Commit | Line | Data |
---|---|---|
d6cd1e9b | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
f2a5fec1 CW |
2 | /* |
3 | * Module-based API test facility for ww_mutexes | |
f2a5fec1 CW |
4 | */ |
5 | ||
6 | #include <linux/kernel.h> | |
7 | ||
8 | #include <linux/completion.h> | |
2a0c1128 | 9 | #include <linux/delay.h> |
f2a5fec1 CW |
10 | #include <linux/kthread.h> |
11 | #include <linux/module.h> | |
2a0c1128 | 12 | #include <linux/random.h> |
d1b42b80 | 13 | #include <linux/slab.h> |
f2a5fec1 CW |
14 | #include <linux/ww_mutex.h> |
15 | ||
08295b3b | 16 | static DEFINE_WD_CLASS(ww_class); |
d1b42b80 | 17 | struct workqueue_struct *wq; |
f2a5fec1 CW |
18 | |
19 | struct test_mutex { | |
20 | struct work_struct work; | |
21 | struct ww_mutex mutex; | |
22 | struct completion ready, go, done; | |
23 | unsigned int flags; | |
24 | }; | |
25 | ||
26 | #define TEST_MTX_SPIN BIT(0) | |
27 | #define TEST_MTX_TRY BIT(1) | |
28 | #define TEST_MTX_CTX BIT(2) | |
29 | #define __TEST_MTX_LAST BIT(3) | |
30 | ||
31 | static void test_mutex_work(struct work_struct *work) | |
32 | { | |
33 | struct test_mutex *mtx = container_of(work, typeof(*mtx), work); | |
34 | ||
35 | complete(&mtx->ready); | |
36 | wait_for_completion(&mtx->go); | |
37 | ||
38 | if (mtx->flags & TEST_MTX_TRY) { | |
39 | while (!ww_mutex_trylock(&mtx->mutex)) | |
2b232e0c | 40 | cond_resched(); |
f2a5fec1 CW |
41 | } else { |
42 | ww_mutex_lock(&mtx->mutex, NULL); | |
43 | } | |
44 | complete(&mtx->done); | |
45 | ww_mutex_unlock(&mtx->mutex); | |
46 | } | |
47 | ||
48 | static int __test_mutex(unsigned int flags) | |
49 | { | |
50 | #define TIMEOUT (HZ / 16) | |
51 | struct test_mutex mtx; | |
52 | struct ww_acquire_ctx ctx; | |
53 | int ret; | |
54 | ||
55 | ww_mutex_init(&mtx.mutex, &ww_class); | |
56 | ww_acquire_init(&ctx, &ww_class); | |
57 | ||
58 | INIT_WORK_ONSTACK(&mtx.work, test_mutex_work); | |
59 | init_completion(&mtx.ready); | |
60 | init_completion(&mtx.go); | |
61 | init_completion(&mtx.done); | |
62 | mtx.flags = flags; | |
63 | ||
64 | schedule_work(&mtx.work); | |
65 | ||
66 | wait_for_completion(&mtx.ready); | |
67 | ww_mutex_lock(&mtx.mutex, (flags & TEST_MTX_CTX) ? &ctx : NULL); | |
68 | complete(&mtx.go); | |
69 | if (flags & TEST_MTX_SPIN) { | |
70 | unsigned long timeout = jiffies + TIMEOUT; | |
71 | ||
72 | ret = 0; | |
73 | do { | |
74 | if (completion_done(&mtx.done)) { | |
75 | ret = -EINVAL; | |
76 | break; | |
77 | } | |
2b232e0c | 78 | cond_resched(); |
f2a5fec1 CW |
79 | } while (time_before(jiffies, timeout)); |
80 | } else { | |
81 | ret = wait_for_completion_timeout(&mtx.done, TIMEOUT); | |
82 | } | |
83 | ww_mutex_unlock(&mtx.mutex); | |
84 | ww_acquire_fini(&ctx); | |
85 | ||
86 | if (ret) { | |
87 | pr_err("%s(flags=%x): mutual exclusion failure\n", | |
88 | __func__, flags); | |
89 | ret = -EINVAL; | |
90 | } | |
91 | ||
92 | flush_work(&mtx.work); | |
93 | destroy_work_on_stack(&mtx.work); | |
94 | return ret; | |
95 | #undef TIMEOUT | |
96 | } | |
97 | ||
98 | static int test_mutex(void) | |
99 | { | |
100 | int ret; | |
101 | int i; | |
