torture: Eliminate torture_runnable and perf_runnable

The purpose of torture_runnable is to allow rcutorture and locktorture
to be started and stopped via sysfs when they are built into the kernel
(as in not compiled as loadable modules).  However, the 0444 permissions
for both instances of torture_runnable prevent this use case from ever
being put into practice.  Given that there have been no complaints
about this deficiency, it is reasonable to conclude that no one actually
makes use of this sysfs capability.  The perf_runnable module parameter
for rcuperf is in the same situation.

This commit therefore removes both torture_runnable instances as well
as perf_runnable.

Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

Documentation/admin-guide/kernel-parameters.txt

@@ -2049,9 +2049,6 @@
 			This tests the locking primitive's ability to
 			transition abruptly to and from idle.
 
-	locktorture.torture_runnable= [BOOT]
-			Start locktorture running at boot time.
-
 	locktorture.torture_type= [KNL]
 			Specify the locking implementation to test.
 
@@ -3459,9 +3456,6 @@
 			the same as for rcuperf.nreaders.
 			N, where N is the number of CPUs
 
-	rcuperf.perf_runnable= [BOOT]
-			Start rcuperf running at boot time.
-
 	rcuperf.perf_type= [KNL]
 			Specify the RCU implementation to test.
 
@@ -3595,9 +3589,6 @@
 			Test RCU's dyntick-idle handling.  See also the
 			rcutorture.shuffle_interval parameter.
 
-	rcutorture.torture_runnable= [BOOT]
-			Start rcutorture running at boot time.
-
 	rcutorture.torture_type= [KNL]
 			Specify the RCU implementation to test.
 

Documentation/locking/locktorture.txt

@@ -57,11 +57,6 @@ torture_type	  Type of lock to torture. By default, only spinlocks will
 
 		     o "rwsem_lock": read/write down() and up() semaphore pairs.
 
-torture_runnable  Start locktorture at boot time in the case where the
-		  module is built into the kernel, otherwise wait for
-		  torture_runnable to be set via sysfs before starting.
-		  By default it will begin once the module is loaded.
-
 
 	    ** Torture-framework (RCU + locking) **
 

include/linux/torture.h

@@ -79,7 +79,7 @@ void stutter_wait(const char *title);
 int torture_stutter_init(int s);
 
 /* Initialization and cleanup. */
-bool torture_init_begin(char *ttype, bool v, int *runnable);
+bool torture_init_begin(char *ttype, bool v);
 void torture_init_end(void);
 bool torture_cleanup_begin(void);
 void torture_cleanup_end(void);

kernel/locking/locktorture.c

@@ -77,10 +77,6 @@ struct lock_stress_stats {
 	long n_lock_acquired;
 };
 
-int torture_runnable = IS_ENABLED(MODULE);
-module_param(torture_runnable, int, 0444);
-MODULE_PARM_DESC(torture_runnable, "Start locktorture at module init");
-
 /* Forward reference. */
 static void lock_torture_cleanup(void);
 
@@ -866,7 +862,7 @@ static int __init lock_torture_init(void)
 		&percpu_rwsem_lock_ops,
 	};
 
-	if (!torture_init_begin(torture_type, verbose, &torture_runnable))
+	if (!torture_init_begin(torture_type, verbose))
 		return -EBUSY;
 
 	/* Process args and tell the world that the torturer is on the job. */

kernel/rcu/rcuperf.c

@@ -106,10 +106,6 @@ static int rcu_perf_writer_state;
 #define MAX_MEAS 10000
 #define MIN_MEAS 100
 
-static int perf_runnable = IS_ENABLED(MODULE);
-module_param(perf_runnable, int, 0444);
-MODULE_PARM_DESC(perf_runnable, "Start rcuperf at boot");
-
 /*
  * Operations vector for selecting different types of tests.
  */
@@ -646,7 +642,7 @@ rcu_perf_init(void)
 		&tasks_ops,
 	};
 
