drivers/gpu/drm/i915/i915_sw_fence.c

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * (C) Copyright 2016 Intel Corporation
   5  */
   6
   7 #include <linux/slab.h>
   8 #include <linux/dma-fence.h>
   9 #include <linux/irq_work.h>
  10 #include <linux/dma-resv.h>
  11
  12 #include "i915_sw_fence.h"
  13 #include "i915_selftest.h"
  14
  15 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG)
  16 #define I915_SW_FENCE_BUG_ON(expr) BUG_ON(expr)
  17 #else
  18 #define I915_SW_FENCE_BUG_ON(expr) BUILD_BUG_ON_INVALID(expr)
  19 #endif
  20
  21 #define I915_SW_FENCE_FLAG_ALLOC BIT(3) /* after WQ_FLAG_* for safety */
  22
  23 static DEFINE_SPINLOCK(i915_sw_fence_lock);
  24
  25 enum {
  26         DEBUG_FENCE_IDLE = 0,
  27         DEBUG_FENCE_NOTIFY,
  28 };
  29
  30 static void *i915_sw_fence_debug_hint(void *addr)
  31 {
  32         return (void *)(((struct i915_sw_fence *)addr)->flags & I915_SW_FENCE_MASK);
  33 }
  34
  35 #ifdef CONFIG_DRM_I915_SW_FENCE_DEBUG_OBJECTS
  36
  37 static struct debug_obj_descr i915_sw_fence_debug_descr = {
  38         .name = "i915_sw_fence",
  39         .debug_hint = i915_sw_fence_debug_hint,
  40 };
  41
  42 static inline void debug_fence_init(struct i915_sw_fence *fence)
  43 {
  44         debug_object_init(fence, &i915_sw_fence_debug_descr);
  45 }
  46
  47 static inline void debug_fence_init_onstack(struct i915_sw_fence *fence)
  48 {
  49         debug_object_init_on_stack(fence, &i915_sw_fence_debug_descr);
  50 }
  51
  52 static inline void debug_fence_activate(struct i915_sw_fence *fence)
  53 {
  54         debug_object_activate(fence, &i915_sw_fence_debug_descr);
  55 }
  56
  57 static inline void debug_fence_set_state(struct i915_sw_fence *fence,
  58                                          int old, int new)
  59 {
  60         debug_object_active_state(fence, &i915_sw_fence_debug_descr, old, new);
  61 }
  62
  63 static inline void debug_fence_deactivate(struct i915_sw_fence *fence)
  64 {
  65         debug_object_deactivate(fence, &i915_sw_fence_debug_descr);
  66 }
  67
  68 static inline void debug_fence_destroy(struct i915_sw_fence *fence)
  69 {
  70         debug_object_destroy(fence, &i915_sw_fence_debug_descr);
  71 }
  72
  73 static inline void debug_fence_free(struct i915_sw_fence *fence)
  74 {
  75         debug_object_free(fence, &i915_sw_fence_debug_descr);
  76         smp_wmb(); /* flush the change in state before reallocation */
  77 }
  78
  79 static inline void debug_fence_assert(struct i915_sw_fence *fence)
  80 {
  81         debug_object_assert_init(fence, &i915_sw_fence_debug_descr);
  82 }
  83
  84 #else
  85
  86 static inline void debug_fence_init(struct i915_sw_fence *fence)
  87 {
  88 }
  89
  90 static inline void debug_fence_init_onstack(struct i915_sw_fence *fence)
  91 {
  92 }
  93
  94 static inline void debug_fence_activate(struct i915_sw_fence *fence)
  95 {
  96 }
  97
  98 static inline void debug_fence_set_state(struct i915_sw_fence *fence,
  99                                          int old, int new)
 100 {
 101 }
 102
 103 static inline void debug_fence_deactivate(struct i915_sw_fence *fence)
 104 {
 105 }
 106
 107 static inline void debug_fence_destroy(struct i915_sw_fence *fence)
 108 {
 109 }
 110
 111 static inline void debug_fence_free(struct i915_sw_fence *fence)
 112 {
 113 }
 114
 115 static inline void debug_fence_assert(struct i915_sw_fence *fence)
 116 {
 117 }
 118
 119 #endif
 120
 121 static int __i915_sw_fence_notify(struct i915_sw_fence *fence,
 122                                   enum i915_sw_fence_notify state)
 123 {
 124         i915_sw_fence_notify_t fn;
 125
 126         fn = (i915_sw_fence_notify_t)(fence->flags & I915_SW_FENCE_MASK);
 127         return fn(fence, state);
 128 }
 129
 130 #ifdef CONFIG_DRM_I915_SW_FENCE_DEBUG_OBJECTS
 131 void i915_sw_fence_fini(struct i915_sw_fence *fence)
 132 {
 133         debug_fence_free(fence);
 134 }
 135 #endif
 136
 137 static void __i915_sw_fence_wake_up_all(struct i915_sw_fence *fence,
 138                                         struct list_head *continuation)
 139 {
 140         wait_queue_head_t *x = &fence->wait;
 141         wait_queue_entry_t *pos, *next;
 142         unsigned long flags;
 143
 144         debug_fence_deactivate(fence);
 145         atomic_set_release(&fence->pending, -1); /* 0 -> -1 [done] */
 146
 147         /*
 148          * To prevent unbounded recursion as we traverse the graph of
 149          * i915_sw_fences, we move the entry list from this, the next ready
 150          * fence, to the tail of the original fence's entry list
 151          * (and so added to the list to be woken).
