[linux-2.6-block.git] / kernel / torture.c

/*
 * Common functions for in-kernel torture tests.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, you can access it online at
 * http://www.gnu.org/licenses/gpl-2.0.html.
 *
 * Copyright (C) IBM Corporation, 2014
 *
 * Author: Paul E. McKenney <paulmck@us.ibm.com>
 *	Based on kernel/rcu/torture.c.
 */
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kthread.h>
#include <linux/err.h>
#include <linux/spinlock.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/atomic.h>
#include <linux/bitops.h>
#include <linux/completion.h>
#include <linux/moduleparam.h>
#include <linux/percpu.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/freezer.h>
#include <linux/cpu.h>
#include <linux/delay.h>
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/trace_clock.h>
#include <asm/byteorder.h>
#include <linux/torture.h>

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);
EXPORT_SYMBOL_GPL(fullstop_mutex);

#ifdef CONFIG_HOTPLUG_CPU

/*
 * Variables for online-offline handling.  Only present if CPU hotplug
 * is enabled, otherwise does nothing.
 */

static struct task_struct *onoff_task;
static long onoff_holdoff;
static long onoff_interval;
static long n_offline_attempts;
static long n_offline_successes;
static unsigned long sum_offline;
static int min_offline = -1;
static int max_offline;
static long n_online_attempts;
static long n_online_successes;
static unsigned long sum_online;
static int min_online = -1;
static int max_online;

/*
 * Execute random CPU-hotplug operations at the interval specified
 * by the onoff_interval.
 */
static int
torture_onoff(void *arg)
{
	int cpu;
	unsigned long delta;
	int maxcpu = -1;
	DEFINE_TORTURE_RANDOM(rand);
	int ret;
	unsigned long starttime;

	VERBOSE_TOROUT_STRING("torture_onoff task started");
	for_each_online_cpu(cpu)
		maxcpu = cpu;
	WARN_ON(maxcpu < 0);
	if (onoff_holdoff > 0) {
		VERBOSE_TOROUT_STRING("torture_onoff begin holdoff");
		schedule_timeout_interruptible(onoff_holdoff);
		VERBOSE_TOROUT_STRING("torture_onoff end holdoff");
	}
	while (!torture_must_stop()) {
		cpu = (torture_random(&rand) >> 4) % (maxcpu + 1);
		if (cpu_online(cpu) && cpu_is_hotpluggable(cpu)) {
			if (verbose)
				pr_alert("%s" TORTURE_FLAG
					 "torture_onoff task: offlining %d\n",
					 torture_type, cpu);
			starttime = jiffies;
			n_offline_attempts++;
			ret = cpu_down(cpu);
			if (ret) {
				if (verbose)
					pr_alert("%s" TORTURE_FLAG
						 "torture_onoff task: offline %d failed: errno %d\n",
						 torture_type, cpu, ret);
			} else {
				if (verbose)
					pr_alert("%s" TORTURE_FLAG
						 "torture_onoff task: offlined %d\n",
						 torture_type, cpu);
				n_offline_successes++;
				delta = jiffies - starttime;
				sum_offline += delta;
				if (min_offline < 0) {
					min_offline = delta;
					max_offline = delta;
				}
				if (min_offline > delta)
					min_offline = delta;
				if (max_offline < delta)
					max_offline = delta;
			}
		} else if (cpu_is_hotpluggable(cpu)) {
			if (verbose)
				pr_alert("%s" TORTURE_FLAG
					 "torture_onoff task: onlining %d\n",
					 torture_type, cpu);
			starttime = jiffies;
			n_online_attempts++;
			ret = cpu_up(cpu);
			if (ret) {
				if (verbose)
					pr_alert("%s" TORTURE_FLAG
						 "torture_onoff task: online %d failed: errno %d\n",
						 torture_type, cpu, ret);
			} else {
				if (verbose)
					pr_alert("%s" TORTURE_FLAG
						 "torture_onoff task: onlined %d\n",
						 torture_type, cpu);
				n_online_successes++;
				delta = jiffies - starttime;
				sum_online += delta;
				if (min_online < 0) {
					min_online = delta;
					max_online = delta;
				}
				if (min_online > delta)
					min_online = delta;
				if (max_online < delta)
					max_online = delta;
			}
		}
		schedule_timeout_interruptible(onoff_interval);
	}
	VERBOSE_TOROUT_STRING("torture_onoff task stopping");
	return 0;
}

