tracing: Add ftrace event call parameter to its field descriptor handler

Add the struct ftrace_event_call as a parameter of its show_format()
callback. This way we can use it from the syscall trace events to
retrieve the syscall name from the ftrace event call parameter and
describe its fields using the syscalls metadata.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 1d289e2..b568ade 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -576,7 +576,7 @@
 	trace_seq_printf(s, "format:\n");
 	trace_write_header(s);
 
-	r = call->show_format(s);
+	r = call->show_format(call, s);
 	if (!r) {
 		/*
 		 * ug!  The format output is bigger than a PAGE!!
diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c
index d06cf89..956d4bc 100644
--- a/kernel/trace/trace_export.c
+++ b/kernel/trace/trace_export.c
@@ -60,7 +60,8 @@
 #undef TRACE_EVENT_FORMAT
 #define TRACE_EVENT_FORMAT(call, proto, args, fmt, tstruct, tpfmt)	\
 static int								\
-ftrace_format_##call(struct trace_seq *s)				\
+ftrace_format_##call(struct ftrace_event_call *unused,			\
+		      struct trace_seq *s)				\
 {									\
 	struct args field;						\
 	int ret;							\
@@ -76,7 +77,8 @@
 #define TRACE_EVENT_FORMAT_NOFILTER(call, proto, args, fmt, tstruct,	\
 				    tpfmt)				\
 static int								\
-ftrace_format_##call(struct trace_seq *s)				\
+ftrace_format_##call(struct ftrace_event_call *unused,			\
+		      struct trace_seq *s)				\
 {									\
 	struct args field;						\
 	int ret;							\