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1/*
2 * Module-based torture test facility for locking
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, you can access it online at
16 * http://www.gnu.org/licenses/gpl-2.0.html.
17 *
18 * Copyright (C) IBM Corporation, 2014
19 *
20 * Author: Paul E. McKenney <paulmck@us.ibm.com>
21 * Based on kernel/rcu/torture.c.
22 */
23#include <linux/types.h>
24#include <linux/kernel.h>
25#include <linux/init.h>
26#include <linux/module.h>
27#include <linux/kthread.h>
28#include <linux/err.h>
29#include <linux/spinlock.h>
30#include <linux/smp.h>
31#include <linux/interrupt.h>
32#include <linux/sched.h>
33#include <linux/atomic.h>
34#include <linux/bitops.h>
35#include <linux/completion.h>
36#include <linux/moduleparam.h>
37#include <linux/percpu.h>
38#include <linux/notifier.h>
39#include <linux/reboot.h>
40#include <linux/freezer.h>
41#include <linux/cpu.h>
42#include <linux/delay.h>
43#include <linux/stat.h>
44#include <linux/slab.h>
45#include <linux/trace_clock.h>
46#include <asm/byteorder.h>
47#include <linux/torture.h>
48
49MODULE_LICENSE("GPL");
50MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
51
52torture_param(int, nwriters_stress, -1,
53 "Number of write-locking stress-test threads");
54torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
55torture_param(int, onoff_interval, 0,
56 "Time between CPU hotplugs (s), 0=disable");
57torture_param(int, shuffle_interval, 3,
58 "Number of jiffies between shuffles, 0=disable");
59torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable.");
60torture_param(int, stat_interval, 60,
61 "Number of seconds between stats printk()s");
62torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
63torture_param(bool, verbose, true,
64 "Enable verbose debugging printk()s");
65
66static char *torture_type = "spin_lock";
67module_param(torture_type, charp, 0444);
68MODULE_PARM_DESC(torture_type,
69 "Type of lock to torture (spin_lock, spin_lock_irq, ...)");
70
71static atomic_t n_lock_torture_errors;
72
73static struct task_struct *stats_task;
74static struct task_struct **writer_tasks;
75
76static int nrealwriters_stress;
77static bool lock_is_write_held;
78
79struct lock_writer_stress_stats {
80 long n_write_lock_fail;
81 long n_write_lock_acquired;
82};
83static struct lock_writer_stress_stats *lwsa;
84
85#if defined(MODULE) || defined(CONFIG_LOCK_TORTURE_TEST_RUNNABLE)
86#define LOCKTORTURE_RUNNABLE_INIT 1
87#else
88#define LOCKTORTURE_RUNNABLE_INIT 0
89#endif
90int locktorture_runnable = LOCKTORTURE_RUNNABLE_INIT;
91module_param(locktorture_runnable, int, 0444);
92MODULE_PARM_DESC(locktorture_runnable, "Start locktorture at boot");
93
94/* Forward reference. */
95static void lock_torture_cleanup(void);
96
97/*
98 * Operations vector for selecting different types of tests.
99 */
100struct lock_torture_ops {
101 void (*init)(void);
102 int (*writelock)(void);
103 void (*write_delay)(struct torture_random_state *trsp);
104 void (*writeunlock)(void);
105 unsigned long flags;
106 const char *name;
107};
108
109static struct lock_torture_ops *cur_ops;
110
111/*
112 * Definitions for lock torture testing.
113 */
114
115static int torture_lock_busted_write_lock(void)
116{
117 return 0; /* BUGGY, do not use in real life!!! */
118}
119
120static void torture_lock_busted_write_delay(struct torture_random_state *trsp)
121{
122 const unsigned long longdelay_us = 100;
123
124 /* We want a long delay occasionally to force massive contention. */
125 if (!(torture_random(trsp) %
126 (nrealwriters_stress * 2000 * longdelay_us)))
127 mdelay(longdelay_us);
128#ifdef CONFIG_PREEMPT
129 if (!(torture_random(trsp) % (nrealwriters_stress * 20000)))
130 preempt_schedule(); /* Allow test to be preempted. */
131#endif
132}
133
134static void torture_lock_busted_write_unlock(void)
135{
136 /* BUGGY, do not use in real life!!! */
137}
138
139static struct lock_torture_ops lock_busted_ops = {
140 .writelock = torture_lock_busted_write_lock,
141 .write_delay = torture_lock_busted_write_delay,
142 .writeunlock = torture_lock_busted_write_unlock,
143 .name = "lock_busted"
144};
145
146static DEFINE_SPINLOCK(torture_spinlock);
147
148static int torture_spin_lock_write_lock(void) __acquires(torture_spinlock)
149{
150 spin_lock(&torture_spinlock);
151 return 0;
152}
153
154static void torture_spin_lock_write_delay(struct torture_random_state *trsp)
155{
156 const unsigned long shortdelay_us = 2;
157 const unsigned long longdelay_us = 100;
158
159 /* We want a short delay mostly to emulate likely code, and
160 * we want a long delay occasionally to force massive contention.
161 */
162 if (!(torture_random(trsp) %
163 (nrealwriters_stress * 2000 * longdelay_us)))
164 mdelay(longdelay_us);
165 if (!(torture_random(trsp) %
166 (nrealwriters_stress * 2 * shortdelay_us)))
167 udelay(shortdelay_us);
168#ifdef CONFIG_PREEMPT
169 if (!(torture_random(trsp) % (nrealwriters_stress * 20000)))
170 preempt_schedule(); /* Allow test to be preempted. */
171#endif
172}
173
174static void torture_spin_lock_write_unlock(void) __releases(torture_spinlock)
175{
176 spin_unlock(&torture_spinlock);
177}
178
179static struct lock_torture_ops spin_lock_ops = {
180 .writelock = torture_spin_lock_write_lock,
181 .write_delay = torture_spin_lock_write_delay,
182 .writeunlock = torture_spin_lock_write_unlock,
183 .name = "spin_lock"
184};
185
186static int torture_spin_lock_write_lock_irq(void)
187__acquires(torture_spinlock_irq)
188{
189 unsigned long flags;
190
191 spin_lock_irqsave(&torture_spinlock, flags);
192 cur_ops->flags = flags;
193 return 0;
194}
195
196static void torture_lock_spin_write_unlock_irq(void)
197__releases(torture_spinlock)
198{
199 spin_unlock_irqrestore(&torture_spinlock, cur_ops->flags);
200}
201
202static struct lock_torture_ops spin_lock_irq_ops = {
203 .writelock = torture_spin_lock_write_lock_irq,
204 .write_delay = torture_spin_lock_write_delay,
205 .writeunlock = torture_lock_spin_write_unlock_irq,
206 .name = "spin_lock_irq"
207};
208
209/*
210 * Lock torture writer kthread. Repeatedly acquires and releases
211 * the lock, checking for duplicate acquisitions.