 152          */
 153
 154         spin_lock_irqsave_nested(&x->lock, flags, 1 + !!continuation);
 155         if (continuation) {
 156                 list_for_each_entry_safe(pos, next, &x->head, entry) {
 157                         if (pos->func == autoremove_wake_function)
 158                                 pos->func(pos, TASK_NORMAL, 0, continuation);
 159                         else
 160                                 list_move_tail(&pos->entry, continuation);
 161                 }
 162         } else {
 163                 LIST_HEAD(extra);
 164
 165                 do {
 166                         list_for_each_entry_safe(pos, next, &x->head, entry) {
 167                                 pos->func(pos,
 168                                           TASK_NORMAL, fence->error,
 169                                           &extra);
 170                         }
 171
 172                         if (list_empty(&extra))
 173                                 break;
 174
 175                         list_splice_tail_init(&extra, &x->head);
 176                 } while (1);
 177         }
 178         spin_unlock_irqrestore(&x->lock, flags);
 179
 180         debug_fence_assert(fence);
 181 }
 182
 183 static void __i915_sw_fence_complete(struct i915_sw_fence *fence,
 184                                      struct list_head *continuation)
 185 {
 186         debug_fence_assert(fence);
 187
 188         if (!atomic_dec_and_test(&fence->pending))
 189                 return;
 190
 191         debug_fence_set_state(fence, DEBUG_FENCE_IDLE, DEBUG_FENCE_NOTIFY);
 192
 193         if (__i915_sw_fence_notify(fence, FENCE_COMPLETE) != NOTIFY_DONE)
 194                 return;
 195
 196         debug_fence_set_state(fence, DEBUG_FENCE_NOTIFY, DEBUG_FENCE_IDLE);
 197
 198         __i915_sw_fence_wake_up_all(fence, continuation);
 199
 200         debug_fence_destroy(fence);
 201         __i915_sw_fence_notify(fence, FENCE_FREE);
 202 }
 203
 204 void i915_sw_fence_complete(struct i915_sw_fence *fence)
 205 {
 206         debug_fence_assert(fence);
 207
 208         if (WARN_ON(i915_sw_fence_done(fence)))
 209                 return;
 210
 211         __i915_sw_fence_complete(fence, NULL);
 212 }
 213
 214 void i915_sw_fence_await(struct i915_sw_fence *fence)
 215 {
 216         debug_fence_assert(fence);
 217         WARN_ON(atomic_inc_return(&fence->pending) <= 1);
 218 }
 219
 220 void __i915_sw_fence_init(struct i915_sw_fence *fence,
 221                           i915_sw_fence_notify_t fn,
 222                           const char *name,
 223                           struct lock_class_key *key)
 224 {
 225         BUG_ON(!fn || (unsigned long)fn & ~I915_SW_FENCE_MASK);
 226
 227         __init_waitqueue_head(&fence->wait, name, key);
 228         fence->flags = (unsigned long)fn;
 229
 230         i915_sw_fence_reinit(fence);
 231 }
 232
 233 void i915_sw_fence_reinit(struct i915_sw_fence *fence)
 234 {
 235         debug_fence_init(fence);
 236
 237         atomic_set(&fence->pending, 1);
 238         fence->error = 0;
 239
 240         I915_SW_FENCE_BUG_ON(!fence->flags);
 241         I915_SW_FENCE_BUG_ON(!list_empty(&fence->wait.head));
 242 }
 243
 244 void i915_sw_fence_commit(struct i915_sw_fence *fence)
 245 {
 246         debug_fence_activate(fence);
 247         i915_sw_fence_complete(fence);
 248 }
 249
 250 static int i915_sw_fence_wake(wait_queue_entry_t *wq, unsigned mode, int flags, void *key)
 251 {
 252         i915_sw_fence_set_error_once(wq->private, flags);
 253
 254         list_del(&wq->entry);
 255         __i915_sw_fence_complete(wq->private, key);
 256
 257         if (wq->flags & I915_SW_FENCE_FLAG_ALLOC)
 258                 kfree(wq);
