drivers/gpu/drm/i915/i915_vma.c

   1 /*
   2  * Copyright © 2016 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  */
  24
  25 #include "i915_vma.h"
  26
  27 #include "i915_drv.h"
  28 #include "intel_ringbuffer.h"
  29 #include "intel_frontbuffer.h"
  30
  31 #include <drm/drm_gem.h>
  32
  33 static void
  34 i915_vma_retire(struct i915_gem_active *active,
  35                 struct drm_i915_gem_request *rq)
  36 {
  37         const unsigned int idx = rq->engine->id;
  38         struct i915_vma *vma =
  39                 container_of(active, struct i915_vma, last_read[idx]);
  40         struct drm_i915_gem_object *obj = vma->obj;
  41
  42         GEM_BUG_ON(!i915_vma_has_active_engine(vma, idx));
  43
  44         i915_vma_clear_active(vma, idx);
  45         if (i915_vma_is_active(vma))
  46                 return;
  47
  48         list_move_tail(&vma->vm_link, &vma->vm->inactive_list);
  49         if (unlikely(i915_vma_is_closed(vma) && !i915_vma_is_pinned(vma)))
  50                 WARN_ON(i915_vma_unbind(vma));
  51
  52         GEM_BUG_ON(!i915_gem_object_is_active(obj));
  53         if (--obj->active_count)
  54                 return;
  55
  56         /* Bump our place on the bound list to keep it roughly in LRU order
  57          * so that we don't steal from recently used but inactive objects
  58          * (unless we are forced to ofc!)
  59          */
  60         if (obj->bind_count)
  61                 list_move_tail(&obj->global_link, &rq->i915->mm.bound_list);
  62
  63         obj->mm.dirty = true; /* be paranoid  */
  64
  65         if (i915_gem_object_has_active_reference(obj)) {
  66                 i915_gem_object_clear_active_reference(obj);
  67                 i915_gem_object_put(obj);
  68         }
  69 }
  70
  71 static struct i915_vma *
  72 __i915_vma_create(struct drm_i915_gem_object *obj,
  73                   struct i915_address_space *vm,
  74                   const struct i915_ggtt_view *view)
  75 {
  76         struct i915_vma *vma;
  77         struct rb_node *rb, **p;
  78         int i;
  79
  80         GEM_BUG_ON(vm->closed);
  81
  82         vma = kmem_cache_zalloc(to_i915(obj->base.dev)->vmas, GFP_KERNEL);
  83         if (vma == NULL)
  84                 return ERR_PTR(-ENOMEM);
  85
  86         INIT_LIST_HEAD(&vma->exec_list);
  87         for (i = 0; i < ARRAY_SIZE(vma->last_read); i++)
  88                 init_request_active(&vma->last_read[i], i915_vma_retire);
  89         init_request_active(&vma->last_fence, NULL);
  90         list_add(&vma->vm_link, &vm->unbound_list);
  91         vma->vm = vm;
  92         vma->obj = obj;
  93         vma->size = obj->base.size;
  94
  95         if (view) {
  96                 vma->ggtt_view = *view;
  97                 if (view->type == I915_GGTT_VIEW_PARTIAL) {
  98                         vma->size = view->params.partial.size;
  99                         vma->size <<= PAGE_SHIFT;
 100                 } else if (view->type == I915_GGTT_VIEW_ROTATED) {
 101                         vma->size =
 102                                 intel_rotation_info_size(&view->params.rotated);
 103                         vma->size <<= PAGE_SHIFT;
 104                 }
 105         }
 106
 107         if (i915_is_ggtt(vm)) {
 108                 vma->flags |= I915_VMA_GGTT;
 109                 list_add(&vma->obj_link, &obj->vma_list);
 110         } else {
 111                 i915_ppgtt_get(i915_vm_to_ppgtt(vm));
 112                 list_add_tail(&vma->obj_link, &obj->vma_list);
 113         }
 114
 115         rb = NULL;
 116         p = &obj->vma_tree.rb_node;
 117         while (*p) {
 118                 struct i915_vma *pos;
 119
 120                 rb = *p;
 121                 pos = rb_entry(rb, struct i915_vma, obj_node);
 122                 if (i915_vma_compare(pos, vm, view) < 0)
 123                         p = &rb->rb_right;
 124                 else
 125                         p = &rb->rb_left;
 126         }
 127         rb_link_node(&vma->obj_node, rb, p);
 128         rb_insert_color(&vma->obj_node, &obj->vma_tree);
 129
 130         return vma;
 131 }
 132
 133 struct i915_vma *
 134 i915_vma_create(struct drm_i915_gem_object *obj,
 135                 struct i915_address_space *vm,
 136                 const struct i915_ggtt_view *view)
 137 {
 138         lockdep_assert_held(&obj->base.dev->struct_mutex);
 139         GEM_BUG_ON(view && !i915_is_ggtt(vm));
 140         GEM_BUG_ON(i915_gem_obj_to_vma(obj, vm, view));
 141
 142         return __i915_vma_create(obj, vm, view);
 143 }
 144
 145 /**
 146  * i915_vma_bind - Sets up PTEs for an VMA in it's corresponding address space.
