rcutorture: Abstract torture_shutdown()

Because auto-shutdown of torture testing is not specific to RCU,
this commit moves the auto-shutdown function 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

@@ -72,8 +72,10 @@ unsigned long torture_random(struct torture_random_state *trsp);
 void torture_shuffle_task_register(struct task_struct *tp);
 int torture_shuffle_init(long shuffint);
 
-/* Shutdown task absorption, for when the tasks cannot safely be killed. */
+/* Test auto-shutdown handling. */
 void torture_shutdown_absorb(const char *title);
+int torture_shutdown_init(int ssecs, void (*cleanup)(void));
+void torture_shutdown_cleanup(void);
 
 /* Task stuttering, which forces load/no-load transitions. */
 void stutter_wait(const char *title);

kernel/rcu/rcutorture.c

@@ -105,7 +105,6 @@ static struct task_struct **reader_tasks;
 static struct task_struct *stats_task;
 static struct task_struct *fqs_task;
 static struct task_struct *boost_tasks[NR_CPUS];
-static struct task_struct *shutdown_task;
 static struct task_struct *stall_task;
 static struct task_struct **barrier_cbs_tasks;
 static struct task_struct *barrier_task;
@@ -173,7 +172,6 @@ static u64 notrace rcu_trace_clock_local(void)
 }
 #endif /* #else #ifdef CONFIG_RCU_TRACE */
 
-static unsigned long shutdown_time;	/* jiffies to system shutdown. */
 static unsigned long boost_starttime;	/* jiffies of next boost test start. */
 DEFINE_MUTEX(boost_mutex);		/* protect setting boost_starttime */
 					/*  and boost task create/destroy. */
@@ -183,9 +181,6 @@ static atomic_t barrier_cbs_invoked;	/* Barrier callbacks invoked. */
 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
 
-/* Forward reference. */
-static void rcu_torture_cleanup(void);
-
 /*
  * Allocate an element from the rcu_tortures pool.
  */
@@ -1086,42 +1081,6 @@ static int rcutorture_booster_init(int cpu)
 	return 0;
 }
 
-/*
- * Cause the rcutorture test to shutdown the system after the test has
- * run for the time specified by the shutdown_secs module parameter.
- */
-static int
-rcu_torture_shutdown(void *arg)
-{
-	long delta;
-	unsigned long jiffies_snap;
-
-	VERBOSE_TOROUT_STRING("rcu_torture_shutdown task started");
-	jiffies_snap = ACCESS_ONCE(jiffies);
-	while (ULONG_CMP_LT(jiffies_snap, shutdown_time) &&
-	       !kthread_should_stop()) {
-		delta = shutdown_time - jiffies_snap;
-		if (verbose)
-			pr_alert("%s" TORTURE_FLAG
-				 "rcu_torture_shutdown task: %lu jiffies remaining\n",
-				 torture_type, delta);
-		schedule_timeout_interruptible(delta);
-		jiffies_snap = ACCESS_ONCE(jiffies);
-	}
-	if (kthread_should_stop()) {
-		VERBOSE_TOROUT_STRING("rcu_torture_shutdown task stopping");
-		return 0;
-	}
-
-	/* OK, shut down the system. */
-
-	VERBOSE_TOROUT_STRING("rcu_torture_shutdown task shutting down system");
-	shutdown_task = NULL;	/* Avoid self-kill deadlock. */
-	rcu_torture_cleanup();	/* Get the success/failure message. */
-	kernel_power_off();	/* Shut down the system. */
-	return 0;
-}
-
 /*
  * CPU-stall kthread.  It waits as specified by stall_cpu_holdoff, then
  * induces a CPU stall for the time specified by stall_cpu.
@@ -1421,11 +1380,7 @@ rcu_torture_cleanup(void)
 		for_each_possible_cpu(i)
 			rcutorture_booster_cleanup(i);
 	}
-	if (shutdown_task != NULL) {
+	torture_shutdown_cleanup();
-		VERBOSE_TOROUT_STRING("Stopping rcu_torture_shutdown task");
-		kthread_stop(shutdown_task);
-	}
-	shutdown_task = NULL;
 