#endif /* #ifdef CONFIG_HOTPLUG_CPU */

/*
 * Initiate online-offline handling.
 */
int torture_onoff_init(long ooholdoff, long oointerval)
{
#ifdef CONFIG_HOTPLUG_CPU
	int ret;

	onoff_holdoff = ooholdoff;
	onoff_interval = oointerval;
	if (onoff_interval <= 0)
		return 0;
	onoff_task = kthread_run(torture_onoff, NULL, "torture_onoff");
	if (IS_ERR(onoff_task)) {
		ret = PTR_ERR(onoff_task);
		onoff_task = NULL;
		return ret;
	}
	torture_shuffle_task_register(onoff_task);
#endif /* #ifdef CONFIG_HOTPLUG_CPU */
	return 0;
}
EXPORT_SYMBOL_GPL(torture_onoff_init);

/*
 * Clean up after online/offline testing.
 */
void torture_onoff_cleanup(void)
{
#ifdef CONFIG_HOTPLUG_CPU
	if (onoff_task == NULL)
		return;
	VERBOSE_TOROUT_STRING("Stopping torture_onoff task");
	kthread_stop(onoff_task);
	onoff_task = NULL;
#endif /* #ifdef CONFIG_HOTPLUG_CPU */
}
EXPORT_SYMBOL_GPL(torture_onoff_cleanup);

/*
 * Print online/offline testing statistics.
 */
char *torture_onoff_stats(char *page)
{
#ifdef CONFIG_HOTPLUG_CPU
	page += sprintf(page,
		       "onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ",
		       n_online_successes, n_online_attempts,
		       n_offline_successes, n_offline_attempts,
		       min_online, max_online,
		       min_offline, max_offline,
		       sum_online, sum_offline, HZ);
#endif /* #ifdef CONFIG_HOTPLUG_CPU */
	return page;
}
EXPORT_SYMBOL_GPL(torture_onoff_stats);

/*
 * Were all the online/offline operations successful?
 */
bool torture_onoff_failures(void)
{
#ifdef CONFIG_HOTPLUG_CPU
	return n_online_successes != n_online_attempts ||
	       n_offline_successes != n_offline_attempts;
#else /* #ifdef CONFIG_HOTPLUG_CPU */
	return false;
#endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
}
EXPORT_SYMBOL_GPL(torture_onoff_failures);

#define TORTURE_RANDOM_MULT	39916801  /* prime */
#define TORTURE_RANDOM_ADD	479001701 /* prime */
#define TORTURE_RANDOM_REFRESH	10000

/*
 * Crude but fast random-number generator.  Uses a linear congruential
 * generator, with occasional help from cpu_clock().
 */
unsigned long
torture_random(struct torture_random_state *trsp)
{
	if (--trsp->trs_count < 0) {
		trsp->trs_state += (unsigned long)local_clock();
		trsp->trs_count = TORTURE_RANDOM_REFRESH;
	}
	trsp->trs_state = trsp->trs_state * TORTURE_RANDOM_MULT +
		TORTURE_RANDOM_ADD;
	return swahw32(trsp->trs_state);
}
EXPORT_SYMBOL_GPL(torture_random);

/*
 * Variables for shuffling.  The idea is to ensure that each CPU stays
 * idle for an extended period to test interactions with dyntick idle,
 * as well as interactions with any per-CPU varibles.
 */
struct shuffle_task {
	struct list_head st_l;
	struct task_struct *st_t;
};

static long shuffle_interval;	/* In jiffies. */
static struct task_struct *shuffler_task;
static cpumask_var_t shuffle_tmp_mask;
static int shuffle_idle_cpu;	/* Force all torture tasks off this CPU */
static struct list_head shuffle_task_list = LIST_HEAD_INIT(shuffle_task_list);
static DEFINE_MUTEX(shuffle_task_mutex);