102 | ||
103 | for (i = 0; i < __TEST_MTX_LAST; i++) { | |
104 | ret = __test_mutex(i); | |
105 | if (ret) | |
106 | return ret; | |
107 | } | |
108 | ||
109 | return 0; | |
110 | } | |
111 | ||
c22fb380 CW |
112 | static int test_aa(void) |
113 | { | |
114 | struct ww_mutex mutex; | |
115 | struct ww_acquire_ctx ctx; | |
116 | int ret; | |
117 | ||
118 | ww_mutex_init(&mutex, &ww_class); | |
119 | ww_acquire_init(&ctx, &ww_class); | |
120 | ||
121 | ww_mutex_lock(&mutex, &ctx); | |
122 | ||
123 | if (ww_mutex_trylock(&mutex)) { | |
124 | pr_err("%s: trylocked itself!\n", __func__); | |
125 | ww_mutex_unlock(&mutex); | |
126 | ret = -EINVAL; | |
127 | goto out; | |
128 | } | |
129 | ||
130 | ret = ww_mutex_lock(&mutex, &ctx); | |
131 | if (ret != -EALREADY) { | |
132 | pr_err("%s: missed deadlock for recursing, ret=%d\n", | |
133 | __func__, ret); | |
134 | if (!ret) | |
135 | ww_mutex_unlock(&mutex); | |
136 | ret = -EINVAL; | |
137 | goto out; | |
138 | } | |
139 | ||
140 | ret = 0; | |
141 | out: | |
142 | ww_mutex_unlock(&mutex); | |
143 | ww_acquire_fini(&ctx); | |
144 | return ret; | |
145 | } | |
146 | ||
70207686 CW |
147 | struct test_abba { |
148 | struct work_struct work; | |
149 | struct ww_mutex a_mutex; | |
150 | struct ww_mutex b_mutex; | |
151 | struct completion a_ready; | |
152 | struct completion b_ready; | |
153 | bool resolve; | |
154 | int result; | |
155 | }; | |
156 | ||
157 | static void test_abba_work(struct work_struct *work) | |
158 | { | |
159 | struct test_abba *abba = container_of(work, typeof(*abba), work); | |
160 | struct ww_acquire_ctx ctx; | |
161 | int err; | |
162 | ||
163 | ww_acquire_init(&ctx, &ww_class); | |
164 | ww_mutex_lock(&abba->b_mutex, &ctx); | |
165 | ||
166 | complete(&abba->b_ready); | |
167 | wait_for_completion(&abba->a_ready); | |
168 | ||
169 | err = ww_mutex_lock(&abba->a_mutex, &ctx); | |
170 | if (abba->resolve && err == -EDEADLK) { | |
171 | ww_mutex_unlock(&abba->b_mutex); | |
172 | ww_mutex_lock_slow(&abba->a_mutex, &ctx); | |
173 | err = ww_mutex_lock(&abba->b_mutex, &ctx); | |
174 | } | |
175 | ||
176 | if (!err) | |
177 | ww_mutex_unlock(&abba->a_mutex); | |
178 | ww_mutex_unlock(&abba->b_mutex); | |
179 | ww_acquire_fini(&ctx); | |
180 | ||
181 | abba->result = err; | |
182 | } | |
183 | ||
184 | static int test_abba(bool resolve) | |
185 | { | |
186 | struct test_abba abba; | |
187 | struct ww_acquire_ctx ctx; | |
188 | int err, ret; | |
189 | ||
190 | ww_mutex_init(&abba.a_mutex, &ww_class); | |
191 | ww_mutex_init(&abba.b_mutex, &ww_class); | |
192 | INIT_WORK_ONSTACK(&abba.work, test_abba_work); | |
193 | init_completion(&abba.a_ready); | |
194 | init_completion(&abba.b_ready); | |
195 | abba.resolve = resolve; | |
196 | ||
197 | schedule_work(&abba.work); | |
198 | ||
199 | ww_acquire_init(&ctx, &ww_class); | |
200 | ww_mutex_lock(&abba.a_mutex, &ctx); | |
201 | ||
202 | complete(&abba.a_ready); | |
203 | wait_for_completion(&abba.b_ready); | |
204 | ||
205 | err = ww_mutex_lock(&abba.b_mutex, &ctx); | |
206 | if (resolve && err == -EDEADLK) { | |
207 | ww_mutex_unlock(&abba.a_mutex); | |