 147  * @vma: VMA to map
 148  * @cache_level: mapping cache level
 149  * @flags: flags like global or local mapping
 150  *
 151  * DMA addresses are taken from the scatter-gather table of this object (or of
 152  * this VMA in case of non-default GGTT views) and PTE entries set up.
 153  * Note that DMA addresses are also the only part of the SG table we care about.
 154  */
 155 int i915_vma_bind(struct i915_vma *vma, enum i915_cache_level cache_level,
 156                   u32 flags)
 157 {
 158         u32 bind_flags;
 159         u32 vma_flags;
 160         int ret;
 161
 162         if (WARN_ON(flags == 0))
 163                 return -EINVAL;
 164
 165         bind_flags = 0;
 166         if (flags & PIN_GLOBAL)
 167                 bind_flags |= I915_VMA_GLOBAL_BIND;
 168         if (flags & PIN_USER)
 169                 bind_flags |= I915_VMA_LOCAL_BIND;
 170
 171         vma_flags = vma->flags & (I915_VMA_GLOBAL_BIND | I915_VMA_LOCAL_BIND);
 172         if (flags & PIN_UPDATE)
 173                 bind_flags |= vma_flags;
 174         else
 175                 bind_flags &= ~vma_flags;
 176         if (bind_flags == 0)
 177                 return 0;
 178
 179         if (vma_flags == 0 && vma->vm->allocate_va_range) {
 180                 trace_i915_va_alloc(vma);
 181                 ret = vma->vm->allocate_va_range(vma->vm,
 182                                                  vma->node.start,
 183                                                  vma->node.size);
 184                 if (ret)
 185                         return ret;
 186         }
 187
 188         trace_i915_vma_bind(vma, bind_flags);
 189         ret = vma->vm->bind_vma(vma, cache_level, bind_flags);
 190         if (ret)
 191                 return ret;
 192
 193         vma->flags |= bind_flags;
 194         return 0;
 195 }
 196
 197 void __iomem *i915_vma_pin_iomap(struct i915_vma *vma)
 198 {
 199         void __iomem *ptr;
 200
 201         /* Access through the GTT requires the device to be awake. */
 202         assert_rpm_wakelock_held(to_i915(vma->vm->dev));
 203
 204         lockdep_assert_held(&vma->vm->dev->struct_mutex);
 205         if (WARN_ON(!i915_vma_is_map_and_fenceable(vma)))
 206                 return IO_ERR_PTR(-ENODEV);
 207
 208         GEM_BUG_ON(!i915_vma_is_ggtt(vma));
 209         GEM_BUG_ON((vma->flags & I915_VMA_GLOBAL_BIND) == 0);
 210
 211         ptr = vma->iomap;
 212         if (ptr == NULL) {
 213                 ptr = io_mapping_map_wc(&i915_vm_to_ggtt(vma->vm)->mappable,
 214                                         vma->node.start,
 215                                         vma->node.size);
 216                 if (ptr == NULL)
 217                         return IO_ERR_PTR(-ENOMEM);
 218
 219                 vma->iomap = ptr;
 220         }
 221
 222         __i915_vma_pin(vma);
 223         return ptr;
 224 }
 225
 226 void i915_vma_unpin_and_release(struct i915_vma **p_vma)
 227 {
 228         struct i915_vma *vma;
 229         struct drm_i915_gem_object *obj;
 230
 231         vma = fetch_and_zero(p_vma);
 232         if (!vma)
 233                 return;
 234
 235         obj = vma->obj;
 236
 237         i915_vma_unpin(vma);
 238         i915_vma_close(vma);
 239
 240         __i915_gem_object_release_unless_active(obj);
 241 }
 242
 243 bool
 244 i915_vma_misplaced(struct i915_vma *vma, u64 size, u64 alignment, u64 flags)
 245 {
 246         if (!drm_mm_node_allocated(&vma->node))
 247                 return false;
 248
 249         if (vma->node.size < size)
 250                 return true;
 251
 252         if (alignment && vma->node.start & (alignment - 1))
 253                 return true;
 254
 255         if (flags & PIN_MAPPABLE && !i915_vma_is_map_and_fenceable(vma))
