drivers/dma-buf/st-dma-fence.c

   1 /* SPDX-License-Identifier: MIT */
   2
   3 /*
   4  * Copyright © 2019 Intel Corporation
   5  */
   6
   7 #include <linux/delay.h>
   8 #include <linux/dma-fence.h>
   9 #include <linux/kernel.h>
  10 #include <linux/kthread.h>
  11 #include <linux/sched/signal.h>
  12 #include <linux/slab.h>
  13 #include <linux/spinlock.h>
  14
  15 #include "selftest.h"
  16
  17 static struct kmem_cache *slab_fences;
  18
  19 static struct mock_fence {
  20         struct dma_fence base;
  21         struct spinlock lock;
  22 } *to_mock_fence(struct dma_fence *f) {
  23         return container_of(f, struct mock_fence, base);
  24 }
  25
  26 static const char *mock_name(struct dma_fence *f)
  27 {
  28         return "mock";
  29 }
  30
  31 static void mock_fence_release(struct dma_fence *f)
  32 {
  33         kmem_cache_free(slab_fences, to_mock_fence(f));
  34 }
  35
  36 struct wait_cb {
  37         struct dma_fence_cb cb;
  38         struct task_struct *task;
  39 };
  40
  41 static void mock_wakeup(struct dma_fence *f, struct dma_fence_cb *cb)
  42 {
  43         wake_up_process(container_of(cb, struct wait_cb, cb)->task);
  44 }
  45
  46 static long mock_wait(struct dma_fence *f, bool intr, long timeout)
  47 {
  48         const int state = intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE;
  49         struct wait_cb cb = { .task = current };
  50
  51         if (dma_fence_add_callback(f, &cb.cb, mock_wakeup))
  52                 return timeout;
  53
  54         while (timeout) {
  55                 set_current_state(state);
  56
  57                 if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &f->flags))
  58                         break;
  59
  60                 if (signal_pending_state(state, current))
  61                         break;
  62
  63                 timeout = schedule_timeout(timeout);
  64         }
  65         __set_current_state(TASK_RUNNING);
  66
  67         if (!dma_fence_remove_callback(f, &cb.cb))
  68                 return timeout;
  69
  70         if (signal_pending_state(state, current))
  71                 return -ERESTARTSYS;
  72
  73         return -ETIME;
  74 }
  75
  76 static const struct dma_fence_ops mock_ops = {
  77         .get_driver_name = mock_name,
  78         .get_timeline_name = mock_name,
  79         .wait = mock_wait,
  80         .release = mock_fence_release,
  81 };
  82
  83 static struct dma_fence *mock_fence(void)
  84 {
  85         struct mock_fence *f;
  86
  87         f = kmem_cache_alloc(slab_fences, GFP_KERNEL);
  88         if (!f)
  89                 return NULL;
  90
  91         spin_lock_init(&f->lock);
  92         dma_fence_init(&f->base, &mock_ops, &f->lock, 0, 0);
  93
  94         return &f->base;
  95 }
  96
  97 static int sanitycheck(void *arg)
  98 {
  99         struct dma_fence *f;
 100
 101         f = mock_fence();
 102         if (!f)
 103                 return -ENOMEM;
 104
 105         dma_fence_signal(f);
 106         dma_fence_put(f);
 107
 108         return 0;
 109 }
 110
 111 static int test_signaling(void *arg)
 112 {
 113         struct dma_fence *f;
 114         int err = -EINVAL;
 115
 116         f = mock_fence();
 117         if (!f)
 118                 return -ENOMEM;
 119
 120         if (dma_fence_is_signaled(f)) {
 121                 pr_err("Fence unexpectedly signaled on creation\n");
 122                 goto err_free;
 123         }
 124
 125         if (dma_fence_signal(f)) {
 126                 pr_err("Fence reported being already signaled\n");
 127                 goto err_free;
 128         }
 129
 130         if (!dma_fence_is_signaled(f)) {
 131                 pr_err("Fence not reporting signaled\n");
 132                 goto err_free;
 133         }
 134
 135         if (!dma_fence_signal(f)) {
 136                 pr_err("Fence reported not being already signaled\n");
 137                 goto err_free;
 138         }
 139
 140         err = 0;
 141 err_free:
 142         dma_fence_put(f);
 143         return err;
 144 }
 145
 146 struct simple_cb {
 147         struct dma_fence_cb cb;
 148         bool seen;
 149 };
 150
 151 static void simple_callback(struct dma_fence *f, struct dma_fence_cb *cb)
 152 {