/*
 * Register a task to be shuffled.  If there is no memory, just splat
 * and don't bother registering.
 */
void torture_shuffle_task_register(struct task_struct *tp)
{
	struct shuffle_task *stp;

	if (WARN_ON_ONCE(tp == NULL))
		return;
	stp = kmalloc(sizeof(*stp), GFP_KERNEL);
	if (WARN_ON_ONCE(stp == NULL))
		return;
	stp->st_t = tp;
	mutex_lock(&shuffle_task_mutex);
	list_add(&stp->st_l, &shuffle_task_list);
	mutex_unlock(&shuffle_task_mutex);
}
EXPORT_SYMBOL_GPL(torture_shuffle_task_register);

/*
 * Unregister all tasks, for example, at the end of the torture run.
 */
static void torture_shuffle_task_unregister_all(void)
{
	struct shuffle_task *stp;
	struct shuffle_task *p;

	mutex_lock(&shuffle_task_mutex);
	list_for_each_entry_safe(stp, p, &shuffle_task_list, st_l) {
		list_del(&stp->st_l);
		kfree(stp);
	}
	mutex_unlock(&shuffle_task_mutex);
}

/* Shuffle tasks such that we allow shuffle_idle_cpu to become idle.
 * A special case is when shuffle_idle_cpu = -1, in which case we allow
 * the tasks to run on all CPUs.
 */
static void torture_shuffle_tasks(void)
{
	struct shuffle_task *stp;

	cpumask_setall(shuffle_tmp_mask);
	get_online_cpus();

	/* No point in shuffling if there is only one online CPU (ex: UP) */
	if (num_online_cpus() == 1) {
		put_online_cpus();
		return;
	}

	/* Advance to the next CPU.  Upon overflow, don't idle any CPUs. */
	shuffle_idle_cpu = cpumask_next(shuffle_idle_cpu, shuffle_tmp_mask);
	if (shuffle_idle_cpu >= nr_cpu_ids)
		shuffle_idle_cpu = -1;
	if (shuffle_idle_cpu != -1) {
		cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask);
		if (cpumask_empty(shuffle_tmp_mask)) {
			put_online_cpus();
			return;
		}
	}

	mutex_lock(&shuffle_task_mutex);
	list_for_each_entry(stp, &shuffle_task_list, st_l)
		set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask);
	mutex_unlock(&shuffle_task_mutex);

	put_online_cpus();
}

/* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
 * system to become idle at a time and cut off its timer ticks. This is meant
 * to test the support for such tickless idle CPU in RCU.
 */
static int torture_shuffle(void *arg)
{
	VERBOSE_TOROUT_STRING("torture_shuffle task started");
	do {
		schedule_timeout_interruptible(shuffle_interval);
		torture_shuffle_tasks();
		torture_shutdown_absorb("torture_shuffle");
	} while (!torture_must_stop());
	VERBOSE_TOROUT_STRING("torture_shuffle task stopping");
	return 0;
}

/*
 * Start the shuffler, with shuffint in jiffies.
 */
int torture_shuffle_init(long shuffint)
{
	int ret;

	shuffle_interval = shuffint;

	shuffle_idle_cpu = -1;

	if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
		VERBOSE_TOROUT_ERRSTRING("Failed to alloc mask");
		return -ENOMEM;
	}

	/* Create the shuffler thread */
	shuffler_task = kthread_run(torture_shuffle, NULL, "torture_shuffle");
	if (IS_ERR(shuffler_task)) {
		ret = PTR_ERR(shuffler_task);
		free_cpumask_var(shuffle_tmp_mask);
		VERBOSE_TOROUT_ERRSTRING("Failed to create shuffler");
		shuffler_task = NULL;
		return ret;
	}
	torture_shuffle_task_register(shuffler_task);
	return 0;
}
EXPORT_SYMBOL_GPL(torture_shuffle_init);

/*
 * Stop the shuffling.
 */
void torture_shuffle_cleanup(void)
{
	torture_shuffle_task_unregister_all();
	if (shuffler_task) {
		VERBOSE_TOROUT_STRING("Stopping torture_shuffle task");
		kthread_stop(shuffler_task);
		free_cpumask_var(shuffle_tmp_mask);
	}
	shuffler_task = NULL;
}
EXPORT_SYMBOL_GPL(torture_shuffle_cleanup);