212 */
213static int lock_torture_writer(void *arg)
214{
215 struct lock_writer_stress_stats *lwsp = arg;
216 static DEFINE_TORTURE_RANDOM(rand);
217
218 VERBOSE_TOROUT_STRING("lock_torture_writer task started");
219 set_user_nice(current, 19);
220
221 do {
222 schedule_timeout_uninterruptible(1);
223 cur_ops->writelock();
224 if (WARN_ON_ONCE(lock_is_write_held))
225 lwsp->n_write_lock_fail++;
226 lock_is_write_held = 1;
227 lwsp->n_write_lock_acquired++;
228 cur_ops->write_delay(&rand);
229 lock_is_write_held = 0;
230 cur_ops->writeunlock();
231 stutter_wait("lock_torture_writer");
232 } while (!torture_must_stop());
233 torture_kthread_stopping("lock_torture_writer");
234 return 0;
235}
236
237/*
238 * Create an lock-torture-statistics message in the specified buffer.
239 */
240static void lock_torture_printk(char *page)
241{
242 bool fail = 0;
243 int i;
244 long max = 0;
245 long min = lwsa[0].n_write_lock_acquired;
246 long long sum = 0;
247
248 for (i = 0; i < nrealwriters_stress; i++) {
249 if (lwsa[i].n_write_lock_fail)
250 fail = true;
251 sum += lwsa[i].n_write_lock_acquired;
252 if (max < lwsa[i].n_write_lock_fail)
253 max = lwsa[i].n_write_lock_fail;
254 if (min > lwsa[i].n_write_lock_fail)
255 min = lwsa[i].n_write_lock_fail;
256 }
257 page += sprintf(page, "%s%s ", torture_type, TORTURE_FLAG);
258 page += sprintf(page,
259 "Writes: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n",
260 sum, max, min, max / 2 > min ? "???" : "",
261 fail, fail ? "!!!" : "");
262 if (fail)
263 atomic_inc(&n_lock_torture_errors);
264}
265
266/*
267 * Print torture statistics. Caller must ensure that there is only one
268 * call to this function at a given time!!! This is normally accomplished
269 * by relying on the module system to only have one copy of the module
270 * loaded, and then by giving the lock_torture_stats kthread full control
271 * (or the init/cleanup functions when lock_torture_stats thread is not
272 * running).
273 */
274static void lock_torture_stats_print(void)
275{
276 int size = nrealwriters_stress * 200 + 8192;
277 char *buf;
278
279 buf = kmalloc(size, GFP_KERNEL);
280 if (!buf) {
281 pr_err("lock_torture_stats_print: Out of memory, need: %d",
282 size);
283 return;
284 }
285 lock_torture_printk(buf);
286 pr_alert("%s", buf);
287 kfree(buf);
288}
289
290/*
291 * Periodically prints torture statistics, if periodic statistics printing
292 * was specified via the stat_interval module parameter.
293 *
294 * No need to worry about fullstop here, since this one doesn't reference
295 * volatile state or register callbacks.
296 */
297static int lock_torture_stats(void *arg)
298{
299 VERBOSE_TOROUT_STRING("lock_torture_stats task started");
300 do {
301 schedule_timeout_interruptible(stat_interval * HZ);
302 lock_torture_stats_print();
303 torture_shutdown_absorb("lock_torture_stats");
304 } while (!torture_must_stop());
305 torture_kthread_stopping("lock_torture_stats");
306 return 0;
307}
308
309static inline void
310lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
311 const char *tag)
312{
313 pr_alert("%s" TORTURE_FLAG
314 "--- %s: nwriters_stress=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d\n",
315 torture_type, tag, nrealwriters_stress, stat_interval, verbose,
316 shuffle_interval, stutter, shutdown_secs,
317 onoff_interval, onoff_holdoff);
318}
319
320static void lock_torture_cleanup(void)
321{
322 int i;
323
324 if (torture_cleanup())
325 return;
326
327 if (writer_tasks) {
328 for (i = 0; i < nrealwriters_stress; i++)
329 torture_stop_kthread(lock_torture_writer,
330 writer_tasks[i]);
331 kfree(writer_tasks);
332 writer_tasks = NULL;
333 }
334
335 torture_stop_kthread(lock_torture_stats, stats_task);
336 lock_torture_stats_print(); /* -After- the stats thread is stopped! */
337
338 if (atomic_read(&n_lock_torture_errors))
339 lock_torture_print_module_parms(cur_ops,
340 "End of test: FAILURE");
341 else if (torture_onoff_failures())
342 lock_torture_print_module_parms(cur_ops,
343 "End of test: LOCK_HOTPLUG");
344 else
345 lock_torture_print_module_parms(cur_ops,
346 "End of test: SUCCESS");
347}
348
349static int __init lock_torture_init(void)
350{
351 int i;
352 int firsterr = 0;
353 static struct lock_torture_ops *torture_ops[] = {
354 &lock_busted_ops, &spin_lock_ops, &spin_lock_irq_ops,
355 };
356
357 torture_init_begin(torture_type, verbose, &locktorture_runnable);
358
359 /* Process args and tell the world that the torturer is on the job. */
360 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
361 cur_ops = torture_ops[i];
362 if (strcmp(torture_type, cur_ops->name) == 0)
363 break;
364 }
365 if (i == ARRAY_SIZE(torture_ops)) {
366 pr_alert("lock-torture: invalid torture type: \"%s\"\n",
367 torture_type);
368 pr_alert("lock-torture types:");
369 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
370 pr_alert(" %s", torture_ops[i]->name);
371 pr_alert("\n");
372 torture_init_end();
373 return -EINVAL;
374 }
375 if (cur_ops->init)
376 cur_ops->init(); /* no "goto unwind" prior to this point!!! */
377
378 if (nwriters_stress >= 0)
379 nrealwriters_stress = nwriters_stress;
380 else
