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-rw-r--r--kernel/tracepoint.c33
1 files changed, 30 insertions, 3 deletions
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 9f478d29b926..976bf8ce8039 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -273,7 +273,8 @@ static void tracepoint_update_call(struct tracepoint *tp, struct tracepoint_func
* Add the probe function to a tracepoint.
*/
static int tracepoint_add_func(struct tracepoint *tp,
- struct tracepoint_func *func, int prio)
+ struct tracepoint_func *func, int prio,
+ bool warn)
{
struct tracepoint_func *old, *tp_funcs;
int ret;
@@ -288,7 +289,7 @@ static int tracepoint_add_func(struct tracepoint *tp,
lockdep_is_held(&tracepoints_mutex));
old = func_add(&tp_funcs, func, prio);
if (IS_ERR(old)) {
- WARN_ON_ONCE(PTR_ERR(old) != -ENOMEM);
+ WARN_ON_ONCE(warn && PTR_ERR(old) != -ENOMEM);
return PTR_ERR(old);
}
@@ -344,6 +345,32 @@ static int tracepoint_remove_func(struct tracepoint *tp,
}
/**
+ * tracepoint_probe_register_prio_may_exist - Connect a probe to a tracepoint with priority
+ * @tp: tracepoint
+ * @probe: probe handler
+ * @data: tracepoint data
+ * @prio: priority of this function over other registered functions
+ *
+ * Same as tracepoint_probe_register_prio() except that it will not warn
+ * if the tracepoint is already registered.
+ */
+int tracepoint_probe_register_prio_may_exist(struct tracepoint *tp, void *probe,
+ void *data, int prio)
+{
+ struct tracepoint_func tp_func;
+ int ret;
+
+ mutex_lock(&tracepoints_mutex);
+ tp_func.func = probe;
+ tp_func.data = data;
+ tp_func.prio = prio;
+ ret = tracepoint_add_func(tp, &tp_func, prio, false);
+ mutex_unlock(&tracepoints_mutex);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(tracepoint_probe_register_prio_may_exist);
+
+/**
* tracepoint_probe_register_prio - Connect a probe to a tracepoint with priority
* @tp: tracepoint
* @probe: probe handler
@@ -366,7 +393,7 @@ int tracepoint_probe_register_prio(struct tracepoint *tp, void *probe,
tp_func.func = probe;
tp_func.data = data;
tp_func.prio = prio;
- ret = tracepoint_add_func(tp, &tp_func, prio);
+ ret = tracepoint_add_func(tp, &tp_func, prio, true);
mutex_unlock(&tracepoints_mutex);
return ret;
}