/*
 * Absorb kthreads into a kernel function that won't return, so that
 * they won't ever access module text or data again.
 */
void torture_shutdown_absorb(const char *title)
{
	while (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
		pr_notice(
		       "torture thread %s parking due to system shutdown\n",
		       title);
		schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
	}
}
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);
Commit	Line	Data
51b1130e PM	1	/*
	2	* Common functions for in-kernel torture tests.
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License as published by
	6	* the Free Software Foundation; either version 2 of the License, or
	7	* (at your option) any later version.
	8	*
	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*
	14	* You should have received a copy of the GNU General Public License
	15	* along with this program; if not, you can access it online at
	16	* http://www.gnu.org/licenses/gpl-2.0.html.
	17	*
	18	* Copyright (C) IBM Corporation, 2014
	19	*
	20	* Author: Paul E. McKenney <paulmck@us.ibm.com>
	21	* Based on kernel/rcu/torture.c.
	22	*/
	23	#include <linux/types.h>
	24	#include <linux/kernel.h>
	25	#include <linux/init.h>
	26	#include <linux/module.h>
	27	#include <linux/kthread.h>
	28	#include <linux/err.h>
	29	#include <linux/spinlock.h>
	30	#include <linux/smp.h>
	31	#include <linux/interrupt.h>
	32	#include <linux/sched.h>
	33	#include <linux/atomic.h>
	34	#include <linux/bitops.h>
	35	#include <linux/completion.h>
	36	#include <linux/moduleparam.h>
	37	#include <linux/percpu.h>
	38	#include <linux/notifier.h>
	39	#include <linux/reboot.h>
	40	#include <linux/freezer.h>
	41	#include <linux/cpu.h>
	42	#include <linux/delay.h>
	43	#include <linux/stat.h>
	44	#include <linux/slab.h>
	45	#include <linux/trace_clock.h>
	46	#include <asm/byteorder.h>
	47	#include <linux/torture.h>
	48
	49	MODULE_LICENSE("GPL");
	50	MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
	51
b5daa8f3 PM	52	static char *torture_type;
	53	static bool verbose;
	54
f67a3356 PM	55	int fullstop = FULLSTOP_RMMOD;
	56	EXPORT_SYMBOL_GPL(fullstop);
	57	DEFINE_MUTEX(fullstop_mutex);
	58	EXPORT_SYMBOL_GPL(fullstop_mutex);
	59
2e9e8081 PM	60	#ifdef CONFIG_HOTPLUG_CPU
	61
	62	/*
	63	* Variables for online-offline handling. Only present if CPU hotplug
	64	* is enabled, otherwise does nothing.
	65	*/
	66
	67	static struct task_struct *onoff_task;
	68	static long onoff_holdoff;
	69	static long onoff_interval;
	70	static long n_offline_attempts;
	71	static long n_offline_successes;
	72	static unsigned long sum_offline;
	73	static int min_offline = -1;
	74	static int max_offline;
	75	static long n_online_attempts;
	76	static long n_online_successes;
	77	static unsigned long sum_online;
	78	static int min_online = -1;
	79	static int max_online;
	80
	81	/*
	82	* Execute random CPU-hotplug operations at the interval specified
	83	* by the onoff_interval.
	84	*/
	85	static int
	86	torture_onoff(void *arg)
	87	{
	88	int cpu;
	89	unsigned long delta;
	90	int maxcpu = -1;
	91	DEFINE_TORTURE_RANDOM(rand);
	92	int ret;
	93	unsigned long starttime;
	94
	95	VERBOSE_TOROUT_STRING("torture_onoff task started");
	96	for_each_online_cpu(cpu)
	97	maxcpu = cpu;
	98	WARN_ON(maxcpu < 0);
	99	if (onoff_holdoff > 0) {
	100	VERBOSE_TOROUT_STRING("torture_onoff begin holdoff");
	101	schedule_timeout_interruptible(onoff_holdoff);
	102	VERBOSE_TOROUT_STRING("torture_onoff end holdoff");