381 nrealwriters_stress = 2 * num_online_cpus();
382 lock_torture_print_module_parms(cur_ops, "Start of test");
383
384 /* Initialize the statistics so that each run gets its own numbers. */
385
386 lock_is_write_held = 0;
387 lwsa = kmalloc(sizeof(*lwsa) * nrealwriters_stress, GFP_KERNEL);
388 if (lwsa == NULL) {
389 VERBOSE_TOROUT_STRING("lwsa: Out of memory");
390 firsterr = -ENOMEM;
391 goto unwind;
392 }
393 for (i = 0; i < nrealwriters_stress; i++) {
394 lwsa[i].n_write_lock_fail = 0;
395 lwsa[i].n_write_lock_acquired = 0;
396 }
397
398 /* Start up the kthreads. */
399
400 if (onoff_interval > 0) {
401 firsterr = torture_onoff_init(onoff_holdoff * HZ,
402 onoff_interval * HZ);
403 if (firsterr)
404 goto unwind;
405 }
406 if (shuffle_interval > 0) {
407 firsterr = torture_shuffle_init(shuffle_interval);
408 if (firsterr)
409 goto unwind;
410 }
411 if (shutdown_secs > 0) {
412 firsterr = torture_shutdown_init(shutdown_secs,
413 lock_torture_cleanup);
414 if (firsterr)
415 goto unwind;
416 }
417 if (stutter > 0) {
418 firsterr = torture_stutter_init(stutter);
419 if (firsterr)
420 goto unwind;
421 }
422
423 writer_tasks = kzalloc(nrealwriters_stress * sizeof(writer_tasks[0]),
424 GFP_KERNEL);
425 if (writer_tasks == NULL) {
426 VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory");
427 firsterr = -ENOMEM;
428 goto unwind;
429 }
430 for (i = 0; i < nrealwriters_stress; i++) {
431 firsterr = torture_create_kthread(lock_torture_writer, &lwsa[i],
432 writer_tasks[i]);
433 if (firsterr)
434 goto unwind;
435 }
436 if (stat_interval > 0) {
437 firsterr = torture_create_kthread(lock_torture_stats, NULL,
438 stats_task);
439 if (firsterr)
440 goto unwind;
441 }
442 torture_init_end();
443 return 0;
444
445unwind:
446 torture_init_end();
447 lock_torture_cleanup();
448 return firsterr;
449}
450
451module_init(lock_torture_init);
452module_exit(lock_torture_cleanup);
1/*
2 * Module-based torture test facility for locking
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, you can access it online at
16 * http://www.gnu.org/licenses/gpl-2.0.html.
17 *
18 * Copyright (C) IBM Corporation, 2014
19 *
20 * Authors: Paul E. McKenney <paulmck@us.ibm.com>
21 * Davidlohr Bueso <dave@stgolabs.net>
22 * Based on kernel/rcu/torture.c.
23 */
24#include <linux/kernel.h>
25#include <linux/module.h>
26#include <linux/kthread.h>
27#include <linux/sched/rt.h>
28#include <linux/spinlock.h>
29#include <linux/rwlock.h>
30#include <linux/mutex.h>
31#include <linux/rwsem.h>
32#include <linux/smp.h>
33#include <linux/interrupt.h>
34#include <linux/sched.h>
35#include <uapi/linux/sched/types.h>
36#include <linux/rtmutex.h>
37#include <linux/atomic.h>
38#include <linux/moduleparam.h>
39#include <linux/delay.h>
40#include <linux/slab.h>
41#include <linux/percpu-rwsem.h>
42#include <linux/torture.h>
43
44MODULE_LICENSE("GPL");
45MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
46
47torture_param(int, nwriters_stress, -1,
48 "Number of write-locking stress-test threads");
49torture_param(int, nreaders_stress, -1,
50 "Number of read-locking stress-test threads");
51torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
52torture_param(int, onoff_interval, 0,
53 "Time between CPU hotplugs (s), 0=disable");
54torture_param(int, shuffle_interval, 3,
55 "Number of jiffies between shuffles, 0=disable");
56torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable.");
57torture_param(int, stat_interval, 60,
58 "Number of seconds between stats printk()s");
59torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
60torture_param(bool, verbose, true,
61 "Enable verbose debugging printk()s");
62
63static char *torture_type = "spin_lock";
64module_param(torture_type, charp, 0444);
65MODULE_PARM_DESC(torture_type,
66 "Type of lock to torture (spin_lock, spin_lock_irq, mutex_lock, ...)");
67
68static struct task_struct *stats_task;
69static struct task_struct **writer_tasks;
70static struct task_struct **reader_tasks;
71
72static bool lock_is_write_held;
73static bool lock_is_read_held;
74
75struct lock_stress_stats {
76 long n_lock_fail;
77 long n_lock_acquired;
78};
79
80/* Forward reference. */
81static void lock_torture_cleanup(void);
82
83/*
84 * Operations vector for selecting different types of tests.
85 */
86struct lock_torture_ops {
87 void (*init)(void);
88 int (*writelock)(void);
89 void (*write_delay)(struct torture_random_state *trsp);
90 void (*task_boost)(struct torture_random_state *trsp);
91 void (*writeunlock)(void);
92 int (*readlock)(void);
93 void (*read_delay)(struct torture_random_state *trsp);
94 void (*readunlock)(void);
95
96 unsigned long flags; /* for irq spinlocks */
97 const char *name;
98};
99
100struct lock_torture_cxt {
101 int nrealwriters_stress;
102 int nrealreaders_stress;
103 bool debug_lock;
104 atomic_t n_lock_torture_errors;
105 struct lock_torture_ops *cur_ops;
106 struct lock_stress_stats *lwsa; /* writer statistics */
107 struct lock_stress_stats *lrsa; /* reader statistics */
108};
109static struct lock_torture_cxt cxt = { 0, 0, false,
110 ATOMIC_INIT(0),
111 NULL, NULL};
112/*
113 * Definitions for lock torture testing.
