Commit dc82ec98 authored by Xiao Guangrong's avatar Xiao Guangrong Committed by Ingo Molnar
Browse files

tracing/filter: Remove empty subsystem and its directory



Remove empty subsystem and its directory when module unload.

Before patch:
 # rmmod trace-events-sample.ko
 # ls sample
 enable  filter

After patch:
 # rmmod trace-events-sample.ko
 # ls sample
 ls: cannot access sample: No such file or directory
Signed-off-by: default avatarXiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Acked-by: default avatarTom Zanussi <tzanussi@gmail.com>
Reviewed-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4A55A8BE.9010707@cn.fujitsu.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent c5cb1836
......@@ -757,6 +757,7 @@ struct event_subsystem {
const char *name;
struct dentry *entry;
void *filter;
int nr_events;
};
struct filter_pred;
......
......@@ -851,8 +851,10 @@ event_subsystem_dir(const char *name, struct dentry *d_events)
/* First see if we did not already create this dir */
list_for_each_entry(system, &event_subsystems, list) {
if (strcmp(system->name, name) == 0)
if (strcmp(system->name, name) == 0) {
system->nr_events++;
return system->entry;
}
}
/* need to create new entry */
......@@ -871,6 +873,7 @@ event_subsystem_dir(const char *name, struct dentry *d_events)
return d_events;
}
system->nr_events = 1;
system->name = kstrdup(name, GFP_KERNEL);
if (!system->name) {
debugfs_remove(system->entry);
......@@ -905,6 +908,32 @@ event_subsystem_dir(const char *name, struct dentry *d_events)
return system->entry;
}
static void remove_subsystem_dir(const char *name)
{
struct event_subsystem *system;
if (strcmp(name, TRACE_SYSTEM) == 0)
return;
list_for_each_entry(system, &event_subsystems, list) {
if (strcmp(system->name, name) == 0) {
if (!--system->nr_events) {
struct event_filter *filter = system->filter;
debugfs_remove_recursive(system->entry);
list_del(&system->list);
if (filter) {
kfree(filter->filter_string);
kfree(filter);
}
kfree(system->name);
kfree(system);
}
break;
}
}
}
static int
event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
const struct file_operations *id,
......@@ -1079,6 +1108,7 @@ static void trace_module_remove_events(struct module *mod)
list_del(&call->list);
trace_destroy_fields(call);
destroy_preds(call);
remove_subsystem_dir(call->system);
}
}
......
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