-	if (!torture_init_begin(perf_type, verbose, &perf_runnable))
+	if (!torture_init_begin(perf_type, verbose))
 		return -EBUSY;
 
 	/* Process args and tell the world that the perf'er is on the job. */

kernel/rcu/rcutorture.c

@@ -187,10 +187,6 @@ static const char *rcu_torture_writer_state_getname(void)
 	return rcu_torture_writer_state_names[i];
 }
 
-static int torture_runnable = IS_ENABLED(MODULE);
-module_param(torture_runnable, int, 0444);
-MODULE_PARM_DESC(torture_runnable, "Start rcutorture at boot");
-
 #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
 #define rcu_can_boost() 1
 #else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
@@ -1729,7 +1725,7 @@ rcu_torture_init(void)
 		&sched_ops, &tasks_ops,
 	};
 
-	if (!torture_init_begin(torture_type, verbose, &torture_runnable))
+	if (!torture_init_begin(torture_type, verbose))
 		return -EBUSY;
 
 	/* Process args and tell the world that the torturer is on the job. */

kernel/torture.c

@@ -61,7 +61,6 @@ static bool verbose;
 #define FULLSTOP_RMMOD    2	/* Normal rmmod of torture. */
 static int fullstop = FULLSTOP_RMMOD;
 static DEFINE_MUTEX(fullstop_mutex);
-static int *torture_runnable;
 
 #ifdef CONFIG_HOTPLUG_CPU
 
@@ -577,7 +576,7 @@ void stutter_wait(const char *title)
 
 	cond_resched_rcu_qs();
 	spt = READ_ONCE(stutter_pause_test);
-	while (spt || (torture_runnable && !READ_ONCE(*torture_runnable))) {
+	while (spt) {
 		if (spt == 1) {
 			schedule_timeout_interruptible(1);
 		} else if (spt == 2) {
@@ -649,7 +648,7 @@ static void torture_stutter_cleanup(void)
  * The runnable parameter points to a flag that controls whether or not
  * the test is currently runnable.  If there is no such flag, pass in NULL.
  */
-bool torture_init_begin(char *ttype, bool v, int *runnable)
+bool torture_init_begin(char *ttype, bool v)
 {
 	mutex_lock(&fullstop_mutex);
 	if (torture_type != NULL) {
@@ -661,7 +660,6 @@ bool torture_init_begin(char *ttype, bool v, int *runnable)
 	}
 	torture_type = ttype;
 	verbose = v;
-	torture_runnable = runnable;
 	fullstop = FULLSTOP_DONTSTOP;
 	return true;
 }

tools/testing/selftests/rcutorture/configs/lock/ver_functions.sh

@@ -38,6 +38,5 @@ per_version_boot_params () {
 	echo $1 `locktorture_param_onoff "$1" "$2"` \
 		locktorture.stat_interval=15 \
 		locktorture.shutdown_secs=$3 \
-		locktorture.torture_runnable=1 \
 		locktorture.verbose=1
 }

tools/testing/selftests/rcutorture/configs/rcu/ver_functions.sh

@@ -51,7 +51,6 @@ per_version_boot_params () {
 		`rcutorture_param_n_barrier_cbs "$1"` \
 		rcutorture.stat_interval=15 \
 		rcutorture.shutdown_secs=$3 \
-		rcutorture.torture_runnable=1 \
 		rcutorture.test_no_idle_hz=1 \
 		rcutorture.verbose=1
 }

tools/testing/selftests/rcutorture/configs/rcuperf/ver_functions.sh

@@ -46,7 +46,6 @@ rcuperf_param_nwriters () {
 per_version_boot_params () {
 	echo $1 `rcuperf_param_nreaders "$1"` \
 		`rcuperf_param_nwriters "$1"` \
-		rcuperf.perf_runnable=1 \
 		rcuperf.shutdown=1 \
 		rcuperf.verbose=1
 }