From c9fe0f8fa4136c2451dcc012e48fbf4470d6b592 Mon Sep 17 00:00:00 2001
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: Sun, 29 Oct 2017 12:21:00 -0700
Subject: [PATCH] hyper-v: trace vmbus_on_msg_dpc()

Add tracing subsystem to Hyper-V VMBus module and add tracepoint
to vmbus_on_msg_dpc() which is called when we receive a message from host.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/hv/Makefile       |  4 +++-
 drivers/hv/hv_trace.c     |  4 ++++
 drivers/hv/hv_trace.h     | 29 +++++++++++++++++++++++++++++
 drivers/hv/hyperv_vmbus.h |  2 ++
 drivers/hv/vmbus_drv.c    |  2 ++
 5 files changed, 40 insertions(+), 1 deletion(-)
 create mode 100644 drivers/hv/hv_trace.c
 create mode 100644 drivers/hv/hv_trace.h

diff --git a/drivers/hv/Makefile b/drivers/hv/Makefile
index 39c9b2c08d33..ad791e00230f 100644
--- a/drivers/hv/Makefile
+++ b/drivers/hv/Makefile
@@ -2,7 +2,9 @@ obj-$(CONFIG_HYPERV)		+= hv_vmbus.o
 obj-$(CONFIG_HYPERV_UTILS)	+= hv_utils.o
 obj-$(CONFIG_HYPERV_BALLOON)	+= hv_balloon.o
 
+CFLAGS_hv_trace.o = -I$(src)
+
 hv_vmbus-y := vmbus_drv.o \
 		 hv.o connection.o channel.o \
-		 channel_mgmt.o ring_buffer.o
+		 channel_mgmt.o ring_buffer.o hv_trace.o
 hv_utils-y := hv_util.o hv_kvp.o hv_snapshot.o hv_fcopy.o hv_utils_transport.o
diff --git a/drivers/hv/hv_trace.c b/drivers/hv/hv_trace.c
new file mode 100644
index 000000000000..df47acd01a81
--- /dev/null
+++ b/drivers/hv/hv_trace.c
@@ -0,0 +1,4 @@
+#include "hyperv_vmbus.h"
+
+#define CREATE_TRACE_POINTS
+#include "hv_trace.h"
diff --git a/drivers/hv/hv_trace.h b/drivers/hv/hv_trace.h
new file mode 100644
index 000000000000..9c2772922c76
--- /dev/null
+++ b/drivers/hv/hv_trace.h
@@ -0,0 +1,29 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM hyperv
+
+#if !defined(_HV_TRACE_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _HV_TRACE_H
+
+#include <linux/tracepoint.h>
+
+DECLARE_EVENT_CLASS(vmbus_hdr_msg,
+	TP_PROTO(const struct vmbus_channel_message_header *hdr),
+	TP_ARGS(hdr),
+	TP_STRUCT__entry(__field(unsigned int, msgtype)),
+	TP_fast_assign(__entry->msgtype = hdr->msgtype;),
+	TP_printk("msgtype=%u", __entry->msgtype)
+);
+
+DEFINE_EVENT(vmbus_hdr_msg, vmbus_on_msg_dpc,
+	TP_PROTO(const struct vmbus_channel_message_header *hdr),
+	TP_ARGS(hdr)
+);
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE hv_trace
+#endif /* _HV_TRACE_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index de6f01df9592..22300ec7b556 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -31,6 +31,8 @@
 #include <linux/hyperv.h>
 #include <linux/interrupt.h>
 
+#include "hv_trace.h"
+
 /*
  * Timeout for services such as KVP and fcopy.
  */
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 8fe13cd76acf..8f9293a87c6b 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -835,6 +835,8 @@ void vmbus_on_msg_dpc(unsigned long data)
 
 	hdr = (struct vmbus_channel_message_header *)msg->u.payload;
 
+	trace_vmbus_on_msg_dpc(hdr);
+
 	if (hdr->msgtype >= CHANNELMSG_COUNT) {
 		WARN_ONCE(1, "unknown msgtype=%d\n", hdr->msgtype);
 		goto msg_handled;