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                         GEM_BUG_ON(range_overflows_t(u64,
  99                                                      view->params.partial.offset,
 100                                                      view->params.partial.size,
 101                                                      obj->base.size >> PAGE_SHIFT));
 102                         vma->size = view->params.partial.size;
 103                         vma->size <<= PAGE_SHIFT;
 104                         GEM_BUG_ON(vma->size >= obj->base.size);
 105                 } else if (view->type == I915_GGTT_VIEW_ROTATED) {
 106                         vma->size =
 107                                 intel_rotation_info_size(&view->params.rotated);
 108                         vma->size <<= PAGE_SHIFT;
 109                 }
 110         }
 111
 112         if (i915_is_ggtt(vm)) {
 113                 vma->flags |= I915_VMA_GGTT;
 114                 list_add(&vma->obj_link, &obj->vma_list);
 115         } else {
 116                 i915_ppgtt_get(i915_vm_to_ppgtt(vm));
 117                 list_add_tail(&vma->obj_link, &obj->vma_list);
 118         }
 119
 120         rb = NULL;
 121         p = &obj->vma_tree.rb_node;
 122         while (*p) {
 123                 struct i915_vma *pos;
 124
 125                 rb = *p;
 126                 pos = rb_entry(rb, struct i915_vma, obj_node);
 127                 if (i915_vma_compare(pos, vm, view) < 0)
 128                         p = &rb->rb_right;
 129                 else
 130                         p = &rb->rb_left;
 131         }
 132         rb_link_node(&vma->obj_node, rb, p);
 133         rb_insert_color(&vma->obj_node, &obj->vma_tree);
 134
 135         return vma;
 136 }
 137
 138 struct i915_vma *
 139 i915_vma_create(struct drm_i915_gem_object *obj,
 140                 struct i915_address_space *vm,
 141                 const struct i915_ggtt_view *view)
 142 {
 143         lockdep_assert_held(&obj->base.dev->struct_mutex);
 144         GEM_BUG_ON(view && !i915_is_ggtt(vm));
 145         GEM_BUG_ON(i915_gem_obj_to_vma(obj, vm, view));
 146
 147         return __i915_vma_create(obj, vm, view);
 148 }
 149
 150 /**
 151  * i915_vma_bind - Sets up PTEs for an VMA in it's corresponding address space.
 152  * @vma: VMA to map
 153  * @cache_level: mapping cache level
 154  * @flags: flags like global or local mapping
 155  *
 156  * DMA addresses are taken from the scatter-gather table of this object (or of
 157  * this VMA in case of non-default GGTT views) and PTE entries set up.
 158  * Note that DMA addresses are also the only part of the SG table we care about.
 159  */
 160 int i915_vma_bind(struct i915_vma *vma, enum i915_cache_level cache_level,
 161                   u32 flags)
 162 {
 163         u32 bind_flags;
 164         u32 vma_flags;
 165         int ret;
 166
 167         if (WARN_ON(flags == 0))
 168                 return -EINVAL;
 169
 170         bind_flags = 0;
 171         if (flags & PIN_GLOBAL)
 172                 bind_flags |= I915_VMA_GLOBAL_BIND;
 173         if (flags & PIN_USER)
 174                 bind_flags |= I915_VMA_LOCAL_BIND;
 175
 176         vma_flags = vma->flags & (I915_VMA_GLOBAL_BIND | I915_VMA_LOCAL_BIND);
 177         if (flags & PIN_UPDATE)
 178                 bind_flags |= vma_flags;
 179         else
 180                 bind_flags &= ~vma_flags;
 181         if (bind_flags == 0)
 182                 return 0;
 183
 184         if (GEM_WARN_ON(range_overflows(vma->node.start,
 185                                         vma->node.size,
 186                                         vma->vm->total)))
 187                 return -ENODEV;
 188
 189         if (vma_flags == 0 && vma->vm->allocate_va_range) {
 190                 trace_i915_va_alloc(vma);
 191                 ret = vma->vm->allocate_va_range(vma->vm,
 192                                                  vma->node.start,
 193                                                  vma->node.size);
 194                 if (ret)
 195                         return ret;
 196         }
 197
 198         ret = vma->vm->bind_vma(vma, cache_level, bind_flags);
 199         if (ret)
 200                 return ret;
 201
 202         vma->flags |= bind_flags;
 203         return 0;
 204 }
 205
 206 void __iomem *i915_vma_pin_iomap(struct i915_vma *vma)
 207 {
 208         void __iomem *ptr;
