rcutorture: Abstract torture-test cleanup

This commit creates a torture_cleanup() that handles the generic
cleanup actions local to kernel/torture.c.

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

include/linux/torture.h

@@ -65,7 +65,6 @@ extern struct mutex fullstop_mutex;
 
 /* Definitions for online/offline exerciser. */
 int torture_onoff_init(long ooholdoff, long oointerval);
-void torture_onoff_cleanup(void);
 char *torture_onoff_stats(char *page);
 bool torture_onoff_failures(void);
 
@@ -80,14 +79,13 @@ unsigned long torture_random(struct torture_random_state *trsp);
 /* Task shuffler, which causes CPUs to occasionally go idle. */
 void torture_shuffle_task_register(struct task_struct *tp);
 int torture_shuffle_init(long shuffint);
-void torture_shuffle_cleanup(void);
 
 /* Shutdown task absorption, for when the tasks cannot safely be killed. */
 void torture_shutdown_absorb(const char *title);
 
 /* Initialization and cleanup. */
-
 void torture_init_begin(char *ttype, bool v);
 void torture_init_end(void);
+bool torture_cleanup(void);
 
 #endif /* __LINUX_TORTURE_H */

kernel/rcu/rcutorture.c

@@ -1423,21 +1423,13 @@ rcu_torture_cleanup(void)
 	int i;
 
 	rcutorture_record_test_transition();
-	mutex_lock(&fullstop_mutex);
+	if (torture_cleanup()) {
-	if (fullstop == FULLSTOP_SHUTDOWN) {
-		pr_warn(/* but going down anyway, so... */
-		       "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
-		mutex_unlock(&fullstop_mutex);
-		schedule_timeout_uninterruptible(10);
 		if (cur_ops->cb_barrier != NULL)
 			cur_ops->cb_barrier();
 		return;
 	}
-	fullstop = FULLSTOP_RMMOD;
-	mutex_unlock(&fullstop_mutex);
 	unregister_reboot_notifier(&rcutorture_shutdown_nb);
 
-	torture_shuffle_cleanup(); /* Must be first task cleaned up. */
 	rcu_torture_barrier_cleanup();
 	rcu_torture_stall_cleanup();
 	if (stutter_task) {
@@ -1501,7 +1493,6 @@ rcu_torture_cleanup(void)
 		kthread_stop(shutdown_task);
 	}
 	shutdown_task = NULL;
-	torture_onoff_cleanup();
 
 	/* Wait for all RCU callbacks to fire.  */
 

kernel/torture.c

@@ -199,7 +199,7 @@ EXPORT_SYMBOL_GPL(torture_onoff_init);
 /*
  * Clean up after online/offline testing.
  */
-void torture_onoff_cleanup(void)
+static void torture_onoff_cleanup(void)
 {
 #ifdef CONFIG_HOTPLUG_CPU
 	if (onoff_task == NULL)
@@ -403,7 +403,7 @@ EXPORT_SYMBOL_GPL(torture_shuffle_init);
 /*
  * Stop the shuffling.
  */
-void torture_shuffle_cleanup(void)
+static void torture_shuffle_cleanup(void)
 {
 	torture_shuffle_task_unregister_all();
 	if (shuffler_task) {
@@ -453,3 +453,29 @@ void __init torture_init_end(void)
 	mutex_unlock(&fullstop_mutex);
 }
 EXPORT_SYMBOL_GPL(torture_init_end);
+
+/*
+ * Clean up torture module.  Please note that this is -not- invoked via
+ * the usual module_exit() mechanism, but rather by an explicit call from
+ * the client torture module.  Returns true if a race with system shutdown
+ * is detected.
+ *
+ * This must be called before the caller starts shutting down its own
+ * kthreads.
+ */
+bool torture_cleanup(void)
+{
+	mutex_lock(&fullstop_mutex);
+	if (fullstop == FULLSTOP_SHUTDOWN) {
+		pr_warn("Concurrent rmmod and shutdown illegal!\n");
+		mutex_unlock(&fullstop_mutex);
+		schedule_timeout_uninterruptible(10);
+		return true;
+	}
+	fullstop = FULLSTOP_RMMOD;
+	mutex_unlock(&fullstop_mutex);
+	torture_shuffle_cleanup();
+	torture_onoff_cleanup();
+	return false;
+}
+EXPORT_SYMBOL_GPL(torture_cleanup);