[PATCH net-next 5/5] net: switchdev: Add tracepoints

[Tobias Waldekranz <tobias@xxxxxxxxxxxxxx>]

Add a basic set of tracepoints:

- switchdev_defer: Triggers whenever an operation is enqueued to the
  switchdev workqueue.

- switchdev_call_atomic/switchdev_call_blocking: Triggers whenever a
  notification is sent on the corresponding notifier block.

- switchdev_call_replay: Triggers whenever a notification is sent back
  to a driver's own notifier block, in response to a replay request.

Signed-off-by: Tobias Waldekranz <tobias@xxxxxxxxxxxxxx>
---
 include/trace/events/switchdev.h | 89 ++++++++++++++++++++++++++++++++
 net/switchdev/switchdev.c        | 24 +++++++--
 2 files changed, 109 insertions(+), 4 deletions(-)
 create mode 100644 include/trace/events/switchdev.h

diff --git a/include/trace/events/switchdev.h b/include/trace/events/switchdev.h
new file mode 100644
index 000000000000..b587965da2f6
--- /dev/null
+++ b/include/trace/events/switchdev.h
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM	switchdev
+
+#if !defined(_TRACE_SWITCHDEV_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_SWITCHDEV_H
+
+#include <linux/tracepoint.h>
+#include <net/switchdev.h>
+
+#define SWITCHDEV_TRACE_MSG_MAX 128
+
+TRACE_EVENT(switchdev_defer,
+	TP_PROTO(unsigned long val,
+		 const struct switchdev_notifier_info *info),
+
+	TP_ARGS(val, info),
+
+	TP_STRUCT__entry(
+		__field(unsigned long, val)
+		__string(dev, info->dev ? netdev_name(info->dev) : "(null)")
+		__field(const struct switchdev_notifier_info *, info)
+		__array(char, msg, SWITCHDEV_TRACE_MSG_MAX)
+	),
+
+	TP_fast_assign(
+		__entry->val = val;
+		__assign_str(dev, info->dev ? netdev_name(info->dev) : "(null)");
+		__entry->info = info;
+		switchdev_notifier_str(val, info, __entry->msg, SWITCHDEV_TRACE_MSG_MAX);
+	),
+
+	TP_printk("dev %s %s", __get_str(dev), __entry->msg)
+);
+
+DECLARE_EVENT_CLASS(switchdev_call,
+	TP_PROTO(unsigned long val,
+		 const struct switchdev_notifier_info *info,
+		 int err),
+
+	TP_ARGS(val, info, err),
+
+	TP_STRUCT__entry(
+		__field(unsigned long, val)
+		__string(dev, info->dev ? netdev_name(info->dev) : "(null)")
+		__field(const struct switchdev_notifier_info *, info)
+		__field(int, err)
+		__array(char, msg, SWITCHDEV_TRACE_MSG_MAX)
+	),
+
+	TP_fast_assign(
+		__entry->val = val;
+		__assign_str(dev, info->dev ? netdev_name(info->dev) : "(null)");
+		__entry->info = info;
+		__entry->err = err;
+		switchdev_notifier_str(val, info, __entry->msg, SWITCHDEV_TRACE_MSG_MAX);
+	),
+
+	TP_printk("dev %s %s -> %d", __get_str(dev), __entry->msg, __entry->err)
+);
+
+DEFINE_EVENT(switchdev_call, switchdev_call_atomic,
+	TP_PROTO(unsigned long val,
+		 const struct switchdev_notifier_info *info,
+		 int err),
+
+	TP_ARGS(val, info, err)
+);
+
+DEFINE_EVENT(switchdev_call, switchdev_call_blocking,
+	TP_PROTO(unsigned long val,
+		 const struct switchdev_notifier_info *info,
+		 int err),
+
+	TP_ARGS(val, info, err)
+);
+
+DEFINE_EVENT(switchdev_call, switchdev_call_replay,
+	TP_PROTO(unsigned long val,
+		 const struct switchdev_notifier_info *info,
+		 int err),
+
+	TP_ARGS(val, info, err)
+);
+
+#endif /* _TRACE_SWITCHDEV_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c
index 6612f8bc79c9..dfd9cf75f397 100644
--- a/net/switchdev/switchdev.c
+++ b/net/switchdev/switchdev.c
@@ -19,6 +19,9 @@
 #include <linux/rtnetlink.h>
 #include <net/switchdev.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/switchdev.h>
+
 static LIST_HEAD(deferred);
 static DEFINE_SPINLOCK(deferred_lock);
 
@@ -171,6 +174,7 @@ static int switchdev_deferred_enqueue(struct switchdev_deferred_item *dfitem)
 	spin_lock_bh(&deferred_lock);
 	list_add_tail(&dfitem->list, &deferred);
 	spin_unlock_bh(&deferred_lock);
+	trace_switchdev_defer(dfitem->nt, &dfitem->info);
 	schedule_work(&deferred_process_work);
 	return 0;
 }
@@ -325,7 +329,11 @@ EXPORT_SYMBOL_GPL(switchdev_port_obj_del);
 int switchdev_call_replay(struct notifier_block *nb, unsigned long type,
 			  struct switchdev_notifier_info *info)
 {
-	return nb->notifier_call(nb, type, info);
+	int ret;
+
+	ret = nb->notifier_call(nb, type, info);
+	trace_switchdev_call_replay(type, info, notifier_to_errno(ret));
+	return ret;
 }
 EXPORT_SYMBOL_GPL(switchdev_call_replay);
 
@@ -368,9 +376,13 @@ int call_switchdev_notifiers(unsigned long val, struct net_device *dev,
 			     struct switchdev_notifier_info *info,
 			     struct netlink_ext_ack *extack)
 {
+	int ret;
+
 	info->dev = dev;
 	info->extack = extack;
-	return atomic_notifier_call_chain(&switchdev_notif_chain, val, info);
+	ret = atomic_notifier_call_chain(&switchdev_notif_chain, val, info);
+	trace_switchdev_call_atomic(val, info, notifier_to_errno(ret));
+	return ret;
 }
 EXPORT_SYMBOL_GPL(call_switchdev_notifiers);
 
@@ -394,10 +406,14 @@ int call_switchdev_blocking_notifiers(unsigned long val, struct net_device *dev,
 				      struct switchdev_notifier_info *info,
 				      struct netlink_ext_ack *extack)
 {
+	int ret;
+
 	info->dev = dev;
 	info->extack = extack;
-	return blocking_notifier_call_chain(&switchdev_blocking_notif_chain,
-					    val, info);
+	ret = blocking_notifier_call_chain(&switchdev_blocking_notif_chain,
+					   val, info);
+	trace_switchdev_call_blocking(val, info, notifier_to_errno(ret));
+	return ret;
 }
 EXPORT_SYMBOL_GPL(call_switchdev_blocking_notifiers);
 
-- 
2.34.1