	103	}
	104	while (!torture_must_stop()) {
	105	cpu = (torture_random(&rand) >> 4) % (maxcpu + 1);
	106	if (cpu_online(cpu) && cpu_is_hotpluggable(cpu)) {
	107	if (verbose)
	108	pr_alert("%s" TORTURE_FLAG
	109	"torture_onoff task: offlining %d\n",
	110	torture_type, cpu);
	111	starttime = jiffies;
	112	n_offline_attempts++;
	113	ret = cpu_down(cpu);
	114	if (ret) {
	115	if (verbose)
	116	pr_alert("%s" TORTURE_FLAG
	117	"torture_onoff task: offline %d failed: errno %d\n",
	118	torture_type, cpu, ret);
	119	} else {
	120	if (verbose)
	121	pr_alert("%s" TORTURE_FLAG
	122	"torture_onoff task: offlined %d\n",
	123	torture_type, cpu);
124	n_offline_successes++;
125	delta = jiffies - starttime;
126	sum_offline += delta;
127	if (min_offline < 0) {
128	min_offline = delta;
129	max_offline = delta;
130	}
131	if (min_offline > delta)
132	min_offline = delta;
133	if (max_offline < delta)
134	max_offline = delta;
135	}
136	} else if (cpu_is_hotpluggable(cpu)) {
137	if (verbose)
138	pr_alert("%s" TORTURE_FLAG
139	"torture_onoff task: onlining %d\n",
140	torture_type, cpu);
141	starttime = jiffies;
142	n_online_attempts++;
143	ret = cpu_up(cpu);
144	if (ret) {
145	if (verbose)
146	pr_alert("%s" TORTURE_FLAG
147	"torture_onoff task: online %d failed: errno %d\n",
148	torture_type, cpu, ret);
149	} else {
150	if (verbose)
151	pr_alert("%s" TORTURE_FLAG
152	"torture_onoff task: onlined %d\n",
153	torture_type, cpu);
154	n_online_successes++;
155	delta = jiffies - starttime;
156	sum_online += delta;
157	if (min_online < 0) {
158	min_online = delta;
159	max_online = delta;
160	}
161	if (min_online > delta)
162	min_online = delta;
163	if (max_online < delta)
164	max_online = delta;
165	}
166	}
167	schedule_timeout_interruptible(onoff_interval);
168	}
169	VERBOSE_TOROUT_STRING("torture_onoff task stopping");
170	return 0;
171	}
172
173	#endif /* #ifdef CONFIG_HOTPLUG_CPU */
174
175	/*
176	* Initiate online-offline handling.
177	*/
178	int torture_onoff_init(long ooholdoff, long oointerval)
179	{
180	#ifdef CONFIG_HOTPLUG_CPU
181	int ret;
182
183	onoff_holdoff = ooholdoff;
184	onoff_interval = oointerval;
185	if (onoff_interval <= 0)
186	return 0;
187	onoff_task = kthread_run(torture_onoff, NULL, "torture_onoff");
188	if (IS_ERR(onoff_task)) {
189	ret = PTR_ERR(onoff_task);
190	onoff_task = NULL;
191	return ret;
192	}
193	torture_shuffle_task_register(onoff_task);
194	#endif /* #ifdef CONFIG_HOTPLUG_CPU */
195	return 0;
196	}
197	EXPORT_SYMBOL_GPL(torture_onoff_init);
198
199	/*
200	* Clean up after online/offline testing.
201	*/
202	void torture_onoff_cleanup(void)
203	{
204	#ifdef CONFIG_HOTPLUG_CPU
205	if (onoff_task == NULL)
206	return;
207	VERBOSE_TOROUT_STRING("Stopping torture_onoff task");
208	kthread_stop(onoff_task);
209	onoff_task = NULL;
210	#endif /* #ifdef CONFIG_HOTPLUG_CPU */
211	}
212	EXPORT_SYMBOL_GPL(torture_onoff_cleanup);
213
214	/*
215	* Print online/offline testing statistics.
216	*/
217	char torture_onoff_stats(char page)
218	{
219	#ifdef CONFIG_HOTPLUG_CPU
220	page += sprintf(page,
221	"onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ",
222	n_online_successes, n_online_attempts,
223	n_offline_successes, n_offline_attempts,
224	min_online, max_online,
225	min_offline, max_offline,
226	sum_online, sum_offline, HZ);
227	#endif /* #ifdef CONFIG_HOTPLUG_CPU */
228	return page;
229	}
230	EXPORT_SYMBOL_GPL(torture_onoff_stats);
231
232	/*
233	* Were all the online/offline operations successful?