114 */
115
116static int torture_lock_busted_write_lock(void)
117{
118 return 0; /* BUGGY, do not use in real life!!! */
119}
120
121static void torture_lock_busted_write_delay(struct torture_random_state *trsp)
122{
123 const unsigned long longdelay_ms = 100;
124
125 /* We want a long delay occasionally to force massive contention. */
126 if (!(torture_random(trsp) %
127 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
128 mdelay(longdelay_ms);
129 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
130 torture_preempt_schedule(); /* Allow test to be preempted. */
131}
132
133static void torture_lock_busted_write_unlock(void)
134{
135 /* BUGGY, do not use in real life!!! */
136}
137
138static void torture_boost_dummy(struct torture_random_state *trsp)
139{
140 /* Only rtmutexes care about priority */
141}
142
143static struct lock_torture_ops lock_busted_ops = {
144 .writelock = torture_lock_busted_write_lock,
145 .write_delay = torture_lock_busted_write_delay,
146 .task_boost = torture_boost_dummy,
147 .writeunlock = torture_lock_busted_write_unlock,
148 .readlock = NULL,
149 .read_delay = NULL,
150 .readunlock = NULL,
151 .name = "lock_busted"
152};
153
154static DEFINE_SPINLOCK(torture_spinlock);
155
156static int torture_spin_lock_write_lock(void) __acquires(torture_spinlock)
157{
158 spin_lock(&torture_spinlock);
159 return 0;
160}
161
162static void torture_spin_lock_write_delay(struct torture_random_state *trsp)
163{
164 const unsigned long shortdelay_us = 2;
165 const unsigned long longdelay_ms = 100;
166
167 /* We want a short delay mostly to emulate likely code, and
168 * we want a long delay occasionally to force massive contention.
169 */
170 if (!(torture_random(trsp) %
171 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
172 mdelay(longdelay_ms);
173 if (!(torture_random(trsp) %
174 (cxt.nrealwriters_stress * 2 * shortdelay_us)))
175 udelay(shortdelay_us);
176 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
177 torture_preempt_schedule(); /* Allow test to be preempted. */
178}
179
180static void torture_spin_lock_write_unlock(void) __releases(torture_spinlock)
181{
182 spin_unlock(&torture_spinlock);
183}
184
185static struct lock_torture_ops spin_lock_ops = {
186 .writelock = torture_spin_lock_write_lock,
187 .write_delay = torture_spin_lock_write_delay,
188 .task_boost = torture_boost_dummy,
189 .writeunlock = torture_spin_lock_write_unlock,
190 .readlock = NULL,
191 .read_delay = NULL,
192 .readunlock = NULL,
193 .name = "spin_lock"
194};
195
196static int torture_spin_lock_write_lock_irq(void)
197__acquires(torture_spinlock)
198{
199 unsigned long flags;
200
201 spin_lock_irqsave(&torture_spinlock, flags);
202 cxt.cur_ops->flags = flags;
203 return 0;
204}
205
206static void torture_lock_spin_write_unlock_irq(void)
207__releases(torture_spinlock)
208{
209 spin_unlock_irqrestore(&torture_spinlock, cxt.cur_ops->flags);
210}
211
212static struct lock_torture_ops spin_lock_irq_ops = {
213 .writelock = torture_spin_lock_write_lock_irq,
214 .write_delay = torture_spin_lock_write_delay,
215 .task_boost = torture_boost_dummy,
216 .writeunlock = torture_lock_spin_write_unlock_irq,
217 .readlock = NULL,
218 .read_delay = NULL,
219 .readunlock = NULL,
220 .name = "spin_lock_irq"
221};
222
223static DEFINE_RWLOCK(torture_rwlock);
224
225static int torture_rwlock_write_lock(void) __acquires(torture_rwlock)
226{
227 write_lock(&torture_rwlock);
228 return 0;
229}
230
231static void torture_rwlock_write_delay(struct torture_random_state *trsp)
232{
233 const unsigned long shortdelay_us = 2;
234 const unsigned long longdelay_ms = 100;
235
236 /* We want a short delay mostly to emulate likely code, and
237 * we want a long delay occasionally to force massive contention.
238 */
239 if (!(torture_random(trsp) %
240 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
241 mdelay(longdelay_ms);
242 else
243 udelay(shortdelay_us);
244}
245
246static void torture_rwlock_write_unlock(void) __releases(torture_rwlock)
247{
248 write_unlock(&torture_rwlock);
249}
250
251static int torture_rwlock_read_lock(void) __acquires(torture_rwlock)
252{
253 read_lock(&torture_rwlock);
254 return 0;
255}
256
257static void torture_rwlock_read_delay(struct torture_random_state *trsp)
258{
259 const unsigned long shortdelay_us = 10;
260 const unsigned long longdelay_ms = 100;
261
262 /* We want a short delay mostly to emulate likely code, and
263 * we want a long delay occasionally to force massive contention.
264 */
265 if (!(torture_random(trsp) %
266 (cxt.nrealreaders_stress * 2000 * longdelay_ms)))
267 mdelay(longdelay_ms);
268 else
269 udelay(shortdelay_us);
270}
271
272static void torture_rwlock_read_unlock(void) __releases(torture_rwlock)
273{
274 read_unlock(&torture_rwlock);
275}
276
277static struct lock_torture_ops rw_lock_ops = {
278 .writelock = torture_rwlock_write_lock,
279 .write_delay = torture_rwlock_write_delay,
280 .task_boost = torture_boost_dummy,
281 .writeunlock = torture_rwlock_write_unlock,
282 .readlock = torture_rwlock_read_lock,
283 .read_delay = torture_rwlock_read_delay,
284 .readunlock = torture_rwlock_read_unlock,
285 .name = "rw_lock"
286};
287
288static int torture_rwlock_write_lock_irq(void) __acquires(torture_rwlock)
289{
290 unsigned long flags;
291
292 write_lock_irqsave(&torture_rwlock, flags);
293 cxt.cur_ops->flags = flags;
294 return 0;
295}
296
297static void torture_rwlock_write_unlock_irq(void)
298__releases(torture_rwlock)
299{