 209
 210         /* Access through the GTT requires the device to be awake. */
 211         assert_rpm_wakelock_held(vma->vm->i915);
 212
 213         lockdep_assert_held(&vma->vm->i915->drm.struct_mutex);
 214         if (WARN_ON(!i915_vma_is_map_and_fenceable(vma)))
 215                 return IO_ERR_PTR(-ENODEV);
 216
 217         GEM_BUG_ON(!i915_vma_is_ggtt(vma));
 218         GEM_BUG_ON((vma->flags & I915_VMA_GLOBAL_BIND) == 0);
 219
 220         ptr = vma->iomap;
 221         if (ptr == NULL) {
 222                 ptr = io_mapping_map_wc(&i915_vm_to_ggtt(vma->vm)->mappable,
 223                                         vma->node.start,
 224                                         vma->node.size);
 225                 if (ptr == NULL)
 226                         return IO_ERR_PTR(-ENOMEM);
 227
 228                 vma->iomap = ptr;
 229         }
 230
 231         __i915_vma_pin(vma);
 232         return ptr;
 233 }
 234
 235 void i915_vma_unpin_and_release(struct i915_vma **p_vma)
 236 {
 237         struct i915_vma *vma;
 238         struct drm_i915_gem_object *obj;
 239
 240         vma = fetch_and_zero(p_vma);
 241         if (!vma)
 242                 return;
 243
 244         obj = vma->obj;
 245
 246         i915_vma_unpin(vma);
 247         i915_vma_close(vma);
 248
 249         __i915_gem_object_release_unless_active(obj);
 250 }
 251
 252 bool
 253 i915_vma_misplaced(struct i915_vma *vma, u64 size, u64 alignment, u64 flags)
 254 {
 255         if (!drm_mm_node_allocated(&vma->node))
 256                 return false;
 257
 258         if (vma->node.size < size)
 259                 return true;
 260
 261         if (alignment && vma->node.start & (alignment - 1))
 262                 return true;
 263
 264         if (flags & PIN_MAPPABLE && !i915_vma_is_map_and_fenceable(vma))
 265                 return true;
 266
 267         if (flags & PIN_OFFSET_BIAS &&
 268             vma->node.start < (flags & PIN_OFFSET_MASK))
 269                 return true;
 270
 271         if (flags & PIN_OFFSET_FIXED &&
 272             vma->node.start != (flags & PIN_OFFSET_MASK))
 273                 return true;
 274
 275         return false;
 276 }
 277
 278 void __i915_vma_set_map_and_fenceable(struct i915_vma *vma)
 279 {
 280         struct drm_i915_gem_object *obj = vma->obj;
 281         struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
 282         bool mappable, fenceable;
 283         u32 fence_size, fence_alignment;
 284
 285         fence_size = i915_gem_get_ggtt_size(dev_priv,
 286                                             vma->size,
 287                                             i915_gem_object_get_tiling(obj));
 288         fence_alignment = i915_gem_get_ggtt_alignment(dev_priv,
 289                                                       vma->size,
 290                                                       i915_gem_object_get_tiling(obj),
 291                                                       true);
 292
 293         fenceable = (vma->node.size == fence_size &&
 294                      (vma->node.start & (fence_alignment - 1)) == 0);
 295
 296         mappable = (vma->node.start + fence_size <=
 297                     dev_priv->ggtt.mappable_end);
 298
 299         /*
 300          * Explicitly disable for rotated VMA since the display does not
 301          * need the fence and the VMA is not accessible to other users.
 302          */
 303         if (mappable && fenceable &&
 304             vma->ggtt_view.type != I915_GGTT_VIEW_ROTATED)
 305                 vma->flags |= I915_VMA_CAN_FENCE;
 306         else
 307                 vma->flags &= ~I915_VMA_CAN_FENCE;
 308 }
 309
 310 static bool color_differs(struct drm_mm_node *node, unsigned long color)
 311 {
 312         return node->allocated && node->color != color;
 313 }
 314
 315 bool i915_gem_valid_gtt_space(struct i915_vma *vma, unsigned long cache_level)
 316 {
 317         struct drm_mm_node *node = &vma->node;
 318         struct drm_mm_node *other;
 319
 320         /*
 321          * On some machines we have to be careful when putting differing types
 322          * of snoopable memory together to avoid the prefetcher crossing memory
 323          * domains and dying. During vm initialisation, we decide whether or not
 324          * these constraints apply and set the drm_mm.color_adjust
 325          * appropriately.
