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Date:	Thu, 10 Jan 2008 17:27:51 +0530
From:	Ananth N Mavinakayanahalli <ananth@...ibm.com>
To:	lkml <linux-kernel@...r.kernel.org>
Cc:	akpm@...ux-foundation.org, mingo@...e.hu, ak@...e.de,
	sam@...nborg.org, paulmck@...ux.vnet.ibm.com,
	Dipankar Sarma <dipankar@...ibm.com>, josh@...nel.org,
	ego@...ibm.com
Subject: [PATCH 3/7] Move rcutorture to tests/

From: Ananth N Mavinakayanahalli <ananth@...ibm.com>

Move the rcutorture infrastructure to tests/

Signed-off-by: Ananth N Mavinakayanahalli <ananth@...ibm.com>
---
 kernel/rcutorture.c |  995 ----------------------------------------------------
 kernel/Makefile     |    1 
 lib/Kconfig.debug   |   13 
 tests/Kconfig       |   13 
 tests/Makefile      |    1 
 tests/rcutorture.c  |  995 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 1009 insertions(+), 1009 deletions(-)

Index: linux-2.6.24-rc6/kernel/Makefile
===================================================================
--- linux-2.6.24-rc6.orig/kernel/Makefile
+++ linux-2.6.24-rc6/kernel/Makefile
@@ -56,7 +56,6 @@ obj-$(CONFIG_DETECT_SOFTLOCKUP) += softl
 obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
 obj-$(CONFIG_SECCOMP) += seccomp.o
 obj-$(CONFIG_DEBUG_SYNCHRO_TEST) += synchro-test.o
-obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o
 obj-$(CONFIG_CLASSIC_RCU) += rcuclassic.o
 obj-$(CONFIG_PREEMPT_RCU) += rcupreempt.o
 ifeq ($(CONFIG_PREEMPT_RCU),y)
Index: linux-2.6.24-rc6/kernel/rcutorture.c
===================================================================
--- linux-2.6.24-rc6.orig/kernel/rcutorture.c
+++ /dev/null
@@ -1,995 +0,0 @@
-/*
- * Read-Copy Update module-based torture test facility
- *
- * 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, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
- * Copyright (C) IBM Corporation, 2005, 2006
- *
- * Authors: Paul E. McKenney <paulmck@...ibm.com>
- *          Josh Triplett <josh@...edesktop.org>
- *
- * See also:  Documentation/RCU/torture.txt
- */
-#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/rcupdate.h>
-#include <linux/interrupt.h>
-#include <linux/sched.h>
-#include <asm/atomic.h>
-#include <linux/bitops.h>
-#include <linux/completion.h>
-#include <linux/moduleparam.h>
-#include <linux/percpu.h>
-#include <linux/notifier.h>
-#include <linux/freezer.h>
-#include <linux/cpu.h>
-#include <linux/delay.h>
-#include <linux/byteorder/swabb.h>
-#include <linux/stat.h>
-#include <linux/srcu.h>
-
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Paul E. McKenney <paulmck@...ibm.com> and "
-              "Josh Triplett <josh@...edesktop.org>");
-
-static int nreaders = -1;	/* # reader threads, defaults to 2*ncpus */
-static int nfakewriters = 4;	/* # fake writer threads */
-static int stat_interval;	/* Interval between stats, in seconds. */
-				/*  Defaults to "only at end of test". */
-static int verbose;		/* Print more debug info. */
-static int test_no_idle_hz;	/* Test RCU's support for tickless idle CPUs. */
-static int shuffle_interval = 5; /* Interval between shuffles (in sec)*/
-static char *torture_type = "rcu"; /* What RCU implementation to torture. */
-
-module_param(nreaders, int, 0444);
-MODULE_PARM_DESC(nreaders, "Number of RCU reader threads");
-module_param(nfakewriters, int, 0444);
-MODULE_PARM_DESC(nfakewriters, "Number of RCU fake writer threads");
-module_param(stat_interval, int, 0444);
-MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s");
-module_param(verbose, bool, 0444);
-MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s");
-module_param(test_no_idle_hz, bool, 0444);
-MODULE_PARM_DESC(test_no_idle_hz, "Test support for tickless idle CPUs");
-module_param(shuffle_interval, int, 0444);
-MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles");
-module_param(torture_type, charp, 0444);
-MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, srcu)");
-
-#define TORTURE_FLAG "-torture:"
-#define PRINTK_STRING(s) \
-	do { printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
-#define VERBOSE_PRINTK_STRING(s) \
-	do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
-#define VERBOSE_PRINTK_ERRSTRING(s) \
-	do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG "!!! " s "\n", torture_type); } while (0)
-
-static char printk_buf[4096];
-
-static int nrealreaders;
-static struct task_struct *writer_task;
-static struct task_struct **fakewriter_tasks;
-static struct task_struct **reader_tasks;
-static struct task_struct *stats_task;
-static struct task_struct *shuffler_task;
-
-#define RCU_TORTURE_PIPE_LEN 10
-
-struct rcu_torture {
-	struct rcu_head rtort_rcu;
-	int rtort_pipe_count;
-	struct list_head rtort_free;
-	int rtort_mbtest;
-};
-
-static int fullstop = 0;	/* stop generating callbacks at test end. */
-static LIST_HEAD(rcu_torture_freelist);
-static struct rcu_torture *rcu_torture_current = NULL;
-static long rcu_torture_current_version = 0;
-static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
-static DEFINE_SPINLOCK(rcu_torture_lock);
-static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) =
-	{ 0 };
-static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) =
-	{ 0 };
-static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
-static atomic_t n_rcu_torture_alloc;
-static atomic_t n_rcu_torture_alloc_fail;
-static atomic_t n_rcu_torture_free;
-static atomic_t n_rcu_torture_mberror;
-static atomic_t n_rcu_torture_error;
-static struct list_head rcu_torture_removed;
-
-/*
- * Allocate an element from the rcu_tortures pool.
- */
-static struct rcu_torture *
-rcu_torture_alloc(void)
-{
-	struct list_head *p;
-
-	spin_lock_bh(&rcu_torture_lock);
-	if (list_empty(&rcu_torture_freelist)) {
-		atomic_inc(&n_rcu_torture_alloc_fail);
-		spin_unlock_bh(&rcu_torture_lock);
-		return NULL;
-	}
-	atomic_inc(&n_rcu_torture_alloc);
-	p = rcu_torture_freelist.next;
-	list_del_init(p);
-	spin_unlock_bh(&rcu_torture_lock);
-	return container_of(p, struct rcu_torture, rtort_free);
-}
-
-/*
- * Free an element to the rcu_tortures pool.
- */
-static void
-rcu_torture_free(struct rcu_torture *p)
-{
-	atomic_inc(&n_rcu_torture_free);
-	spin_lock_bh(&rcu_torture_lock);
-	list_add_tail(&p->rtort_free, &rcu_torture_freelist);
-	spin_unlock_bh(&rcu_torture_lock);
-}
-
-struct rcu_random_state {
-	unsigned long rrs_state;
-	long rrs_count;
-};
-
-#define RCU_RANDOM_MULT 39916801  /* prime */
-#define RCU_RANDOM_ADD	479001701 /* prime */
-#define RCU_RANDOM_REFRESH 10000
-
-#define DEFINE_RCU_RANDOM(name) struct rcu_random_state name = { 0, 0 }
-
-/*
- * Crude but fast random-number generator.  Uses a linear congruential
- * generator, with occasional help from cpu_clock().
- */
-static unsigned long
-rcu_random(struct rcu_random_state *rrsp)
-{
-	if (--rrsp->rrs_count < 0) {
-		rrsp->rrs_state +=
-			(unsigned long)cpu_clock(raw_smp_processor_id());
-		rrsp->rrs_count = RCU_RANDOM_REFRESH;
-	}
-	rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD;
-	return swahw32(rrsp->rrs_state);
-}
-
-/*
- * Operations vector for selecting different types of tests.
- */
-
-struct rcu_torture_ops {
-	void (*init)(void);
-	void (*cleanup)(void);
-	int (*readlock)(void);
-	void (*readdelay)(struct rcu_random_state *rrsp);
-	void (*readunlock)(int idx);
-	int (*completed)(void);
-	void (*deferredfree)(struct rcu_torture *p);
-	void (*sync)(void);
-	int (*stats)(char *page);
-	char *name;
-};
-static struct rcu_torture_ops *cur_ops = NULL;
-
-/*
- * Definitions for rcu torture testing.
