devlink: add hardware messages tracing facility

Define a tracepoint and allow user to trace messages going to and from
hardware associated with devlink instance.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/trace/events/devlink.h

+#if IS_ENABLED(CONFIG_NET_DEVLINK)
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM devlink
+
+#if !defined(_TRACE_DEVLINK_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_DEVLINK_H
+
+#include <linux/device.h>
+#include <net/devlink.h>
+#include <linux/tracepoint.h>
+
+/*
+ * Tracepoint for devlink hardware message:
+ */
+TRACE_EVENT(devlink_hwmsg,
+	TP_PROTO(const struct devlink *devlink, bool incoming,
+		 unsigned long type, const u8 *buf, size_t len),
+
+	TP_ARGS(devlink, incoming, type, buf, len),
+
+	TP_STRUCT__entry(
+		__string(bus_name, devlink->dev->bus->name)
+		__string(dev_name, dev_name(devlink->dev))
+		__string(owner_name, devlink->dev->driver->owner->name)
+		__field(bool, incoming)
+		__field(unsigned long, type)
+		__dynamic_array(u8, buf, len)
+		__field(size_t, len)
+	),
+
+	TP_fast_assign(
+		__assign_str(bus_name, devlink->dev->bus->name);
+		__assign_str(dev_name, dev_name(devlink->dev));
+		__assign_str(owner_name, devlink->dev->driver->owner->name);
+		__entry->incoming = incoming;
+		__entry->type = type;
+		memcpy(__get_dynamic_array(buf), buf, len);
+		__entry->len = len;
+	),
+
+	TP_printk("bus_name=%s dev_name=%s owner_name=%s incoming=%d type=%lu buf=0x[%*phD] len=%lu",
+		  __get_str(bus_name), __get_str(dev_name),
+		  __get_str(owner_name), __entry->incoming, __entry->type,
+		  (int) __entry->len, __get_dynamic_array(buf), __entry->len)
+);
+
+#endif /* _TRACE_DEVLINK_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
+
+#else /* CONFIG_NET_DEVLINK */
+
+#if !defined(_TRACE_DEVLINK_H)
+#define _TRACE_DEVLINK_H
+
+#include <net/devlink.h>
+
+static inline void trace_devlink_hwmsg(const struct devlink *devlink,
+				       bool incoming, unsigned long type,
+				       const u8 *buf, size_t len)
+{
+}
+
+#endif /* _TRACE_DEVLINK_H */
+
+#endif

net/core/devlink.c

@@ -26,6 +26,10 @@
 #include <net/net_namespace.h>
 #include <net/sock.h>
 #include <net/devlink.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/devlink.h>
+
+EXPORT_TRACEPOINT_SYMBOL_GPL(devlink_hwmsg);
 
 static LIST_HEAD(devlink_list);