rcutorture: Abstract torture-test initialization

This commit creates torture_init_begin() and torture_init_end() functions
to abstract locking and allow the torture_type and verbose variables
in kernel/torture.o to become static.  With a bit more abstraction,
fullstop_mutex will also become static.

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

include/linux/torture.h

@@ -49,10 +49,6 @@ extern int fullstop;
 /* Protect fullstop transitions and spawning of kthreads.  */
 extern struct mutex fullstop_mutex;
 
-/* Common module parameters. */
-extern char *torture_type;
-extern bool verbose;
-
 #define TORTURE_FLAG "-torture:"
 #define TOROUT_STRING(s) \
 	pr_alert("%s" TORTURE_FLAG s "\n", torture_type)
@@ -89,4 +85,9 @@ 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);
+
 #endif /* __LINUX_TORTURE_H */

kernel/rcu/rcutorture.c

@@ -91,15 +91,12 @@ torture_param(int, test_boost_interval, 7,
 	     "Interval between boost tests, seconds.");
 torture_param(bool, test_no_idle_hz, true,
 	     "Test support for tickless idle CPUs");
+torture_param(bool, verbose, true,
+	     "Enable verbose debugging printk()s");
 
-char *torture_type = "rcu";
+static char *torture_type = "rcu";
-EXPORT_SYMBOL_GPL(torture_type);
 module_param(torture_type, charp, 0444);
 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)");
-bool verbose;
-EXPORT_SYMBOL_GPL(verbose);
-module_param(verbose, bool, 0444);
-MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s");
 
 static int nrealreaders;
 static struct task_struct *writer_task;
@@ -1425,8 +1422,8 @@ rcu_torture_cleanup(void)
 {
 	int i;
 
-	mutex_lock(&fullstop_mutex);
 	rcutorture_record_test_transition();
+	mutex_lock(&fullstop_mutex);
 	if (fullstop == FULLSTOP_SHUTDOWN) {
 		pr_warn(/* but going down anyway, so... */
 		       "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
@@ -1589,7 +1586,7 @@ rcu_torture_init(void)
 		&rcu_ops, &rcu_bh_ops, &srcu_ops, &sched_ops,
 	};
 
-	mutex_lock(&fullstop_mutex);
+	torture_init_begin(torture_type, verbose);
 
 	/* Process args and tell the world that the torturer is on the job. */
 	for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
@@ -1604,7 +1601,7 @@ rcu_torture_init(void)
 		for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
 			pr_alert(" %s", torture_ops[i]->name);
 		pr_alert("\n");
-		mutex_unlock(&fullstop_mutex);
+		torture_init_end();
 		return -EINVAL;
 	}
 	if (cur_ops->fqs == NULL && fqs_duration != 0) {
@@ -1800,11 +1797,11 @@ rcu_torture_init(void)
 	if (object_debug)
 		rcu_test_debug_objects();
 	rcutorture_record_test_transition();
-	mutex_unlock(&fullstop_mutex);
+	torture_init_end();
 	return 0;
 
 unwind:
-	mutex_unlock(&fullstop_mutex);
+	torture_init_end();
 	rcu_torture_cleanup();
 	return firsterr;
 }

kernel/torture.c

@@ -49,6 +49,9 @@
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
 
+static char *torture_type;
+static bool verbose;
+
 int fullstop = FULLSTOP_RMMOD;
 EXPORT_SYMBOL_GPL(fullstop);
 DEFINE_MUTEX(fullstop_mutex);
@@ -426,3 +429,27 @@ void torture_shutdown_absorb(const char *title)
 	}
 }
 EXPORT_SYMBOL_GPL(torture_shutdown_absorb);
+
+/*
+ * 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
+ * torture_init_end().
+ */
+void __init torture_init_begin(char *ttype, bool v)
+{
+	mutex_lock(&fullstop_mutex);
+	torture_type = ttype;
+	verbose = v;
+
+}
+EXPORT_SYMBOL_GPL(torture_init_begin);
+
+/*
+ * Tell the torture module that initialization is complete.
+ */
+void __init torture_init_end(void)
+{
+	mutex_unlock(&fullstop_mutex);
+}
+EXPORT_SYMBOL_GPL(torture_init_end);