 259         return 0;
 260 }
 261
 262 static bool __i915_sw_fence_check_if_after(struct i915_sw_fence *fence,
 263                                     const struct i915_sw_fence * const signaler)
 264 {
 265         wait_queue_entry_t *wq;
 266
 267         if (__test_and_set_bit(I915_SW_FENCE_CHECKED_BIT, &fence->flags))
 268                 return false;
 269
 270         if (fence == signaler)
 271                 return true;
 272
 273         list_for_each_entry(wq, &fence->wait.head, entry) {
 274                 if (wq->func != i915_sw_fence_wake)
 275                         continue;
 276
 277                 if (__i915_sw_fence_check_if_after(wq->private, signaler))
 278                         return true;
 279         }
 280
 281         return false;
 282 }
 283
 284 static void __i915_sw_fence_clear_checked_bit(struct i915_sw_fence *fence)
 285 {
 286         wait_queue_entry_t *wq;
 287
 288         if (!__test_and_clear_bit(I915_SW_FENCE_CHECKED_BIT, &fence->flags))
 289                 return;
 290
 291         list_for_each_entry(wq, &fence->wait.head, entry) {
 292                 if (wq->func != i915_sw_fence_wake)
 293                         continue;
 294
 295                 __i915_sw_fence_clear_checked_bit(wq->private);
 296         }
 297 }
 298
 299 static bool i915_sw_fence_check_if_after(struct i915_sw_fence *fence,
 300                                   const struct i915_sw_fence * const signaler)
 301 {
 302         unsigned long flags;
 303         bool err;
 304
 305         if (!IS_ENABLED(CONFIG_DRM_I915_SW_FENCE_CHECK_DAG))
 306                 return false;
 307
 308         spin_lock_irqsave(&i915_sw_fence_lock, flags);
 309         err = __i915_sw_fence_check_if_after(fence, signaler);
 310         __i915_sw_fence_clear_checked_bit(fence);
 311         spin_unlock_irqrestore(&i915_sw_fence_lock, flags);
 312
 313         return err;
 314 }
 315
 316 static int __i915_sw_fence_await_sw_fence(struct i915_sw_fence *fence,
 317                                           struct i915_sw_fence *signaler,
 318                                           wait_queue_entry_t *wq, gfp_t gfp)
 319 {
 320         unsigned long flags;
 321         int pending;
 322
 323         debug_fence_assert(fence);
 324         might_sleep_if(gfpflags_allow_blocking(gfp));
 325
 326         if (i915_sw_fence_done(signaler)) {
 327                 i915_sw_fence_set_error_once(fence, signaler->error);
 328                 return 0;
 329         }
 330
 331         debug_fence_assert(signaler);
 332
 333         /* The dependency graph must be acyclic. */
 334         if (unlikely(i915_sw_fence_check_if_after(fence, signaler)))
 335                 return -EINVAL;
 336
 337         pending = 0;
 338         if (!wq) {
 339                 wq = kmalloc(sizeof(*wq), gfp);
 340                 if (!wq) {
 341                         if (!gfpflags_allow_blocking(gfp))
 342                                 return -ENOMEM;
 343
 344                         i915_sw_fence_wait(signaler);
 345                         i915_sw_fence_set_error_once(fence, signaler->error);
 346                         return 0;
 347                 }
 348
 349                 pending |= I915_SW_FENCE_FLAG_ALLOC;
 350         }
 351
 352         INIT_LIST_HEAD(&wq->entry);
 353         wq->flags = pending;
 354         wq->func = i915_sw_fence_wake;
 355         wq->private = fence;
 356
 357         i915_sw_fence_await(fence);
 358
 359         spin_lock_irqsave(&signaler->wait.lock, flags);
 360         if (likely(!i915_sw_fence_done(signaler))) {
 361                 __add_wait_queue_entry_tail(&signaler->wait, wq);
 362                 pending = 1;
 363         } else {
