lttng-ftrace module can be unloaded safely

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/probes/lttng-ftrace.c b/probes/lttng-ftrace.c
index 7c4fc9f55d78f5fc98898cd45af8a630b37e90ae..7637e4b54dff1b1f1effda651ee3587e335ec03c 100644 (file)
--- a/probes/lttng-ftrace.c
+++ b/probes/lttng-ftrace.c
@@ -152,7 +152,6 @@ void lttng_ftrace_unregister(struct ltt_event *event)
 }
 EXPORT_SYMBOL_GPL(lttng_ftrace_unregister);
 
-/* This module is permanent. */
 int lttng_ftrace_init(void)
 {
        wrapper_vmalloc_sync_all();
@@ -160,6 +159,15 @@ int lttng_ftrace_init(void)
 }
 module_init(lttng_ftrace_init)
 
+/*
+ * Ftrace takes care of waiting for a grace period (RCU sched) at probe
+ * unregistration, and disables preemption around probe call.
+ */
+void lttng_ftrace_exit(void)
+{
+}
+module_exit(lttng_ftrace_exit)
+
 MODULE_LICENSE("GPL and additional rights");
 MODULE_AUTHOR("Mathieu Desnoyers");
 MODULE_DESCRIPTION("Linux Trace Toolkit Ftrace Support");