net: dsa: add trace points for VLAN operations

These are not as critical as the FDB/MDB trace points (I'm not aware of
outstanding VLAN related bugs), but maybe they are useful to somebody,
either debugging something or simply trying to learn more.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dsa/switch.c

@@ -695,8 +695,12 @@ static int dsa_port_do_vlan_add(struct dsa_port *dp,
 	int err = 0;
 
 	/* No need to bother with refcounting for user ports. */
-	if (!(dsa_port_is_cpu(dp) || dsa_port_is_dsa(dp)))
-		return ds->ops->port_vlan_add(ds, port, vlan, extack);
+	if (!(dsa_port_is_cpu(dp) || dsa_port_is_dsa(dp))) {
+		err = ds->ops->port_vlan_add(ds, port, vlan, extack);
+		trace_dsa_vlan_add_hw(dp, vlan, err);
+
+		return err;
+	}
 
 	/* No need to propagate on shared ports the existing VLANs that were
 	 * re-notified after just the flags have changed. This would cause a
@@ -711,6 +715,7 @@ static int dsa_port_do_vlan_add(struct dsa_port *dp,
 	v = dsa_vlan_find(&dp->vlans, vlan);
 	if (v) {
 		refcount_inc(&v->refcount);
+		trace_dsa_vlan_add_bump(dp, vlan, &v->refcount);
 		goto out;
 	}
 
@@ -721,6 +726,7 @@ static int dsa_port_do_vlan_add(struct dsa_port *dp,
 	}
 
 	err = ds->ops->port_vlan_add(ds, port, vlan, extack);
+	trace_dsa_vlan_add_hw(dp, vlan, err);
 	if (err) {
 		kfree(v);
 		goto out;
@@ -745,21 +751,29 @@ static int dsa_port_do_vlan_del(struct dsa_port *dp,
 	int err = 0;
 
 	/* No need to bother with refcounting for user ports */
-	if (!(dsa_port_is_cpu(dp) || dsa_port_is_dsa(dp)))
-		return ds->ops->port_vlan_del(ds, port, vlan);
+	if (!(dsa_port_is_cpu(dp) || dsa_port_is_dsa(dp))) {
+		err = ds->ops->port_vlan_del(ds, port, vlan);
+		trace_dsa_vlan_del_hw(dp, vlan, err);
+
+		return err;
+	}
 
 	mutex_lock(&dp->vlans_lock);
 
 	v = dsa_vlan_find(&dp->vlans, vlan);
 	if (!v) {
+		trace_dsa_vlan_del_not_found(dp, vlan);
 		err = -ENOENT;
 		goto out;
 	}
 
-	if (!refcount_dec_and_test(&v->refcount))
+	if (!refcount_dec_and_test(&v->refcount)) {
+		trace_dsa_vlan_del_drop(dp, vlan, &v->refcount);
 		goto out;
+	}
 
 	err = ds->ops->port_vlan_del(ds, port, vlan);
+	trace_dsa_vlan_del_hw(dp, vlan, err);
 	if (err) {
 		refcount_set(&v->refcount, 1);
 		goto out;

net/dsa/trace.h

@@ -9,7 +9,9 @@
 #define _NET_DSA_TRACE_H
 
 #include <net/dsa.h>
+#include <net/switchdev.h>
 #include <linux/etherdevice.h>
+#include <linux/if_bridge.h>
 #include <linux/refcount.h>
 #include <linux/tracepoint.h>
 
@@ -318,6 +320,122 @@ TRACE_EVENT(dsa_lag_fdb_del_not_found,
 		  __get_str(dev), __entry->addr, __entry->vid, __entry->db_buf)
 );
 
