tracing/filters: return proper error code when writing filter file

- propagate return value of filter_add_pred() to the user

- return -ENOSPC but not -ENOMEM or -EINVAL when the filter array
  is full

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Tom Zanussi <tzanussi@gmail.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <49E04CF0.3010105@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 8 insertions, 6 deletions

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 054bc1802bc..576f4fa2af0 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -521,9 +521,10 @@ event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
                 return cnt;
         }
 
-        if (filter_add_pred(call, pred)) {
+        err = filter_add_pred(call, pred);
+        if (err < 0) {
                 filter_free_pred(pred);
-                return -EINVAL;
+                return err;
         }
 
         *ppos += cnt;
@@ -588,10 +589,11 @@ subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
                 return cnt;
         }
 
-        if (filter_add_subsystem_pred(system, pred)) {
+        err = filter_add_subsystem_pred(system, pred);
+        if (err < 0) {
                 filter_free_subsystem_preds(system);
                 filter_free_pred(pred);
-                return -EINVAL;
+                return err;
         }
 
         *ppos += cnt;
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 49b3ef54ec4..e03cbf1e38f 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -215,7 +215,7 @@ static int __filter_add_pred(struct ftrace_event_call *call,
                 }
         }
 
-        return -ENOMEM;
+        return -ENOSPC;
 }
 
 static int is_string_field(const char *type)
@@ -319,7 +319,7 @@ int filter_add_subsystem_pred(struct event_subsystem *system,
         }
 
         if (i == MAX_FILTER_PRED)
-                return -EINVAL;
+                return -ENOSPC;
 
         events_for_each(call) {
                 int err;