 326          */
 327         if (vma->vm->mm.color_adjust == NULL)
 328                 return true;
 329
 330         /* Only valid to be called on an already inserted vma */
 331         GEM_BUG_ON(!drm_mm_node_allocated(node));
 332         GEM_BUG_ON(list_empty(&node->node_list));
 333
 334         other = list_prev_entry(node, node_list);
 335         if (color_differs(other, cache_level) && !other->hole_follows)
 336                 return false;
 337
 338         other = list_next_entry(node, node_list);
 339         if (color_differs(other, cache_level) && !node->hole_follows)
 340                 return false;
 341
 342         return true;
 343 }
 344
 345 /**
 346  * i915_vma_insert - finds a slot for the vma in its address space
 347  * @vma: the vma
 348  * @size: requested size in bytes (can be larger than the VMA)
 349  * @alignment: required alignment
 350  * @flags: mask of PIN_* flags to use
 351  *
 352  * First we try to allocate some free space that meets the requirements for
 353  * the VMA. Failiing that, if the flags permit, it will evict an old VMA,
 354  * preferrably the oldest idle entry to make room for the new VMA.
 355  *
 356  * Returns:
 357  * 0 on success, negative error code otherwise.
 358  */
 359 static int
 360 i915_vma_insert(struct i915_vma *vma, u64 size, u64 alignment, u64 flags)
 361 {
 362         struct drm_i915_private *dev_priv = vma->vm->i915;
 363         struct drm_i915_gem_object *obj = vma->obj;
 364         u64 start, end;
 365         int ret;
 366
 367         GEM_BUG_ON(vma->flags & (I915_VMA_GLOBAL_BIND | I915_VMA_LOCAL_BIND));
 368         GEM_BUG_ON(drm_mm_node_allocated(&vma->node));
 369
 370         size = max(size, vma->size);
 371         if (flags & PIN_MAPPABLE)
 372                 size = i915_gem_get_ggtt_size(dev_priv, size,
 373                                               i915_gem_object_get_tiling(obj));
 374
 375         alignment = max(max(alignment, vma->display_alignment),
 376                         i915_gem_get_ggtt_alignment(dev_priv, size,
 377                                                     i915_gem_object_get_tiling(obj),
 378                                                     flags & PIN_MAPPABLE));
 379
 380         start = flags & PIN_OFFSET_BIAS ? flags & PIN_OFFSET_MASK : 0;
 381
 382         end = vma->vm->total;
 383         if (flags & PIN_MAPPABLE)
 384                 end = min_t(u64, end, dev_priv->ggtt.mappable_end);
 385         if (flags & PIN_ZONE_4G)
 386                 end = min_t(u64, end, (1ULL << 32) - PAGE_SIZE);
 387
 388         /* If binding the object/GGTT view requires more space than the entire
 389          * aperture has, reject it early before evicting everything in a vain
 390          * attempt to find space.
 391          */
 392         if (size > end) {
 393                 DRM_DEBUG("Attempting to bind an object larger than the aperture: request=%llu [object=%zd] > %s aperture=%llu\n",
 394                           size, obj->base.size,
 395                           flags & PIN_MAPPABLE ? "mappable" : "total",
 396                           end);
 397                 return -E2BIG;
 398         }
 399
 400         ret = i915_gem_object_pin_pages(obj);
 401         if (ret)
 402                 return ret;
 403
 404         if (flags & PIN_OFFSET_FIXED) {
 405                 u64 offset = flags & PIN_OFFSET_MASK;
 406                 if (offset & (alignment - 1) || offset > end - size) {
 407                         ret = -EINVAL;
 408                         goto err_unpin;
 409                 }
 410
 411                 vma->node.start = offset;
 412                 vma->node.size = size;
 413                 vma->node.color = obj->cache_level;
 414                 ret = drm_mm_reserve_node(&vma->vm->mm, &vma->node);
 415                 if (ret) {
 416                         ret = i915_gem_evict_for_vma(vma, flags);
 417                         if (ret == 0)
 418                                 ret = drm_mm_reserve_node(&vma->vm->mm, &vma->node);
 419                         if (ret)
 420                                 goto err_unpin;
 421                 }
 422         } else {
 423                 u32 search_flag, alloc_flag;
 424
 425                 if (flags & PIN_HIGH) {
 426                         search_flag = DRM_MM_SEARCH_BELOW;
 427                         alloc_flag = DRM_MM_CREATE_TOP;
 428                 } else {
 429                         search_flag = DRM_MM_SEARCH_DEFAULT;
 430                         alloc_flag = DRM_MM_CREATE_DEFAULT;
 431                 }
 432
 433                 /* We only allocate in PAGE_SIZE/GTT_PAGE_SIZE (4096) chunks,
 434                  * so we know that we always have a minimum alignment of 4096.
