text: /* SPDX-License-Identifier: GPL-2.0 OR MIT */
  /**************************************************************************
   *
   * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
   * All Rights Reserved.
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the
   * "Software"), to deal in the Software without restriction, including
   * without limitation the rights to use, copy, modify, merge, publish,
   * distribute, sub license, and/or sell copies of the Software, and to
   * permit persons to whom the Software is furnished to do so, subject to
   * the following conditions:
   *
   * The above copyright notice and this permission notice (including the
   * next paragraph) shall be included in all copies or substantial portions
   * of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
   * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
   * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
   * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
   * USE OR OTHER DEALINGS IN THE SOFTWARE.
   *
   **************************************************************************/
  /*
   * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
   */
  
  #define pr_fmt(fmt) "[TTM] " fmt
  
  #include <drm/ttm/ttm_module.h>
  #include <drm/ttm/ttm_bo_driver.h>
  #include <drm/ttm/ttm_placement.h>
  #include <linux/jiffies.h>
  #include <linux/slab.h>
  #include <linux/sched.h>
  #include <linux/mm.h>
  #include <linux/file.h>
  #include <linux/module.h>
  #include <linux/atomic.h>
  #include <linux/dma-resv.h>
  
  static void ttm_bo_global_kobj_release(struct kobject *kobj);
  
  /**
   * ttm_global_mutex - protecting the global BO state
   */
  DEFINE_MUTEX(ttm_global_mutex);
  unsigned ttm_bo_glob_use_count;
  struct ttm_bo_global ttm_bo_glob;
  EXPORT_SYMBOL(ttm_bo_glob);
  
  static struct attribute ttm_bo_count = {
  	.name = "bo_count",
  	.mode = S_IRUGO
  };
  
  /* default destructor */
  static void ttm_bo_default_destroy(struct ttm_buffer_object *bo)
  {
  	kfree(bo);
  }
  
  static inline int ttm_mem_type_from_place(const struct ttm_place *place,
  					  uint32_t *mem_type)
  {
  	int pos;
  
  	pos = ffs(place->flags & TTM_PL_MASK_MEM);
  	if (unlikely(!pos))
  		return -EINVAL;
  
  	*mem_type = pos - 1;
  	return 0;
  }
  
  static void ttm_mem_type_debug(struct ttm_bo_device *bdev, struct drm_printer *p,
  			       int mem_type)
  {
  	struct ttm_mem_type_manager *man = &bdev->man[mem_type];
  
  	drm_printf(p, "    has_type: %d\n", man->has_type);
  	drm_printf(p, "    use_type: %d\n", man->use_type);
  	drm_printf(p, "    flags: 0x%08X\n", man->flags);
  	drm_printf(p, "    gpu_offset: 0x%08llX\n", man->gpu_offset);
  	drm_printf(p, "    size: %llu\n", man->size);
  	drm_printf(p, "    available_caching: 0x%08X\n", man->available_caching);
  	drm_printf(p, "    default_caching: 0x%08X\n", man->default_caching);
  	if (mem_type != TTM_PL_SYSTEM)
  		(*man->func->debug)(man, p);
  }
  
  static void ttm_bo_mem_space_debug(struct ttm_buffer_object *bo,
  					struct ttm_placement *placement)
  {
  	struct drm_printer p = drm_debug_printer(TTM_PFX);
  	int i, ret, mem_type;
  
  	drm_printf(&p, "No space for %p (%lu pages, %luK, %luM)\n",
  		   bo, bo->mem.num_pages, bo->mem.size >> 10,
  		   bo->mem.size >> 20);
  	for (i = 0; i < placement->num_placement; i++) {
  		ret = ttm_mem_type_from_place(&placement->placement[i],
  						&mem_type);
  		if (ret)
  			return;
  		drm_printf(&p, "  placement[%d]=0x%08X (%d)\n",
  			   i, placement->placement[i].flags, mem_type);
  		ttm_mem_type_debug(bo->bdev, &p, mem_type);
  	}
  }
  
  static ssize_t ttm_bo_global_show(struct kobject *kobj,
  				  struct attribute *attr,
  				  char *buffer)
  {
  	struct ttm_bo_global *glob =
  		container_of(kobj, struct ttm_bo_global, kobj);
  
  	return snprintf(buffer, PAGE_SIZE, "%d\n",
  				atomic_read(&glob->bo_count));
  }
  