300 write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
301}
302
303static int torture_rwlock_read_lock_irq(void) __acquires(torture_rwlock)
304{
305 unsigned long flags;
306
307 read_lock_irqsave(&torture_rwlock, flags);
308 cxt.cur_ops->flags = flags;
309 return 0;
310}
311
312static void torture_rwlock_read_unlock_irq(void)
313__releases(torture_rwlock)
314{
315 read_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
316}
317
318static struct lock_torture_ops rw_lock_irq_ops = {
319 .writelock = torture_rwlock_write_lock_irq,
320 .write_delay = torture_rwlock_write_delay,
321 .task_boost = torture_boost_dummy,
322 .writeunlock = torture_rwlock_write_unlock_irq,
323 .readlock = torture_rwlock_read_lock_irq,
324 .read_delay = torture_rwlock_read_delay,
325 .readunlock = torture_rwlock_read_unlock_irq,
326 .name = "rw_lock_irq"
327};
328
329static DEFINE_MUTEX(torture_mutex);
330
331static int torture_mutex_lock(void) __acquires(torture_mutex)
332{
333 mutex_lock(&torture_mutex);
334 return 0;
335}
336
337static void torture_mutex_delay(struct torture_random_state *trsp)
338{
339 const unsigned long longdelay_ms = 100;
340
341 /* We want a long delay occasionally to force massive contention. */
342 if (!(torture_random(trsp) %
343 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
344 mdelay(longdelay_ms * 5);
345 else
346 mdelay(longdelay_ms / 5);
347 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
348 torture_preempt_schedule(); /* Allow test to be preempted. */
349}
350
351static void torture_mutex_unlock(void) __releases(torture_mutex)
352{
353 mutex_unlock(&torture_mutex);
354}
355
356static struct lock_torture_ops mutex_lock_ops = {
357 .writelock = torture_mutex_lock,
358 .write_delay = torture_mutex_delay,
359 .task_boost = torture_boost_dummy,
360 .writeunlock = torture_mutex_unlock,
361 .readlock = NULL,
362 .read_delay = NULL,
363 .readunlock = NULL,
364 .name = "mutex_lock"
365};
366
367#include <linux/ww_mutex.h>
368static DEFINE_WW_CLASS(torture_ww_class);
369static DEFINE_WW_MUTEX(torture_ww_mutex_0, &torture_ww_class);
370static DEFINE_WW_MUTEX(torture_ww_mutex_1, &torture_ww_class);
371static DEFINE_WW_MUTEX(torture_ww_mutex_2, &torture_ww_class);
372
373static int torture_ww_mutex_lock(void)
374__acquires(torture_ww_mutex_0)
375__acquires(torture_ww_mutex_1)
376__acquires(torture_ww_mutex_2)
377{
378 LIST_HEAD(list);
379 struct reorder_lock {
380 struct list_head link;
381 struct ww_mutex *lock;
382 } locks[3], *ll, *ln;
383 struct ww_acquire_ctx ctx;
384
385 locks[0].lock = &torture_ww_mutex_0;
386 list_add(&locks[0].link, &list);
387
388 locks[1].lock = &torture_ww_mutex_1;
389 list_add(&locks[1].link, &list);
390
391 locks[2].lock = &torture_ww_mutex_2;
392 list_add(&locks[2].link, &list);
393
394 ww_acquire_init(&ctx, &torture_ww_class);
395
396 list_for_each_entry(ll, &list, link) {
397 int err;
398
399 err = ww_mutex_lock(ll->lock, &ctx);
400 if (!err)
401 continue;
402
403 ln = ll;
404 list_for_each_entry_continue_reverse(ln, &list, link)
405 ww_mutex_unlock(ln->lock);
406
407 if (err != -EDEADLK)
408 return err;
409
410 ww_mutex_lock_slow(ll->lock, &ctx);
411 list_move(&ll->link, &list);
412 }
413
414 ww_acquire_fini(&ctx);
415 return 0;
416}
417
418static void torture_ww_mutex_unlock(void)
419__releases(torture_ww_mutex_0)
420__releases(torture_ww_mutex_1)
421__releases(torture_ww_mutex_2)
422{
423 ww_mutex_unlock(&torture_ww_mutex_0);
424 ww_mutex_unlock(&torture_ww_mutex_1);
425 ww_mutex_unlock(&torture_ww_mutex_2);
426}
427
428static struct lock_torture_ops ww_mutex_lock_ops = {
429 .writelock = torture_ww_mutex_lock,
430 .write_delay = torture_mutex_delay,
431 .task_boost = torture_boost_dummy,
432 .writeunlock = torture_ww_mutex_unlock,
433 .readlock = NULL,
434 .read_delay = NULL,
435 .readunlock = NULL,
436 .name = "ww_mutex_lock"
437};
438
439#ifdef CONFIG_RT_MUTEXES
440static DEFINE_RT_MUTEX(torture_rtmutex);
441
442static int torture_rtmutex_lock(void) __acquires(torture_rtmutex)
443{
444 rt_mutex_lock(&torture_rtmutex);
445 return 0;
446}
447
448static void torture_rtmutex_boost(struct torture_random_state *trsp)
449{
450 int policy;
451 struct sched_param param;
452 const unsigned int factor = 50000; /* yes, quite arbitrary */
453
454 if (!rt_task(current)) {
455 /*
456 * Boost priority once every ~50k operations. When the
457 * task tries to take the lock, the rtmutex it will account
458 * for the new priority, and do any corresponding pi-dance.
459 */
460 if (trsp && !(torture_random(trsp) %
461 (cxt.nrealwriters_stress * factor))) {
462 policy = SCHED_FIFO;
463 param.sched_priority = MAX_RT_PRIO - 1;
464 } else /* common case, do nothing */
465 return;
466 } else {
467 /*
468 * The task will remain boosted for another ~500k operations,
469 * then restored back to its original prio, and so forth.
470 *
471 * When @trsp is nil, we want to force-reset the task for
472 * stopping the kthread.
473 */
474 if (!trsp || !(torture_random(trsp) %
475 (cxt.nrealwriters_stress * factor * 2))) {
476 policy = SCHED_NORMAL;
477 param.sched_priority = 0;
478 } else /* common case, do nothing */
479 return;
480 }
481
482 sched_setscheduler_nocheck(current, policy, ¶m);
483}
484
485static void torture_rtmutex_delay(struct torture_random_state *trsp)
486{
487 const unsigned long shortdelay_us = 2;
488 const unsigned long longdelay_ms = 100;
489
490 /*
491 * We want a short delay mostly to emulate likely code, and
492 * we want a long delay occasionally to force massive contention.