- */
-
-static int rcu_torture_read_lock(void) __acquires(RCU)
-{
-	rcu_read_lock();
-	return 0;
-}
-
-static void rcu_read_delay(struct rcu_random_state *rrsp)
-{
-	long delay;
-	const long longdelay = 200;
-
-	/* We want there to be long-running readers, but not all the time. */
-
-	delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay);
-	if (!delay)
-		udelay(longdelay);
-}
-
-static void rcu_torture_read_unlock(int idx) __releases(RCU)
-{
-	rcu_read_unlock();
-}
-
-static int rcu_torture_completed(void)
-{
-	return rcu_batches_completed();
-}
-
-static void
-rcu_torture_cb(struct rcu_head *p)
-{
-	int i;
-	struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
-
-	if (fullstop) {
-		/* Test is ending, just drop callbacks on the floor. */
-		/* The next initialization will pick up the pieces. */
-		return;
-	}
-	i = rp->rtort_pipe_count;
-	if (i > RCU_TORTURE_PIPE_LEN)
-		i = RCU_TORTURE_PIPE_LEN;
-	atomic_inc(&rcu_torture_wcount[i]);
-	if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
-		rp->rtort_mbtest = 0;
-		rcu_torture_free(rp);
-	} else
-		cur_ops->deferredfree(rp);
-}
-
-static void rcu_torture_deferred_free(struct rcu_torture *p)
-{
-	call_rcu(&p->rtort_rcu, rcu_torture_cb);
-}
-
-static struct rcu_torture_ops rcu_ops = {
-	.init = NULL,
-	.cleanup = NULL,
-	.readlock = rcu_torture_read_lock,
-	.readdelay = rcu_read_delay,
-	.readunlock = rcu_torture_read_unlock,
-	.completed = rcu_torture_completed,
-	.deferredfree = rcu_torture_deferred_free,
-	.sync = synchronize_rcu,
-	.stats = NULL,
-	.name = "rcu"
-};
-
-static void rcu_sync_torture_deferred_free(struct rcu_torture *p)
-{
-	int i;
-	struct rcu_torture *rp;
-	struct rcu_torture *rp1;
-
-	cur_ops->sync();
-	list_add(&p->rtort_free, &rcu_torture_removed);
-	list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
-		i = rp->rtort_pipe_count;
-		if (i > RCU_TORTURE_PIPE_LEN)
-			i = RCU_TORTURE_PIPE_LEN;
-		atomic_inc(&rcu_torture_wcount[i]);
-		if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
-			rp->rtort_mbtest = 0;
-			list_del(&rp->rtort_free);
-			rcu_torture_free(rp);
-		}
-	}
-}
-
-static void rcu_sync_torture_init(void)
-{
-	INIT_LIST_HEAD(&rcu_torture_removed);
-}
-
-static struct rcu_torture_ops rcu_sync_ops = {
-	.init = rcu_sync_torture_init,
-	.cleanup = NULL,
-	.readlock = rcu_torture_read_lock,
-	.readdelay = rcu_read_delay,
-	.readunlock = rcu_torture_read_unlock,
-	.completed = rcu_torture_completed,
-	.deferredfree = rcu_sync_torture_deferred_free,
-	.sync = synchronize_rcu,
-	.stats = NULL,
-	.name = "rcu_sync"
-};
-
-/*
- * Definitions for rcu_bh torture testing.
- */
-
-static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
-{
-	rcu_read_lock_bh();
-	return 0;
-}
-
-static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
-{
-	rcu_read_unlock_bh();
-}
-
-static int rcu_bh_torture_completed(void)
-{
-	return rcu_batches_completed_bh();
-}
-
-static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
-{
-	call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
-}
-
-struct rcu_bh_torture_synchronize {
-	struct rcu_head head;
-	struct completion completion;
-};
-
-static void rcu_bh_torture_wakeme_after_cb(struct rcu_head *head)
-{
-	struct rcu_bh_torture_synchronize *rcu;
-
-	rcu = container_of(head, struct rcu_bh_torture_synchronize, head);
-	complete(&rcu->completion);
-}
-
-static void rcu_bh_torture_synchronize(void)
-{
-	struct rcu_bh_torture_synchronize rcu;
-
-	init_completion(&rcu.completion);
-	call_rcu_bh(&rcu.head, rcu_bh_torture_wakeme_after_cb);
-	wait_for_completion(&rcu.completion);
-}
-
-static struct rcu_torture_ops rcu_bh_ops = {
-	.init = NULL,
-	.cleanup = NULL,
-	.readlock = rcu_bh_torture_read_lock,
-	.readdelay = rcu_read_delay,  /* just reuse rcu's version. */
-	.readunlock = rcu_bh_torture_read_unlock,
-	.completed = rcu_bh_torture_completed,
-	.deferredfree = rcu_bh_torture_deferred_free,
-	.sync = rcu_bh_torture_synchronize,
-	.stats = NULL,
-	.name = "rcu_bh"
-};
-
-static struct rcu_torture_ops rcu_bh_sync_ops = {
-	.init = rcu_sync_torture_init,
-	.cleanup = NULL,
-	.readlock = rcu_bh_torture_read_lock,
-	.readdelay = rcu_read_delay,  /* just reuse rcu's version. */
-	.readunlock = rcu_bh_torture_read_unlock,
-	.completed = rcu_bh_torture_completed,
-	.deferredfree = rcu_sync_torture_deferred_free,
-	.sync = rcu_bh_torture_synchronize,
-	.stats = NULL,
-	.name = "rcu_bh_sync"
-};
-
-/*
- * Definitions for srcu torture testing.
- */
-
-static struct srcu_struct srcu_ctl;
-
-static void srcu_torture_init(void)
-{
-	init_srcu_struct(&srcu_ctl);
-	rcu_sync_torture_init();
-}
-
-static void srcu_torture_cleanup(void)
-{
-	synchronize_srcu(&srcu_ctl);
-	cleanup_srcu_struct(&srcu_ctl);
-}
-
-static int srcu_torture_read_lock(void) __acquires(&srcu_ctl)
-{
-	return srcu_read_lock(&srcu_ctl);
-}
-
-static void srcu_read_delay(struct rcu_random_state *rrsp)
-{
-	long delay;
-	const long uspertick = 1000000 / HZ;
-	const long longdelay = 10;
-
-	/* We want there to be long-running readers, but not all the time. */
-
-	delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay * uspertick);
-	if (!delay)
-		schedule_timeout_interruptible(longdelay);
-}
-
-static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl)
-{
-	srcu_read_unlock(&srcu_ctl, idx);
-}
-
-static int srcu_torture_completed(void)
-{
-	return srcu_batches_completed(&srcu_ctl);
-}
-
-static void srcu_torture_synchronize(void)
-{
-	synchronize_srcu(&srcu_ctl);
-}
-
-static int srcu_torture_stats(char *page)
-{
-	int cnt = 0;
-	int cpu;
-	int idx = srcu_ctl.completed & 0x1;
-
-	cnt += sprintf(&page[cnt], "%s%s per-CPU(idx=%d):",
-		       torture_type, TORTURE_FLAG, idx);
-	for_each_possible_cpu(cpu) {
-		cnt += sprintf(&page[cnt], " %d(%d,%d)", cpu,
-			       per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx],
-			       per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx]);
-	}
-	cnt += sprintf(&page[cnt], "\n");
-	return cnt;
-}
-
-static struct rcu_torture_ops srcu_ops = {
-	.init = srcu_torture_init,
-	.cleanup = srcu_torture_cleanup,
-	.readlock = srcu_torture_read_lock,
-	.readdelay = srcu_read_delay,
-	.readunlock = srcu_torture_read_unlock,
-	.completed = srcu_torture_completed,
-	.deferredfree = rcu_sync_torture_deferred_free,
-	.sync = srcu_torture_synchronize,
-	.stats = srcu_torture_stats,
-	.name = "srcu"
-};
-
-/*
- * Definitions for sched torture testing.
- */
-
-static int sched_torture_read_lock(void)
-{
-	preempt_disable();
-	return 0;
-}
-
-static void sched_torture_read_unlock(int idx)
-{
-	preempt_enable();
-}
-
-static int sched_torture_completed(void)
-{
-	return 0;
-}
-
-static void sched_torture_synchronize(void)
-{
-	synchronize_sched();
-}
-
-static struct rcu_torture_ops sched_ops = {
-	.init = rcu_sync_torture_init,
-	.cleanup = NULL,
-	.readlock = sched_torture_read_lock,
-	.readdelay = rcu_read_delay,  /* just reuse rcu's version. */
-	.readunlock = sched_torture_read_unlock,
-	.completed = sched_torture_completed,
-	.deferredfree = rcu_sync_torture_deferred_free,
-	.sync = sched_torture_synchronize,
-	.stats = NULL,
-	.name = "sched"
-};
-
-/*
- * RCU torture writer kthread.  Repeatedly substitutes a new structure
- * for that pointed to by rcu_torture_current, freeing the old structure
- * after a series of grace periods (the "pipeline").
