trace: make the trace_event callbacks return enum print_line_t

As they actually all return these enumerators.

Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/trace_output.h b/kernel/trace/trace_output.h
index 3aeb31f..551a25a 100644
--- a/kernel/trace/trace_output.h
+++ b/kernel/trace/trace_output.h
@@ -3,7 +3,8 @@
 
 #include "trace.h"
 
-typedef int (*trace_print_func)(struct trace_iterator *iter, int flags);
+typedef enum print_line_t (*trace_print_func)(struct trace_iterator *iter,
+					      int flags);
 
 struct trace_event {
 	struct hlist_node	node;
@@ -39,7 +40,7 @@
 int register_ftrace_event(struct trace_event *event);
 int unregister_ftrace_event(struct trace_event *event);
 
-int trace_nop_print(struct trace_iterator *iter, int flags);
+enum print_line_t trace_nop_print(struct trace_iterator *iter, int flags);
 
 #define MAX_MEMHEX_BYTES	8
 #define HEX_CHARS		(MAX_MEMHEX_BYTES*2 + 1)