 364                 i915_sw_fence_wake(wq, 0, signaler->error, NULL);
 365                 pending = 0;
 366         }
 367         spin_unlock_irqrestore(&signaler->wait.lock, flags);
 368
 369         return pending;
 370 }
 371
 372 int i915_sw_fence_await_sw_fence(struct i915_sw_fence *fence,
 373                                  struct i915_sw_fence *signaler,
 374                                  wait_queue_entry_t *wq)
 375 {
 376         return __i915_sw_fence_await_sw_fence(fence, signaler, wq, 0);
 377 }
 378
 379 int i915_sw_fence_await_sw_fence_gfp(struct i915_sw_fence *fence,
 380                                      struct i915_sw_fence *signaler,
 381                                      gfp_t gfp)
 382 {
 383         return __i915_sw_fence_await_sw_fence(fence, signaler, NULL, gfp);
 384 }
 385
 386 struct i915_sw_dma_fence_cb_timer {
 387         struct i915_sw_dma_fence_cb base;
 388         struct dma_fence *dma;
 389         struct timer_list timer;
 390         struct irq_work work;
 391         struct rcu_head rcu;
 392 };
 393
 394 static void dma_i915_sw_fence_wake(struct dma_fence *dma,
 395                                    struct dma_fence_cb *data)
 396 {
 397         struct i915_sw_dma_fence_cb *cb = container_of(data, typeof(*cb), base);
 398
 399         i915_sw_fence_set_error_once(cb->fence, dma->error);
 400         i915_sw_fence_complete(cb->fence);
 401         kfree(cb);
 402 }
 403
 404 static void timer_i915_sw_fence_wake(struct timer_list *t)
 405 {
 406         struct i915_sw_dma_fence_cb_timer *cb = from_timer(cb, t, timer);
 407         struct i915_sw_fence *fence;
 408
 409         fence = xchg(&cb->base.fence, NULL);
 410         if (!fence)
 411                 return;
 412
 413         pr_notice("Asynchronous wait on fence %s:%s:%llx timed out (hint:%pS)\n",
 414                   cb->dma->ops->get_driver_name(cb->dma),
 415                   cb->dma->ops->get_timeline_name(cb->dma),
 416                   cb->dma->seqno,
 417                   i915_sw_fence_debug_hint(fence));
 418
 419         i915_sw_fence_set_error_once(fence, -ETIMEDOUT);
 420         i915_sw_fence_complete(fence);
 421 }
 422
 423 static void dma_i915_sw_fence_wake_timer(struct dma_fence *dma,
 424                                          struct dma_fence_cb *data)
 425 {
 426         struct i915_sw_dma_fence_cb_timer *cb =
 427                 container_of(data, typeof(*cb), base.base);
 428         struct i915_sw_fence *fence;
 429
 430         fence = xchg(&cb->base.fence, NULL);
 431         if (fence) {
 432                 i915_sw_fence_set_error_once(fence, dma->error);
 433                 i915_sw_fence_complete(fence);
 434         }
 435
 436         irq_work_queue(&cb->work);
 437 }
 438
 439 static void irq_i915_sw_fence_work(struct irq_work *wrk)
 440 {
 441         struct i915_sw_dma_fence_cb_timer *cb =
 442                 container_of(wrk, typeof(*cb), work);
 443
 444         del_timer_sync(&cb->timer);
 445         dma_fence_put(cb->dma);
 446
 447         kfree_rcu(cb, rcu);
 448 }
 449
 450 int i915_sw_fence_await_dma_fence(struct i915_sw_fence *fence,
 451                                   struct dma_fence *dma,
 452                                   unsigned long timeout,
 453                                   gfp_t gfp)
 454 {
 455         struct i915_sw_dma_fence_cb *cb;
 456         dma_fence_func_t func;
 457         int ret;
 458
 459         debug_fence_assert(fence);
 460         might_sleep_if(gfpflags_allow_blocking(gfp));
 461
 462         if (dma_fence_is_signaled(dma)) {
 463                 i915_sw_fence_set_error_once(fence, dma->error);
 464                 return 0;
 465         }
 466
 467         cb = kmalloc(timeout ?