+DECLARE_EVENT_CLASS(dsa_vlan_op_hw,
+
+	TP_PROTO(const struct dsa_port *dp,
+		 const struct switchdev_obj_port_vlan *vlan, int err),
+
+	TP_ARGS(dp, vlan, err),
+
+	TP_STRUCT__entry(
+		__string(dev, dev_name(dp->ds->dev))
+		__string(kind, dsa_port_kind(dp))
+		__field(int, port)
+		__field(u16, vid)
+		__field(u16, flags)
+		__field(bool, changed)
+		__field(int, err)
+	),
+
+	TP_fast_assign(
+		__assign_str(dev, dev_name(dp->ds->dev));
+		__assign_str(kind, dsa_port_kind(dp));
+		__entry->port = dp->index;
+		__entry->vid = vlan->vid;
+		__entry->flags = vlan->flags;
+		__entry->changed = vlan->changed;
+		__entry->err = err;
+	),
+
+	TP_printk("%s %s port %d vid %u%s%s%s",
+		  __get_str(dev), __get_str(kind), __entry->port, __entry->vid,
+		  __entry->flags & BRIDGE_VLAN_INFO_PVID ? " pvid" : "",
+		  __entry->flags & BRIDGE_VLAN_INFO_UNTAGGED ? " untagged" : "",
+		  __entry->changed ? " (changed)" : "")
+);
+
+DEFINE_EVENT(dsa_vlan_op_hw, dsa_vlan_add_hw,
+	     TP_PROTO(const struct dsa_port *dp,
+		      const struct switchdev_obj_port_vlan *vlan, int err),
+	     TP_ARGS(dp, vlan, err));
+
+DEFINE_EVENT(dsa_vlan_op_hw, dsa_vlan_del_hw,
+	     TP_PROTO(const struct dsa_port *dp,
+		      const struct switchdev_obj_port_vlan *vlan, int err),
+	     TP_ARGS(dp, vlan, err));
+
+DECLARE_EVENT_CLASS(dsa_vlan_op_refcount,
+
+	TP_PROTO(const struct dsa_port *dp,
+		 const struct switchdev_obj_port_vlan *vlan,
+		 const refcount_t *refcount),
+
+	TP_ARGS(dp, vlan, refcount),
+
+	TP_STRUCT__entry(
+		__string(dev, dev_name(dp->ds->dev))
+		__string(kind, dsa_port_kind(dp))
+		__field(int, port)
+		__field(u16, vid)
+		__field(u16, flags)
+		__field(bool, changed)
+		__field(unsigned int, refcount)
+	),
+
+	TP_fast_assign(
+		__assign_str(dev, dev_name(dp->ds->dev));
+		__assign_str(kind, dsa_port_kind(dp));
+		__entry->port = dp->index;
+		__entry->vid = vlan->vid;
+		__entry->flags = vlan->flags;
+		__entry->changed = vlan->changed;
+		__entry->refcount = refcount_read(refcount);
+	),
+
+	TP_printk("%s %s port %d vid %u%s%s%s refcount %u",
+		  __get_str(dev), __get_str(kind), __entry->port, __entry->vid,
+		  __entry->flags & BRIDGE_VLAN_INFO_PVID ? " pvid" : "",
+		  __entry->flags & BRIDGE_VLAN_INFO_UNTAGGED ? " untagged" : "",
+		  __entry->changed ? " (changed)" : "", __entry->refcount)
+);
+
+DEFINE_EVENT(dsa_vlan_op_refcount, dsa_vlan_add_bump,
+	     TP_PROTO(const struct dsa_port *dp,
+		      const struct switchdev_obj_port_vlan *vlan,
+		      const refcount_t *refcount),
+	     TP_ARGS(dp, vlan, refcount));
+
+DEFINE_EVENT(dsa_vlan_op_refcount, dsa_vlan_del_drop,
+	     TP_PROTO(const struct dsa_port *dp,
+		      const struct switchdev_obj_port_vlan *vlan,
+		      const refcount_t *refcount),
+	     TP_ARGS(dp, vlan, refcount));
+
+TRACE_EVENT(dsa_vlan_del_not_found,
+
+	TP_PROTO(const struct dsa_port *dp,
+		 const struct switchdev_obj_port_vlan *vlan),
+
+	TP_ARGS(dp, vlan),
+
+	TP_STRUCT__entry(
+		__string(dev, dev_name(dp->ds->dev))
+		__string(kind, dsa_port_kind(dp))
+		__field(int, port)
+		__field(u16, vid)
+	),
+
+	TP_fast_assign(
+		__assign_str(dev, dev_name(dp->ds->dev));
+		__assign_str(kind, dsa_port_kind(dp));
+		__entry->port = dp->index;
+		__entry->vid = vlan->vid;
+	),
+
+	TP_printk("%s %s port %d vid %u",
+		  __get_str(dev), __get_str(kind), __entry->port, __entry->vid)
+);
+
 #endif /* _NET_DSA_TRACE_H */
 
 /* We don't want to use include/trace/events */