Merge tag 'v3.15-rc1' into patchwork

Linux 3.15-rc1

* tag 'v3.15-rc1': (12180 commits)
  Linux 3.15-rc1
  mm: Initialize error in shmem_file_aio_read()
  cifs: Use min_t() when comparing "size_t" and "unsigned long"
  sym53c8xx_2: Set DID_REQUEUE return code when aborting squeue
  powerpc: Don't try to set LPCR unless we're in hypervisor mode
  futex: update documentation for ordering guarantees
  ceph: fix pr_fmt() redefinition
  vti: don't allow to add the same tunnel twice
  gre: don't allow to add the same tunnel twice
  drivers: net: xen-netfront: fix array initialization bug
  missing bits of "splice: fix racy pipe->buffers uses"
  cifs: fix the race in cifs_writev()
  ceph_sync_{,direct_}write: fix an oops on ceph_osdc_new_request() failure
  pktgen: be friendly to LLTX devices
  r8152: check RTL8152_UNPLUG
  net: sun4i-emac: add promiscuous support
  net/apne: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERO
  blackfin: cleanup board files
  bf609: clock: drop unused clock bit set/clear functions
  Blackfin: bf537: rename "CONFIG_ADT75"
  ...

1 files changed, 719 insertions, 0 deletions

diff --git a/kernel/torture.c b/kernel/torture.c
new file mode 100644
index 000000000000..acc9afc2f26e
--- /dev/null
+++ b/kernel/torture.c
@@ -0,0 +1,719 @@
+/*
+ * 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;
+
+/* Mediate rmmod and system shutdown.  Concurrent rmmod & shutdown illegal! */
+#define FULLSTOP_DONTSTOP 0     /* Normal operation. */
+#define FULLSTOP_SHUTDOWN 1     /* System shutdown with torture running. */
+#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
+
+/*
+ * 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);
+        }
+        torture_kthread_stopping("torture_onoff");
+        return 0;
+}
+
+#endif /* #ifdef CONFIG_HOTPLUG_CPU */
+
+/*
+ * Initiate online-offline handling.
+ */
+int torture_onoff_init(long ooholdoff, long oointerval)
+{
+        int ret = 0;
+
+#ifdef CONFIG_HOTPLUG_CPU
+        onoff_holdoff = ooholdoff;
+        onoff_interval = oointerval;
+        if (onoff_interval <= 0)
+                return 0;
+        ret = torture_create_kthread(torture_onoff, NULL, onoff_task);
+#endif /* #ifdef CONFIG_HOTPLUG_CPU */
+        return ret;
+}
+EXPORT_SYMBOL_GPL(torture_onoff_init);
+
+/*
+ * Clean up after online/offline testing.
+ */
+static 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());
+        torture_kthread_stopping("torture_shuffle");
+        return 0;
+}
+
+/*
+ * Start the shuffler, with shuffint in jiffies.
+ */
+int torture_shuffle_init(long shuffint)
+{
+        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 */
+        return torture_create_kthread(torture_shuffle, NULL, shuffler_task);
+}
+EXPORT_SYMBOL_GPL(torture_shuffle_init);
+
+/*
+ * Stop the shuffling.
+ */
+static 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);
+
+/*
+ * Variables for auto-shutdown.  This allows "lights out" torture runs
+ * to be fully scripted.
+ */
+static int shutdown_secs;               /* desired test duration in seconds. */
+static struct task_struct *shutdown_task;
+static unsigned long shutdown_time;     /* jiffies to system shutdown. */
+static void (*torture_shutdown_hook)(void);
+
+/*
+ * Absorb kthreads into a kernel function that won't return, so that
+ * they won't ever access module text or data again.
+ */
+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);
+
+/*
+ * Cause the torture test to shutdown the system after the test has
+ * run for the time specified by the shutdown_secs parameter.
+ */
+static int torture_shutdown(void *arg)
+{
+        long delta;
+        unsigned long jiffies_snap;
+
+        VERBOSE_TOROUT_STRING("torture_shutdown task started");
+        jiffies_snap = jiffies;
+        while (ULONG_CMP_LT(jiffies_snap, shutdown_time) &&
+               !torture_must_stop()) {
+                delta = shutdown_time - jiffies_snap;
+                if (verbose)
+                        pr_alert("%s" TORTURE_FLAG
+                                 "torture_shutdown task: %lu jiffies remaining\n",
+                                 torture_type, delta);
+                schedule_timeout_interruptible(delta);
+                jiffies_snap = jiffies;
+        }
+        if (torture_must_stop()) {
+                torture_kthread_stopping("torture_shutdown");
+                return 0;
+        }
+
+        /* OK, shut down the system. */
+
+        VERBOSE_TOROUT_STRING("torture_shutdown task shutting down system");
+        shutdown_task = NULL;   /* Avoid self-kill deadlock. */
+        if (torture_shutdown_hook)
+                torture_shutdown_hook();
+        else
+                VERBOSE_TOROUT_STRING("No torture_shutdown_hook(), skipping.");
+        kernel_power_off();     /* Shut down the system. */
+        return 0;
+}
+
+/*
+ * Start up the shutdown task.