  static struct attribute *ttm_bo_global_attrs[] = {
  	&ttm_bo_count,
  	NULL
  };
  
  static const struct sysfs_ops ttm_bo_global_ops = {
  	.show = &ttm_bo_global_show
  };
  
  static struct kobj_type ttm_bo_glob_kobj_type  = {
  	.release = &ttm_bo_global_kobj_release,
  	.sysfs_ops = &ttm_bo_global_ops,
  	.default_attrs = ttm_bo_global_attrs
  };
  
  
  static inline uint32_t ttm_bo_type_flags(unsigned type)
  {
  	return 1 << (type);
  }
  
  static void ttm_bo_add_mem_to_lru(struct ttm_buffer_object *bo,
  				  struct ttm_mem_reg *mem)
  {
  	struct ttm_bo_device *bdev = bo->bdev;
  	struct ttm_mem_type_manager *man;
  
  	if (!list_empty(&bo->lru))
  		return;
  
  	if (mem->placement & TTM_PL_FLAG_NO_EVICT)
  		return;
  
  	man = &bdev->man[mem->mem_type];
  	list_add_tail(&bo->lru, &man->lru[bo->priority]);
  
  	if (!(man->flags & TTM_MEMTYPE_FLAG_FIXED) && bo->ttm &&
  	    !(bo->ttm->page_flags & (TTM_PAGE_FLAG_SG |
  				     TTM_PAGE_FLAG_SWAPPED))) {
  		list_add_tail(&bo->swap, &ttm_bo_glob.swap_lru[bo->priority]);
  	}
  }
  
  static void ttm_bo_del_from_lru(struct ttm_buffer_object *bo)
  {
  	struct ttm_bo_device *bdev = bo->bdev;
  	bool notify = false;
  
  	if (!list_empty(&bo->swap)) {
  		list_del_init(&bo->swap);
  		notify = true;
  	}
  	if (!list_empty(&bo->lru)) {
  		list_del_init(&bo->lru);
  		notify = true;
  	}
  
  	if (notify && bdev->driver->del_from_lru_notify)
  		bdev->driver->del_from_lru_notify(bo);
  }
  
  static void ttm_bo_bulk_move_set_pos(struct ttm_lru_bulk_move_pos *pos,
  				     struct ttm_buffer_object *bo)
  {
  	if (!pos->first)
  		pos->first = bo;
  	pos->last = bo;
  }
  
  void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo,
  			     struct ttm_lru_bulk_move *bulk)
  {
  	dma_resv_assert_held(bo->base.resv);
  
  	ttm_bo_del_from_lru(bo);
  	ttm_bo_add_mem_to_lru(bo, &bo->mem);
  
  	if (bulk && !(bo->mem.placement & TTM_PL_FLAG_NO_EVICT)) {
  		switch (bo->mem.mem_type) {
  		case TTM_PL_TT:
  			ttm_bo_bulk_move_set_pos(&bulk->tt[bo->priority], bo);
  			break;
  
  		case TTM_PL_VRAM:
  			ttm_bo_bulk_move_set_pos(&bulk->vram[bo->priority], bo);
  			break;
  		}
  		if (bo->ttm && !(bo->ttm->page_flags &
  				 (TTM_PAGE_FLAG_SG | TTM_PAGE_FLAG_SWAPPED)))
  			ttm_bo_bulk_move_set_pos(&bulk->swap[bo->priority], bo);
  	}
  }
  EXPORT_SYMBOL(ttm_bo_move_to_lru_tail);
  
  void ttm_bo_bulk_move_lru_tail(struct ttm_lru_bulk_move *bulk)
  {
  	unsigned i;
  
  	for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
  		struct ttm_lru_bulk_move_pos *pos = &bulk->tt[i];
  		struct ttm_mem_type_manager *man;
  
  		if (!pos->first)
  			continue;
  
  		dma_resv_assert_held(pos->first->base.resv);
  		dma_resv_assert_held(pos->last->base.resv);
  
  		man = &pos->first->bdev->man[TTM_PL_TT];
  		list_bulk_move_tail(&man->lru[i], &pos->first->lru,
  				    &pos->last->lru);
  	}
  
  	for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
  		struct ttm_lru_bulk_move_pos *pos = &bulk->vram[i];
  		struct ttm_mem_type_manager *man;
  