 153         smp_store_mb(container_of(cb, struct simple_cb, cb)->seen, true);
 154 }
 155
 156 static int test_add_callback(void *arg)
 157 {
 158         struct simple_cb cb = {};
 159         struct dma_fence *f;
 160         int err = -EINVAL;
 161
 162         f = mock_fence();
 163         if (!f)
 164                 return -ENOMEM;
 165
 166         if (dma_fence_add_callback(f, &cb.cb, simple_callback)) {
 167                 pr_err("Failed to add callback, fence already signaled!\n");
 168                 goto err_free;
 169         }
 170
 171         dma_fence_signal(f);
 172         if (!cb.seen) {
 173                 pr_err("Callback failed!\n");
 174                 goto err_free;
 175         }
 176
 177         err = 0;
 178 err_free:
 179         dma_fence_put(f);
 180         return err;
 181 }
 182
 183 static int test_late_add_callback(void *arg)
 184 {
 185         struct simple_cb cb = {};
 186         struct dma_fence *f;
 187         int err = -EINVAL;
 188
 189         f = mock_fence();
 190         if (!f)
 191                 return -ENOMEM;
 192
 193         dma_fence_signal(f);
 194
 195         if (!dma_fence_add_callback(f, &cb.cb, simple_callback)) {
 196                 pr_err("Added callback, but fence was already signaled!\n");
 197                 goto err_free;
 198         }
 199
 200         dma_fence_signal(f);
 201         if (cb.seen) {
 202                 pr_err("Callback called after failed attachment !\n");
 203                 goto err_free;
 204         }
 205
 206         err = 0;
 207 err_free:
 208         dma_fence_put(f);
 209         return err;
 210 }
 211
 212 static int test_rm_callback(void *arg)
 213 {
 214         struct simple_cb cb = {};
 215         struct dma_fence *f;
 216         int err = -EINVAL;
 217
 218         f = mock_fence();
 219         if (!f)
 220                 return -ENOMEM;
 221
 222         if (dma_fence_add_callback(f, &cb.cb, simple_callback)) {
 223                 pr_err("Failed to add callback, fence already signaled!\n");
 224                 goto err_free;
 225         }
 226
 227         if (!dma_fence_remove_callback(f, &cb.cb)) {
 228                 pr_err("Failed to remove callback!\n");
 229                 goto err_free;
 230         }
 231
 232         dma_fence_signal(f);
 233         if (cb.seen) {
 234                 pr_err("Callback still signaled after removal!\n");
 235                 goto err_free;
 236         }
 237
 238         err = 0;
 239 err_free:
 240         dma_fence_put(f);
 241         return err;
 242 }
 243
 244 static int test_late_rm_callback(void *arg)
 245 {
 246         struct simple_cb cb = {};
 247         struct dma_fence *f;
 248         int err = -EINVAL;
 249
 250         f = mock_fence();
 251         if (!f)
 252                 return -ENOMEM;
 253
 254         if (dma_fence_add_callback(f, &cb.cb, simple_callback)) {
 255                 pr_err("Failed to add callback, fence already signaled!\n");
 256                 goto err_free;
 257         }
 258
 259         dma_fence_signal(f);
 260         if (!cb.seen) {
 261                 pr_err("Callback failed!\n");
 262                 goto err_free;
 263         }
 264
 265         if (dma_fence_remove_callback(f, &cb.cb)) {
 266                 pr_err("Callback removal succeed after being executed!\n");
 267                 goto err_free;
 268         }
 269
 270         err = 0;
 271 err_free:
 272         dma_fence_put(f);
 273         return err;
 274 }
 275
 276 static int test_status(void *arg)
 277 {
 278         struct dma_fence *f;
 279         int err = -EINVAL;
 280
 281         f = mock_fence();
 282         if (!f)
 283                 return -ENOMEM;
 284
 285         if (dma_fence_get_status(f)) {
 286                 pr_err("Fence unexpectedly has signaled status on creation\n");
 287                 goto err_free;
 288         }
 289
 290         dma_fence_signal(f);
 291         if (!dma_fence_get_status(f)) {
 292                 pr_err("Fence not reporting signaled status\n");
 293                 goto err_free;
 294         }
 295
 296         err = 0;
 297 err_free:
 298         dma_fence_put(f);
 299         return err;
 300 }
 301
 302 static int test_error(void *arg)
 303 {
 304         struct dma_fence *f;
 305         int err = -EINVAL;