+ */
+int torture_shutdown_init(int ssecs, void (*cleanup)(void))
+{
+        int ret = 0;
+
+        shutdown_secs = ssecs;
+        torture_shutdown_hook = cleanup;
+        if (shutdown_secs > 0) {
+                shutdown_time = jiffies + shutdown_secs * HZ;
+                ret = torture_create_kthread(torture_shutdown, NULL,
+                                             shutdown_task);
+        }
+        return ret;
+}
+EXPORT_SYMBOL_GPL(torture_shutdown_init);
+
+/*
+ * Detect and respond to a system shutdown.
+ */
+static int torture_shutdown_notify(struct notifier_block *unused1,
+                                   unsigned long unused2, void *unused3)
+{
+        mutex_lock(&fullstop_mutex);
+        if (ACCESS_ONCE(fullstop) == FULLSTOP_DONTSTOP) {
+                VERBOSE_TOROUT_STRING("Unscheduled system shutdown detected");
+                ACCESS_ONCE(fullstop) = FULLSTOP_SHUTDOWN;
+        } else {
+                pr_warn("Concurrent rmmod and shutdown illegal!\n");
+        }
+        mutex_unlock(&fullstop_mutex);
+        return NOTIFY_DONE;
+}
+
+static struct notifier_block torture_shutdown_nb = {
+        .notifier_call = torture_shutdown_notify,
+};
+
+/*
+ * Shut down the shutdown task.  Say what???  Heh!  This can happen if
+ * the torture module gets an rmmod before the shutdown time arrives.  ;-)
+ */
+static void torture_shutdown_cleanup(void)
+{
+        unregister_reboot_notifier(&torture_shutdown_nb);
+        if (shutdown_task != NULL) {
+                VERBOSE_TOROUT_STRING("Stopping torture_shutdown task");
+                kthread_stop(shutdown_task);
+        }
+        shutdown_task = NULL;
+}
+
+/*
+ * Variables for stuttering, which means to periodically pause and
+ * restart testing in order to catch bugs that appear when load is
+ * suddenly applied to or removed from the system.
+ */
+static struct task_struct *stutter_task;
+static int stutter_pause_test;
+static int stutter;
+
+/*
+ * Block until the stutter interval ends.  This must be called periodically
+ * by all running kthreads that need to be subject to stuttering.
+ */
+void stutter_wait(const char *title)
+{
+        while (ACCESS_ONCE(stutter_pause_test) ||
+               (torture_runnable && !ACCESS_ONCE(*torture_runnable))) {
+                if (stutter_pause_test)
+                        schedule_timeout_interruptible(1);
+                else
+                        schedule_timeout_interruptible(round_jiffies_relative(HZ));
+                torture_shutdown_absorb(title);
+        }
+}
+EXPORT_SYMBOL_GPL(stutter_wait);
+
+/*
+ * Cause the torture test to "stutter", starting and stopping all
+ * threads periodically.
+ */
+static int torture_stutter(void *arg)
+{
+        VERBOSE_TOROUT_STRING("torture_stutter task started");
+        do {
+                if (!torture_must_stop()) {
+                        schedule_timeout_interruptible(stutter);
+                        ACCESS_ONCE(stutter_pause_test) = 1;
+                }
+                if (!torture_must_stop())
+                        schedule_timeout_interruptible(stutter);
+                ACCESS_ONCE(stutter_pause_test) = 0;
+                torture_shutdown_absorb("torture_stutter");
+        } while (!torture_must_stop());
+        torture_kthread_stopping("torture_stutter");
+        return 0;
+}
+
+/*
+ * Initialize and kick off the torture_stutter kthread.
+ */
+int torture_stutter_init(int s)
+{
+        int ret;
+
+        stutter = s;
+        ret = torture_create_kthread(torture_stutter, NULL, stutter_task);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(torture_stutter_init);
+
+/*
+ * Cleanup after the torture_stutter kthread.