  		if (!pos->first)
  			continue;
  
  		dma_resv_assert_held(pos->first->base.resv);
  		dma_resv_assert_held(pos->last->base.resv);
  
  		man = &pos->first->bdev->man[TTM_PL_VRAM];
  		list_bulk_move_tail(&man->lru[i], &pos->first->lru,
  				    &pos->last->lru);
  	}
  
  	for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
  		struct ttm_lru_bulk_move_pos *pos = &bulk->swap[i];
  		struct list_head *lru;
  
  		if (!pos->first)
  			continue;
  
  		dma_resv_assert_held(pos->first->base.resv);
  		dma_resv_assert_held(pos->last->base.resv);
  
  		lru = &ttm_bo_glob.swap_lru[i];
  		list_bulk_move_tail(lru, &pos->first->swap, &pos->last->swap);
  	}
  }
  EXPORT_SYMBOL(ttm_bo_bulk_move_lru_tail);
  
  static int ttm_bo_handle_move_mem(struct ttm_buffer_object *bo,
  				  struct ttm_mem_reg *mem, bool evict,
  				  struct ttm_operation_ctx *ctx)
  {
  	struct ttm_bo_device *bdev = bo->bdev;
  	bool old_is_pci = ttm_mem_reg_is_pci(bdev, &bo->mem);
  	bool new_is_pci = ttm_mem_reg_is_pci(bdev, mem);
  	struct ttm_mem_type_manager *old_man = &bdev->man[bo->mem.mem_type];
  	struct ttm_mem_type_manager *new_man = &bdev->man[mem->mem_type];
  	int ret = 0;
  
  	if (old_is_pci || new_is_pci ||
  	    ((mem->placement & bo->mem.placement & TTM_PL_MASK_CACHING) == 0)) {
  		ret = ttm_mem_io_lock(old_man, true);
  		if (unlikely(ret != 0))
  			goto out_err;
  		ttm_bo_unmap_virtual_locked(bo);
  		ttm_mem_io_unlock(old_man);
  	}
  
  	/*
  	 * Create and bind a ttm if required.
  	 */
  
  	if (!(new_man->flags & TTM_MEMTYPE_FLAG_FIXED)) {
  		if (bo->ttm == NULL) {
  			bool zero = !(old_man->flags & TTM_MEMTYPE_FLAG_FIXED);
  			ret = ttm_tt_create(bo, zero);
  			if (ret)
  				goto out_err;
  		}
  
  		ret = ttm_tt_set_placement_caching(bo->ttm, mem->placement);
  		if (ret)
  			goto out_err;
  
  		if (mem->mem_type != TTM_PL_SYSTEM) {
  			ret = ttm_tt_bind(bo->ttm, mem, ctx);
  			if (ret)
  				goto out_err;
  		}
  
  		if (bo->mem.mem_type == TTM_PL_SYSTEM) {
  			if (bdev->driver->move_notify)
  				bdev->driver->move_notify(bo, evict, mem);
  			bo->mem = *mem;
  			mem->mm_node = NULL;
  			goto moved;
  		}
  	}
  
  	if (bdev->driver->move_notify)
  		bdev->driver->move_notify(bo, evict, mem);
  
  	if (!(old_man->flags & TTM_MEMTYPE_FLAG_FIXED) &&
  	    !(new_man->flags & TTM_MEMTYPE_FLAG_FIXED))
  		ret = ttm_bo_move_ttm(bo, ctx, mem);
  	else if (bdev->driver->move)
  		ret = bdev->driver->move(bo, evict, ctx, mem);
  	else
  		ret = ttm_bo_move_memcpy(bo, ctx, mem);
  
  	if (ret) {
  		if (bdev->driver->move_notify) {
  			swap(*mem, bo->mem);
  			bdev->driver->move_notify(bo, false, mem);
  			swap(*mem, bo->mem);
  		}
  
  		goto out_err;
  	}
  
  moved:
  	bo->evicted = false;
  
  	if (bo->mem.mm_node)
  		bo->offset = (bo->mem.start << PAGE_SHIFT) +
  		    bdev->man[bo->mem.mem_type].gpu_offset;
  	else
  		bo->offset = 0;
  
  	ctx->bytes_moved += bo->num_pages << PAGE_SHIFT;
  	return 0;
  