493 */
494 if (!(torture_random(trsp) %
495 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
496 mdelay(longdelay_ms);
497 if (!(torture_random(trsp) %
498 (cxt.nrealwriters_stress * 2 * shortdelay_us)))
499 udelay(shortdelay_us);
500 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
501 torture_preempt_schedule(); /* Allow test to be preempted. */
502}
503
504static void torture_rtmutex_unlock(void) __releases(torture_rtmutex)
505{
506 rt_mutex_unlock(&torture_rtmutex);
507}
508
509static struct lock_torture_ops rtmutex_lock_ops = {
510 .writelock = torture_rtmutex_lock,
511 .write_delay = torture_rtmutex_delay,
512 .task_boost = torture_rtmutex_boost,
513 .writeunlock = torture_rtmutex_unlock,
514 .readlock = NULL,
515 .read_delay = NULL,
516 .readunlock = NULL,
517 .name = "rtmutex_lock"
518};
519#endif
520
521static DECLARE_RWSEM(torture_rwsem);
522static int torture_rwsem_down_write(void) __acquires(torture_rwsem)
523{
524 down_write(&torture_rwsem);
525 return 0;
526}
527
528static void torture_rwsem_write_delay(struct torture_random_state *trsp)
529{
530 const unsigned long longdelay_ms = 100;
531
532 /* We want a long delay occasionally to force massive contention. */
533 if (!(torture_random(trsp) %
534 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
535 mdelay(longdelay_ms * 10);
536 else
537 mdelay(longdelay_ms / 10);
538 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
539 torture_preempt_schedule(); /* Allow test to be preempted. */
540}
541
542static void torture_rwsem_up_write(void) __releases(torture_rwsem)
543{
544 up_write(&torture_rwsem);
545}
546
547static int torture_rwsem_down_read(void) __acquires(torture_rwsem)
548{
549 down_read(&torture_rwsem);
550 return 0;
551}
552
553static void torture_rwsem_read_delay(struct torture_random_state *trsp)
554{
555 const unsigned long longdelay_ms = 100;
556
557 /* We want a long delay occasionally to force massive contention. */
558 if (!(torture_random(trsp) %
559 (cxt.nrealreaders_stress * 2000 * longdelay_ms)))
560 mdelay(longdelay_ms * 2);
561 else
562 mdelay(longdelay_ms / 2);
563 if (!(torture_random(trsp) % (cxt.nrealreaders_stress * 20000)))
564 torture_preempt_schedule(); /* Allow test to be preempted. */
565}
566
567static void torture_rwsem_up_read(void) __releases(torture_rwsem)
568{
569 up_read(&torture_rwsem);
570}
571
572static struct lock_torture_ops rwsem_lock_ops = {
573 .writelock = torture_rwsem_down_write,
574 .write_delay = torture_rwsem_write_delay,
575 .task_boost = torture_boost_dummy,
576 .writeunlock = torture_rwsem_up_write,
577 .readlock = torture_rwsem_down_read,
578 .read_delay = torture_rwsem_read_delay,
579 .readunlock = torture_rwsem_up_read,
580 .name = "rwsem_lock"
581};
582
583#include <linux/percpu-rwsem.h>
584static struct percpu_rw_semaphore pcpu_rwsem;
585
586void torture_percpu_rwsem_init(void)
587{
588 BUG_ON(percpu_init_rwsem(&pcpu_rwsem));
589}
590
591static int torture_percpu_rwsem_down_write(void) __acquires(pcpu_rwsem)
592{
593 percpu_down_write(&pcpu_rwsem);
594 return 0;
595}
596
597static void torture_percpu_rwsem_up_write(void) __releases(pcpu_rwsem)
598{
599 percpu_up_write(&pcpu_rwsem);
600}
601
602static int torture_percpu_rwsem_down_read(void) __acquires(pcpu_rwsem)
603{
604 percpu_down_read(&pcpu_rwsem);
605 return 0;
606}
607
608static void torture_percpu_rwsem_up_read(void) __releases(pcpu_rwsem)
609{
610 percpu_up_read(&pcpu_rwsem);
611}
612
613static struct lock_torture_ops percpu_rwsem_lock_ops = {
614 .init = torture_percpu_rwsem_init,
615 .writelock = torture_percpu_rwsem_down_write,
616 .write_delay = torture_rwsem_write_delay,
617 .task_boost = torture_boost_dummy,
618 .writeunlock = torture_percpu_rwsem_up_write,
619 .readlock = torture_percpu_rwsem_down_read,
620 .read_delay = torture_rwsem_read_delay,
621 .readunlock = torture_percpu_rwsem_up_read,
622 .name = "percpu_rwsem_lock"
623};
624
625/*
626 * Lock torture writer kthread. Repeatedly acquires and releases
627 * the lock, checking for duplicate acquisitions.
628 */
629static int lock_torture_writer(void *arg)
630{
631 struct lock_stress_stats *lwsp = arg;
632 static DEFINE_TORTURE_RANDOM(rand);
633
634 VERBOSE_TOROUT_STRING("lock_torture_writer task started");
635 set_user_nice(current, MAX_NICE);
636
637 do {
638 if ((torture_random(&rand) & 0xfffff) == 0)
639 schedule_timeout_uninterruptible(1);
640
641 cxt.cur_ops->task_boost(&rand);
642 cxt.cur_ops->writelock();
643 if (WARN_ON_ONCE(lock_is_write_held))
644 lwsp->n_lock_fail++;
645 lock_is_write_held = 1;
646 if (WARN_ON_ONCE(lock_is_read_held))
647 lwsp->n_lock_fail++; /* rare, but... */
648
649 lwsp->n_lock_acquired++;
650 cxt.cur_ops->write_delay(&rand);
651 lock_is_write_held = 0;
652 cxt.cur_ops->writeunlock();
653
654 stutter_wait("lock_torture_writer");
655 } while (!torture_must_stop());
656
657 cxt.cur_ops->task_boost(NULL); /* reset prio */
658 torture_kthread_stopping("lock_torture_writer");
659 return 0;
660}
661
662/*
663 * Lock torture reader kthread. Repeatedly acquires and releases
664 * the reader lock.
665 */
666static int lock_torture_reader(void *arg)
667{
668 struct lock_stress_stats *lrsp = arg;
669 static DEFINE_TORTURE_RANDOM(rand);
670
671 VERBOSE_TOROUT_STRING("lock_torture_reader task started");
672 set_user_nice(current, MAX_NICE);
673
674 do {
675 if ((torture_random(&rand) & 0xfffff) == 0)
676 schedule_timeout_uninterruptible(1);
677
678 cxt.cur_ops->readlock();
679 lock_is_read_held = 1;
680 if (WARN_ON_ONCE(lock_is_write_held))
681 lrsp->n_lock_fail++; /* rare, but... */
682
683 lrsp->n_lock_acquired++;
684 cxt.cur_ops->read_delay(&rand);
685 lock_is_read_held = 0;
686 cxt.cur_ops->readunlock();
687
688 stutter_wait("lock_torture_reader");
689 } while (!torture_must_stop());
690 torture_kthread_stopping("lock_torture_reader");
691 return 0;
692}
693
694/*
695 * Create an lock-torture-statistics message in the specified buffer.