 	/* Wait for all RCU callbacks to fire.  */
 
@@ -1681,18 +1636,10 @@ rcu_torture_init(void)
 			}
 		}
 	}
-	if (shutdown_secs > 0) {
+	i = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
-		shutdown_time = jiffies + shutdown_secs * HZ;
+	if (i != 0) {
-		shutdown_task = kthread_create(rcu_torture_shutdown, NULL,
+		firsterr = i;
-					       "rcu_torture_shutdown");
+		goto unwind;
-		if (IS_ERR(shutdown_task)) {
-			firsterr = PTR_ERR(shutdown_task);
-			VERBOSE_TOROUT_ERRSTRING("Failed to create shutdown");
-			shutdown_task = NULL;
-			goto unwind;
-		}
-		torture_shuffle_task_register(shutdown_task);
-		wake_up_process(shutdown_task);
 	}
 	i = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ);
 	if (i != 0) {

kernel/torture.c

@@ -418,6 +418,15 @@ static void torture_shuffle_cleanup(void)
 }
 EXPORT_SYMBOL_GPL(torture_shuffle_cleanup);
 
+/*
+ * Variables for auto-shutdown.  This allows "lights out" torture runs
+ * to be fully scripted.
+ */
+static int shutdown_secs;		/* desired test duration in seconds. */
+static struct task_struct *shutdown_task;
+static unsigned long shutdown_time;	/* jiffies to system shutdown. */
+static void (*torture_shutdown_hook)(void);
+
 /*
  * Absorb kthreads into a kernel function that won't return, so that
  * they won't ever access module text or data again.
@@ -432,6 +441,81 @@ void torture_shutdown_absorb(const char *title)
 }
 EXPORT_SYMBOL_GPL(torture_shutdown_absorb);
 
+/*
+ * Cause the torture test to shutdown the system after the test has
+ * run for the time specified by the shutdown_secs parameter.
+ */
+static int torture_shutdown(void *arg)
+{
+	long delta;
+	unsigned long jiffies_snap;
+
+	VERBOSE_TOROUT_STRING("torture_shutdown task started");
+	jiffies_snap = jiffies;
+	while (ULONG_CMP_LT(jiffies_snap, shutdown_time) &&
+	       !torture_must_stop()) {
+		delta = shutdown_time - jiffies_snap;
+		if (verbose)
+			pr_alert("%s" TORTURE_FLAG
+				 "torture_shutdown task: %lu jiffies remaining\n",
+				 torture_type, delta);
+		schedule_timeout_interruptible(delta);
+		jiffies_snap = jiffies;
+	}
+	if (torture_must_stop()) {
+		VERBOSE_TOROUT_STRING("torture_shutdown task stopping");
+		return 0;
+	}
+
+	/* OK, shut down the system. */
+
+	VERBOSE_TOROUT_STRING("torture_shutdown task shutting down system");
+	shutdown_task = NULL;	/* Avoid self-kill deadlock. */
+	torture_shutdown_hook();/* Shut down the enclosing torture test. */
+	kernel_power_off();	/* Shut down the system. */
+	return 0;
+}
+
+/*
+ * Start up the shutdown task.
+ */
+int torture_shutdown_init(int ssecs, void (*cleanup)(void))
+{
+	int ret;
+
+	shutdown_secs = ssecs;
+	torture_shutdown_hook = cleanup;
+	if (shutdown_secs > 0) {
+		shutdown_time = jiffies + shutdown_secs * HZ;
+		shutdown_task = kthread_create(torture_shutdown, NULL,
+					       "torture_shutdown");
+		if (IS_ERR(shutdown_task)) {
+			ret = PTR_ERR(shutdown_task);
+			VERBOSE_TOROUT_ERRSTRING("Failed to create shutdown");
+			shutdown_task = NULL;
+			return ret;
+		}
+		torture_shuffle_task_register(shutdown_task);
+		wake_up_process(shutdown_task);
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(torture_shutdown_init);
+
+/*
+ * Shut down the shutdown task.  Say what???  Heh!  This can happen if
+ * the torture module gets an rmmod before the shutdown time arrives.  ;-)
+ */
+void torture_shutdown_cleanup(void)
+{
+	if (shutdown_task != NULL) {
+		VERBOSE_TOROUT_STRING("Stopping torture_shutdown task");
+		kthread_stop(shutdown_task);
+	}
+	shutdown_task = NULL;
+}
+EXPORT_SYMBOL_GPL(torture_shutdown_cleanup);
+
 /*
  * Detect and respond to a system shutdown.
  */