 306
 307         f = mock_fence();
 308         if (!f)
 309                 return -ENOMEM;
 310
 311         dma_fence_set_error(f, -EIO);
 312
 313         if (dma_fence_get_status(f)) {
 314                 pr_err("Fence unexpectedly has error status before signal\n");
 315                 goto err_free;
 316         }
 317
 318         dma_fence_signal(f);
 319         if (dma_fence_get_status(f) != -EIO) {
 320                 pr_err("Fence not reporting error status, got %d\n",
 321                        dma_fence_get_status(f));
 322                 goto err_free;
 323         }
 324
 325         err = 0;
 326 err_free:
 327         dma_fence_put(f);
 328         return err;
 329 }
 330
 331 static int test_wait(void *arg)
 332 {
 333         struct dma_fence *f;
 334         int err = -EINVAL;
 335
 336         f = mock_fence();
 337         if (!f)
 338                 return -ENOMEM;
 339
 340         if (dma_fence_wait_timeout(f, false, 0) != -ETIME) {
 341                 pr_err("Wait reported complete before being signaled\n");
 342                 goto err_free;
 343         }
 344
 345         dma_fence_signal(f);
 346
 347         if (dma_fence_wait_timeout(f, false, 0) != 0) {
 348                 pr_err("Wait reported incomplete after being signaled\n");
 349                 goto err_free;
 350         }
 351
 352         err = 0;
 353 err_free:
 354         dma_fence_signal(f);
 355         dma_fence_put(f);
 356         return err;
 357 }
 358
 359 struct wait_timer {
 360         struct timer_list timer;
 361         struct dma_fence *f;
 362 };
 363
 364 static void wait_timer(struct timer_list *timer)
 365 {
 366         struct wait_timer *wt = from_timer(wt, timer, timer);
 367
 368         dma_fence_signal(wt->f);
 369 }
 370
 371 static int test_wait_timeout(void *arg)
 372 {
 373         struct wait_timer wt;
 374         int err = -EINVAL;
 375
 376         timer_setup_on_stack(&wt.timer, wait_timer, 0);
 377
 378         wt.f = mock_fence();
 379         if (!wt.f)
 380                 return -ENOMEM;
 381
 382         if (dma_fence_wait_timeout(wt.f, false, 1) != -ETIME) {
 383                 pr_err("Wait reported complete before being signaled\n");
 384                 goto err_free;
 385         }
 386
 387         mod_timer(&wt.timer, jiffies + 1);
 388
 389         if (dma_fence_wait_timeout(wt.f, false, 2) == -ETIME) {
 390                 if (timer_pending(&wt.timer)) {
 391                         pr_notice("Timer did not fire within the jiffie!\n");
 392                         err = 0; /* not our fault! */
 393                 } else {
 394                         pr_err("Wait reported incomplete after timeout\n");
 395                 }
 396                 goto err_free;
 397         }
 398
 399         err = 0;
 400 err_free:
 401         del_timer_sync(&wt.timer);
 402         destroy_timer_on_stack(&wt.timer);
 403         dma_fence_signal(wt.f);
 404         dma_fence_put(wt.f);
 405         return err;
 406 }
 407
 408 static int test_stub(void *arg)
 409 {
 410         struct dma_fence *f[64];
 411         int err = -EINVAL;
 412         int i;
 413
 414         for (i = 0; i < ARRAY_SIZE(f); i++) {
 415                 f[i] = dma_fence_get_stub();
 416                 if (!dma_fence_is_signaled(f[i])) {
 417                         pr_err("Obtained unsignaled stub fence!\n");
 418                         goto err;
 419                 }
 420         }
 421
 422         err = 0;
 423 err:
 424         while (i--)
 425                 dma_fence_put(f[i]);
 426         return err;
 427 }
 428
 429 /* Now off to the races! */
 430
 431 struct race_thread {
 432         struct dma_fence __rcu **fences;
 433         struct task_struct *task;
 434         bool before;
 435         int id;
 436 };
 437
 438 static void __wait_for_callbacks(struct dma_fence *f)
 439 {
 440         spin_lock_irq(f->lock);
 441         spin_unlock_irq(f->lock);
 442 }
 443
 444 static int thread_signal_callback(void *arg)
 445 {
 446         const struct race_thread *t = arg;
 447         unsigned long pass = 0;
 448         unsigned long miss = 0;
 449         int err = 0;
 450
 451         while (!err && !kthread_should_stop()) {
 452                 struct dma_fence *f1, *f2;
