function-graph: Allow writing the same val to set_graph_function

# echo 'do_open' > set_graph_function
 # echo 'do_open' >> set_graph_function
 bash: echo: write error: Invalid argument

Make it valid to write the same value to set_graph_function,
which is consistent with set_ftrace_filter interface.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
LKML-reference: <4B1DC4E1.1060303@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

1 files changed, 2 insertions, 3 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index ff8aecdc6dd6..7968762c8167 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2552,10 +2552,9 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer)
                                         exists = true;
                                         break;
                                 }
-                        if (!exists) {
+                        if (!exists)
                                 array[(*idx)++] = rec->ip;
-                                found = 1;
-                        }
+                        found = 1;
                 }
         } while_for_each_ftrace_rec();