 256                 return true;
 257
 258         if (flags & PIN_OFFSET_BIAS &&
 259             vma->node.start < (flags & PIN_OFFSET_MASK))
 260                 return true;
 261
 262         if (flags & PIN_OFFSET_FIXED &&
 263             vma->node.start != (flags & PIN_OFFSET_MASK))
 264                 return true;
 265
 266         return false;
 267 }
 268
 269 void __i915_vma_set_map_and_fenceable(struct i915_vma *vma)
 270 {
 271         struct drm_i915_gem_object *obj = vma->obj;
 272         struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
 273         bool mappable, fenceable;
 274         u32 fence_size, fence_alignment;
 275
 276         fence_size = i915_gem_get_ggtt_size(dev_priv,
 277                                             vma->size,
 278                                             i915_gem_object_get_tiling(obj));
 279         fence_alignment = i915_gem_get_ggtt_alignment(dev_priv,
 280                                                       vma->size,
 281                                                       i915_gem_object_get_tiling(obj),
 282                                                       true);
 283
 284         fenceable = (vma->node.size == fence_size &&
 285                      (vma->node.start & (fence_alignment - 1)) == 0);
 286
 287         mappable = (vma->node.start + fence_size <=
 288                     dev_priv->ggtt.mappable_end);
 289
 290         /*
 291          * Explicitly disable for rotated VMA since the display does not
 292          * need the fence and the VMA is not accessible to other users.
 293          */
 294         if (mappable && fenceable &&
 295             vma->ggtt_view.type != I915_GGTT_VIEW_ROTATED)
 296                 vma->flags |= I915_VMA_CAN_FENCE;
 297         else
 298                 vma->flags &= ~I915_VMA_CAN_FENCE;
 299 }
 300
 301 bool i915_gem_valid_gtt_space(struct i915_vma *vma,
 302                               unsigned long cache_level)
 303 {
 304         struct drm_mm_node *gtt_space = &vma->node;
 305         struct drm_mm_node *other;
 306
 307         /*
 308          * On some machines we have to be careful when putting differing types
 309          * of snoopable memory together to avoid the prefetcher crossing memory
 310          * domains and dying. During vm initialisation, we decide whether or not
 311          * these constraints apply and set the drm_mm.color_adjust
 312          * appropriately.
 313          */
 314         if (vma->vm->mm.color_adjust == NULL)
 315                 return true;
 316
 317         if (!drm_mm_node_allocated(gtt_space))
 318                 return true;
 319
 320         if (list_empty(&gtt_space->node_list))
 321                 return true;
 322
 323         other = list_entry(gtt_space->node_list.prev, struct drm_mm_node, node_list);
 324         if (other->allocated && !other->hole_follows && other->color != cache_level)
 325                 return false;
 326
 327         other = list_entry(gtt_space->node_list.next, struct drm_mm_node, node_list);
 328         if (other->allocated && !gtt_space->hole_follows && other->color != cache_level)
 329                 return false;
 330
 331         return true;
 332 }
 333
 334 /**
 335  * i915_vma_insert - finds a slot for the vma in its address space
 336  * @vma: the vma
 337  * @size: requested size in bytes (can be larger than the VMA)
 338  * @alignment: required alignment
 339  * @flags: mask of PIN_* flags to use
 340  *
 341  * First we try to allocate some free space that meets the requirements for
 342  * the VMA. Failiing that, if the flags permit, it will evict an old VMA,
 343  * preferrably the oldest idle entry to make room for the new VMA.