  out_err:
  	new_man = &bdev->man[bo->mem.mem_type];
  	if (new_man->flags & TTM_MEMTYPE_FLAG_FIXED) {
  		ttm_tt_destroy(bo->ttm);
  		bo->ttm = NULL;
  	}
  
  	return ret;
  }
  
  /**
   * Call bo::reserved.
   * Will release GPU memory type usage on destruction.
   * This is the place to put in driver specific hooks to release
   * driver private resources.
   * Will release the bo::reserved lock.
   */
  
  static void ttm_bo_cleanup_memtype_use(struct ttm_buffer_object *bo)
  {
  	if (bo->bdev->driver->move_notify)
  		bo->bdev->driver->move_notify(bo, false, NULL);
  
  	ttm_tt_destroy(bo->ttm);
  	bo->ttm = NULL;
  	ttm_bo_mem_put(bo, &bo->mem);
  }
  
  static int ttm_bo_individualize_resv(struct ttm_buffer_object *bo)
  {
  	int r;
  
  	if (bo->base.resv == &bo->base._resv)
  		return 0;
  
  	BUG_ON(!dma_resv_trylock(&bo->base._resv));
  
  	r = dma_resv_copy_fences(&bo->base._resv, bo->base.resv);
  	dma_resv_unlock(&bo->base._resv);
  	if (r)
  		return r;
  
  	if (bo->type != ttm_bo_type_sg) {
  		/* This works because the BO is about to be destroyed and nobody
  		 * reference it any more. The only tricky case is the trylock on
  		 * the resv object while holding the lru_lock.
  		 */
  		spin_lock(&ttm_bo_glob.lru_lock);
  		bo->base.resv = &bo->base._resv;
  		spin_unlock(&ttm_bo_glob.lru_lock);
  	}
  
  	return r;
  }
  
  static void ttm_bo_flush_all_fences(struct ttm_buffer_object *bo)
  {
  	struct dma_resv *resv = &bo->base._resv;
  	struct dma_resv_list *fobj;
  	struct dma_fence *fence;
  	int i;
  
  	rcu_read_lock();
  	fobj = rcu_dereference(resv->fence);
  	fence = rcu_dereference(resv->fence_excl);
  	if (fence && !fence->ops->signaled)
  		dma_fence_enable_sw_signaling(fence);
  
  	for (i = 0; fobj && i < fobj->shared_count; ++i) {
  		fence = rcu_dereference(fobj->shared[i]);
  
  		if (!fence->ops->signaled)
  			dma_fence_enable_sw_signaling(fence);
  	}
  	rcu_read_unlock();
  }
  
  /**
   * function ttm_bo_cleanup_refs
   * If bo idle, remove from lru lists, and unref.
   * If not idle, block if possible.
   *
   * Must be called with lru_lock and reservation held, this function
   * will drop the lru lock and optionally the reservation lock before returning.
   *
   * @interruptible         Any sleeps should occur interruptibly.
   * @no_wait_gpu           Never wait for gpu. Return -EBUSY instead.
   * @unlock_resv           Unlock the reservation lock as well.
   */
  
  static int ttm_bo_cleanup_refs(struct ttm_buffer_object *bo,
  			       bool interruptible, bool no_wait_gpu,
  			       bool unlock_resv)
  {
  	struct dma_resv *resv = &bo->base._resv;
  	int ret;
  
  	if (dma_resv_test_signaled_rcu(resv, true))
  		ret = 0;
  	else
  		ret = -EBUSY;
  
  	if (ret && !no_wait_gpu) {
  		long lret;
  
  		if (unlock_resv)
  			dma_resv_unlock(bo->base.resv);
  		spin_unlock(&ttm_bo_glob.lru_lock);
  
  		lret = dma_resv_wait_timeout_rcu(resv, true, interruptible,
  						 30 * HZ);
  
  		if (lret < 0)
  			return lret;
  		else if (lret == 0)
  			return -EBUSY;
  
  		spin_lock(&ttm_bo_glob.lru_lock);
  		if (unlock_resv && !dma_resv_trylock(bo->base.resv)) {
  			/*
  			 * We raced, and lost, someone else holds the reservation now,
  			 * and is probably busy in ttm_bo_cleanup_memtype_use.
  			 *
  			 * Even if it's not the case, because we finished waiting any
  			 * delayed destruction would succeed, so just return success
  			 * here.
  			 */
  			spin_unlock(&ttm_bo_glob.lru_lock);
  			return 0;
  		}
  		ret = 0;
  	}
  
