rcutorture: Abstract torture_shutdown_notify()

Because handling the race between rmmod and system shutdown is not
specific to RCU, this commit abstracts torture_shutdown_notify(),
placing this code into kernel/torture.c.  This change also allows
fullstop_mutex to be private to kernel/torture.c.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

1 files changed, 24 insertions, 5 deletions

diff --git a/kernel/torture.c b/kernel/torture.c
index 41ae5cc3c4c3..b02fa2785bbb 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -54,8 +54,7 @@ static bool verbose;
 
 int fullstop = FULLSTOP_RMMOD;
 EXPORT_SYMBOL_GPL(fullstop);
-DEFINE_MUTEX(fullstop_mutex);
-EXPORT_SYMBOL_GPL(fullstop_mutex);
+static DEFINE_MUTEX(fullstop_mutex);
 
 #ifdef CONFIG_HOTPLUG_CPU
 
@@ -422,15 +421,33 @@ EXPORT_SYMBOL_GPL(torture_shuffle_cleanup);
 void torture_shutdown_absorb(const char *title)
 {
 	while (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
-		pr_notice(
-		       "torture thread %s parking due to system shutdown\n",
-		       title);
+		pr_notice("torture thread %s parking due to system shutdown\n",
+			  title);
 		schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
 	}
 }
 EXPORT_SYMBOL_GPL(torture_shutdown_absorb);
 
 /*
+ * Detect and respond to a system shutdown.
+ */
+static int torture_shutdown_notify(struct notifier_block *unused1,
+				   unsigned long unused2, void *unused3)
+{
+	mutex_lock(&fullstop_mutex);
+	if (fullstop == FULLSTOP_DONTSTOP)
+		fullstop = FULLSTOP_SHUTDOWN;
+	else
+		pr_warn("Concurrent rmmod and shutdown illegal!\n");
+	mutex_unlock(&fullstop_mutex);
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block torture_shutdown_nb = {
+	.notifier_call = torture_shutdown_notify,
+};
+
+/*
  * Initialize torture module.  Please note that this is -not- invoked via
  * the usual module_init() mechanism, but rather by an explicit call from
  * the client torture module.  This call must be paired with a later
@@ -451,6 +468,7 @@ EXPORT_SYMBOL_GPL(torture_init_begin);
 void __init torture_init_end(void)
 {
 	mutex_unlock(&fullstop_mutex);
+	register_reboot_notifier(&torture_shutdown_nb);
 }
 EXPORT_SYMBOL_GPL(torture_init_end);
 
@@ -474,6 +492,7 @@ bool torture_cleanup(void)
 	}
 	fullstop = FULLSTOP_RMMOD;
 	mutex_unlock(&fullstop_mutex);
+	unregister_reboot_notifier(&torture_shutdown_nb);
 	torture_shuffle_cleanup();
 	torture_onoff_cleanup();
 	return false;