From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Tue, 24 May 2011 03:48:10 +0000 (-0400)
Subject: lttng-ftrace module can be unloaded safely
X-Git-Tag: v2.0-pre1~103
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=1695dc9a055c3383067cccac91cb8918cb2eaab1;p=lttng-modules.git

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 7c4fc9f5..7637e4b5 100644
--- 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");