tracing: Only add filter list when needed

replace_system_preds() creates a filter list to free even when it doesn't
really need to have it. Only save filters that require synchronize_sched()
in the filter list to free. This will allow the code to be updated a bit
easier in the future.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 3d60bbeb2ef163b5d68ecae92a8ffa55a1f4720e..2401b7c727a327a4e264611fc655cfaa8ca4c8f2 100644 (file)
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -1769,6 +1769,7 @@ static int replace_system_preds(struct trace_subsystem_dir *dir,
 {
        struct trace_event_file *file;
        struct filter_list *filter_item;
+       struct event_filter *filter = NULL;
        struct filter_list *tmp;
        LIST_HEAD(filter_list);
        bool fail = true;
@@ -1790,7 +1791,6 @@ static int replace_system_preds(struct trace_subsystem_dir *dir,
        }
 
        list_for_each_entry(file, &tr->events, list) {
-               struct event_filter *filter;
 
                if (file->system != dir)
                        continue;
@@ -1798,16 +1798,9 @@ static int replace_system_preds(struct trace_subsystem_dir *dir,
                if (event_no_set_filter_flag(file))
                        continue;
 
-               filter_item = kzalloc(sizeof(*filter_item), GFP_KERNEL);
-               if (!filter_item)
-                       goto fail_mem;
-
-               list_add_tail(&filter_item->list, &filter_list);
-
-               filter_item->filter = kzalloc(sizeof(*filter), GFP_KERNEL);
-               if (!filter_item->filter)
+               filter = kzalloc(sizeof(*filter), GFP_KERNEL);
+               if (!filter)
                        goto fail_mem;
-               filter = filter_item->filter;
 
                /* Can only fail on no memory */
                err = replace_filter_string(filter, filter_string);
@@ -1821,13 +1814,20 @@ static int replace_system_preds(struct trace_subsystem_dir *dir,
                        append_filter_err(ps, filter);
                } else
                        event_set_filtered_flag(file);
+
+
+               filter_item = kzalloc(sizeof(*filter_item), GFP_KERNEL);
+               if (!filter_item)
+                       goto fail_mem;
+
+               list_add_tail(&filter_item->list, &filter_list);
                /*
                 * Regardless of if this returned an error, we still
                 * replace the filter for the call.
                 */
-               filter = event_filter(file);
-               event_set_filter(file, filter_item->filter);
-               filter_item->filter = filter;
+               filter_item->filter = event_filter(file);
+               event_set_filter(file, filter);
+               filter = NULL;
 
                fail = false;
        }
@@ -1856,6 +1856,7 @@ static int replace_system_preds(struct trace_subsystem_dir *dir,
        parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
        return -EINVAL;
  fail_mem:
+       kfree(filter);
        /* If any call succeeded, we still need to sync */
        if (!fail)
                synchronize_sched();