- */
-static int
-rcu_torture_writer(void *arg)
-{
-	int i;
-	long oldbatch = rcu_batches_completed();
-	struct rcu_torture *rp;
-	struct rcu_torture *old_rp;
-	static DEFINE_RCU_RANDOM(rand);
-
-	VERBOSE_PRINTK_STRING("rcu_torture_writer task started");
-	set_user_nice(current, 19);
-
-	do {
-		schedule_timeout_uninterruptible(1);
-		if ((rp = rcu_torture_alloc()) == NULL)
-			continue;
-		rp->rtort_pipe_count = 0;
-		udelay(rcu_random(&rand) & 0x3ff);
-		old_rp = rcu_torture_current;
-		rp->rtort_mbtest = 1;
-		rcu_assign_pointer(rcu_torture_current, rp);
-		smp_wmb();
-		if (old_rp) {
-			i = old_rp->rtort_pipe_count;
-			if (i > RCU_TORTURE_PIPE_LEN)
-				i = RCU_TORTURE_PIPE_LEN;
-			atomic_inc(&rcu_torture_wcount[i]);
-			old_rp->rtort_pipe_count++;
-			cur_ops->deferredfree(old_rp);
-		}
-		rcu_torture_current_version++;
-		oldbatch = cur_ops->completed();
-	} while (!kthread_should_stop() && !fullstop);
-	VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
-	while (!kthread_should_stop())
-		schedule_timeout_uninterruptible(1);
-	return 0;
-}
-
-/*
- * RCU torture fake writer kthread.  Repeatedly calls sync, with a random
- * delay between calls.
- */
-static int
-rcu_torture_fakewriter(void *arg)
-{
-	DEFINE_RCU_RANDOM(rand);
-
-	VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started");
-	set_user_nice(current, 19);
-
-	do {
-		schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10);
-		udelay(rcu_random(&rand) & 0x3ff);
-		cur_ops->sync();
-	} while (!kthread_should_stop() && !fullstop);
-
-	VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
-	while (!kthread_should_stop())
-		schedule_timeout_uninterruptible(1);
-	return 0;
-}
-
-/*
- * RCU torture reader kthread.  Repeatedly dereferences rcu_torture_current,
- * incrementing the corresponding element of the pipeline array.  The
- * counter in the element should never be greater than 1, otherwise, the
- * RCU implementation is broken.
- */
-static int
-rcu_torture_reader(void *arg)
-{
-	int completed;
-	int idx;
-	DEFINE_RCU_RANDOM(rand);
-	struct rcu_torture *p;
-	int pipe_count;
-
-	VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
-	set_user_nice(current, 19);
-
-	do {
-		idx = cur_ops->readlock();
-		completed = cur_ops->completed();
-		p = rcu_dereference(rcu_torture_current);
-		if (p == NULL) {
-			/* Wait for rcu_torture_writer to get underway */
-			cur_ops->readunlock(idx);
-			schedule_timeout_interruptible(HZ);
-			continue;
-		}
-		if (p->rtort_mbtest == 0)
-			atomic_inc(&n_rcu_torture_mberror);
-		cur_ops->readdelay(&rand);
-		preempt_disable();
-		pipe_count = p->rtort_pipe_count;
-		if (pipe_count > RCU_TORTURE_PIPE_LEN) {
-			/* Should not happen, but... */
-			pipe_count = RCU_TORTURE_PIPE_LEN;
-		}
-		++__get_cpu_var(rcu_torture_count)[pipe_count];
-		completed = cur_ops->completed() - completed;
-		if (completed > RCU_TORTURE_PIPE_LEN) {
-			/* Should not happen, but... */
-			completed = RCU_TORTURE_PIPE_LEN;
-		}
-		++__get_cpu_var(rcu_torture_batch)[completed];
-		preempt_enable();
-		cur_ops->readunlock(idx);
-		schedule();
-	} while (!kthread_should_stop() && !fullstop);
-	VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
-	while (!kthread_should_stop())
-		schedule_timeout_uninterruptible(1);
-	return 0;
-}
-
-/*
- * Create an RCU-torture statistics message in the specified buffer.
- */
-static int
-rcu_torture_printk(char *page)
-{
-	int cnt = 0;
-	int cpu;
-	int i;
-	long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
-	long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
-
-	for_each_possible_cpu(cpu) {
-		for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
-			pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
-			batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
-		}
-	}
-	for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
-		if (pipesummary[i] != 0)
-			break;
-	}
-	cnt += sprintf(&page[cnt], "%s%s ", torture_type, TORTURE_FLAG);
-	cnt += sprintf(&page[cnt],
-		       "rtc: %p ver: %ld tfle: %d rta: %d rtaf: %d rtf: %d "
-		       "rtmbe: %d",
-		       rcu_torture_current,
-		       rcu_torture_current_version,
-		       list_empty(&rcu_torture_freelist),
-		       atomic_read(&n_rcu_torture_alloc),
-		       atomic_read(&n_rcu_torture_alloc_fail),
-		       atomic_read(&n_rcu_torture_free),
-		       atomic_read(&n_rcu_torture_mberror));
-	if (atomic_read(&n_rcu_torture_mberror) != 0)
-		cnt += sprintf(&page[cnt], " !!!");
-	cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
-	if (i > 1) {
-		cnt += sprintf(&page[cnt], "!!! ");
-		atomic_inc(&n_rcu_torture_error);
-	}
-	cnt += sprintf(&page[cnt], "Reader Pipe: ");
-	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
-		cnt += sprintf(&page[cnt], " %ld", pipesummary[i]);
-	cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
-	cnt += sprintf(&page[cnt], "Reader Batch: ");
-	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
-		cnt += sprintf(&page[cnt], " %ld", batchsummary[i]);
-	cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
-	cnt += sprintf(&page[cnt], "Free-Block Circulation: ");
-	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
-		cnt += sprintf(&page[cnt], " %d",
-			       atomic_read(&rcu_torture_wcount[i]));
-	}
-	cnt += sprintf(&page[cnt], "\n");
-	if (cur_ops->stats)
-		cnt += cur_ops->stats(&page[cnt]);
-	return cnt;
-}
-
-/*
- * Print torture statistics.  Caller must ensure that there is only
- * one call to this function at a given time!!!  This is normally
- * accomplished by relying on the module system to only have one copy
- * of the module loaded, and then by giving the rcu_torture_stats
- * kthread full control (or the init/cleanup functions when rcu_torture_stats
- * thread is not running).
- */
-static void
-rcu_torture_stats_print(void)
-{
-	int cnt;
-
-	cnt = rcu_torture_printk(printk_buf);
-	printk(KERN_ALERT "%s", printk_buf);
-}
-
-/*
- * Periodically prints torture statistics, if periodic statistics printing
- * was specified via the stat_interval module parameter.
- *
- * No need to worry about fullstop here, since this one doesn't reference
- * volatile state or register callbacks.
- */
-static int
-rcu_torture_stats(void *arg)
-{
-	VERBOSE_PRINTK_STRING("rcu_torture_stats task started");
-	do {
-		schedule_timeout_interruptible(stat_interval * HZ);
-		rcu_torture_stats_print();
-	} while (!kthread_should_stop());
-	VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping");
-	return 0;
-}
-
-static int rcu_idle_cpu;	/* Force all torture tasks off this CPU */
-
-/* Shuffle tasks such that we allow @rcu_idle_cpu to become idle. A special case
- * is when @rcu_idle_cpu = -1, when we allow the tasks to run on all CPUs.