234	*/
235	bool torture_onoff_failures(void)
236	{
237	#ifdef CONFIG_HOTPLUG_CPU
238	return n_online_successes != n_online_attempts \|\|
239	n_offline_successes != n_offline_attempts;
240	#else /* #ifdef CONFIG_HOTPLUG_CPU */
241	return false;
242	#endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
243	}
244	EXPORT_SYMBOL_GPL(torture_onoff_failures);
245
51b1130e PM	246	#define TORTURE_RANDOM_MULT 39916801 /* prime */
	247	#define TORTURE_RANDOM_ADD 479001701 /* prime */
	248	#define TORTURE_RANDOM_REFRESH 10000
	249
	250	/*
	251	* Crude but fast random-number generator. Uses a linear congruential
	252	* generator, with occasional help from cpu_clock().
	253	*/
	254	unsigned long
	255	torture_random(struct torture_random_state *trsp)
	256	{
	257	if (--trsp->trs_count < 0) {
	258	trsp->trs_state += (unsigned long)local_clock();
	259	trsp->trs_count = TORTURE_RANDOM_REFRESH;
	260	}
	261	trsp->trs_state = trsp->trs_state * TORTURE_RANDOM_MULT +
	262	TORTURE_RANDOM_ADD;
	263	return swahw32(trsp->trs_state);
	264	}
	265	EXPORT_SYMBOL_GPL(torture_random);
f67a3356	266
3808dc9f PM	267	/*
	268	* Variables for shuffling. The idea is to ensure that each CPU stays
	269	* idle for an extended period to test interactions with dyntick idle,
	270	* as well as interactions with any per-CPU varibles.
	271	*/
	272	struct shuffle_task {
	273	struct list_head st_l;
	274	struct task_struct *st_t;
	275	};
	276
	277	static long shuffle_interval; /* In jiffies. */
	278	static struct task_struct *shuffler_task;
	279	static cpumask_var_t shuffle_tmp_mask;
	280	static int shuffle_idle_cpu; /* Force all torture tasks off this CPU */
	281	static struct list_head shuffle_task_list = LIST_HEAD_INIT(shuffle_task_list);
	282	static DEFINE_MUTEX(shuffle_task_mutex);
	283
	284	/*
	285	* Register a task to be shuffled. If there is no memory, just splat
	286	* and don't bother registering.
	287	*/
	288	void torture_shuffle_task_register(struct task_struct *tp)
	289	{
	290	struct shuffle_task *stp;
	291
	292	if (WARN_ON_ONCE(tp == NULL))
	293	return;
	294	stp = kmalloc(sizeof(*stp), GFP_KERNEL);
	295	if (WARN_ON_ONCE(stp == NULL))
	296	return;
	297	stp->st_t = tp;
	298	mutex_lock(&shuffle_task_mutex);
	299	list_add(&stp->st_l, &shuffle_task_list);
	300	mutex_unlock(&shuffle_task_mutex);
	301	}
	302	EXPORT_SYMBOL_GPL(torture_shuffle_task_register);
	303
	304	/*
	305	* Unregister all tasks, for example, at the end of the torture run.
	306	*/
	307	static void torture_shuffle_task_unregister_all(void)
	308	{
	309	struct shuffle_task *stp;
	310	struct shuffle_task *p;
	311
	312	mutex_lock(&shuffle_task_mutex);
	313	list_for_each_entry_safe(stp, p, &shuffle_task_list, st_l) {
	314	list_del(&stp->st_l);
	315	kfree(stp);
	316	}
	317	mutex_unlock(&shuffle_task_mutex);
	318	}
	319
	320	/* Shuffle tasks such that we allow shuffle_idle_cpu to become idle.
	321	* A special case is when shuffle_idle_cpu = -1, in which case we allow
	322	* the tasks to run on all CPUs.
	323	*/
	324	static void torture_shuffle_tasks(void)
	325	{
	326	struct shuffle_task *stp;
	327
	328	cpumask_setall(shuffle_tmp_mask);
	329	get_online_cpus();
	330
331	/* No point in shuffling if there is only one online CPU (ex: UP) */
332	if (num_online_cpus() == 1) {
333	put_online_cpus();
334	return;
335	}
336
337	/* Advance to the next CPU. Upon overflow, don't idle any CPUs. */
338	shuffle_idle_cpu = cpumask_next(shuffle_idle_cpu, shuffle_tmp_mask);