208 | ww_mutex_lock_slow(&abba.b_mutex, &ctx); | |
209 | err = ww_mutex_lock(&abba.a_mutex, &ctx); | |
210 | } | |
211 | ||
212 | if (!err) | |
213 | ww_mutex_unlock(&abba.b_mutex); | |
214 | ww_mutex_unlock(&abba.a_mutex); | |
215 | ww_acquire_fini(&ctx); | |
216 | ||
217 | flush_work(&abba.work); | |
218 | destroy_work_on_stack(&abba.work); | |
219 | ||
220 | ret = 0; | |
221 | if (resolve) { | |
222 | if (err || abba.result) { | |
223 | pr_err("%s: failed to resolve ABBA deadlock, A err=%d, B err=%d\n", | |
224 | __func__, err, abba.result); | |
225 | ret = -EINVAL; | |
226 | } | |
227 | } else { | |
228 | if (err != -EDEADLK && abba.result != -EDEADLK) { | |
229 | pr_err("%s: missed ABBA deadlock, A err=%d, B err=%d\n", | |
230 | __func__, err, abba.result); | |
231 | ret = -EINVAL; | |
232 | } | |
233 | } | |
234 | return ret; | |
235 | } | |
236 | ||
d1b42b80 CW |
237 | struct test_cycle { |
238 | struct work_struct work; | |
239 | struct ww_mutex a_mutex; | |
240 | struct ww_mutex *b_mutex; | |
241 | struct completion *a_signal; | |
242 | struct completion b_signal; | |
243 | int result; | |
244 | }; | |
245 | ||
246 | static void test_cycle_work(struct work_struct *work) | |
247 | { | |
248 | struct test_cycle *cycle = container_of(work, typeof(*cycle), work); | |
249 | struct ww_acquire_ctx ctx; | |
e4a02ed2 | 250 | int err, erra = 0; |
d1b42b80 CW |
251 | |
252 | ww_acquire_init(&ctx, &ww_class); | |
253 | ww_mutex_lock(&cycle->a_mutex, &ctx); | |
254 | ||
255 | complete(cycle->a_signal); | |
256 | wait_for_completion(&cycle->b_signal); | |
257 | ||
258 | err = ww_mutex_lock(cycle->b_mutex, &ctx); | |
259 | if (err == -EDEADLK) { | |
e4a02ed2 | 260 | err = 0; |
d1b42b80 CW |
261 | ww_mutex_unlock(&cycle->a_mutex); |
262 | ww_mutex_lock_slow(cycle->b_mutex, &ctx); | |
e4a02ed2 | 263 | erra = ww_mutex_lock(&cycle->a_mutex, &ctx); |
d1b42b80 CW |
264 | } |
265 | ||
266 | if (!err) | |
267 | ww_mutex_unlock(cycle->b_mutex); | |
e4a02ed2 GR |
268 | if (!erra) |
269 | ww_mutex_unlock(&cycle->a_mutex); | |
d1b42b80 CW |
270 | ww_acquire_fini(&ctx); |
271 | ||
e4a02ed2 | 272 | cycle->result = err ?: erra; |
d1b42b80 CW |
273 | } |
274 | ||
275 | static int __test_cycle(unsigned int nthreads) | |
276 | { | |
277 | struct test_cycle *cycles; | |
278 | unsigned int n, last = nthreads - 1; | |
279 | int ret; | |
280 | ||
281 | cycles = kmalloc_array(nthreads, sizeof(*cycles), GFP_KERNEL); | |
282 | if (!cycles) | |
283 | return -ENOMEM; | |
284 | ||
285 | for (n = 0; n < nthreads; n++) { | |
286 | struct test_cycle *cycle = &cycles[n]; | |
287 | ||
288 | ww_mutex_init(&cycle->a_mutex, &ww_class); | |
289 | if (n == last) | |
290 | cycle->b_mutex = &cycles[0].a_mutex; | |
291 | else | |
292 | cycle->b_mutex = &cycles[n + 1].a_mutex; | |
293 | ||
294 | if (n == 0) | |
295 | cycle->a_signal = &cycles[last].b_signal; | |
296 | else | |
297 | cycle->a_signal = &cycles[n - 1].b_signal; | |
298 | init_completion(&cycle->b_signal); | |
299 | ||
300 | INIT_WORK(&cycle->work, test_cycle_work); | |
301 | cycle->result = 0; | |
302 | } | |
303 | ||
