hyper-v: trace vmbus_on_message()

Add tracepoint to vmbus_on_message() which is called when we start
processing a blocking from work context.

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/channel_mgmt.c

@@ -1176,6 +1176,8 @@ void vmbus_onmessage(void *context)
 	hdr = (struct vmbus_channel_message_header *)msg->u.payload;
 	size = msg->header.payload_size;
 
+	trace_vmbus_on_message(hdr);
+
 	if (hdr->msgtype >= CHANNELMSG_COUNT) {
 		pr_err("Received invalid channel message type %d size %d\n",
 			   hdr->msgtype, size);

drivers/hv/hv_trace.h

@@ -19,6 +19,11 @@ DEFINE_EVENT(vmbus_hdr_msg, vmbus_on_msg_dpc,
 	TP_ARGS(hdr)
 );
 
+DEFINE_EVENT(vmbus_hdr_msg, vmbus_on_message,
+	TP_PROTO(const struct vmbus_channel_message_header *hdr),
+	TP_ARGS(hdr)
+);
+
 #undef TRACE_INCLUDE_PATH
 #define TRACE_INCLUDE_PATH .
 #undef TRACE_INCLUDE_FILE