696 */
697static void __torture_print_stats(char *page,
698 struct lock_stress_stats *statp, bool write)
699{
700 bool fail = 0;
701 int i, n_stress;
702 long max = 0, min = statp ? statp[0].n_lock_acquired : 0;
703 long long sum = 0;
704
705 n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress;
706 for (i = 0; i < n_stress; i++) {
707 if (statp[i].n_lock_fail)
708 fail = true;
709 sum += statp[i].n_lock_acquired;
710 if (max < statp[i].n_lock_fail)
711 max = statp[i].n_lock_fail;
712 if (min > statp[i].n_lock_fail)
713 min = statp[i].n_lock_fail;
714 }
715 page += sprintf(page,
716 "%s: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n",
717 write ? "Writes" : "Reads ",
718 sum, max, min, max / 2 > min ? "???" : "",
719 fail, fail ? "!!!" : "");
720 if (fail)
721 atomic_inc(&cxt.n_lock_torture_errors);
722}
723
724/*
725 * Print torture statistics. Caller must ensure that there is only one
726 * call to this function at a given time!!! This is normally accomplished
727 * by relying on the module system to only have one copy of the module
728 * loaded, and then by giving the lock_torture_stats kthread full control
729 * (or the init/cleanup functions when lock_torture_stats thread is not
730 * running).
731 */
732static void lock_torture_stats_print(void)
733{
734 int size = cxt.nrealwriters_stress * 200 + 8192;
735 char *buf;
736
737 if (cxt.cur_ops->readlock)
738 size += cxt.nrealreaders_stress * 200 + 8192;
739
740 buf = kmalloc(size, GFP_KERNEL);
741 if (!buf) {
742 pr_err("lock_torture_stats_print: Out of memory, need: %d",
743 size);
744 return;
745 }
746
747 __torture_print_stats(buf, cxt.lwsa, true);
748 pr_alert("%s", buf);
749 kfree(buf);
750
751 if (cxt.cur_ops->readlock) {
752 buf = kmalloc(size, GFP_KERNEL);
753 if (!buf) {
754 pr_err("lock_torture_stats_print: Out of memory, need: %d",
755 size);
756 return;
757 }
758
759 __torture_print_stats(buf, cxt.lrsa, false);
760 pr_alert("%s", buf);
761 kfree(buf);
762 }
763}
764
765/*
766 * Periodically prints torture statistics, if periodic statistics printing
767 * was specified via the stat_interval module parameter.
768 *
769 * No need to worry about fullstop here, since this one doesn't reference
770 * volatile state or register callbacks.
771 */
772static int lock_torture_stats(void *arg)
773{
774 VERBOSE_TOROUT_STRING("lock_torture_stats task started");
775 do {
776 schedule_timeout_interruptible(stat_interval * HZ);
777 lock_torture_stats_print();
778 torture_shutdown_absorb("lock_torture_stats");
779 } while (!torture_must_stop());
780 torture_kthread_stopping("lock_torture_stats");
781 return 0;
782}
783
784static inline void
785lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
786 const char *tag)
787{
788 pr_alert("%s" TORTURE_FLAG
789 "--- %s%s: nwriters_stress=%d nreaders_stress=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d\n",
790 torture_type, tag, cxt.debug_lock ? " [debug]": "",
791 cxt.nrealwriters_stress, cxt.nrealreaders_stress, stat_interval,
792 verbose, shuffle_interval, stutter, shutdown_secs,
793 onoff_interval, onoff_holdoff);
794}
795
796static void lock_torture_cleanup(void)
797{
798 int i;
799
800 if (torture_cleanup_begin())
801 return;
802
803 /*
804 * Indicates early cleanup, meaning that the test has not run,
805 * such as when passing bogus args when loading the module. As
806 * such, only perform the underlying torture-specific cleanups,
807 * and avoid anything related to locktorture.
808 */
809 if (!cxt.lwsa && !cxt.lrsa)
810 goto end;
811
812 if (writer_tasks) {
813 for (i = 0; i < cxt.nrealwriters_stress; i++)
814 torture_stop_kthread(lock_torture_writer,
815 writer_tasks[i]);
816 kfree(writer_tasks);
817 writer_tasks = NULL;
818 }
819
820 if (reader_tasks) {
821 for (i = 0; i < cxt.nrealreaders_stress; i++)
822 torture_stop_kthread(lock_torture_reader,
823 reader_tasks[i]);
824 kfree(reader_tasks);
825 reader_tasks = NULL;
826 }
827
828 torture_stop_kthread(lock_torture_stats, stats_task);
829 lock_torture_stats_print(); /* -After- the stats thread is stopped! */
830
831 if (atomic_read(&cxt.n_lock_torture_errors))
832 lock_torture_print_module_parms(cxt.cur_ops,
833 "End of test: FAILURE");
834 else if (torture_onoff_failures())
835 lock_torture_print_module_parms(cxt.cur_ops,
836 "End of test: LOCK_HOTPLUG");
837 else
838 lock_torture_print_module_parms(cxt.cur_ops,
839 "End of test: SUCCESS");
840
841 kfree(cxt.lwsa);
842 kfree(cxt.lrsa);
843
844end:
845 torture_cleanup_end();
846}
847
848static int __init lock_torture_init(void)
849{
850 int i, j;
851 int firsterr = 0;
852 static struct lock_torture_ops *torture_ops[] = {
853 &lock_busted_ops,
854 &spin_lock_ops, &spin_lock_irq_ops,
855 &rw_lock_ops, &rw_lock_irq_ops,
856 &mutex_lock_ops,
857 &ww_mutex_lock_ops,
858#ifdef CONFIG_RT_MUTEXES
859 &rtmutex_lock_ops,
860#endif
861 &rwsem_lock_ops,
862 &percpu_rwsem_lock_ops,
863 };
864
865 if (!torture_init_begin(torture_type, verbose))
866 return -EBUSY;
867
868 /* Process args and tell the world that the torturer is on the job. */
869 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
870 cxt.cur_ops = torture_ops[i];
871 if (strcmp(torture_type, cxt.cur_ops->name) == 0)