  	if (ret || unlikely(list_empty(&bo->ddestroy))) {
  		if (unlock_resv)
  			dma_resv_unlock(bo->base.resv);
  		spin_unlock(&ttm_bo_glob.lru_lock);
  		return ret;
  	}
  
  	ttm_bo_del_from_lru(bo);
  	list_del_init(&bo->ddestroy);
  	spin_unlock(&ttm_bo_glob.lru_lock);
  	ttm_bo_cleanup_memtype_use(bo);
  
  	if (unlock_resv)
  		dma_resv_unlock(bo->base.resv);
  
  	ttm_bo_put(bo);
  
  	return 0;
  }
  
  /**
   * Traverse the delayed list, and call ttm_bo_cleanup_refs on all
   * encountered buffers.
   */
  static bool ttm_bo_delayed_delete(struct ttm_bo_device *bdev, bool remove_all)
  {
  	struct ttm_bo_global *glob = &ttm_bo_glob;
  	struct list_head removed;
  	bool empty;
  
  	INIT_LIST_HEAD(&removed);
  
  	spin_lock(&glob->lru_lock);
  	while (!list_empty(&bdev->ddestroy)) {
  		struct ttm_buffer_object *bo;
  
  		bo = list_first_entry(&bdev->ddestroy, struct ttm_buffer_object,
  				      ddestroy);
  		list_move_tail(&bo->ddestroy, &removed);
  		if (!ttm_bo_get_unless_zero(bo))
  			continue;
  
  		if (remove_all || bo->base.resv != &bo->base._resv) {
  			spin_unlock(&glob->lru_lock);
  			dma_resv_lock(bo->base.resv, NULL);
  
  			spin_lock(&glob->lru_lock);
  			ttm_bo_cleanup_refs(bo, false, !remove_all, true);
  
  		} else if (dma_resv_trylock(bo->base.resv)) {
  			ttm_bo_cleanup_refs(bo, false, !remove_all, true);
  		} else {
  			spin_unlock(&glob->lru_lock);
  		}
  
  		ttm_bo_put(bo);
  		spin_lock(&glob->lru_lock);
  	}
  	list_splice_tail(&removed, &bdev->ddestroy);
  	empty = list_empty(&bdev->ddestroy);
  	spin_unlock(&glob->lru_lock);
  
  	return empty;
  }
  
  static void ttm_bo_delayed_workqueue(struct work_struct *work)
  {
  	struct ttm_bo_device *bdev =
  	    container_of(work, struct ttm_bo_device, wq.work);
  
  	if (!ttm_bo_delayed_delete(bdev, false))
  		schedule_delayed_work(&bdev->wq,
  				      ((HZ / 100) < 1) ? 1 : HZ / 100);
  }
  
  static void ttm_bo_release(struct kref *kref)
  {
  	struct ttm_buffer_object *bo =
  	    container_of(kref, struct ttm_buffer_object, kref);
  	struct ttm_bo_device *bdev = bo->bdev;
  	struct ttm_mem_type_manager *man = &bdev->man[bo->mem.mem_type];
  	size_t acc_size = bo->acc_size;
  	int ret;
  
  	if (!bo->deleted) {
  		ret = ttm_bo_individualize_resv(bo);
  		if (ret) {
  			/* Last resort, if we fail to allocate memory for the
  			 * fences block for the BO to become idle
  			 */
  			dma_resv_wait_timeout_rcu(bo->base.resv, true, false,
  						  30 * HZ);
  		}
  
  		if (bo->bdev->driver->release_notify)
  			bo->bdev->driver->release_notify(bo);
  
  		drm_vma_offset_remove(bdev->vma_manager, &bo->base.vma_node);
  		ttm_mem_io_lock(man, false);
  		ttm_mem_io_free_vm(bo);
  		ttm_mem_io_unlock(man);
  	}
  
  	if (!dma_resv_test_signaled_rcu(bo->base.resv, true) ||
  	    !dma_resv_trylock(bo->base.resv)) {
  		/* The BO is not idle, resurrect it for delayed destroy */
  		ttm_bo_flush_all_fences(bo);
  		bo->deleted = true;
  
  		spin_lock(&ttm_bo_glob.lru_lock);
  