- */
-static void rcu_torture_shuffle_tasks(void)
-{
-	cpumask_t tmp_mask = CPU_MASK_ALL;
-	int i;
-
-	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;
-	}
-
-	if (rcu_idle_cpu != -1)
-		cpu_clear(rcu_idle_cpu, tmp_mask);
-
-	set_cpus_allowed(current, tmp_mask);
-
-	if (reader_tasks) {
-		for (i = 0; i < nrealreaders; i++)
-			if (reader_tasks[i])
-				set_cpus_allowed(reader_tasks[i], tmp_mask);
-	}
-
-	if (fakewriter_tasks) {
-		for (i = 0; i < nfakewriters; i++)
-			if (fakewriter_tasks[i])
-				set_cpus_allowed(fakewriter_tasks[i], tmp_mask);
-	}
-
-	if (writer_task)
-		set_cpus_allowed(writer_task, tmp_mask);
-
-	if (stats_task)
-		set_cpus_allowed(stats_task, tmp_mask);
-
-	if (rcu_idle_cpu == -1)
-		rcu_idle_cpu = num_online_cpus() - 1;
-	else
-		rcu_idle_cpu--;
-
-	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
-rcu_torture_shuffle(void *arg)
-{
-	VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started");
-	do {
-		schedule_timeout_interruptible(shuffle_interval * HZ);
-		rcu_torture_shuffle_tasks();
-	} while (!kthread_should_stop());
-	VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping");
-	return 0;
-}
-
-static inline void
-rcu_torture_print_module_parms(char *tag)
-{
-	printk(KERN_ALERT "%s" TORTURE_FLAG
-		"--- %s: nreaders=%d nfakewriters=%d "
-		"stat_interval=%d verbose=%d test_no_idle_hz=%d "
-		"shuffle_interval = %d\n",
-		torture_type, tag, nrealreaders, nfakewriters,
-		stat_interval, verbose, test_no_idle_hz, shuffle_interval);
-}
-
-static void
-rcu_torture_cleanup(void)
-{
-	int i;
-
-	fullstop = 1;
-	if (shuffler_task) {
-		VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task");
-		kthread_stop(shuffler_task);
-	}
-	shuffler_task = NULL;
-
-	if (writer_task) {
-		VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task");
-		kthread_stop(writer_task);
-	}
-	writer_task = NULL;
-
-	if (reader_tasks) {
-		for (i = 0; i < nrealreaders; i++) {
-			if (reader_tasks[i]) {
-				VERBOSE_PRINTK_STRING(
-					"Stopping rcu_torture_reader task");
-				kthread_stop(reader_tasks[i]);
-			}
-			reader_tasks[i] = NULL;
-		}
-		kfree(reader_tasks);
-		reader_tasks = NULL;
-	}
-	rcu_torture_current = NULL;
-
-	if (fakewriter_tasks) {
-		for (i = 0; i < nfakewriters; i++) {
-			if (fakewriter_tasks[i]) {
-				VERBOSE_PRINTK_STRING(
-					"Stopping rcu_torture_fakewriter task");
-				kthread_stop(fakewriter_tasks[i]);
-			}
-			fakewriter_tasks[i] = NULL;
-		}
-		kfree(fakewriter_tasks);
-		fakewriter_tasks = NULL;
-	}
-
-	if (stats_task) {
-		VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task");
-		kthread_stop(stats_task);
-	}
-	stats_task = NULL;
-
-	/* Wait for all RCU callbacks to fire.  */
-	rcu_barrier();
-
-	rcu_torture_stats_print();  /* -After- the stats thread is stopped! */
-
-	if (cur_ops->cleanup)
-		cur_ops->cleanup();
-	if (atomic_read(&n_rcu_torture_error))
-		rcu_torture_print_module_parms("End of test: FAILURE");
-	else
-		rcu_torture_print_module_parms("End of test: SUCCESS");
-}
-
-static int __init
-rcu_torture_init(void)
-{
-	int i;
-	int cpu;
-	int firsterr = 0;
-	static struct rcu_torture_ops *torture_ops[] =
-		{ &rcu_ops, &rcu_sync_ops, &rcu_bh_ops, &rcu_bh_sync_ops,
-		  &srcu_ops, &sched_ops, };
-
-	/* Process args and tell the world that the torturer is on the job. */
-	for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
-		cur_ops = torture_ops[i];
-		if (strcmp(torture_type, cur_ops->name) == 0)
-			break;
-	}
-	if (i == ARRAY_SIZE(torture_ops)) {
-		printk(KERN_ALERT "rcutorture: invalid torture type: \"%s\"\n",
-		       torture_type);
-		return (-EINVAL);
-	}
-	if (cur_ops->init)
-		cur_ops->init(); /* no "goto unwind" prior to this point!!! */
-
-	if (nreaders >= 0)
-		nrealreaders = nreaders;
-	else
-		nrealreaders = 2 * num_online_cpus();
-	rcu_torture_print_module_parms("Start of test");
-	fullstop = 0;
-
-	/* Set up the freelist. */
-
-	INIT_LIST_HEAD(&rcu_torture_freelist);
-	for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
-		rcu_tortures[i].rtort_mbtest = 0;
-		list_add_tail(&rcu_tortures[i].rtort_free,
-			      &rcu_torture_freelist);
-	}
-
-	/* Initialize the statistics so that each run gets its own numbers. */
-
-	rcu_torture_current = NULL;
-	rcu_torture_current_version = 0;
-	atomic_set(&n_rcu_torture_alloc, 0);
-	atomic_set(&n_rcu_torture_alloc_fail, 0);
-	atomic_set(&n_rcu_torture_free, 0);
-	atomic_set(&n_rcu_torture_mberror, 0);
-	atomic_set(&n_rcu_torture_error, 0);
-	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
-		atomic_set(&rcu_torture_wcount[i], 0);
-	for_each_possible_cpu(cpu) {
-		for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
-			per_cpu(rcu_torture_count, cpu)[i] = 0;
-			per_cpu(rcu_torture_batch, cpu)[i] = 0;
-		}
-	}
-
-	/* Start up the kthreads. */
-
-	VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task");
-	writer_task = kthread_run(rcu_torture_writer, NULL,
-				  "rcu_torture_writer");
-	if (IS_ERR(writer_task)) {
-		firsterr = PTR_ERR(writer_task);
-		VERBOSE_PRINTK_ERRSTRING("Failed to create writer");
-		writer_task = NULL;
-		goto unwind;
-	}
-	fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]),
-	                           GFP_KERNEL);
-	if (fakewriter_tasks == NULL) {
-		VERBOSE_PRINTK_ERRSTRING("out of memory");
-		firsterr = -ENOMEM;
-		goto unwind;
-	}
-	for (i = 0; i < nfakewriters; i++) {
-		VERBOSE_PRINTK_STRING("Creating rcu_torture_fakewriter task");
-		fakewriter_tasks[i] = kthread_run(rcu_torture_fakewriter, NULL,
-		                                  "rcu_torture_fakewriter");
-		if (IS_ERR(fakewriter_tasks[i])) {
-			firsterr = PTR_ERR(fakewriter_tasks[i]);
-			VERBOSE_PRINTK_ERRSTRING("Failed to create fakewriter");
-			fakewriter_tasks[i] = NULL;
-			goto unwind;
-		}
-	}
-	reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
-			       GFP_KERNEL);
-	if (reader_tasks == NULL) {
-		VERBOSE_PRINTK_ERRSTRING("out of memory");
-		firsterr = -ENOMEM;
-		goto unwind;
-	}
-	for (i = 0; i < nrealreaders; i++) {
-		VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task");
-		reader_tasks[i] = kthread_run(rcu_torture_reader, NULL,
-					      "rcu_torture_reader");
-		if (IS_ERR(reader_tasks[i])) {
-			firsterr = PTR_ERR(reader_tasks[i]);
-			VERBOSE_PRINTK_ERRSTRING("Failed to create reader");
-			reader_tasks[i] = NULL;
-			goto unwind;
-		}
-	}
-	if (stat_interval > 0) {
-		VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task");
-		stats_task = kthread_run(rcu_torture_stats, NULL,
-					"rcu_torture_stats");
-		if (IS_ERR(stats_task)) {
-			firsterr = PTR_ERR(stats_task);
-			VERBOSE_PRINTK_ERRSTRING("Failed to create stats");
-			stats_task = NULL;
-			goto unwind;
-		}
-	}
-	if (test_no_idle_hz) {
-		rcu_idle_cpu = num_online_cpus() - 1;
-		/* Create the shuffler thread */
-		shuffler_task = kthread_run(rcu_torture_shuffle, NULL,
-					  "rcu_torture_shuffle");
-		if (IS_ERR(shuffler_task)) {
-			firsterr = PTR_ERR(shuffler_task);
-			VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler");
-			shuffler_task = NULL;
-			goto unwind;
-		}
-	}
-	return 0;
-
-unwind:
-	rcu_torture_cleanup();
-	return firsterr;
-}
-
-module_init(rcu_torture_init);
-module_exit(rcu_torture_cleanup);
Index: linux-2.6.24-rc6/lib/Kconfig.debug
===================================================================
--- linux-2.6.24-rc6.orig/lib/Kconfig.debug
+++ linux-2.6.24-rc6/lib/Kconfig.debug
@@ -487,19 +487,6 @@ config DEBUG_SYNCHRO_TEST
 
 	  See Documentation/synchro-test.txt.
