diff options
Diffstat (limited to 'kernel/trace/trace_output.c')
| -rw-r--r-- | kernel/trace/trace_output.c | 25 |
1 files changed, 18 insertions, 7 deletions
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index 489c0e8ada0..7136420603a 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -14,7 +14,7 @@ /* must be a power of 2 */ #define EVENT_HASHSIZE 128 -static DEFINE_MUTEX(trace_event_mutex); +static DECLARE_RWSEM(trace_event_mutex); static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly; static int next_event_type = __TRACE_LAST_TYPE + 1; @@ -466,6 +466,7 @@ static int task_state_char(unsigned long state) * @type: the type of event to look for * * Returns an event of type @type otherwise NULL + * Called with trace_event_read_lock() held. */ struct trace_event *ftrace_find_event(int type) { @@ -475,7 +476,7 @@ struct trace_event *ftrace_find_event(int type) key = type & (EVENT_HASHSIZE - 1); - hlist_for_each_entry_rcu(event, n, &event_hash[key], node) { + hlist_for_each_entry(event, n, &event_hash[key], node) { if (event->type == type) return event; } @@ -513,6 +514,16 @@ static int trace_search_list(struct list_head **list) return last + 1; } +void trace_event_read_lock(void) +{ + down_read(&trace_event_mutex); +} + +void trace_event_read_unlock(void) +{ + up_read(&trace_event_mutex); +} + /** * register_ftrace_event - register output for an event type * @event: the event type to register @@ -533,7 +544,7 @@ int register_ftrace_event(struct trace_event *event) unsigned key; int ret = 0; - mutex_lock(&trace_event_mutex); + down_write(&trace_event_mutex); if (WARN_ON(!event)) goto out; @@ -581,11 +592,11 @@ int register_ftrace_event(struct trace_event *event) key = event->type & (EVENT_HASHSIZE - 1); - hlist_add_head_rcu(&event->node, &event_hash[key]); + hlist_add_head(&event->node, &event_hash[key]); ret = event->type; out: - mutex_unlock(&trace_event_mutex); + up_write(&trace_event_mutex); return ret; } @@ -597,10 +608,10 @@ EXPORT_SYMBOL_GPL(register_ftrace_event); */ int unregister_ftrace_event(struct trace_event *event) { - mutex_lock(&trace_event_mutex); + down_write(&trace_event_mutex); hlist_del(&event->node); list_del(&event->list); - mutex_unlock(&trace_event_mutex); + up_write(&trace_event_mutex); return 0; } |