304 | for (n = 0; n < nthreads; n++) | |
305 | queue_work(wq, &cycles[n].work); | |
306 | ||
307 | flush_workqueue(wq); | |
308 | ||
309 | ret = 0; | |
310 | for (n = 0; n < nthreads; n++) { | |
311 | struct test_cycle *cycle = &cycles[n]; | |
312 | ||
313 | if (!cycle->result) | |
314 | continue; | |
315 | ||
0b405c65 | 316 | pr_err("cyclic deadlock not resolved, ret[%d/%d] = %d\n", |
d1b42b80 CW |
317 | n, nthreads, cycle->result); |
318 | ret = -EINVAL; | |
319 | break; | |
320 | } | |
321 | ||
322 | for (n = 0; n < nthreads; n++) | |
323 | ww_mutex_destroy(&cycles[n].a_mutex); | |
324 | kfree(cycles); | |
325 | return ret; | |
326 | } | |
327 | ||
328 | static int test_cycle(unsigned int ncpus) | |
329 | { | |
330 | unsigned int n; | |
331 | int ret; | |
332 | ||
333 | for (n = 2; n <= ncpus + 1; n++) { | |
334 | ret = __test_cycle(n); | |
335 | if (ret) | |
336 | return ret; | |
337 | } | |
338 | ||
339 | return 0; | |
340 | } | |
341 | ||
2a0c1128 CW |
342 | struct stress { |
343 | struct work_struct work; | |
344 | struct ww_mutex *locks; | |
57dd924e | 345 | unsigned long timeout; |
2a0c1128 | 346 | int nlocks; |
2a0c1128 CW |
347 | }; |
348 | ||
349 | static int *get_random_order(int count) | |
350 | { | |
351 | int *order; | |
352 | int n, r, tmp; | |
353 | ||
0ee931c4 | 354 | order = kmalloc_array(count, sizeof(*order), GFP_KERNEL); |
2a0c1128 CW |
355 | if (!order) |
356 | return order; | |
357 | ||
358 | for (n = 0; n < count; n++) | |
359 | order[n] = n; | |
360 | ||
361 | for (n = count - 1; n > 1; n--) { | |
362 | r = get_random_int() % (n + 1); | |
363 | if (r != n) { | |
364 | tmp = order[n]; | |
365 | order[n] = order[r]; | |
366 | order[r] = tmp; | |
367 | } | |
368 | } | |
369 | ||
370 | return order; | |
371 | } | |
372 | ||
373 | static void dummy_load(struct stress *stress) | |
374 | { | |
375 | usleep_range(1000, 2000); | |
376 | } | |
377 | ||
378 | static void stress_inorder_work(struct work_struct *work) | |
379 | { | |
380 | struct stress *stress = container_of(work, typeof(*stress), work); | |
381 | const int nlocks = stress->nlocks; | |
382 | struct ww_mutex *locks = stress->locks; | |
383 | struct ww_acquire_ctx ctx; | |
384 | int *order; | |
385 | ||
386 | order = get_random_order(nlocks); | |
387 | if (!order) | |
388 | return; | |
389 | ||
2a0c1128 CW |
390 | do { |
391 | int contended = -1; | |
392 | int n, err; | |
393 | ||
bf7b3ac2 | 394 | ww_acquire_init(&ctx, &ww_class); |
2a0c1128 CW |
395 | retry: |
396 | err = 0; | |
397 | for (n = 0; n < nlocks; n++) { | |
398 | if (n == contended) | |
399 | continue; | |
400 | ||
401 | err = ww_mutex_lock(&locks[order[n]], &ctx); | |
402 | if (err < 0) | |
403 | break; | |
404 | } | |
405 | if (!err) | |
406 | dummy_load(stress); | |
407 | ||
408 | if (contended > n) | |
409 | ww_mutex_unlock(&locks[order[contended]]); | |
410 | contended = n; | |
411 | while (n--) | |
412 | ww_mutex_unlock(&locks[order[n]]); | |
413 | ||
414 | if (err == -EDEADLK) { | |
415 | ww_mutex_lock_slow(&locks[order[contended]], &ctx); | |
416 | goto retry; | |
417 | } | |
418 | ||
419 | if (err) { | |