 
-config RCU_TORTURE_TEST
-	tristate "torture tests for RCU"
-	depends on DEBUG_KERNEL
-	depends on m
-	default n
-	help
-	  This option provides a kernel module that runs torture tests
-	  on the RCU infrastructure.  The kernel module may be built
-	  after the fact on the running kernel to be tested, if desired.
-
-	  Say M if you want the RCU torture tests to build as a module.
-	  Say N if you are unsure.
-
 config LKDTM
 	tristate "Linux Kernel Dump Test Tool Module"
 	depends on DEBUG_KERNEL
Index: linux-2.6.24-rc6/tests/Kconfig
===================================================================
--- linux-2.6.24-rc6.orig/tests/Kconfig
+++ linux-2.6.24-rc6/tests/Kconfig
@@ -18,5 +18,18 @@ config DEBUG_LOCKING_API_SELFTESTS
 	  The following locking APIs are covered: spinlocks, rwlocks,
 	  mutexes and rwsems.
 
+config RCU_TORTURE_TEST
+	tristate "torture tests for RCU"
+	depends on DEBUG_KERNEL
+	depends on m
+	default n
+	help
+	  This option provides a kernel module that runs torture tests
+	  on the RCU infrastructure.  The kernel module may be built
+	  after the fact on the running kernel to be tested, if desired.
+
+	  Say M if you want the RCU torture tests to build as a module.
+	  Say N if you are unsure.
+
 endif # KERNEL_TESTS
 
Index: linux-2.6.24-rc6/tests/Makefile
===================================================================
--- linux-2.6.24-rc6.orig/tests/Makefile
+++ linux-2.6.24-rc6/tests/Makefile
@@ -3,3 +3,4 @@
 #
 
 obj-$(CONFIG_DEBUG_LOCKING_API_SELFTESTS) += locking-selftest.o
+obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o
Index: linux-2.6.24-rc6/tests/rcutorture.c
===================================================================
--- /dev/null
+++ linux-2.6.24-rc6/tests/rcutorture.c
@@ -0,0 +1,995 @@
+/*
+ * Read-Copy Update module-based torture test facility
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) IBM Corporation, 2005, 2006
+ *
+ * Authors: Paul E. McKenney <paulmck@...ibm.com>
+ *          Josh Triplett <josh@...edesktop.org>
+ *
+ * See also:  Documentation/RCU/torture.txt
+ */
+#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/rcupdate.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <asm/atomic.h>
+#include <linux/bitops.h>
+#include <linux/completion.h>
+#include <linux/moduleparam.h>
+#include <linux/percpu.h>
+#include <linux/notifier.h>
+#include <linux/freezer.h>
+#include <linux/cpu.h>
+#include <linux/delay.h>
+#include <linux/byteorder/swabb.h>
+#include <linux/stat.h>
+#include <linux/srcu.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Paul E. McKenney <paulmck@...ibm.com> and "
+              "Josh Triplett <josh@...edesktop.org>");
+
+static int nreaders = -1;	/* # reader threads, defaults to 2*ncpus */
+static int nfakewriters = 4;	/* # fake writer threads */
+static int stat_interval;	/* Interval between stats, in seconds. */
+				/*  Defaults to "only at end of test". */
+static int verbose;		/* Print more debug info. */
+static int test_no_idle_hz;	/* Test RCU's support for tickless idle CPUs. */
+static int shuffle_interval = 5; /* Interval between shuffles (in sec)*/
+static char *torture_type = "rcu"; /* What RCU implementation to torture. */
+
+module_param(nreaders, int, 0444);
+MODULE_PARM_DESC(nreaders, "Number of RCU reader threads");
+module_param(nfakewriters, int, 0444);
+MODULE_PARM_DESC(nfakewriters, "Number of RCU fake writer threads");
+module_param(stat_interval, int, 0444);
+MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s");
+module_param(verbose, bool, 0444);
+MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s");
+module_param(test_no_idle_hz, bool, 0444);
+MODULE_PARM_DESC(test_no_idle_hz, "Test support for tickless idle CPUs");
+module_param(shuffle_interval, int, 0444);
+MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles");
+module_param(torture_type, charp, 0444);
+MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, srcu)");
+
+#define TORTURE_FLAG "-torture:"
+#define PRINTK_STRING(s) \
+	do { printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
+#define VERBOSE_PRINTK_STRING(s) \
+	do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
+#define VERBOSE_PRINTK_ERRSTRING(s) \
+	do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG "!!! " s "\n", torture_type); } while (0)
+
+static char printk_buf[4096];
+
+static int nrealreaders;
+static struct task_struct *writer_task;
+static struct task_struct **fakewriter_tasks;
+static struct task_struct **reader_tasks;
+static struct task_struct *stats_task;
+static struct task_struct *shuffler_task;
+
+#define RCU_TORTURE_PIPE_LEN 10
+
+struct rcu_torture {
+	struct rcu_head rtort_rcu;
+	int rtort_pipe_count;
+	struct list_head rtort_free;
+	int rtort_mbtest;
+};
+
+static int fullstop = 0;	/* stop generating callbacks at test end. */
+static LIST_HEAD(rcu_torture_freelist);
+static struct rcu_torture *rcu_torture_current = NULL;
+static long rcu_torture_current_version = 0;
+static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
+static DEFINE_SPINLOCK(rcu_torture_lock);
+static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) =
+	{ 0 };
+static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) =
+	{ 0 };
+static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
+static atomic_t n_rcu_torture_alloc;
+static atomic_t n_rcu_torture_alloc_fail;
+static atomic_t n_rcu_torture_free;
+static atomic_t n_rcu_torture_mberror;
+static atomic_t n_rcu_torture_error;
+static struct list_head rcu_torture_removed;
+
+/*
+ * Allocate an element from the rcu_tortures pool.
+ */
+static struct rcu_torture *
+rcu_torture_alloc(void)
+{
+	struct list_head *p;
+
+	spin_lock_bh(&rcu_torture_lock);
+	if (list_empty(&rcu_torture_freelist)) {
+		atomic_inc(&n_rcu_torture_alloc_fail);
+		spin_unlock_bh(&rcu_torture_lock);
+		return NULL;
+	}
+	atomic_inc(&n_rcu_torture_alloc);
+	p = rcu_torture_freelist.next;
+	list_del_init(p);
+	spin_unlock_bh(&rcu_torture_lock);
+	return container_of(p, struct rcu_torture, rtort_free);
+}
+
+/*
+ * Free an element to the rcu_tortures pool.
+ */
+static void
+rcu_torture_free(struct rcu_torture *p)
+{
+	atomic_inc(&n_rcu_torture_free);
+	spin_lock_bh(&rcu_torture_lock);
+	list_add_tail(&p->rtort_free, &rcu_torture_freelist);
+	spin_unlock_bh(&rcu_torture_lock);
+}
+
+struct rcu_random_state {
+	unsigned long rrs_state;
+	long rrs_count;
+};
+
+#define RCU_RANDOM_MULT 39916801  /* prime */
+#define RCU_RANDOM_ADD	479001701 /* prime */
+#define RCU_RANDOM_REFRESH 10000
+
+#define DEFINE_RCU_RANDOM(name) struct rcu_random_state name = { 0, 0 }
+
+/*
+ * Crude but fast random-number generator.  Uses a linear congruential
+ * generator, with occasional help from cpu_clock().
+ */
+static unsigned long
+rcu_random(struct rcu_random_state *rrsp)
+{
+	if (--rrsp->rrs_count < 0) {
+		rrsp->rrs_state +=
+			(unsigned long)cpu_clock(raw_smp_processor_id());
+		rrsp->rrs_count = RCU_RANDOM_REFRESH;
+	}
+	rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD;
+	return swahw32(rrsp->rrs_state);
+}
+
+/*
+ * Operations vector for selecting different types of tests.
+ */
+
+struct rcu_torture_ops {
+	void (*init)(void);
+	void (*cleanup)(void);
+	int (*readlock)(void);
+	void (*readdelay)(struct rcu_random_state *rrsp);
+	void (*readunlock)(int idx);
+	int (*completed)(void);
+	void (*deferredfree)(struct rcu_torture *p);
+	void (*sync)(void);
+	int (*stats)(char *page);
+	char *name;
+};
+static struct rcu_torture_ops *cur_ops = NULL;
+
+/*
+ * Definitions for rcu torture testing.
