tracing/filters: Add __field_ext() to TRACE_EVENT

Add __field_ext(), so a field can be assigned to a specific
filter_type, which matches a corresponding filter function.

For example, a later patch will allow this:
	__field_ext(const char *, str, FILTER_PTR_STR);

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4A7B9272.6050709@cn.fujitsu.com>

[
  Fixed a -1 to FILTER_OTHER
  Forward ported to latest kernel.
]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 46c1b977a..97a2454 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -194,7 +194,8 @@
 	for (i = 0; i < meta->nb_args; i++) {
 		ret = trace_define_field(call, meta->types[i],
 					 meta->args[i], offset,
-					 sizeof(unsigned long), 0);
+					 sizeof(unsigned long), 0,
+					 FILTER_OTHER);
 		offset += sizeof(unsigned long);
 	}
 
@@ -210,7 +211,8 @@
 	if (ret)
 		return ret;
 
-	ret = trace_define_field(call, SYSCALL_FIELD(unsigned long, ret), 0);
+	ret = trace_define_field(call, SYSCALL_FIELD(unsigned long, ret), 0,
+				 FILTER_OTHER);
 
 	return ret;
 }