[for-next][PATCH 42/46] tracing: Only add filter list when needed

Steven Rostedt
2018-03-21T02:22:47Z

[-- Attachment #1: 0042-tracing-Only-add-filter-list-when-needed.patch --]
[-- Type: text/plain, Size: 2736 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

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>
---
kernel/trace/trace_events_filter.c | 27 ++++++++++++++-------------
1 file changed, 14 insertions(+), 13 deletions(-)

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 3d60bbeb2ef1..2401b7c727a3 100644
--- 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();
--
2.15.1