  		/*
  		 * Make NO_EVICT bos immediately available to
  		 * shrinkers, now that they are queued for
  		 * destruction.
  		 */
  		if (bo->mem.placement & TTM_PL_FLAG_NO_EVICT) {
  			bo->mem.placement &= ~TTM_PL_FLAG_NO_EVICT;
  			ttm_bo_del_from_lru(bo);
  			ttm_bo_add_mem_to_lru(bo, &bo->mem);
  		}
  
  		kref_init(&bo->kref);
  		list_add_tail(&bo->ddestroy, &bdev->ddestroy);
  		spin_unlock(&ttm_bo_glob.lru_lock);
  
  		schedule_delayed_work(&bdev->wq,
  				      ((HZ / 100) < 1) ? 1 : HZ / 100);
  		return;
  	}
  
  	spin_lock(&ttm_bo_glob.lru_lock);
  	ttm_bo_del_from_lru(bo);
  	list_del(&bo->ddestroy);
  	spin_unlock(&ttm_bo_glob.lru_lock);
  
  	ttm_bo_cleanup_memtype_use(bo);
  	dma_resv_unlock(bo->base.resv);
  
  	BUG_ON(bo->mem.mm_node != NULL);
  	atomic_dec(&ttm_bo_glob.bo_count);
  	dma_fence_put(bo->moving);
  	if (!ttm_bo_uses_embedded_gem_object(bo))
  		dma_resv_fini(&bo->base._resv);
  	bo->destroy(bo);
  	ttm_mem_global_free(&ttm_mem_glob, acc_size);
  }
  
  void ttm_bo_put(struct ttm_buffer_object *bo)
  {
  	kref_put(&bo->kref, ttm_bo_release);
  }
  EXPORT_SYMBOL(ttm_bo_put);
  
  int ttm_bo_lock_delayed_workqueue(struct ttm_bo_device *bdev)
  {
  	return cancel_delayed_work_sync(&bdev->wq);
  }
  EXPORT_SYMBOL(ttm_bo_lock_delayed_workqueue);
  
  void ttm_bo_unlock_delayed_workqueue(struct ttm_bo_device *bdev, int resched)
  {
  	if (resched)
  		schedule_delayed_work(&bdev->wq,
  				      ((HZ / 100) < 1) ? 1 : HZ / 100);
  }
  EXPORT_SYMBOL(ttm_bo_unlock_delayed_workqueue);
  
  static int ttm_bo_evict(struct ttm_buffer_object *bo,
  			struct ttm_operation_ctx *ctx)
  {
  	struct ttm_bo_device *bdev = bo->bdev;
  	struct ttm_mem_reg evict_mem;
  	struct ttm_placement placement;
  	int ret = 0;
  
  	dma_resv_assert_held(bo->base.resv);
  
  	placement.num_placement = 0;
  	placement.num_busy_placement = 0;
  	bdev->driver->evict_flags(bo, &placement);
  
  	if (!placement.num_placement && !placement.num_busy_placement) {
  		ret = ttm_bo_pipeline_gutting(bo);
  		if (ret)
  			return ret;
  
  		return ttm_tt_create(bo, false);
  	}
  
  	evict_mem = bo->mem;
  	evict_mem.mm_node = NULL;
  	evict_mem.bus.io_reserved_vm = false;
  	evict_mem.bus.io_reserved_count = 0;
  
  	ret = ttm_bo_mem_space(bo, &placement, &evict_mem, ctx);
  	if (ret) {
  		if (ret != -ERESTARTSYS) {
  			pr_err("Failed to find memory space for buffer 0x%p eviction\n",
  			       bo);
  			ttm_bo_mem_space_debug(bo, &placement);
  		}
  		goto out;
  	}
  
  	ret = ttm_bo_handle_move_mem(bo, &evict_mem, true, ctx);
  	if (unlikely(ret)) {
  		if (ret != -ERESTARTSYS)
  			pr_err("Buffer eviction failed\n");
  		ttm_bo_mem_put(bo, &evict_mem);
  		goto out;
  	}
  	bo->evicted = true;
  out:
  	return ret;
  }
  
  bool ttm_bo_eviction_valuable(struct ttm_buffer_object *bo,
  			      const struct ttm_place *place)
  {
  	/* Don't evict this BO if it's outside of the
  	 * requested placement range
  	 */
  	if (place->fpfn >= (bo->mem.start + bo->mem.size) ||
  	    (place->lpfn && place->lpfn <= bo->mem.start))
  		return false;
  
  	return true;
  }
  EXPORT_SYMBOL(ttm_bo_eviction_valuable);
  
