greybus: greybus_trace: Fix broken greybus ftrace

Enabling greybus ftrace event causes null pointer access due to
that gb_message to SVC has no Bundle. Fix it by handling this in
the trace header.

Testing Done:
$ echo 1 > /d/tracing/event/greybus/enable
 [002] ...1    54.504426: gb_message_send: greybus:1-svc op=0023 if_id=0 hd_id=0 l=0
 [002] ...1    54.504461: gb_host_device_send: greybus:greybus1 if_id=0 l=8

Signed-off-by: David Lin <dtwlin@google.com>
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

diff --git a/drivers/staging/greybus/greybus_trace.h b/drivers/staging/greybus/greybus_trace.h
index 96c5151..6f3e101 100644 (file)
--- a/drivers/staging/greybus/greybus_trace.h
+++ b/drivers/staging/greybus/greybus_trace.h
@@ -17,6 +17,11 @@
 struct gb_message;
 struct gb_host_device;
 
+#define gb_bundle_name(message)                                  \
+       (message->operation->connection->bundle ?                 \
+       dev_name(&message->operation->connection->bundle->dev) :  \
+       dev_name(&message->operation->connection->hd->svc->dev))
+
 DECLARE_EVENT_CLASS(gb_message,
 
        TP_PROTO(struct gb_message *message),
@@ -24,7 +29,7 @@ DECLARE_EVENT_CLASS(gb_message,
        TP_ARGS(message),
 
        TP_STRUCT__entry(
-               __string(name, dev_name(&message->operation->connection->bundle->dev))
+               __string(name, gb_bundle_name(message))
                __field(u16, op_id)
                __field(u16, intf_cport_id)
                __field(u16, hd_cport_id)
@@ -32,7 +37,7 @@ DECLARE_EVENT_CLASS(gb_message,
        ),
 
        TP_fast_assign(
-               __assign_str(name, dev_name(&message->operation->connection->bundle->dev))
+               __assign_str(name, gb_bundle_name(message))
                __entry->op_id = message->operation->id;
                __entry->intf_cport_id =
                        message->operation->connection->intf_cport_id;