tracing/events: Add trace_define_common_fields()

Extract duplicate code. Also prepare for the later patch.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A8BAFB8.1010304@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 25 insertions, 5 deletions

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index af8fb8ebef0b..9c7ecfb3416f 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -62,6 +62,28 @@ err:
 }
 EXPORT_SYMBOL_GPL(trace_define_field);
 
+#define __common_field(type, item)                                      \
+        ret = trace_define_field(call, #type, "common_" #item,          \
+                                 offsetof(typeof(ent), item),           \
+                                 sizeof(ent.item),                      \
+                                 is_signed_type(type));                 \
+        if (ret)                                                        \
+                return ret;
+
+int trace_define_common_fields(struct ftrace_event_call *call)
+{
+        int ret;
+        struct trace_entry ent;
+
+        __common_field(unsigned short, type);
+        __common_field(unsigned char, flags);
+        __common_field(unsigned char, preempt_count);
+        __common_field(int, pid);
+        __common_field(int, tgid);
+
+        return ret;
+}
+
 #ifdef CONFIG_MODULES
 
 static void trace_destroy_fields(struct ftrace_event_call *call)
diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c
index cf2c752a25bf..70875303ae46 100644
--- a/kernel/trace/trace_export.c
+++ b/kernel/trace/trace_export.c
@@ -189,11 +189,9 @@ ftrace_define_fields_##call(struct ftrace_event_call *event_call)	\
         struct args field;                                              \
         int ret;                                                        \
                                                                         \
-        __common_field(unsigned char, type, 0);                         \
-        __common_field(unsigned char, flags, 0);                        \
-        __common_field(unsigned char, preempt_count, 0);                \
-        __common_field(int, pid, 1);                                    \
-        __common_field(int, tgid, 1);                                   \
+        ret = trace_define_common_fields(event_call);                   \
+        if (ret)                                                        \
+                return ret;                                             \
                                                                         \
         tstruct;                                                        \
                                                                         \