From dc82ec98a4727fd51b77e92d05fe7d2db3dcc11c Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Thu, 9 Jul 2009 16:22:22 +0800 Subject: [PATCH] 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: Xiao Guangrong Acked-by: Tom Zanussi Reviewed-by: Li Zefan Cc: Frederic Weisbecker Cc: Steven Rostedt LKML-Reference: <4A55A8BE.9010707@cn.fujitsu.com> Signed-off-by: Ingo Molnar --- kernel/trace/trace.h | 1 + kernel/trace/trace_events.c | 32 +++++++++++++++++++++++++++++++- 2 files changed, 32 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 52eb0d8dcd75..94305c7bc11c 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -757,6 +757,7 @@ struct event_subsystem { const char *name; struct dentry *entry; void *filter; + int nr_events; }; struct filter_pred; diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index fecac1314cbe..90cf9360e140 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -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); } } -- 2.34.1