopt *opt)
 			.stats.qstats = &sch->qstats,
 		},
 	};
-	int err;
-
-	sch->flags &= ~TCQ_F_OFFLOADED;
-
-	if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
-		return 0;
-
-	err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED,
-					    &hw_stats);
-	if (err == -EOPNOTSUPP)
-		return 0;
 
-	if (!err)
-		sch->flags |= TCQ_F_OFFLOADED;
-
-	return err;
+	return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_RED, &hw_stats);
 }
 
 static int red_dump(struct Qdisc *sch, struct sk_buff *skb)