[PATCH v2 6/7] tracing: change apply_subsystem_event_filter() paths to check file->system == dir

Oleg Nesterov
2014-07-15T18:50:23Z

filter_free_subsystem_preds(), filter_free_subsystem_filters() and
replace_system_preds() can simply check file->system->subsystem and
avoid strcmp(call->class->system).

Better yet, we can pass "struct ftrace_subsystem_dir *dir" instead of
event_subsystem and just check file->system == dir.

Thanks to Namhyung Kim who pointed out that replace_system_preds() can
be changed too.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
kernel/trace/trace_events_filter.c | 39 ++++++++++++++---------------------
1 files changed, 16 insertions(+), 23 deletions(-)

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 54a125c..c2ef5a5 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -842,17 +842,14 @@ static inline void __remove_filter(struct ftrace_event_file *file)
remove_filter_string(file->filter);
}

-static void filter_free_subsystem_preds(struct event_subsystem *system,
+static void filter_free_subsystem_preds(struct ftrace_subsystem_dir *dir,
struct trace_array *tr)
{
struct ftrace_event_file *file;
- struct ftrace_event_call *call;

list_for_each_entry(file, &tr->events, list) {
- call = file->event_call;
- if (strcmp(call->class->system, system->name) != 0)
+ if (file->system != dir)
continue;
-
__remove_filter(file);
}
}
@@ -870,15 +867,13 @@ static inline void __free_subsystem_filter(struct ftrace_event_file *file)
}
}

-static void filter_free_subsystem_filters(struct event_subsystem *system,
+static void filter_free_subsystem_filters(struct ftrace_subsystem_dir *dir,
struct trace_array *tr)
{
struct ftrace_event_file *file;
- struct ftrace_event_call *call;

list_for_each_entry(file, &tr->events, list) {
- call = file->event_call;
- if (strcmp(call->class->system, system->name) != 0)
+ if (file->system != dir)
continue;
__free_subsystem_filter(file);
}
@@ -1724,13 +1719,12 @@ struct filter_list {
struct event_filter *filter;
};

-static int replace_system_preds(struct event_subsystem *system,
+static int replace_system_preds(struct ftrace_subsystem_dir *dir,
struct trace_array *tr,
struct filter_parse_state *ps,
char *filter_string)
{
struct ftrace_event_file *file;
- struct ftrace_event_call *call;
struct filter_list *filter_item;
struct filter_list *tmp;
LIST_HEAD(filter_list);
@@ -1738,15 +1732,15 @@ static int replace_system_preds(struct event_subsystem *system,
int err;

list_for_each_entry(file, &tr->events, list) {
- call = file->event_call;
- if (strcmp(call->class->system, system->name) != 0)
+ if (file->system != dir)
continue;

/*
* Try to see if the filter can be applied
* (filter arg is ignored on dry_run)
*/
- err = replace_preds(call, NULL, ps, filter_string, true);
+ err = replace_preds(file->event_call, NULL, ps,
+ filter_string, true);
if (err)
event_set_no_set_filter_flag(file);
else
@@ -1756,9 +1750,7 @@ static int replace_system_preds(struct event_subsystem *system,
list_for_each_entry(file, &tr->events, list) {
struct event_filter *filter;

- call = file->event_call;
-
- if (strcmp(call->class->system, system->name) != 0)
+ if (file->system != dir)
continue;

if (event_no_set_filter_flag(file))
@@ -1780,7 +1772,8 @@ static int replace_system_preds(struct event_subsystem *system,
if (err)
goto fail_mem;

- err = replace_preds(call, filter, ps, filter_string, false);
+ err = replace_preds(file->event_call, filter, ps,
+ filter_string, false);
if (err) {
filter_disable(file);
parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
@@ -1928,7 +1921,7 @@ int create_event_filter(struct ftrace_event_call *call,
* Identical to create_filter() except that it creates a subsystem filter
* and always remembers @filter_str.
*/
-static int create_system_filter(struct event_subsystem *system,
+static int create_system_filter(struct ftrace_subsystem_dir *dir,
struct trace_array *tr,
char *filter_str, struct event_filter **filterp)
{
@@ -1938,7 +1931,7 @@ static int create_system_filter(struct event_subsystem *system,

err = create_filter_start(filter_str, true, &ps, &filter);
if (!err) {
- err = replace_system_preds(system, tr, ps, filter_str);
+ err = replace_system_preds(dir, tr, ps, filter_str);
if (!err) {
/* System filters just show a default message */
kfree(filter->filter_string);
@@ -2022,18 +2015,18 @@ int apply_subsystem_event_filter(struct ftrace_subsystem_dir *dir,
}

if (!strcmp(strstrip(filter_string), "0")) {
- filter_free_subsystem_preds(system, tr);
+ filter_free_subsystem_preds(dir, tr);
remove_filter_string(system->filter);
filter = system->filter;
system->filter = NULL;
/* Ensure all filters are no longer used */
synchronize_sched();
- filter_free_subsystem_filters(system, tr);
+ filter_free_subsystem_filters(dir, tr);
__free_filter(filter);
goto out_unlock;
}

- err = create_system_filter(system, tr, filter_string, &filter);
+ err = create_system_filter(dir, tr, filter_string, &filter);
if (filter) {
/*
* No event actually uses the system filter
--
1.5.5.1