+ */
+static void torture_stutter_cleanup(void)
+{
+        if (!stutter_task)
+                return;
+        VERBOSE_TOROUT_STRING("Stopping torture_stutter task");
+        kthread_stop(stutter_task);
+        stutter_task = NULL;
+}
+
+/*
+ * 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().
+ *
+ * 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.
+ */
+void __init torture_init_begin(char *ttype, bool v, int *runnable)
+{
+        mutex_lock(&fullstop_mutex);
+        torture_type = ttype;
+        verbose = v;
+        torture_runnable = runnable;
+        fullstop = FULLSTOP_DONTSTOP;
+
+}
+EXPORT_SYMBOL_GPL(torture_init_begin);
+
+/*
+ * Tell the torture module that initialization is complete.
+ */
+void __init torture_init_end(void)
+{
+        mutex_unlock(&fullstop_mutex);
+        register_reboot_notifier(&torture_shutdown_nb);
+}
+EXPORT_SYMBOL_GPL(torture_init_end);
+
+/*
+ * Clean up torture module.  Please note that this is -not- invoked via
+ * the usual module_exit() mechanism, but rather by an explicit call from
+ * the client torture module.  Returns true if a race with system shutdown
+ * is detected, otherwise, all kthreads started by functions in this file
+ * will be shut down.
+ *
+ * This must be called before the caller starts shutting down its own
+ * kthreads.
+ */
+bool torture_cleanup(void)
+{
+        mutex_lock(&fullstop_mutex);
+        if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
+                pr_warn("Concurrent rmmod and shutdown illegal!\n");
+                mutex_unlock(&fullstop_mutex);
+                schedule_timeout_uninterruptible(10);
+                return true;
+        }
+        ACCESS_ONCE(fullstop) = FULLSTOP_RMMOD;
+        mutex_unlock(&fullstop_mutex);
+        torture_shutdown_cleanup();
+        torture_shuffle_cleanup();
+        torture_stutter_cleanup();
+        torture_onoff_cleanup();
+        return false;
+}
+EXPORT_SYMBOL_GPL(torture_cleanup);
+
+/*
+ * Is it time for the current torture test to stop?
+ */
+bool torture_must_stop(void)
+{
+        return torture_must_stop_irq() || kthread_should_stop();
+}
+EXPORT_SYMBOL_GPL(torture_must_stop);
+
+/*
+ * Is it time for the current torture test to stop?  This is the irq-safe
+ * version, hence no check for kthread_should_stop().
+ */
+bool torture_must_stop_irq(void)
+{
+        return ACCESS_ONCE(fullstop) != FULLSTOP_DONTSTOP;
+}
+EXPORT_SYMBOL_GPL(torture_must_stop_irq);
+
+/*
+ * Each kthread must wait for kthread_should_stop() before returning from
+ * its top-level function, otherwise segfaults ensue.  This function
+ * prints a "stopping" message and waits for kthread_should_stop(), and
+ * should be called from all torture kthreads immediately prior to
+ * returning.
+ */
+void torture_kthread_stopping(char *title)
+{
+        if (verbose)
+                VERBOSE_TOROUT_STRING(title);
+        while (!kthread_should_stop()) {
+                torture_shutdown_absorb(title);
+                schedule_timeout_uninterruptible(1);
+        }
+}
+EXPORT_SYMBOL_GPL(torture_kthread_stopping);
+
+/*
+ * Create a generic torture kthread that is immediately runnable.  If you
+ * need the kthread to be stopped so that you can do something to it before
+ * it starts, you will need to open-code your own.
+ */
+int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
+                            char *f, struct task_struct **tp)
+{
+        int ret = 0;
+
+        VERBOSE_TOROUT_STRING(m);
+        *tp = kthread_run(fn, arg, s);
+        if (IS_ERR(*tp)) {
+                ret = PTR_ERR(*tp);
+                VERBOSE_TOROUT_ERRSTRING(f);
+                *tp = NULL;
+        }
+        torture_shuffle_task_register(*tp);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(_torture_create_kthread);
+
+/*
+ * Stop a generic kthread, emitting a message.
+ */
+void _torture_stop_kthread(char *m, struct task_struct **tp)
+{
+        if (*tp == NULL)
+                return;
+        VERBOSE_TOROUT_STRING(m);
+        kthread_stop(*tp);
+        *tp = NULL;
+}
+EXPORT_SYMBOL_GPL(_torture_stop_kthread);