Revision 0ee931c4e31a5efb134c76440405e9219f896e33 authored by Michal Hocko on 13 September 2017, 23:28:29 UTC, committed by Linus Torvalds on 14 September 2017, 01:53:16 UTC
GFP_TEMPORARY was introduced by commit e12ba74d8ff3 ("Group short-lived and reclaimable kernel allocations") along with __GFP_RECLAIMABLE. It's primary motivation was to allow users to tell that an allocation is short lived and so the allocator can try to place such allocations close together and prevent long term fragmentation. As much as this sounds like a reasonable semantic it becomes much less clear when to use the highlevel GFP_TEMPORARY allocation flag. How long is temporary? Can the context holding that memory sleep? Can it take locks? It seems there is no good answer for those questions. The current implementation of GFP_TEMPORARY is basically GFP_KERNEL | __GFP_RECLAIMABLE which in itself is tricky because basically none of the existing caller provide a way to reclaim the allocated memory. So this is rather misleading and hard to evaluate for any benefits. I have checked some random users and none of them has added the flag with a specific justification. I suspect most of them just copied from other existing users and others just thought it might be a good idea to use without any measuring. This suggests that GFP_TEMPORARY just motivates for cargo cult usage without any reasoning. I believe that our gfp flags are quite complex already and especially those with highlevel semantic should be clearly defined to prevent from confusion and abuse. Therefore I propose dropping GFP_TEMPORARY and replace all existing users to simply use GFP_KERNEL. Please note that SLAB users with shrinkers will still get __GFP_RECLAIMABLE heuristic and so they will be placed properly for memory fragmentation prevention. I can see reasons we might want some gfp flag to reflect shorterm allocations but I propose starting from a clear semantic definition and only then add users with proper justification. This was been brought up before LSF this year by Matthew [1] and it turned out that GFP_TEMPORARY really doesn't have a clear semantic. It seems to be a heuristic without any measured advantage for most (if not all) its current users. The follow up discussion has revealed that opinions on what might be temporary allocation differ a lot between developers. So rather than trying to tweak existing users into a semantic which they haven't expected I propose to simply remove the flag and start from scratch if we really need a semantic for short term allocations. [1] http://lkml.kernel.org/r/20170118054945.GD18349@bombadil.infradead.org [akpm@linux-foundation.org: fix typo] [akpm@linux-foundation.org: coding-style fixes] [sfr@canb.auug.org.au: drm/i915: fix up] Link: http://lkml.kernel.org/r/20170816144703.378d4f4d@canb.auug.org.au Link: http://lkml.kernel.org/r/20170728091904.14627-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Matthew Wilcox <willy@infradead.org> Cc: Neil Brown <neilb@suse.de> Cc: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent d0dbf77
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/sched/clock.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 <linux/ktime.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;
/*
* Attempt to take a CPU offline. Return false if the CPU is already
* offline or if it is not subject to CPU-hotplug operations. The
* caller can detect other failures by looking at the statistics.
*/
bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes,
unsigned long *sum_offl, int *min_offl, int *max_offl)
{
unsigned long delta;
int ret;
unsigned long starttime;
if (!cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
return false;
if (verbose)
pr_alert("%s" TORTURE_FLAG
"torture_onoff task: offlining %d\n",
torture_type, cpu);
starttime = jiffies;
(*n_offl_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_offl_successes)++;
delta = jiffies - starttime;
*sum_offl += delta;
if (*min_offl < 0) {
*min_offl = delta;
*max_offl = delta;
}
if (*min_offl > delta)
*min_offl = delta;
if (*max_offl < delta)
*max_offl = delta;
}
return true;
}
EXPORT_SYMBOL_GPL(torture_offline);
/*
* Attempt to bring a CPU online. Return false if the CPU is already
* online or if it is not subject to CPU-hotplug operations. The
* caller can detect other failures by looking at the statistics.
*/
bool torture_online(int cpu, long *n_onl_attempts, long *n_onl_successes,
unsigned long *sum_onl, int *min_onl, int *max_onl)
{
unsigned long delta;
int ret;
unsigned long starttime;
if (cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
return false;
if (verbose)
pr_alert("%s" TORTURE_FLAG
"torture_onoff task: onlining %d\n",
torture_type, cpu);
starttime = jiffies;
(*n_onl_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_onl_successes)++;
delta = jiffies - starttime;
*sum_onl += delta;
if (*min_onl < 0) {
*min_onl = delta;
*max_onl = delta;
}
if (*min_onl > delta)
*min_onl = delta;
if (*max_onl < delta)
*max_onl = delta;
}
return true;
}
EXPORT_SYMBOL_GPL(torture_online);
/*
* Execute random CPU-hotplug operations at the interval specified
* by the onoff_interval.
