diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 07e0a6d64a24..78a9ba24cbf6 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -56,6 +56,7 @@ typedef enum print_line_t (*trace_print_func)(struct trace_iterator *iter, int flags); struct trace_event { struct hlist_node node; + struct list_head list; int type; trace_print_func trace; trace_print_func raw; diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index 06997e75114b..5fc51f0f75fc 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -483,6 +483,36 @@ struct trace_event *ftrace_find_event(int type) return NULL; } +static LIST_HEAD(ftrace_event_list); + +static int trace_search_list(struct list_head **list) +{ + struct trace_event *e; + int last = __TRACE_LAST_TYPE; + + if (list_empty(&ftrace_event_list)) { + *list = &ftrace_event_list; + return last + 1; + } + + /* + * We used up all possible max events, + * lets see if somebody freed one. + */ + list_for_each_entry(e, &ftrace_event_list, list) { + if (e->type != last + 1) + break; + last++; + } + + /* Did we used up all 65 thousand events??? */ + if ((last + 1) > FTRACE_MAX_EVENT) + return 0; + + *list = &e->list; + return last + 1; +} + /** * register_ftrace_event - register output for an event type * @event: the event type to register @@ -505,20 +535,40 @@ int register_ftrace_event(struct trace_event *event) mutex_lock(&trace_event_mutex); - if (!event) { - ret = next_event_type++; + if (WARN_ON(!event)) goto out; - } - if (!event->type) - event->type = next_event_type++; - else if (event->type > __TRACE_LAST_TYPE) { + INIT_LIST_HEAD(&event->list); + + if (!event->type) { + struct list_head *list; + + if (next_event_type > FTRACE_MAX_EVENT) { + + event->type = trace_search_list(&list); + if (!event->type) + goto out; + + } else { + + event->type = next_event_type++; + list = &ftrace_event_list; + } + + if (WARN_ON(ftrace_find_event(event->type))) + goto out; + + list_add_tail(&event->list, list); + + } else if (event->type > __TRACE_LAST_TYPE) { printk(KERN_WARNING "Need to add type to trace.h\n"); WARN_ON(1); - } - - if (ftrace_find_event(event->type)) goto out; + } else { + /* Is this event already used */ + if (ftrace_find_event(event->type)) + goto out; + } if (event->trace == NULL) event->trace = trace_nop_print; @@ -537,8 +587,6 @@ int register_ftrace_event(struct trace_event *event) out: mutex_unlock(&trace_event_mutex); - WARN_ON_ONCE(next_event_type > FTRACE_MAX_EVENT); - return ret; } EXPORT_SYMBOL_GPL(register_ftrace_event); @@ -551,6 +599,7 @@ int unregister_ftrace_event(struct trace_event *event) { mutex_lock(&trace_event_mutex); hlist_del(&event->node); + list_del(&event->list); mutex_unlock(&trace_event_mutex); return 0;