+ */
+
+static int rcu_torture_read_lock(void) __acquires(RCU)
+{
+	rcu_read_lock();
+	return 0;
+}
+
+static void rcu_read_delay(struct rcu_random_state *rrsp)
+{
+	long delay;
+	const long longdelay = 200;
+
+	/* We want there to be long-running readers, but not all the time. */
+
+	delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay);
+	if (!delay)
+		udelay(longdelay);
+}
+
+static void rcu_torture_read_unlock(int idx) __releases(RCU)
+{
+	rcu_read_unlock();
+}
+
+static int rcu_torture_completed(void)
+{
+	return rcu_batches_completed();
+}
+
+static void
+rcu_torture_cb(struct rcu_head *p)
+{
+	int i;
+	struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
+
+	if (fullstop) {
+		/* Test is ending, just drop callbacks on the floor. */
+		/* The next initialization will pick up the pieces. */
+		return;
+	}
+	i = rp->rtort_pipe_count;
+	if (i > RCU_TORTURE_PIPE_LEN)
+		i = RCU_TORTURE_PIPE_LEN;
+	atomic_inc(&rcu_torture_wcount[i]);
+	if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
+		rp->rtort_mbtest = 0;
+		rcu_torture_free(rp);
+	} else
+		cur_ops->deferredfree(rp);
+}
+
+static void rcu_torture_deferred_free(struct rcu_torture *p)
+{
+	call_rcu(&p->rtort_rcu, rcu_torture_cb);
+}
+
+static struct rcu_torture_ops rcu_ops = {
+	.init = NULL,
+	.cleanup = NULL,
+	.readlock = rcu_torture_read_lock,
+	.readdelay = rcu_read_delay,
+	.readunlock = rcu_torture_read_unlock,
+	.completed = rcu_torture_completed,
+	.deferredfree = rcu_torture_deferred_free,
+	.sync = synchronize_rcu,
+	.stats = NULL,
+	.name = "rcu"
+};
+
+static void rcu_sync_torture_deferred_free(struct rcu_torture *p)
+{
+	int i;
+	struct rcu_torture *rp;
+	struct rcu_torture *rp1;
+
+	cur_ops->sync();
+	list_add(&p->rtort_free, &rcu_torture_removed);
+	list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
+		i = rp->rtort_pipe_count;
+		if (i > RCU_TORTURE_PIPE_LEN)
+			i = RCU_TORTURE_PIPE_LEN;
+		atomic_inc(&rcu_torture_wcount[i]);
+		if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
+			rp->rtort_mbtest = 0;
+			list_del(&rp->rtort_free);
+			rcu_torture_free(rp);
+		}
+	}
+}
+
+static void rcu_sync_torture_init(void)
+{
+	INIT_LIST_HEAD(&rcu_torture_removed);
+}
+
+static struct rcu_torture_ops rcu_sync_ops = {
+	.init = rcu_sync_torture_init,
+	.cleanup = NULL,
+	.readlock = rcu_torture_read_lock,
+	.readdelay = rcu_read_delay,
+	.readunlock = rcu_torture_read_unlock,
+	.completed = rcu_torture_completed,
+	.deferredfree = rcu_sync_torture_deferred_free,
+	.sync = synchronize_rcu,
+	.stats = NULL,
+	.name = "rcu_sync"
+};
+
+/*
+ * Definitions for rcu_bh torture testing.
+ */
+
+static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
+{
+	rcu_read_lock_bh();
+	return 0;
+}
+
+static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
+{
+	rcu_read_unlock_bh();
+}
+
+static int rcu_bh_torture_completed(void)
+{
+	return rcu_batches_completed_bh();
+}
+
+static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
+{
+	call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
+}
+
+struct rcu_bh_torture_synchronize {
+	struct rcu_head head;
+	struct completion completion;
+};
+
+static void rcu_bh_torture_wakeme_after_cb(struct rcu_head *head)
+{
+	struct rcu_bh_torture_synchronize *rcu;
+
+	rcu = container_of(head, struct rcu_bh_torture_synchronize, head);
+	complete(&rcu->completion);
+}
+
+static void rcu_bh_torture_synchronize(void)
+{
+	struct rcu_bh_torture_synchronize rcu;
+
+	init_completion(&rcu.completion);
+	call_rcu_bh(&rcu.head, rcu_bh_torture_wakeme_after_cb);
+	wait_for_completion(&rcu.completion);
+}
+
+static struct rcu_torture_ops rcu_bh_ops = {
+	.init = NULL,
+	.cleanup = NULL,
+	.readlock = rcu_bh_torture_read_lock,
+	.readdelay = rcu_read_delay,  /* just reuse rcu's version. */
+	.readunlock = rcu_bh_torture_read_unlock,
+	.completed = rcu_bh_torture_completed,
+	.deferredfree = rcu_bh_torture_deferred_free,
+	.sync = rcu_bh_torture_synchronize,
+	.stats = NULL,
+	.name = "rcu_bh"
+};
+
+static struct rcu_torture_ops rcu_bh_sync_ops = {
+	.init = rcu_sync_torture_init,
+	.cleanup = NULL,
+	.readlock = rcu_bh_torture_read_lock,
+	.readdelay = rcu_read_delay,  /* just reuse rcu's version. */
+	.readunlock = rcu_bh_torture_read_unlock,
+	.completed = rcu_bh_torture_completed,
+	.deferredfree = rcu_sync_torture_deferred_free,
+	.sync = rcu_bh_torture_synchronize,
+	.stats = NULL,
+	.name = "rcu_bh_sync"
+};
+
+/*
+ * Definitions for srcu torture testing.
+ */
+
+static struct srcu_struct srcu_ctl;
+
+static void srcu_torture_init(void)
+{
+	init_srcu_struct(&srcu_ctl);
+	rcu_sync_torture_init();
+}
+
+static void srcu_torture_cleanup(void)
+{
+	synchronize_srcu(&srcu_ctl);
+	cleanup_srcu_struct(&srcu_ctl);
+}
+
+static int srcu_torture_read_lock(void) __acquires(&srcu_ctl)
+{
+	return srcu_read_lock(&srcu_ctl);
+}
+
+static void srcu_read_delay(struct rcu_random_state *rrsp)
+{
+	long delay;
+	const long uspertick = 1000000 / HZ;
+	const long longdelay = 10;
+
+	/* We want there to be long-running readers, but not all the time. */
+
+	delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay * uspertick);
+	if (!delay)
+		schedule_timeout_interruptible(longdelay);
+}
+
+static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl)
+{
+	srcu_read_unlock(&srcu_ctl, idx);
+}
+
+static int srcu_torture_completed(void)
+{
+	return srcu_batches_completed(&srcu_ctl);
+}
+
+static void srcu_torture_synchronize(void)
+{
+	synchronize_srcu(&srcu_ctl);
+}
+
+static int srcu_torture_stats(char *page)
+{
+	int cnt = 0;
+	int cpu;
+	int idx = srcu_ctl.completed & 0x1;
+
+	cnt += sprintf(&page[cnt], "%s%s per-CPU(idx=%d):",
+		       torture_type, TORTURE_FLAG, idx);
+	for_each_possible_cpu(cpu) {
+		cnt += sprintf(&page[cnt], " %d(%d,%d)", cpu,
+			       per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx],
+			       per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx]);
+	}
+	cnt += sprintf(&page[cnt], "\n");
+	return cnt;
+}
+
+static struct rcu_torture_ops srcu_ops = {
+	.init = srcu_torture_init,
+	.cleanup = srcu_torture_cleanup,
+	.readlock = srcu_torture_read_lock,
+	.readdelay = srcu_read_delay,
+	.readunlock = srcu_torture_read_unlock,
+	.completed = srcu_torture_completed,
+	.deferredfree = rcu_sync_torture_deferred_free,
+	.sync = srcu_torture_synchronize,
+	.stats = srcu_torture_stats,
+	.name = "srcu"
+};
+
+/*
+ * Definitions for sched torture testing.
+ */
+
+static int sched_torture_read_lock(void)
+{
+	preempt_disable();
+	return 0;
+}
+
+static void sched_torture_read_unlock(int idx)
+{
+	preempt_enable();
+}
+
+static int sched_torture_completed(void)
+{
+	return 0;
+}
+
+static void sched_torture_synchronize(void)
+{
+	synchronize_sched();
+}
+
+static struct rcu_torture_ops sched_ops = {
+	.init = rcu_sync_torture_init,
+	.cleanup = NULL,
+	.readlock = sched_torture_read_lock,
+	.readdelay = rcu_read_delay,  /* just reuse rcu's version. */
+	.readunlock = sched_torture_read_unlock,
+	.completed = sched_torture_completed,
+	.deferredfree = rcu_sync_torture_deferred_free,
+	.sync = sched_torture_synchronize,
+	.stats = NULL,
+	.name = "sched"
+};
+
+/*
+ * RCU torture writer kthread.  Repeatedly substitutes a new structure
+ * for that pointed to by rcu_torture_current, freeing the old structure
+ * after a series of grace periods (the "pipeline").