339	if (shuffle_idle_cpu >= nr_cpu_ids)
340	shuffle_idle_cpu = -1;
341	if (shuffle_idle_cpu != -1) {
342	cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask);
343	if (cpumask_empty(shuffle_tmp_mask)) {
344	put_online_cpus();
345	return;
346	}
347	}
348
349	mutex_lock(&shuffle_task_mutex);
350	list_for_each_entry(stp, &shuffle_task_list, st_l)
351	set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask);
352	mutex_unlock(&shuffle_task_mutex);
353
354	put_online_cpus();
355	}
356
357	/* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
358	* system to become idle at a time and cut off its timer ticks. This is meant
359	* to test the support for such tickless idle CPU in RCU.
360	*/
361	static int torture_shuffle(void *arg)
362	{
363	VERBOSE_TOROUT_STRING("torture_shuffle task started");
364	do {
365	schedule_timeout_interruptible(shuffle_interval);
366	torture_shuffle_tasks();
367	torture_shutdown_absorb("torture_shuffle");
368	} while (!torture_must_stop());
369	VERBOSE_TOROUT_STRING("torture_shuffle task stopping");
370	return 0;
371	}
372
373	/*
374	* Start the shuffler, with shuffint in jiffies.
375	*/
376	int torture_shuffle_init(long shuffint)
377	{
378	int ret;
379
380	shuffle_interval = shuffint;
381
382	shuffle_idle_cpu = -1;
383
384	if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
385	VERBOSE_TOROUT_ERRSTRING("Failed to alloc mask");
386	return -ENOMEM;
387	}
388
389	/* Create the shuffler thread */
390	shuffler_task = kthread_run(torture_shuffle, NULL, "torture_shuffle");
391	if (IS_ERR(shuffler_task)) {
392	ret = PTR_ERR(shuffler_task);
393	free_cpumask_var(shuffle_tmp_mask);
394	VERBOSE_TOROUT_ERRSTRING("Failed to create shuffler");
395	shuffler_task = NULL;
396	return ret;
397	}
398	torture_shuffle_task_register(shuffler_task);
399	return 0;
400	}
401	EXPORT_SYMBOL_GPL(torture_shuffle_init);
402
403	/*
404	* Stop the shuffling.
405	*/
406	void torture_shuffle_cleanup(void)
407	{
408	torture_shuffle_task_unregister_all();
409	if (shuffler_task) {
410	VERBOSE_TOROUT_STRING("Stopping torture_shuffle task");
411	kthread_stop(shuffler_task);
412	free_cpumask_var(shuffle_tmp_mask);
413	}
414	shuffler_task = NULL;
415	}
416	EXPORT_SYMBOL_GPL(torture_shuffle_cleanup);
417
f67a3356 PM	418	/*
	419	* Absorb kthreads into a kernel function that won't return, so that
	420	* they won't ever access module text or data again.
	421	*/
	422	void torture_shutdown_absorb(const char *title)
	423	{
	424	while (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
	425	pr_notice(
	426	"torture thread %s parking due to system shutdown\n",
	427	title);
	428	schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
	429	}
	430	}
	431	EXPORT_SYMBOL_GPL(torture_shutdown_absorb);
b5daa8f3 PM	432
	433	/*
	434	* Initialize torture module. Please note that this is -not- invoked via
	435	* the usual module_init() mechanism, but rather by an explicit call from
	436	* the client torture module. This call must be paired with a later
	437	* torture_init_end().
	438	*/
	439	void __init torture_init_begin(char *ttype, bool v)
	440	{
	441	mutex_lock(&fullstop_mutex);
	442	torture_type = ttype;
	443	verbose = v;
	444
	445	}
	446	EXPORT_SYMBOL_GPL(torture_init_begin);
	447
	448	/*
	449	* Tell the torture module that initialization is complete.
	450	*/
	451	void __init torture_init_end(void)
	452	{
	453	mutex_unlock(&fullstop_mutex);
	454	}
	455	EXPORT_SYMBOL_GPL(torture_init_end);