 344  *
 345  * Returns:
 346  * 0 on success, negative error code otherwise.
 347  */
 348 static int
 349 i915_vma_insert(struct i915_vma *vma, u64 size, u64 alignment, u64 flags)
 350 {
 351         struct drm_i915_private *dev_priv = to_i915(vma->vm->dev);
 352         struct drm_i915_gem_object *obj = vma->obj;
 353         u64 start, end;
 354         int ret;
 355
 356         GEM_BUG_ON(vma->flags & (I915_VMA_GLOBAL_BIND | I915_VMA_LOCAL_BIND));
 357         GEM_BUG_ON(drm_mm_node_allocated(&vma->node));
 358
 359         size = max(size, vma->size);
 360         if (flags & PIN_MAPPABLE)
 361                 size = i915_gem_get_ggtt_size(dev_priv, size,
 362                                               i915_gem_object_get_tiling(obj));
 363
 364         alignment = max(max(alignment, vma->display_alignment),
 365                         i915_gem_get_ggtt_alignment(dev_priv, size,
 366                                                     i915_gem_object_get_tiling(obj),
 367                                                     flags & PIN_MAPPABLE));
 368
 369         start = flags & PIN_OFFSET_BIAS ? flags & PIN_OFFSET_MASK : 0;
 370
 371         end = vma->vm->total;
 372         if (flags & PIN_MAPPABLE)
 373                 end = min_t(u64, end, dev_priv->ggtt.mappable_end);
 374         if (flags & PIN_ZONE_4G)
 375                 end = min_t(u64, end, (1ULL << 32) - PAGE_SIZE);
 376
 377         /* If binding the object/GGTT view requires more space than the entire
 378          * aperture has, reject it early before evicting everything in a vain
 379          * attempt to find space.
 380          */
 381         if (size > end) {
 382                 DRM_DEBUG("Attempting to bind an object larger than the aperture: request=%llu [object=%zd] > %s aperture=%llu\n",
 383                           size, obj->base.size,
 384                           flags & PIN_MAPPABLE ? "mappable" : "total",
 385                           end);
 386                 return -E2BIG;
 387         }
 388
 389         ret = i915_gem_object_pin_pages(obj);
 390         if (ret)
 391                 return ret;
 392
 393         if (flags & PIN_OFFSET_FIXED) {
 394                 u64 offset = flags & PIN_OFFSET_MASK;
 395                 if (offset & (alignment - 1) || offset > end - size) {
 396                         ret = -EINVAL;
 397                         goto err_unpin;
 398                 }
 399
 400                 vma->node.start = offset;
 401                 vma->node.size = size;
 402                 vma->node.color = obj->cache_level;
 403                 ret = drm_mm_reserve_node(&vma->vm->mm, &vma->node);
 404                 if (ret) {
 405                         ret = i915_gem_evict_for_vma(vma);
 406                         if (ret == 0)
 407                                 ret = drm_mm_reserve_node(&vma->vm->mm, &vma->node);
 408                         if (ret)
 409                                 goto err_unpin;
 410                 }
 411         } else {
 412                 u32 search_flag, alloc_flag;
 413
 414                 if (flags & PIN_HIGH) {
 415                         search_flag = DRM_MM_SEARCH_BELOW;
 416                         alloc_flag = DRM_MM_CREATE_TOP;
 417                 } else {
 418                         search_flag = DRM_MM_SEARCH_DEFAULT;
 419                         alloc_flag = DRM_MM_CREATE_DEFAULT;
 420                 }
 421
 422                 /* We only allocate in PAGE_SIZE/GTT_PAGE_SIZE (4096) chunks,
 423                  * so we know that we always have a minimum alignment of 4096.