+ */
+static int
+rcu_torture_writer(void *arg)
+{
+	int i;
+	long oldbatch = rcu_batches_completed();
+	struct rcu_torture *rp;
+	struct rcu_torture *old_rp;
+	static DEFINE_RCU_RANDOM(rand);
+
+	VERBOSE_PRINTK_STRING("rcu_torture_writer task started");
+	set_user_nice(current, 19);
+
+	do {
+		schedule_timeout_uninterruptible(1);
+		if ((rp = rcu_torture_alloc()) == NULL)
+			continue;
+		rp->rtort_pipe_count = 0;
+		udelay(rcu_random(&rand) & 0x3ff);
+		old_rp = rcu_torture_current;
+		rp->rtort_mbtest = 1;
+		rcu_assign_pointer(rcu_torture_current, rp);
+		smp_wmb();
+		if (old_rp) {
+			i = old_rp->rtort_pipe_count;
+			if (i > RCU_TORTURE_PIPE_LEN)
+				i = RCU_TORTURE_PIPE_LEN;
+			atomic_inc(&rcu_torture_wcount[i]);
+			old_rp->rtort_pipe_count++;
+			cur_ops->deferredfree(old_rp);
+		}
+		rcu_torture_current_version++;
+		oldbatch = cur_ops->completed();
+	} while (!kthread_should_stop() && !fullstop);
+	VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
+	while (!kthread_should_stop())
+		schedule_timeout_uninterruptible(1);
+	return 0;
+}
+
+/*
+ * RCU torture fake writer kthread.  Repeatedly calls sync, with a random
+ * delay between calls.
+ */
+static int
+rcu_torture_fakewriter(void *arg)
+{
+	DEFINE_RCU_RANDOM(rand);
+
+	VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started");
+	set_user_nice(current, 19);
+
+	do {
+		schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10);
+		udelay(rcu_random(&rand) & 0x3ff);
+		cur_ops->sync();
+	} while (!kthread_should_stop() && !fullstop);
+
+	VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
+	while (!kthread_should_stop())
+		schedule_timeout_uninterruptible(1);
+	return 0;
+}
+
+/*
+ * RCU torture reader kthread.  Repeatedly dereferences rcu_torture_current,
+ * incrementing the corresponding element of the pipeline array.  The
+ * counter in the element should never be greater than 1, otherwise, the
+ * RCU implementation is broken.
+ */
+static int
+rcu_torture_reader(void *arg)
+{
+	int completed;
+	int idx;
+	DEFINE_RCU_RANDOM(rand);
+	struct rcu_torture *p;
+	int pipe_count;
+
+	VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
+	set_user_nice(current, 19);
+
+	do {
+		idx = cur_ops->readlock();
+		completed = cur_ops->completed();
+		p = rcu_dereference(rcu_torture_current);
+		if (p == NULL) {
+			/* Wait for rcu_torture_writer to get underway */
+			cur_ops->readunlock(idx);
+			schedule_timeout_interruptible(HZ);
+			continue;
+		}
+		if (p->rtort_mbtest == 0)
+			atomic_inc(&n_rcu_torture_mberror);
+		cur_ops->readdelay(&rand);
+		preempt_disable();
+		pipe_count = p->rtort_pipe_count;
+		if (pipe_count > RCU_TORTURE_PIPE_LEN) {
+			/* Should not happen, but... */
+			pipe_count = RCU_TORTURE_PIPE_LEN;
+		}
+		++__get_cpu_var(rcu_torture_count)[pipe_count];
+		completed = cur_ops->completed() - completed;
+		if (completed > RCU_TORTURE_PIPE_LEN) {
+			/* Should not happen, but... */
+			completed = RCU_TORTURE_PIPE_LEN;
+		}
+		++__get_cpu_var(rcu_torture_batch)[completed];
+		preempt_enable();
+		cur_ops->readunlock(idx);
+		schedule();
+	} while (!kthread_should_stop() && !fullstop);
+	VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
+	while (!kthread_should_stop())
+		schedule_timeout_uninterruptible(1);
+	return 0;
+}
+
+/*
+ * Create an RCU-torture statistics message in the specified buffer.
+ */
+static int
+rcu_torture_printk(char *page)
+{
+	int cnt = 0;
+	int cpu;
+	int i;
+	long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
+	long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
+
+	for_each_possible_cpu(cpu) {
+		for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
+			pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
+			batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
+		}
+	}
+	for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
+		if (pipesummary[i] != 0)
+			break;
+	}
+	cnt += sprintf(&page[cnt], "%s%s ", torture_type, TORTURE_FLAG);
+	cnt += sprintf(&page[cnt],
+		       "rtc: %p ver: %ld tfle: %d rta: %d rtaf: %d rtf: %d "
+		       "rtmbe: %d",
+		       rcu_torture_current,
+		       rcu_torture_current_version,
+		       list_empty(&rcu_torture_freelist),
+		       atomic_read(&n_rcu_torture_alloc),
+		       atomic_read(&n_rcu_torture_alloc_fail),
+		       atomic_read(&n_rcu_torture_free),
+		       atomic_read(&n_rcu_torture_mberror));
+	if (atomic_read(&n_rcu_torture_mberror) != 0)
+		cnt += sprintf(&page[cnt], " !!!");
+	cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
+	if (i > 1) {
+		cnt += sprintf(&page[cnt], "!!! ");
+		atomic_inc(&n_rcu_torture_error);
+	}
+	cnt += sprintf(&page[cnt], "Reader Pipe: ");
+	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
+		cnt += sprintf(&page[cnt], " %ld", pipesummary[i]);
+	cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
+	cnt += sprintf(&page[cnt], "Reader Batch: ");
+	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
+		cnt += sprintf(&page[cnt], " %ld", batchsummary[i]);
+	cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
+	cnt += sprintf(&page[cnt], "Free-Block Circulation: ");
+	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
+		cnt += sprintf(&page[cnt], " %d",
+			       atomic_read(&rcu_torture_wcount[i]));
+	}
+	cnt += sprintf(&page[cnt], "\n");
+	if (cur_ops->stats)
+		cnt += cur_ops->stats(&page[cnt]);
+	return cnt;
+}
+
+/*
+ * Print torture statistics.  Caller must ensure that there is only
+ * one call to this function at a given time!!!  This is normally
+ * accomplished by relying on the module system to only have one copy
+ * of the module loaded, and then by giving the rcu_torture_stats
+ * kthread full control (or the init/cleanup functions when rcu_torture_stats
+ * thread is not running).
+ */
+static void
+rcu_torture_stats_print(void)
+{
+	int cnt;
+
+	cnt = rcu_torture_printk(printk_buf);
+	printk(KERN_ALERT "%s", printk_buf);
+}
+
+/*
+ * Periodically prints torture statistics, if periodic statistics printing
+ * was specified via the stat_interval module parameter.
+ *
+ * No need to worry about fullstop here, since this one doesn't reference
+ * volatile state or register callbacks.
+ */
+static int
+rcu_torture_stats(void *arg)
+{
+	VERBOSE_PRINTK_STRING("rcu_torture_stats task started");
+	do {
+		schedule_timeout_interruptible(stat_interval * HZ);
+		rcu_torture_stats_print();
+	} while (!kthread_should_stop());
+	VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping");
+	return 0;
+}
+
+static int rcu_idle_cpu;	/* Force all torture tasks off this CPU */
+
+/* Shuffle tasks such that we allow @rcu_idle_cpu to become idle. A special case
+ * is when @rcu_idle_cpu = -1, when we allow the tasks to run on all CPUs.