 435                  * The drm_mm range manager is optimised to return results
 436                  * with zero alignment, so where possible use the optimal
 437                  * path.
 438                  */
 439                 if (alignment <= 4096)
 440                         alignment = 0;
 441
 442 search_free:
 443                 ret = drm_mm_insert_node_in_range_generic(&vma->vm->mm,
 444                                                           &vma->node,
 445                                                           size, alignment,
 446                                                           obj->cache_level,
 447                                                           start, end,
 448                                                           search_flag,
 449                                                           alloc_flag);
 450                 if (ret) {
 451                         ret = i915_gem_evict_something(vma->vm, size, alignment,
 452                                                        obj->cache_level,
 453                                                        start, end,
 454                                                        flags);
 455                         if (ret == 0)
 456                                 goto search_free;
 457
 458                         goto err_unpin;
 459                 }
 460
 461                 GEM_BUG_ON(vma->node.start < start);
 462                 GEM_BUG_ON(vma->node.start + vma->node.size > end);
 463         }
 464         GEM_BUG_ON(!i915_gem_valid_gtt_space(vma, obj->cache_level));
 465
 466         list_move_tail(&obj->global_link, &dev_priv->mm.bound_list);
 467         list_move_tail(&vma->vm_link, &vma->vm->inactive_list);
 468         obj->bind_count++;
 469         GEM_BUG_ON(atomic_read(&obj->mm.pages_pin_count) < obj->bind_count);
 470
 471         return 0;
 472
 473 err_unpin:
 474         i915_gem_object_unpin_pages(obj);
 475         return ret;
 476 }
 477
 478 int __i915_vma_do_pin(struct i915_vma *vma,
 479                       u64 size, u64 alignment, u64 flags)
 480 {
 481         unsigned int bound = vma->flags;
 482         int ret;
 483
 484         lockdep_assert_held(&vma->vm->i915->drm.struct_mutex);
 485         GEM_BUG_ON((flags & (PIN_GLOBAL | PIN_USER)) == 0);
 486         GEM_BUG_ON((flags & PIN_GLOBAL) && !i915_vma_is_ggtt(vma));
 487
 488         if (WARN_ON(bound & I915_VMA_PIN_OVERFLOW)) {
 489                 ret = -EBUSY;
 490                 goto err;
 491         }
 492
 493         if ((bound & I915_VMA_BIND_MASK) == 0) {
 494                 ret = i915_vma_insert(vma, size, alignment, flags);
 495                 if (ret)
 496                         goto err;
 497         }
 498
 499         ret = i915_vma_bind(vma, vma->obj->cache_level, flags);
 500         if (ret)
 501                 goto err;
 502
 503         if ((bound ^ vma->flags) & I915_VMA_GLOBAL_BIND)
 504                 __i915_vma_set_map_and_fenceable(vma);
 505
 506         GEM_BUG_ON(i915_vma_misplaced(vma, size, alignment, flags));
 507         return 0;
 508
 509 err:
 510         __i915_vma_unpin(vma);
 511         return ret;
 512 }
 513
 514 void i915_vma_destroy(struct i915_vma *vma)
 515 {
 516         GEM_BUG_ON(vma->node.allocated);
 517         GEM_BUG_ON(i915_vma_is_active(vma));
 518         GEM_BUG_ON(!i915_vma_is_closed(vma));
 519         GEM_BUG_ON(vma->fence);
 520
 521         list_del(&vma->vm_link);
 522         if (!i915_vma_is_ggtt(vma))
 523                 i915_ppgtt_put(i915_vm_to_ppgtt(vma->vm));
 524
 525         kmem_cache_free(to_i915(vma->obj->base.dev)->vmas, vma);
 526 }
 527
 528 void i915_vma_close(struct i915_vma *vma)
 529 {
 530         GEM_BUG_ON(i915_vma_is_closed(vma));
 531         vma->flags |= I915_VMA_CLOSED;
 532
 533         list_del(&vma->obj_link);
 534         rb_erase(&vma->obj_node, &vma->obj->vma_tree);
 535
 536         if (!i915_vma_is_active(vma) && !i915_vma_is_pinned(vma))
 537                 WARN_ON(i915_vma_unbind(vma));
 538 }
 539
 540 static void __i915_vma_iounmap(struct i915_vma *vma)
 541 {
 542         GEM_BUG_ON(i915_vma_is_pinned(vma));
 543
 544         if (vma->iomap == NULL)
 545                 return;
 546
 547         io_mapping_unmap(vma->iomap);
 548         vma->iomap = NULL;
 549 }
 550
 551 int i915_vma_unbind(struct i915_vma *vma)
 552 {
 553         struct drm_i915_gem_object *obj = vma->obj;
 554         unsigned long active;
 555         int ret;
 556
 557         lockdep_assert_held(&obj->base.dev->struct_mutex);
 558
 559         /* First wait upon any activity as retiring the request may
 560          * have side-effects such as unpinning or even unbinding this vma.