 424                  * The drm_mm range manager is optimised to return results
 425                  * with zero alignment, so where possible use the optimal
 426                  * path.
 427                  */
 428                 if (alignment <= 4096)
 429                         alignment = 0;
 430
 431 search_free:
 432                 ret = drm_mm_insert_node_in_range_generic(&vma->vm->mm,
 433                                                           &vma->node,
 434                                                           size, alignment,
 435                                                           obj->cache_level,
 436                                                           start, end,
 437                                                           search_flag,
 438                                                           alloc_flag);
 439                 if (ret) {
 440                         ret = i915_gem_evict_something(vma->vm, size, alignment,
 441                                                        obj->cache_level,
 442                                                        start, end,
 443                                                        flags);
 444                         if (ret == 0)
 445                                 goto search_free;
 446
 447                         goto err_unpin;
 448                 }
 449
 450                 GEM_BUG_ON(vma->node.start < start);
 451                 GEM_BUG_ON(vma->node.start + vma->node.size > end);
 452         }
 453         GEM_BUG_ON(!i915_gem_valid_gtt_space(vma, obj->cache_level));
 454
 455         list_move_tail(&obj->global_link, &dev_priv->mm.bound_list);
 456         list_move_tail(&vma->vm_link, &vma->vm->inactive_list);
 457         obj->bind_count++;
 458         GEM_BUG_ON(atomic_read(&obj->mm.pages_pin_count) < obj->bind_count);
 459
 460         return 0;
 461
 462 err_unpin:
 463         i915_gem_object_unpin_pages(obj);
 464         return ret;
 465 }
 466
 467 int __i915_vma_do_pin(struct i915_vma *vma,
 468                       u64 size, u64 alignment, u64 flags)
 469 {
 470         unsigned int bound = vma->flags;
 471         int ret;
 472
 473         lockdep_assert_held(&vma->vm->dev->struct_mutex);
 474         GEM_BUG_ON((flags & (PIN_GLOBAL | PIN_USER)) == 0);
 475         GEM_BUG_ON((flags & PIN_GLOBAL) && !i915_vma_is_ggtt(vma));
 476
 477         if (WARN_ON(bound & I915_VMA_PIN_OVERFLOW)) {
 478                 ret = -EBUSY;
 479                 goto err;
 480         }
 481
 482         if ((bound & I915_VMA_BIND_MASK) == 0) {
 483                 ret = i915_vma_insert(vma, size, alignment, flags);
 484                 if (ret)
 485                         goto err;
 486         }
 487
 488         ret = i915_vma_bind(vma, vma->obj->cache_level, flags);
 489         if (ret)
 490                 goto err;
 491
 492         if ((bound ^ vma->flags) & I915_VMA_GLOBAL_BIND)
 493                 __i915_vma_set_map_and_fenceable(vma);
 494
 495         GEM_BUG_ON(i915_vma_misplaced(vma, size, alignment, flags));
 496         return 0;
 497
 498 err:
 499         __i915_vma_unpin(vma);
 500         return ret;
 501 }
 502
 503 void i915_vma_destroy(struct i915_vma *vma)
 504 {
 505         GEM_BUG_ON(vma->node.allocated);
 506         GEM_BUG_ON(i915_vma_is_active(vma));
 507         GEM_BUG_ON(!i915_vma_is_closed(vma));
 508         GEM_BUG_ON(vma->fence);
 509
 510         list_del(&vma->vm_link);
 511         if (!i915_vma_is_ggtt(vma))
 512                 i915_ppgtt_put(i915_vm_to_ppgtt(vma->vm));
 513
 514         kmem_cache_free(to_i915(vma->obj->base.dev)->vmas, vma);
 515 }
 516
 517 void i915_vma_close(struct i915_vma *vma)
 518 {
 519         GEM_BUG_ON(i915_vma_is_closed(vma));
 520         vma->flags |= I915_VMA_CLOSED;
 521
 522         list_del(&vma->obj_link);
 523         rb_erase(&vma->obj_node, &vma->obj->vma_tree);
 524
 525         if (!i915_vma_is_active(vma) && !i915_vma_is_pinned(vma))
 526                 WARN_ON(i915_vma_unbind(vma));
 527 }
 528
 529 static void __i915_vma_iounmap(struct i915_vma *vma)
 530 {
 531         GEM_BUG_ON(i915_vma_is_pinned(vma));
 532
 533         if (vma->iomap == NULL)
 534                 return;
 535
 536         io_mapping_unmap(vma->iomap);
 537         vma->iomap = NULL;
 538 }
 539
 540 int i915_vma_unbind(struct i915_vma *vma)
 541 {
 542         struct drm_i915_gem_object *obj = vma->obj;
 543         unsigned long active;
 544         int ret;
 545
 546         lockdep_assert_held(&obj->base.dev->struct_mutex);
 547
 548         /* First wait upon any activity as retiring the request may
 549          * have side-effects such as unpinning or even unbinding this vma.