872 break;
873 }
874 if (i == ARRAY_SIZE(torture_ops)) {
875 pr_alert("lock-torture: invalid torture type: \"%s\"\n",
876 torture_type);
877 pr_alert("lock-torture types:");
878 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
879 pr_alert(" %s", torture_ops[i]->name);
880 pr_alert("\n");
881 firsterr = -EINVAL;
882 goto unwind;
883 }
884
885 if (nwriters_stress == 0 && nreaders_stress == 0) {
886 pr_alert("lock-torture: must run at least one locking thread\n");
887 firsterr = -EINVAL;
888 goto unwind;
889 }
890
891 if (cxt.cur_ops->init)
892 cxt.cur_ops->init();
893
894 if (nwriters_stress >= 0)
895 cxt.nrealwriters_stress = nwriters_stress;
896 else
897 cxt.nrealwriters_stress = 2 * num_online_cpus();
898
899#ifdef CONFIG_DEBUG_MUTEXES
900 if (strncmp(torture_type, "mutex", 5) == 0)
901 cxt.debug_lock = true;
902#endif
903#ifdef CONFIG_DEBUG_RT_MUTEXES
904 if (strncmp(torture_type, "rtmutex", 7) == 0)
905 cxt.debug_lock = true;
906#endif
907#ifdef CONFIG_DEBUG_SPINLOCK
908 if ((strncmp(torture_type, "spin", 4) == 0) ||
909 (strncmp(torture_type, "rw_lock", 7) == 0))
910 cxt.debug_lock = true;
911#endif
912
913 /* Initialize the statistics so that each run gets its own numbers. */
914 if (nwriters_stress) {
915 lock_is_write_held = 0;
916 cxt.lwsa = kmalloc(sizeof(*cxt.lwsa) * cxt.nrealwriters_stress, GFP_KERNEL);
917 if (cxt.lwsa == NULL) {
918 VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory");
919 firsterr = -ENOMEM;
920 goto unwind;
921 }
922
923 for (i = 0; i < cxt.nrealwriters_stress; i++) {
924 cxt.lwsa[i].n_lock_fail = 0;
925 cxt.lwsa[i].n_lock_acquired = 0;
926 }
927 }
928
929 if (cxt.cur_ops->readlock) {
930 if (nreaders_stress >= 0)
931 cxt.nrealreaders_stress = nreaders_stress;
932 else {
933 /*
934 * By default distribute evenly the number of
935 * readers and writers. We still run the same number
936 * of threads as the writer-only locks default.
937 */
938 if (nwriters_stress < 0) /* user doesn't care */
939 cxt.nrealwriters_stress = num_online_cpus();
940 cxt.nrealreaders_stress = cxt.nrealwriters_stress;
941 }
942
943 if (nreaders_stress) {
944 lock_is_read_held = 0;
945 cxt.lrsa = kmalloc(sizeof(*cxt.lrsa) * cxt.nrealreaders_stress, GFP_KERNEL);
946 if (cxt.lrsa == NULL) {
947 VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory");
948 firsterr = -ENOMEM;
949 kfree(cxt.lwsa);
950 cxt.lwsa = NULL;
951 goto unwind;
952 }
953
954 for (i = 0; i < cxt.nrealreaders_stress; i++) {
955 cxt.lrsa[i].n_lock_fail = 0;
956 cxt.lrsa[i].n_lock_acquired = 0;
957 }
958 }
959 }
960
961 lock_torture_print_module_parms(cxt.cur_ops, "Start of test");
962
963 /* Prepare torture context. */
964 if (onoff_interval > 0) {
965 firsterr = torture_onoff_init(onoff_holdoff * HZ,
966 onoff_interval * HZ);
967 if (firsterr)
968 goto unwind;
969 }
970 if (shuffle_interval > 0) {
971 firsterr = torture_shuffle_init(shuffle_interval);
972 if (firsterr)
973 goto unwind;
974 }
975 if (shutdown_secs > 0) {
976 firsterr = torture_shutdown_init(shutdown_secs,
977 lock_torture_cleanup);
978 if (firsterr)
979 goto unwind;
980 }
981 if (stutter > 0) {
982 firsterr = torture_stutter_init(stutter);
983 if (firsterr)
984 goto unwind;
985 }
986
987 if (nwriters_stress) {
988 writer_tasks = kzalloc(cxt.nrealwriters_stress * sizeof(writer_tasks[0]),
989 GFP_KERNEL);
990 if (writer_tasks == NULL) {
991 VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory");
992 firsterr = -ENOMEM;
993 goto unwind;
994 }
995 }
996
997 if (cxt.cur_ops->readlock) {
998 reader_tasks = kzalloc(cxt.nrealreaders_stress * sizeof(reader_tasks[0]),
999 GFP_KERNEL);
1000 if (reader_tasks == NULL) {
1001 VERBOSE_TOROUT_ERRSTRING("reader_tasks: Out of memory");
1002 kfree(writer_tasks);
1003 writer_tasks = NULL;
1004 firsterr = -ENOMEM;
1005 goto unwind;
1006 }
1007 }
1008
1009 /*
1010 * Create the kthreads and start torturing (oh, those poor little locks).
1011 *
1012 * TODO: Note that we interleave writers with readers, giving writers a
1013 * slight advantage, by creating its kthread first. This can be modified
1014 * for very specific needs, or even let the user choose the policy, if
1015 * ever wanted.
1016 */
1017 for (i = 0, j = 0; i < cxt.nrealwriters_stress ||
1018 j < cxt.nrealreaders_stress; i++, j++) {
1019 if (i >= cxt.nrealwriters_stress)
1020 goto create_reader;
1021
1022 /* Create writer. */
1023 firsterr = torture_create_kthread(lock_torture_writer, &cxt.lwsa[i],
1024 writer_tasks[i]);
1025 if (firsterr)
1026 goto unwind;
1027
1028 create_reader:
1029 if (cxt.cur_ops->readlock == NULL || (j >= cxt.nrealreaders_stress))
1030 continue;
1031 /* Create reader. */
1032 firsterr = torture_create_kthread(lock_torture_reader, &cxt.lrsa[j],
1033 reader_tasks[j]);
1034 if (firsterr)
1035 goto unwind;
1036 }
1037 if (stat_interval > 0) {
1038 firsterr = torture_create_kthread(lock_torture_stats, NULL,
1039 stats_task);
1040 if (firsterr)
1041 goto unwind;
1042 }
1043 torture_init_end();
1044 return 0;
1045
1046unwind:
1047 torture_init_end();
1048 lock_torture_cleanup();
1049 return firsterr;
1050}
1051
1052module_init(lock_torture_init);
1053module_exit(lock_torture_cleanup);