 561          */
 562         active = i915_vma_get_active(vma);
 563         if (active) {
 564                 int idx;
 565
 566                 /* When a closed VMA is retired, it is unbound - eek.
 567                  * In order to prevent it from being recursively closed,
 568                  * take a pin on the vma so that the second unbind is
 569                  * aborted.
 570                  *
 571                  * Even more scary is that the retire callback may free
 572                  * the object (last active vma). To prevent the explosion
 573                  * we defer the actual object free to a worker that can
 574                  * only proceed once it acquires the struct_mutex (which
 575                  * we currently hold, therefore it cannot free this object
 576                  * before we are finished).
 577                  */
 578                 __i915_vma_pin(vma);
 579
 580                 for_each_active(active, idx) {
 581                         ret = i915_gem_active_retire(&vma->last_read[idx],
 582                                                      &vma->vm->i915->drm.struct_mutex);
 583                         if (ret)
 584                                 break;
 585                 }
 586
 587                 __i915_vma_unpin(vma);
 588                 if (ret)
 589                         return ret;
 590
 591                 GEM_BUG_ON(i915_vma_is_active(vma));
 592         }
 593
 594         if (i915_vma_is_pinned(vma))
 595                 return -EBUSY;
 596
 597         if (!drm_mm_node_allocated(&vma->node))
 598                 goto destroy;
 599
 600         GEM_BUG_ON(obj->bind_count == 0);
 601         GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));
 602
 603         if (i915_vma_is_map_and_fenceable(vma)) {
 604                 /* release the fence reg _after_ flushing */
 605                 ret = i915_vma_put_fence(vma);
 606                 if (ret)
 607                         return ret;
 608
 609                 /* Force a pagefault for domain tracking on next user access */
 610                 i915_gem_release_mmap(obj);
 611
 612                 __i915_vma_iounmap(vma);
 613                 vma->flags &= ~I915_VMA_CAN_FENCE;
 614         }
 615
 616         if (likely(!vma->vm->closed)) {
 617                 trace_i915_vma_unbind(vma);
 618                 vma->vm->unbind_vma(vma);
 619         }
 620         vma->flags &= ~(I915_VMA_GLOBAL_BIND | I915_VMA_LOCAL_BIND);
 621
 622         drm_mm_remove_node(&vma->node);
 623         list_move_tail(&vma->vm_link, &vma->vm->unbound_list);
 624
 625         if (vma->pages != obj->mm.pages) {
 626                 GEM_BUG_ON(!vma->pages);
 627                 sg_free_table(vma->pages);
 628                 kfree(vma->pages);
 629         }
 630         vma->pages = NULL;
 631
 632         /* Since the unbound list is global, only move to that list if
 633          * no more VMAs exist. */
 634         if (--obj->bind_count == 0)
 635                 list_move_tail(&obj->global_link,
 636                                &to_i915(obj->base.dev)->mm.unbound_list);
 637
 638         /* And finally now the object is completely decoupled from this vma,
 639          * we can drop its hold on the backing storage and allow it to be
 640          * reaped by the shrinker.
 641          */
 642         i915_gem_object_unpin_pages(obj);
 643
 644 destroy:
 645         if (unlikely(i915_vma_is_closed(vma)))
 646                 i915_vma_destroy(vma);
 647
 648         return 0;
 649 }
 650