ftrace: Change filter/notrace set functions to return exit code

Currently the ftrace_set_filter and ftrace_set_notrace functions
do not return any return code. So there's no way for ftrace_ops
user to tell wether the filter was correctly applied.

The set_ftrace_filter interface returns error in case the filter
did not match:

  # echo krava > set_ftrace_filter
  bash: echo: write error: Invalid argument

Changing both ftrace_set_filter and ftrace_set_notrace functions
to return zero if the filter was applied correctly or -E* values
in case of error.

Link: http://lkml.kernel.org/r/1325495060-6402-2-git-send-email-jolsa@redhat.com

Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 9 insertions, 6 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 683d559a0eef..e2e0597c0845 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3146,8 +3146,10 @@ ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
         mutex_lock(&ftrace_regex_lock);
         if (reset)
                 ftrace_filter_reset(hash);
-        if (buf)
-                ftrace_match_records(hash, buf, len);
+        if (buf && !ftrace_match_records(hash, buf, len)) {
+                ret = -EINVAL;
+                goto out_regex_unlock;
+        }
 
         mutex_lock(&ftrace_lock);
         ret = ftrace_hash_move(ops, enable, orig_hash, hash);
@@ -3157,6 +3159,7 @@ ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
 
         mutex_unlock(&ftrace_lock);
 
+ out_regex_unlock:
         mutex_unlock(&ftrace_regex_lock);
 
         free_ftrace_hash(hash);
@@ -3173,10 +3176,10 @@ ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
  * Filters denote which functions should be enabled when tracing is enabled.
  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
  */
-void ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
+int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
                        int len, int reset)
 {
-        ftrace_set_regex(ops, buf, len, reset, 1);
+        return ftrace_set_regex(ops, buf, len, reset, 1);
 }
 EXPORT_SYMBOL_GPL(ftrace_set_filter);
 
@@ -3191,10 +3194,10 @@ EXPORT_SYMBOL_GPL(ftrace_set_filter);
  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
  * for tracing.
  */
-void ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
+int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
                         int len, int reset)
 {
-        ftrace_set_regex(ops, buf, len, reset, 0);
+        return ftrace_set_regex(ops, buf, len, reset, 0);
 }
 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
 /**