tracing/ftrace: Fix to check create_event_dir() when adding new events

Check result of event_create_dir() and add ftrace_event_call to
ftrace_events list only if it is succeeded. Thanks to Li for pointing
it out.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <20090925182054.10157.55219.stgit@omoto>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index a4b7c9a9130cfbacebf4fb1578ad3cae6c28bc9f..155b5d5a4e45d61ce3f449a7a933da7995a34c12 100644 (file)
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -957,12 +957,12 @@ static int __trace_add_event_call(struct ftrace_event_call *call)
        if (!d_events)
                return -ENOENT;
 
-       list_add(&call->list, &ftrace_events);
        ret = event_create_dir(call, d_events, &ftrace_event_id_fops,
                                &ftrace_enable_fops, &ftrace_event_filter_fops,
                                &ftrace_event_format_fops);
-       if (ret < 0)
-               list_del(&call->list);
+       if (!ret)
+               list_add(&call->list, &ftrace_events);
+
        return ret;
 }
 
@@ -1124,10 +1124,11 @@ static void trace_module_add_events(struct module *mod)
                                return;
                }
                call->mod = mod;
-               list_add(&call->list, &ftrace_events);
-               event_create_dir(call, d_events,
-                                &file_ops->id, &file_ops->enable,
-                                &file_ops->filter, &file_ops->format);
+               ret = event_create_dir(call, d_events,
+                                      &file_ops->id, &file_ops->enable,
+                                      &file_ops->filter, &file_ops->format);
+               if (!ret)
+                       list_add(&call->list, &ftrace_events);
        }
 }
 
@@ -1267,10 +1268,12 @@ static __init int event_trace_init(void)
                                continue;
                        }
                }
-               list_add(&call->list, &ftrace_events);
-               event_create_dir(call, d_events, &ftrace_event_id_fops,
-                                &ftrace_enable_fops, &ftrace_event_filter_fops,
-                                &ftrace_event_format_fops);
+               ret = event_create_dir(call, d_events, &ftrace_event_id_fops,
+                                      &ftrace_enable_fops,
+                                      &ftrace_event_filter_fops,
+                                      &ftrace_event_format_fops);
+               if (!ret)
+                       list_add(&call->list, &ftrace_events);
        }
 
        while (true) {