420 | pr_err_once("stress (%s) failed with %d\n", | |
421 | __func__, err); | |
422 | break; | |
423 | } | |
2a0c1128 | 424 | |
bf7b3ac2 | 425 | ww_acquire_fini(&ctx); |
57dd924e | 426 | } while (!time_after(jiffies, stress->timeout)); |
2a0c1128 CW |
427 | |
428 | kfree(order); | |
429 | kfree(stress); | |
430 | } | |
431 | ||
432 | struct reorder_lock { | |
433 | struct list_head link; | |
434 | struct ww_mutex *lock; | |
435 | }; | |
436 | ||
437 | static void stress_reorder_work(struct work_struct *work) | |
438 | { | |
439 | struct stress *stress = container_of(work, typeof(*stress), work); | |
440 | LIST_HEAD(locks); | |
441 | struct ww_acquire_ctx ctx; | |
442 | struct reorder_lock *ll, *ln; | |
443 | int *order; | |
444 | int n, err; | |
445 | ||
446 | order = get_random_order(stress->nlocks); | |
447 | if (!order) | |
448 | return; | |
449 | ||
450 | for (n = 0; n < stress->nlocks; n++) { | |
451 | ll = kmalloc(sizeof(*ll), GFP_KERNEL); | |
452 | if (!ll) | |
453 | goto out; | |
454 | ||
455 | ll->lock = &stress->locks[order[n]]; | |
456 | list_add(&ll->link, &locks); | |
457 | } | |
458 | kfree(order); | |
459 | order = NULL; | |
460 | ||
2a0c1128 | 461 | do { |
bf7b3ac2 PZ |
462 | ww_acquire_init(&ctx, &ww_class); |
463 | ||
2a0c1128 CW |
464 | list_for_each_entry(ll, &locks, link) { |
465 | err = ww_mutex_lock(ll->lock, &ctx); | |
466 | if (!err) | |
467 | continue; | |
468 | ||
469 | ln = ll; | |
470 | list_for_each_entry_continue_reverse(ln, &locks, link) | |
471 | ww_mutex_unlock(ln->lock); | |
472 | ||
473 | if (err != -EDEADLK) { | |
474 | pr_err_once("stress (%s) failed with %d\n", | |
475 | __func__, err); | |
476 | break; | |
477 | } | |
478 | ||
479 | ww_mutex_lock_slow(ll->lock, &ctx); | |
480 | list_move(&ll->link, &locks); /* restarts iteration */ | |
481 | } | |
482 | ||
483 | dummy_load(stress); | |
484 | list_for_each_entry(ll, &locks, link) | |
485 | ww_mutex_unlock(ll->lock); | |
2a0c1128 | 486 | |
bf7b3ac2 | 487 | ww_acquire_fini(&ctx); |
57dd924e | 488 | } while (!time_after(jiffies, stress->timeout)); |
2a0c1128 CW |
489 | |
490 | out: | |
491 | list_for_each_entry_safe(ll, ln, &locks, link) | |
492 | kfree(ll); | |
493 | kfree(order); | |
494 | kfree(stress); | |
495 | } | |
496 | ||
497 | static void stress_one_work(struct work_struct *work) | |
498 | { | |
499 | struct stress *stress = container_of(work, typeof(*stress), work); | |
500 | const int nlocks = stress->nlocks; | |
501 | struct ww_mutex *lock = stress->locks + (get_random_int() % nlocks); | |
502 | int err; | |
503 | ||
504 | do { | |
505 | err = ww_mutex_lock(lock, NULL); | |
506 | if (!err) { | |
507 | dummy_load(stress); | |
508 | ww_mutex_unlock(lock); | |
509 | } else { | |
510 | pr_err_once("stress (%s) failed with %d\n", | |
511 | __func__, err); | |
512 | break; | |
513 | } | |
57dd924e | 514 | } while (!time_after(jiffies, stress->timeout)); |
2a0c1128 CW |
515 | |
516 | kfree(stress); | |
517 | } | |
518 | ||
519 | #define STRESS_INORDER BIT(0) | |
520 | #define STRESS_REORDER BIT(1) | |
521 | #define STRESS_ONE BIT(2) | |
