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Date: Thu, 09 Jul 2009 23:06:54 -0500 From: Tom Zanussi <tzanussi@...il.com> To: Xiao Guangrong <xiaoguangrong@...fujitsu.com> Cc: Ingo Molnar <mingo@...e.hu>, Frederic Weisbecker <fweisbec@...il.com>, Steven Rostedt <rostedt@...dmis.org>, LKML <linux-kernel@...r.kernel.org> Subject: Re: [PATCH 2/2] tracing/filter: remove empty subsystem and it's directory On Thu, 2009-07-09 at 16:22 +0800, Xiao Guangrong wrote: > Remove empty subsystem and it's 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 <xiaoguangrong@...fujitsu.com> Looks like it does the trick. Acked-by: Tom Zanussi <tzanussi@...il.com> > --- > kernel/trace/trace.h | 1 + > kernel/trace/trace_events.c | 32 +++++++++++++++++++++++++++++++- > 2 files changed, 32 insertions(+), 1 deletions(-) > > diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h > index 61b4e94..0e7de4b 100644 > --- a/kernel/trace/trace.h > +++ b/kernel/trace/trace.h > @@ -780,6 +780,7 @@ 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 fecac13..90cf936 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); > } > } > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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