trace_syscalls: Add syscall nr field

Field syscall number is missed in syscall_enter_define_fields()/
syscall_exit_define_fields().

Syscall number is also needed for event filter or other users.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4B0E330D.1070206@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/trace/trace_syscalls.c

@@ -261,6 +261,10 @@ int syscall_enter_define_fields(struct ftrace_event_call *call)
 	if (ret)
 		return ret;
 
+	ret = trace_define_field(call, SYSCALL_FIELD(int, nr), FILTER_OTHER);
+	if (ret)
+		return ret;
+
 	for (i = 0; i < meta->nb_args; i++) {
 		ret = trace_define_field(call, meta->types[i],
 					 meta->args[i], offset,
@@ -281,6 +285,10 @@ int syscall_exit_define_fields(struct ftrace_event_call *call)
 	if (ret)
 		return ret;
 
+	ret = trace_define_field(call, SYSCALL_FIELD(int, nr), FILTER_OTHER);
+	if (ret)
+		return ret;
+
 	ret = trace_define_field(call, SYSCALL_FIELD(long, ret),
 				 FILTER_OTHER);