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>

3 files changed, 92 insertions, 59 deletions

diff --git a/include/linux/torture.h b/include/linux/torture.h
index 203f127d9ddf..c79c41d543ef 100644
--- a/include/linux/torture.h
+++ b/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);
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 4329ad14f8dc..897b0f91f899 100644
--- a/kernel/rcu/rcutorture.c
+++ b/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.
  */
@@ -1087,42 +1082,6 @@ static int rcutorture_booster_init(int cpu)
 }
 
 /*
- * 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) {
-                VERBOSE_TOROUT_STRING("Stopping rcu_torture_shutdown task");
-                kthread_stop(shutdown_task);
-        }
-        shutdown_task = NULL;
+        torture_shutdown_cleanup();
 
         /* Wait for all RCU callbacks to fire.  */
 
@@ -1681,18 +1636,10 @@ rcu_torture_init(void)
                         }
                 }
         }
-        if (shutdown_secs > 0) {
-                shutdown_time = jiffies + shutdown_secs * HZ;
-                shutdown_task = kthread_create(rcu_torture_shutdown, NULL,
-                                               "rcu_torture_shutdown");
-                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_shutdown_init(shutdown_secs, rcu_torture_cleanup);
+        if (i != 0) {
+                firsterr = i;
+                goto unwind;
         }
         i = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ);
         if (i != 0) {
diff --git a/kernel/torture.c b/kernel/torture.c
index 1bafd02d1eed..df2c700e96e4 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -419,6 +419,15 @@ 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.
  */
@@ -433,6 +442,81 @@ 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.
  */
 static int torture_shutdown_notify(struct notifier_block *unused1,