 468                      sizeof(struct i915_sw_dma_fence_cb_timer) :
 469                      sizeof(struct i915_sw_dma_fence_cb),
 470                      gfp);
 471         if (!cb) {
 472                 if (!gfpflags_allow_blocking(gfp))
 473                         return -ENOMEM;
 474
 475                 ret = dma_fence_wait(dma, false);
 476                 if (ret)
 477                         return ret;
 478
 479                 i915_sw_fence_set_error_once(fence, dma->error);
 480                 return 0;
 481         }
 482
 483         cb->fence = fence;
 484         i915_sw_fence_await(fence);
 485
 486         func = dma_i915_sw_fence_wake;
 487         if (timeout) {
 488                 struct i915_sw_dma_fence_cb_timer *timer =
 489                         container_of(cb, typeof(*timer), base);
 490
 491                 timer->dma = dma_fence_get(dma);
 492                 init_irq_work(&timer->work, irq_i915_sw_fence_work);
 493
 494                 timer_setup(&timer->timer,
 495                             timer_i915_sw_fence_wake, TIMER_IRQSAFE);
 496                 mod_timer(&timer->timer, round_jiffies_up(jiffies + timeout));
 497
 498                 func = dma_i915_sw_fence_wake_timer;
 499         }
 500
 501         ret = dma_fence_add_callback(dma, &cb->base, func);
 502         if (ret == 0) {
 503                 ret = 1;
 504         } else {
 505                 func(dma, &cb->base);
 506                 if (ret == -ENOENT) /* fence already signaled */
 507                         ret = 0;
 508         }
 509
 510         return ret;
 511 }
 512
 513 static void __dma_i915_sw_fence_wake(struct dma_fence *dma,
 514                                      struct dma_fence_cb *data)
 515 {
 516         struct i915_sw_dma_fence_cb *cb = container_of(data, typeof(*cb), base);
 517
 518         i915_sw_fence_set_error_once(cb->fence, dma->error);
 519         i915_sw_fence_complete(cb->fence);
 520 }
 521
 522 int __i915_sw_fence_await_dma_fence(struct i915_sw_fence *fence,
 523                                     struct dma_fence *dma,
 524                                     struct i915_sw_dma_fence_cb *cb)
 525 {
 526         int ret;
 527
 528         debug_fence_assert(fence);
 529
 530         if (dma_fence_is_signaled(dma)) {
 531                 i915_sw_fence_set_error_once(fence, dma->error);
 532                 return 0;
 533         }
 534
 535         cb->fence = fence;
 536         i915_sw_fence_await(fence);
 537
 538         ret = dma_fence_add_callback(dma, &cb->base, __dma_i915_sw_fence_wake);
 539         if (ret == 0) {
 540                 ret = 1;
 541         } else {
 542                 __dma_i915_sw_fence_wake(dma, &cb->base);
 543                 if (ret == -ENOENT) /* fence already signaled */
 544                         ret = 0;
 545         }
 546
 547         return ret;
 548 }
 549
 550 int i915_sw_fence_await_reservation(struct i915_sw_fence *fence,
 551                                     struct dma_resv *resv,
 552                                     const struct dma_fence_ops *exclude,
 553                                     bool write,
 554                                     unsigned long timeout,
 555                                     gfp_t gfp)
 556 {
 557         struct dma_fence *excl;
 558         int ret = 0, pending;
 559
 560         debug_fence_assert(fence);
 561         might_sleep_if(gfpflags_allow_blocking(gfp));
 562
 563         if (write) {
 564                 struct dma_fence **shared;
 565                 unsigned int count, i;
 566
 567                 ret = dma_resv_get_fences_rcu(resv, &excl, &count, &shared);
 568                 if (ret)
 569                         return ret;
 570
 571                 for (i = 0; i < count; i++) {
 572                         if (shared[i]->ops == exclude)
 573                                 continue;
 574
 575                         pending = i915_sw_fence_await_dma_fence(fence,
 576                                                                 shared[i],
 577                                                                 timeout,
 578                                                                 gfp);
 579                         if (pending < 0) {
 580                                 ret = pending;
 581                                 break;
 582                         }
 583
 584                         ret |= pending;
 585                 }
 586
 587                 for (i = 0; i < count; i++)
 588                         dma_fence_put(shared[i]);
 589                 kfree(shared);
 590         } else {
 591                 excl = dma_resv_get_excl_rcu(resv);
 592         }
 593
 594         if (ret >= 0 && excl && excl->ops != exclude) {
 595                 pending = i915_sw_fence_await_dma_fence(fence,
 596                                                         excl,
 597                                                         timeout,
 598                                                         gfp);
 599                 if (pending < 0)
 600                         ret = pending;
 601                 else
 602                         ret |= pending;
 603         }
 604
 605         dma_fence_put(excl);
 606
 607         return ret;
 608 }
 609
 610 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
 611 #include "selftests/lib_sw_fence.c"
 612 #include "selftests/i915_sw_fence.c"
 613 #endif