*/
static int
torture_onoff(void *arg)
{
int cpu;
int maxcpu = -1;
DEFINE_TORTURE_RANDOM(rand);
VERBOSE_TOROUT_STRING("torture_onoff task started");
for_each_online_cpu(cpu)
maxcpu = cpu;
WARN_ON(maxcpu < 0);
if (maxcpu == 0) {
VERBOSE_TOROUT_STRING("Only one CPU, so CPU-hotplug testing is disabled");
goto stop;
}
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 (!torture_offline(cpu,
&n_offline_attempts, &n_offline_successes,
&sum_offline, &min_offline, &max_offline))
torture_online(cpu,
&n_online_attempts, &n_online_successes,
&sum_online, &min_online, &max_online);
schedule_timeout_interruptible(onoff_interval);
}
stop:
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.
*/
void torture_onoff_stats(void)
{
#ifdef CONFIG_HOTPLUG_CPU
pr_cont("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 */
}
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 variables.
*/
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;
else
cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask);
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 struct task_struct *shutdown_task;
static ktime_t shutdown_time; /* time 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 (READ_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)
{
ktime_t ktime_snap;
VERBOSE_TOROUT_STRING("torture_shutdown task started");
ktime_snap = ktime_get();
while (ktime_before(ktime_snap, shutdown_time) &&
!torture_must_stop()) {
if (verbose)
pr_alert("%s" TORTURE_FLAG
"torture_shutdown task: %llu ms remaining\n",
torture_type,
ktime_ms_delta(shutdown_time, ktime_snap));
set_current_state(TASK_INTERRUPTIBLE);
schedule_hrtimeout(&shutdown_time, HRTIMER_MODE_ABS);
ktime_snap = ktime_get();
}
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.");
ftrace_dump(DUMP_ALL);
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;
torture_shutdown_hook = cleanup;
if (ssecs > 0) {
shutdown_time = ktime_add(ktime_get(), ktime_set(ssecs, 0));
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 (READ_ONCE(fullstop) == FULLSTOP_DONTSTOP) {
VERBOSE_TOROUT_STRING("Unscheduled system shutdown detected");
WRITE_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)
{
cond_resched_rcu_qs();
while (READ_ONCE(stutter_pause_test) ||
(torture_runnable && !READ_ONCE(*torture_runnable))) {
if (stutter_pause_test)
if (READ_ONCE(stutter_pause_test) == 1)
schedule_timeout_interruptible(1);
else
while (READ_ONCE(stutter_pause_test))
cond_resched();
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()) {
if (stutter > 1) {
schedule_timeout_interruptible(stutter - 1);
WRITE_ONCE(stutter_pause_test, 2);
}
schedule_timeout_interruptible(1);
WRITE_ONCE(stutter_pause_test, 1);
}
if (!torture_must_stop())
schedule_timeout_interruptible(stutter);
WRITE_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.
*/
bool torture_init_begin(char *ttype, bool v, int *runnable)
{
mutex_lock(&fullstop_mutex);
if (torture_type != NULL) {
pr_alert("torture_init_begin: Refusing %s init: %s running.\n",
ttype, torture_type);
pr_alert("torture_init_begin: One torture test at a time!\n");
mutex_unlock(&fullstop_mutex);
return false;
}
torture_type = ttype;
verbose = v;
torture_runnable = runnable;
fullstop = FULLSTOP_DONTSTOP;
return true;
}
EXPORT_SYMBOL_GPL(torture_init_begin);
/*
* Tell the torture module that initialization is complete.
*/
void 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.
*
* Both torture_cleanup_begin() and torture_cleanup_end() must be paired,
* in order to correctly perform the cleanup. They are separated because
* threads can still need to reference the torture_type type, thus nullify
* only after completing all other relevant calls.
*/
bool torture_cleanup_begin(void)
{
mutex_lock(&fullstop_mutex);
if (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
pr_warn("Concurrent rmmod and shutdown illegal!\n");
mutex_unlock(&fullstop_mutex);
schedule_timeout_uninterruptible(10);
return true;
}
WRITE_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_begin);
void torture_cleanup_end(void)
{
mutex_lock(&fullstop_mutex);
torture_type = NULL;
mutex_unlock(&fullstop_mutex);
}
EXPORT_SYMBOL_GPL(torture_cleanup_end);
/*
* 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 READ_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)
{
char buf[128];
snprintf(buf, sizeof(buf), "Stopping %s", title);
VERBOSE_TOROUT_STRING(buf);
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", 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);
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