 453                 struct simple_cb cb;
 454
 455                 f1 = mock_fence();
 456                 if (!f1) {
 457                         err = -ENOMEM;
 458                         break;
 459                 }
 460
 461                 rcu_assign_pointer(t->fences[t->id], f1);
 462                 smp_wmb();
 463
 464                 rcu_read_lock();
 465                 do {
 466                         f2 = dma_fence_get_rcu_safe(&t->fences[!t->id]);
 467                 } while (!f2 && !kthread_should_stop());
 468                 rcu_read_unlock();
 469
 470                 if (t->before)
 471                         dma_fence_signal(f1);
 472
 473                 smp_store_mb(cb.seen, false);
 474                 if (!f2 || dma_fence_add_callback(f2, &cb.cb, simple_callback))
 475                         miss++, cb.seen = true;
 476
 477                 if (!t->before)
 478                         dma_fence_signal(f1);
 479
 480                 if (!cb.seen) {
 481                         dma_fence_wait(f2, false);
 482                         __wait_for_callbacks(f2);
 483                 }
 484
 485                 if (!READ_ONCE(cb.seen)) {
 486                         pr_err("Callback not seen on thread %d, pass %lu (%lu misses), signaling %s add_callback; fence signaled? %s\n",
 487                                t->id, pass, miss,
 488                                t->before ? "before" : "after",
 489                                dma_fence_is_signaled(f2) ? "yes" : "no");
 490                         err = -EINVAL;
 491                 }
 492
 493                 dma_fence_put(f2);
 494
 495                 rcu_assign_pointer(t->fences[t->id], NULL);
 496                 smp_wmb();
 497
 498                 dma_fence_put(f1);
 499
 500                 pass++;
 501         }
 502
 503         pr_info("%s[%d] completed %lu passes, %lu misses\n",
 504                 __func__, t->id, pass, miss);
 505         return err;
 506 }
 507
 508 static int race_signal_callback(void *arg)
 509 {
 510         struct dma_fence __rcu *f[2] = {};
 511         int ret = 0;
 512         int pass;
 513
 514         for (pass = 0; !ret && pass <= 1; pass++) {
 515                 struct race_thread t[2];
 516                 int i;
 517
 518                 for (i = 0; i < ARRAY_SIZE(t); i++) {
 519                         t[i].fences = f;
 520                         t[i].id = i;
 521                         t[i].before = pass;
 522                         t[i].task = kthread_run(thread_signal_callback, &t[i],
 523                                                 "dma-fence:%d", i);
 524                         get_task_struct(t[i].task);
 525                 }
 526
 527                 msleep(50);
 528
 529                 for (i = 0; i < ARRAY_SIZE(t); i++) {
 530                         int err;
 531
 532                         err = kthread_stop(t[i].task);
 533                         if (err && !ret)
 534                                 ret = err;
 535
 536                         put_task_struct(t[i].task);
 537                 }
 538         }
 539
 540         return ret;
 541 }
 542
 543 int dma_fence(void)
 544 {
 545         static const struct subtest tests[] = {
 546                 SUBTEST(sanitycheck),
 547                 SUBTEST(test_signaling),
 548                 SUBTEST(test_add_callback),
 549                 SUBTEST(test_late_add_callback),
 550                 SUBTEST(test_rm_callback),
 551                 SUBTEST(test_late_rm_callback),
 552                 SUBTEST(test_status),
 553                 SUBTEST(test_error),
 554                 SUBTEST(test_wait),
 555                 SUBTEST(test_wait_timeout),
 556                 SUBTEST(test_stub),
 557                 SUBTEST(race_signal_callback),
 558         };
 559         int ret;
 560
 561         pr_info("sizeof(dma_fence)=%zu\n", sizeof(struct dma_fence));
 562
 563         slab_fences = KMEM_CACHE(mock_fence,
 564                                  SLAB_TYPESAFE_BY_RCU |
 565                                  SLAB_HWCACHE_ALIGN);
 566         if (!slab_fences)
 567                 return -ENOMEM;
 568
 569         ret = subtests(tests, NULL);
 570
 571         kmem_cache_destroy(slab_fences);
 572
 573         return ret;
 574 }