 550          */
 551         active = i915_vma_get_active(vma);
 552         if (active) {
 553                 int idx;
 554
 555                 /* When a closed VMA is retired, it is unbound - eek.
 556                  * In order to prevent it from being recursively closed,
 557                  * take a pin on the vma so that the second unbind is
 558                  * aborted.
 559                  *
 560                  * Even more scary is that the retire callback may free
 561                  * the object (last active vma). To prevent the explosion
 562                  * we defer the actual object free to a worker that can
 563                  * only proceed once it acquires the struct_mutex (which
 564                  * we currently hold, therefore it cannot free this object
 565                  * before we are finished).
 566                  */
 567                 __i915_vma_pin(vma);
 568
 569                 for_each_active(active, idx) {
 570                         ret = i915_gem_active_retire(&vma->last_read[idx],
 571                                                    &vma->vm->dev->struct_mutex);
 572                         if (ret)
 573                                 break;
 574                 }
 575
 576                 __i915_vma_unpin(vma);
 577                 if (ret)
 578                         return ret;
 579
 580                 GEM_BUG_ON(i915_vma_is_active(vma));
 581         }
 582
 583         if (i915_vma_is_pinned(vma))
 584                 return -EBUSY;
 585
 586         if (!drm_mm_node_allocated(&vma->node))
 587                 goto destroy;
 588
 589         GEM_BUG_ON(obj->bind_count == 0);
 590         GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));
 591
 592         if (i915_vma_is_map_and_fenceable(vma)) {
 593                 /* release the fence reg _after_ flushing */
 594                 ret = i915_vma_put_fence(vma);
 595                 if (ret)
 596                         return ret;
 597
 598                 /* Force a pagefault for domain tracking on next user access */
 599                 i915_gem_release_mmap(obj);
 600
 601                 __i915_vma_iounmap(vma);
 602                 vma->flags &= ~I915_VMA_CAN_FENCE;
 603         }
 604
 605         if (likely(!vma->vm->closed)) {
 606                 trace_i915_vma_unbind(vma);
 607                 vma->vm->unbind_vma(vma);
 608         }
 609         vma->flags &= ~(I915_VMA_GLOBAL_BIND | I915_VMA_LOCAL_BIND);
 610
 611         drm_mm_remove_node(&vma->node);
 612         list_move_tail(&vma->vm_link, &vma->vm->unbound_list);
 613
 614         if (vma->pages != obj->mm.pages) {
 615                 GEM_BUG_ON(!vma->pages);
 616                 sg_free_table(vma->pages);
 617                 kfree(vma->pages);
 618         }
 619         vma->pages = NULL;
 620
 621         /* Since the unbound list is global, only move to that list if
 622          * no more VMAs exist. */
 623         if (--obj->bind_count == 0)
 624                 list_move_tail(&obj->global_link,
 625                                &to_i915(obj->base.dev)->mm.unbound_list);
 626
 627         /* And finally now the object is completely decoupled from this vma,
 628          * we can drop its hold on the backing storage and allow it to be
 629          * reaped by the shrinker.
 630          */
 631         i915_gem_object_unpin_pages(obj);
 632
 633 destroy:
 634         if (unlikely(i915_vma_is_closed(vma)))
 635                 i915_vma_destroy(vma);
 636
 637         return 0;
 638 }
 639