From 4de21a4bdd32a4833180703cb4ad33a3e7a411f1 Mon Sep 17 00:00:00 2001
From: Steven Rostedt <srostedt@redhat.com>
Date: Tue, 9 Jun 2009 17:29:07 -0400
Subject: [PATCH] --- yaml --- r: 146223 b: refs/heads/master c:
 110bf2b764eb6026b868d84499263cb24b1bcc8d h: refs/heads/master i:   146221:
 054ce9e3fcb1a8a86bf3c2ba4f488fc7804e84d2   146219:
 f76f489d1311735c9db53fb1ff867dc14f9ffc5b   146215:
 7e0da963f680bc82306067fb674a9d6f50aa2336   146207:
 8d60fc41af79dae8afc91c4a40224a935116f875 v: v3

---
 [refs]                            |  2 +-
 trunk/kernel/trace/trace_events.c |  4 +++-
 trunk/kernel/trace/trace_output.c | 15 ++++++++++++---
 trunk/kernel/trace/trace_output.h |  4 ++++
 4 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/[refs] b/[refs]
index a4a56a190502..a8b13fbc1dc3 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 725c624a58a10ef90a2ff889e122158fabf36147
+refs/heads/master: 110bf2b764eb6026b868d84499263cb24b1bcc8d
diff --git a/trunk/kernel/trace/trace_events.c b/trunk/kernel/trace/trace_events.c
index 6c81f9c21426..aa08be69a1b6 100644
--- a/trunk/kernel/trace/trace_events.c
+++ b/trunk/kernel/trace/trace_events.c
@@ -1050,12 +1050,13 @@ static void trace_module_remove_events(struct module *mod)
 	struct ftrace_event_call *call, *p;
 	bool found = false;
 
+	down_write(&trace_event_mutex);
 	list_for_each_entry_safe(call, p, &ftrace_events, list) {
 		if (call->mod == mod) {
 			found = true;
 			ftrace_event_enable_disable(call, 0);
 			if (call->event)
-				unregister_ftrace_event(call->event);
+				__unregister_ftrace_event(call->event);
 			debugfs_remove_recursive(call->dir);
 			list_del(&call->list);
 			trace_destroy_fields(call);
@@ -1079,6 +1080,7 @@ static void trace_module_remove_events(struct module *mod)
 	 */
 	if (found)
 		tracing_reset_current_online_cpus();
+	up_write(&trace_event_mutex);
 }
 
 static int trace_module_notify(struct notifier_block *self,
diff --git a/trunk/kernel/trace/trace_output.c b/trunk/kernel/trace/trace_output.c
index c05aff465dc9..7938f3ae93e3 100644
--- a/trunk/kernel/trace/trace_output.c
+++ b/trunk/kernel/trace/trace_output.c
@@ -14,7 +14,7 @@
 /* must be a power of 2 */
 #define EVENT_HASHSIZE	128
 
-static DECLARE_RWSEM(trace_event_mutex);
+DECLARE_RWSEM(trace_event_mutex);
 
 DEFINE_PER_CPU(struct trace_seq, ftrace_event_seq);
 EXPORT_PER_CPU_SYMBOL(ftrace_event_seq);
@@ -702,6 +702,16 @@ int register_ftrace_event(struct trace_event *event)
 }
 EXPORT_SYMBOL_GPL(register_ftrace_event);
 
+/*
+ * Used by module code with the trace_event_mutex held for write.
+ */
+int __unregister_ftrace_event(struct trace_event *event)
+{
+	hlist_del(&event->node);
+	list_del(&event->list);
+	return 0;
+}
+
 /**
  * unregister_ftrace_event - remove a no longer used event
  * @event: the event to remove
@@ -709,8 +719,7 @@ EXPORT_SYMBOL_GPL(register_ftrace_event);
 int unregister_ftrace_event(struct trace_event *event)
 {
 	down_write(&trace_event_mutex);
-	hlist_del(&event->node);
-	list_del(&event->list);
+	__unregister_ftrace_event(event);
 	up_write(&trace_event_mutex);
 
 	return 0;
diff --git a/trunk/kernel/trace/trace_output.h b/trunk/kernel/trace/trace_output.h
index ac240e76eb01..d38bec4a9c30 100644
--- a/trunk/kernel/trace/trace_output.h
+++ b/trunk/kernel/trace/trace_output.h
@@ -27,6 +27,10 @@ extern struct trace_event *ftrace_find_event(int type);
 extern enum print_line_t trace_nop_print(struct trace_iterator *iter,
 					 int flags);
 
+/* used by module unregistering */
+extern int __unregister_ftrace_event(struct trace_event *event);
+extern struct rw_semaphore trace_event_mutex;
+
 #define MAX_MEMHEX_BYTES	8
 #define HEX_CHARS		(MAX_MEMHEX_BYTES*2 + 1)