522 | #define STRESS_ALL (STRESS_INORDER | STRESS_REORDER | STRESS_ONE) | |
523 | ||
57dd924e | 524 | static int stress(int nlocks, int nthreads, unsigned int flags) |
2a0c1128 CW |
525 | { |
526 | struct ww_mutex *locks; | |
527 | int n; | |
528 | ||
529 | locks = kmalloc_array(nlocks, sizeof(*locks), GFP_KERNEL); | |
530 | if (!locks) | |
531 | return -ENOMEM; | |
532 | ||
533 | for (n = 0; n < nlocks; n++) | |
534 | ww_mutex_init(&locks[n], &ww_class); | |
535 | ||
536 | for (n = 0; nthreads; n++) { | |
537 | struct stress *stress; | |
538 | void (*fn)(struct work_struct *work); | |
539 | ||
540 | fn = NULL; | |
541 | switch (n & 3) { | |
542 | case 0: | |
543 | if (flags & STRESS_INORDER) | |
544 | fn = stress_inorder_work; | |
545 | break; | |
546 | case 1: | |
547 | if (flags & STRESS_REORDER) | |
548 | fn = stress_reorder_work; | |
549 | break; | |
550 | case 2: | |
551 | if (flags & STRESS_ONE) | |
552 | fn = stress_one_work; | |
553 | break; | |
554 | } | |
555 | ||
556 | if (!fn) | |
557 | continue; | |
558 | ||
559 | stress = kmalloc(sizeof(*stress), GFP_KERNEL); | |
560 | if (!stress) | |
561 | break; | |
562 | ||
563 | INIT_WORK(&stress->work, fn); | |
564 | stress->locks = locks; | |
565 | stress->nlocks = nlocks; | |
57dd924e | 566 | stress->timeout = jiffies + 2*HZ; |
2a0c1128 CW |
567 | |
568 | queue_work(wq, &stress->work); | |
569 | nthreads--; | |
570 | } | |
571 | ||
572 | flush_workqueue(wq); | |
573 | ||
574 | for (n = 0; n < nlocks; n++) | |
575 | ww_mutex_destroy(&locks[n]); | |
576 | kfree(locks); | |
577 | ||
578 | return 0; | |
579 | } | |
580 | ||
f2a5fec1 CW |
581 | static int __init test_ww_mutex_init(void) |
582 | { | |
d1b42b80 | 583 | int ncpus = num_online_cpus(); |
f2a5fec1 CW |
584 | int ret; |
585 | ||
d1b42b80 CW |
586 | wq = alloc_workqueue("test-ww_mutex", WQ_UNBOUND, 0); |
587 | if (!wq) | |
588 | return -ENOMEM; | |
589 | ||
f2a5fec1 CW |
590 | ret = test_mutex(); |
591 | if (ret) | |
592 | return ret; | |
593 | ||
c22fb380 CW |
594 | ret = test_aa(); |
595 | if (ret) | |
596 | return ret; | |
597 | ||
70207686 CW |
598 | ret = test_abba(false); |
599 | if (ret) | |
600 | return ret; | |
601 | ||
602 | ret = test_abba(true); | |
603 | if (ret) | |
604 | return ret; | |
605 | ||
d1b42b80 CW |
606 | ret = test_cycle(ncpus); |
607 | if (ret) | |
608 | return ret; | |
609 | ||
57dd924e | 610 | ret = stress(16, 2*ncpus, STRESS_INORDER); |
2a0c1128 CW |
611 | if (ret) |
612 | return ret; | |
613 | ||
57dd924e | 614 | ret = stress(16, 2*ncpus, STRESS_REORDER); |
2a0c1128 CW |
615 | if (ret) |
616 | return ret; | |
617 | ||
57dd924e | 618 | ret = stress(4095, hweight32(STRESS_ALL)*ncpus, STRESS_ALL); |
2a0c1128 CW |
619 | if (ret) |
620 | return ret; | |
621 | ||
f2a5fec1 CW |
622 | return 0; |
623 | } | |
624 | ||
625 | static void __exit test_ww_mutex_exit(void) | |
626 | { | |
d1b42b80 | 627 | destroy_workqueue(wq); |
f2a5fec1 CW |
628 | } |
629 | ||
630 | module_init(test_ww_mutex_init); | |
631 | module_exit(test_ww_mutex_exit); | |
632 | ||
633 | MODULE_LICENSE("GPL"); | |
634 | MODULE_AUTHOR("Intel Corporation"); |