ftrace: Unify effect of writing to trace_options and option/*
"echo noglobal-clock > trace_options" can be used to change trace
clock but "echo 0 > options/global-clock" can't. The flag toggling
will be silently accepted without actually changing the clock callback.
We can fix it by using set_tracer_flags() in
trace_options_core_write().
Changelog:
v1->v2: Simplified switch() after Li Zefan <lizf@cn.fujitsu.com>'s
suggestion
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index c22b40f..8c35839 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3896,17 +3896,9 @@
if (ret < 0)
return ret;
- switch (val) {
- case 0:
- trace_flags &= ~(1 << index);
- break;
- case 1:
- trace_flags |= 1 << index;
- break;
-
- default:
+ if (val != 0 && val != 1)
return -EINVAL;
- }
+ set_tracer_flags(1 << index, val);
*ppos += cnt;