+ */
+static void rcu_torture_shuffle_tasks(void)
+{
+	cpumask_t tmp_mask = CPU_MASK_ALL;
+	int i;
+
+	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;
+	}
+
+	if (rcu_idle_cpu != -1)
+		cpu_clear(rcu_idle_cpu, tmp_mask);
+
+	set_cpus_allowed(current, tmp_mask);
+
+	if (reader_tasks) {
+		for (i = 0; i < nrealreaders; i++)
+			if (reader_tasks[i])
+				set_cpus_allowed(reader_tasks[i], tmp_mask);
+	}
+
+	if (fakewriter_tasks) {
+		for (i = 0; i < nfakewriters; i++)
+			if (fakewriter_tasks[i])
+				set_cpus_allowed(fakewriter_tasks[i], tmp_mask);
+	}
+
+	if (writer_task)
+		set_cpus_allowed(writer_task, tmp_mask);
+
+	if (stats_task)
+		set_cpus_allowed(stats_task, tmp_mask);
+
+	if (rcu_idle_cpu == -1)
+		rcu_idle_cpu = num_online_cpus() - 1;
+	else
+		rcu_idle_cpu--;
+
+	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
+rcu_torture_shuffle(void *arg)
+{
+	VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started");
+	do {
+		schedule_timeout_interruptible(shuffle_interval * HZ);
+		rcu_torture_shuffle_tasks();
+	} while (!kthread_should_stop());
+	VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping");
+	return 0;
+}
+
+static inline void
+rcu_torture_print_module_parms(char *tag)
+{
+	printk(KERN_ALERT "%s" TORTURE_FLAG
+		"--- %s: nreaders=%d nfakewriters=%d "
+		"stat_interval=%d verbose=%d test_no_idle_hz=%d "
+		"shuffle_interval = %d\n",
+		torture_type, tag, nrealreaders, nfakewriters,
+		stat_interval, verbose, test_no_idle_hz, shuffle_interval);
+}
+
+static void
+rcu_torture_cleanup(void)
+{
+	int i;
+
+	fullstop = 1;
+	if (shuffler_task) {
+		VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task");
+		kthread_stop(shuffler_task);
+	}
+	shuffler_task = NULL;
+
+	if (writer_task) {
+		VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task");
+		kthread_stop(writer_task);
+	}
+	writer_task = NULL;
+
+	if (reader_tasks) {
+		for (i = 0; i < nrealreaders; i++) {
+			if (reader_tasks[i]) {
+				VERBOSE_PRINTK_STRING(
+					"Stopping rcu_torture_reader task");
+				kthread_stop(reader_tasks[i]);
+			}
+			reader_tasks[i] = NULL;
+		}
+		kfree(reader_tasks);
+		reader_tasks = NULL;
+	}
+	rcu_torture_current = NULL;
+
+	if (fakewriter_tasks) {
+		for (i = 0; i < nfakewriters; i++) {
+			if (fakewriter_tasks[i]) {
+				VERBOSE_PRINTK_STRING(
+					"Stopping rcu_torture_fakewriter task");
+				kthread_stop(fakewriter_tasks[i]);
+			}
+			fakewriter_tasks[i] = NULL;
+		}
+		kfree(fakewriter_tasks);
+		fakewriter_tasks = NULL;
+	}
+
+	if (stats_task) {
+		VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task");
+		kthread_stop(stats_task);
+	}
+	stats_task = NULL;
+
+	/* Wait for all RCU callbacks to fire.  */
+	rcu_barrier();
+
+	rcu_torture_stats_print();  /* -After- the stats thread is stopped! */
+
+	if (cur_ops->cleanup)
+		cur_ops->cleanup();
+	if (atomic_read(&n_rcu_torture_error))
+		rcu_torture_print_module_parms("End of test: FAILURE");
+	else
+		rcu_torture_print_module_parms("End of test: SUCCESS");
+}
+
+static int __init
+rcu_torture_init(void)
+{
+	int i;
+	int cpu;
+	int firsterr = 0;
+	static struct rcu_torture_ops *torture_ops[] =
+		{ &rcu_ops, &rcu_sync_ops, &rcu_bh_ops, &rcu_bh_sync_ops,
+		  &srcu_ops, &sched_ops, };
+
+	/* Process args and tell the world that the torturer is on the job. */
+	for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
+		cur_ops = torture_ops[i];
+		if (strcmp(torture_type, cur_ops->name) == 0)
+			break;
+	}
+	if (i == ARRAY_SIZE(torture_ops)) {
+		printk(KERN_ALERT "rcutorture: invalid torture type: \"%s\"\n",
+		       torture_type);
+		return (-EINVAL);
+	}
+	if (cur_ops->init)
+		cur_ops->init(); /* no "goto unwind" prior to this point!!! */
+
+	if (nreaders >= 0)
+		nrealreaders = nreaders;
+	else
+		nrealreaders = 2 * num_online_cpus();
+	rcu_torture_print_module_parms("Start of test");
+	fullstop = 0;
+
+	/* Set up the freelist. */
+
+	INIT_LIST_HEAD(&rcu_torture_freelist);
+	for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
+		rcu_tortures[i].rtort_mbtest = 0;
+		list_add_tail(&rcu_tortures[i].rtort_free,
+			      &rcu_torture_freelist);
+	}
+
+	/* Initialize the statistics so that each run gets its own numbers. */
+
+	rcu_torture_current = NULL;
+	rcu_torture_current_version = 0;
+	atomic_set(&n_rcu_torture_alloc, 0);
+	atomic_set(&n_rcu_torture_alloc_fail, 0);
+	atomic_set(&n_rcu_torture_free, 0);
+	atomic_set(&n_rcu_torture_mberror, 0);
+	atomic_set(&n_rcu_torture_error, 0);
+	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
+		atomic_set(&rcu_torture_wcount[i], 0);
+	for_each_possible_cpu(cpu) {
+		for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
+			per_cpu(rcu_torture_count, cpu)[i] = 0;
+			per_cpu(rcu_torture_batch, cpu)[i] = 0;
+		}
+	}
+
+	/* Start up the kthreads. */
+
+	VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task");
+	writer_task = kthread_run(rcu_torture_writer, NULL,
+				  "rcu_torture_writer");
+	if (IS_ERR(writer_task)) {
+		firsterr = PTR_ERR(writer_task);
+		VERBOSE_PRINTK_ERRSTRING("Failed to create writer");
+		writer_task = NULL;
+		goto unwind;
+	}
+	fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]),
+	                           GFP_KERNEL);
+	if (fakewriter_tasks == NULL) {
+		VERBOSE_PRINTK_ERRSTRING("out of memory");
+		firsterr = -ENOMEM;
+		goto unwind;
+	}
+	for (i = 0; i < nfakewriters; i++) {
+		VERBOSE_PRINTK_STRING("Creating rcu_torture_fakewriter task");
+		fakewriter_tasks[i] = kthread_run(rcu_torture_fakewriter, NULL,
+		                                  "rcu_torture_fakewriter");
+		if (IS_ERR(fakewriter_tasks[i])) {
+			firsterr = PTR_ERR(fakewriter_tasks[i]);
+			VERBOSE_PRINTK_ERRSTRING("Failed to create fakewriter");
+			fakewriter_tasks[i] = NULL;
+			goto unwind;
+		}
+	}
+	reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
+			       GFP_KERNEL);
+	if (reader_tasks == NULL) {
+		VERBOSE_PRINTK_ERRSTRING("out of memory");
+		firsterr = -ENOMEM;
+		goto unwind;
+	}
+	for (i = 0; i < nrealreaders; i++) {
+		VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task");
+		reader_tasks[i] = kthread_run(rcu_torture_reader, NULL,
+					      "rcu_torture_reader");
+		if (IS_ERR(reader_tasks[i])) {
+			firsterr = PTR_ERR(reader_tasks[i]);
+			VERBOSE_PRINTK_ERRSTRING("Failed to create reader");
+			reader_tasks[i] = NULL;
+			goto unwind;
+		}
+	}
+	if (stat_interval > 0) {
+		VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task");
+		stats_task = kthread_run(rcu_torture_stats, NULL,
+					"rcu_torture_stats");
+		if (IS_ERR(stats_task)) {
+			firsterr = PTR_ERR(stats_task);
+			VERBOSE_PRINTK_ERRSTRING("Failed to create stats");
+			stats_task = NULL;
+			goto unwind;
+		}
+	}
+	if (test_no_idle_hz) {
+		rcu_idle_cpu = num_online_cpus() - 1;
+		/* Create the shuffler thread */
+		shuffler_task = kthread_run(rcu_torture_shuffle, NULL,
+					  "rcu_torture_shuffle");
+		if (IS_ERR(shuffler_task)) {
+			firsterr = PTR_ERR(shuffler_task);
+			VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler");
+			shuffler_task = NULL;
+			goto unwind;
+		}
+	}
+	return 0;
+
+unwind:
+	rcu_torture_cleanup();
+	return firsterr;
+}
+
+module_init(rcu_torture_init);
+module_exit(rcu_torture_cleanup);
--
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