  /**
   * Check the target bo is allowable to be evicted or swapout, including cases:
   *
   * a. if share same reservation object with ctx->resv, have assumption
   * reservation objects should already be locked, so not lock again and
   * return true directly when either the opreation allow_reserved_eviction
   * or the target bo already is in delayed free list;
   *
   * b. Otherwise, trylock it.
   */
  static bool ttm_bo_evict_swapout_allowable(struct ttm_buffer_object *bo,
  			struct ttm_operation_ctx *ctx, bool *locked, bool *busy)
  {
  	bool ret = false;
  
  	if (bo->base.resv == ctx->resv) {
  		dma_resv_assert_held(bo->base.resv);
  		if (ctx->flags & TTM_OPT_FLAG_ALLOW_RES_EVICT)
  			ret = true;
  		*locked = false;
  		if (busy)
  			*busy = false;
  	} else {
  		ret = dma_resv_trylock(bo->base.resv);
  		*locked = ret;
  		if (busy)
  			*busy = !ret;
  	}
  
  	return ret;
  }
  
  /**
   * ttm_mem_evict_wait_busy - wait for a busy BO to become available
   *
   * @busy_bo: BO which couldn't be locked with trylock
   * @ctx: operation context
   * @ticket: acquire ticket
   *
   * Try to lock a busy buffer object to avoid failing eviction.
   */
  static int ttm_mem_evict_wait_busy(struct ttm_buffer_object *busy_bo,
  				   struct ttm_operation_ctx *ctx,
  				   struct ww_acquire_ctx *ticket)
  {
  	int r;
  
  	if (!busy_bo || !ticket)
  		return -EBUSY;
  
  	if (ctx->interruptible)
  		r = dma_resv_lock_interruptible(busy_bo->base.resv,
  							  ticket);
  	else
  		r = dma_resv_lock(busy_bo->base.resv, ticket);
  
  	/*
  	 * TODO: It would be better to keep the BO locked until allocation is at
  	 * least tried one more time, but that would mean a much larger rework
  	 * of TTM.
  	 */
  	if (!r)
  		dma_resv_unlock(busy_bo->base.resv);
  
  	return r == -EDEADLK ? -EBUSY : r;
  }
  
  static int ttm_mem_evict_first(struct ttm_bo_device *bdev,
  			       uint32_t mem_type,
  			       const struct ttm_place *place,
  			       struct ttm_operation_ctx *ctx,
  			       struct ww_acquire_ctx *ticket)
  {
  	struct ttm_buffer_object *bo = NULL, *busy_bo = NULL;
  	struct ttm_mem_type_manager *man = &bdev->man[mem_type];
  	bool locked = false;
  	unsigned i;
  	int ret;
  
  	spin_lock(&ttm_bo_glob.lru_lock);
  	for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
  		list_for_each_entry(bo, &man->lru[i], lru) {
  			bool busy;
  
  			if (!ttm_bo_evict_swapout_allowable(bo, ctx, &locked,
  							    &busy)) {
  				if (busy && !busy_bo && ticket !=
  				    dma_resv_locking_ctx(bo->base.resv))
  					busy_bo = bo;
  				continue;
  			}
  
  			if (place && !bdev->driver->eviction_valuable(bo,
  								      place)) {
  				if (locked)
  					dma_resv_unlock(bo->base.resv);
  				continue;
  			}
  			if (!ttm_bo_get_unless_zero(bo)) {
  				if (locked)
  					dma_resv_unlock(bo->base.resv);
  				continue;
  			}
  			break;
  		}
  
  		/* If the inner loop terminated early, we have our candidate */
  		if (&bo->lru != &man->lru[i])
  			break;
  
  		bo = NULL;
  	}
  
  	if (!bo) {
  		if (busy_bo && !ttm_bo_get_unless_zero(busy_bo))
  			busy_bo = NULL;
  		spin_unlock(&ttm_bo_glob.lru_lock);
  		ret = ttm_mem_evict_wait_busy(busy_bo, ctx, ticket);
  		if (busy_bo)
  			ttm_bo_put(busy_bo);
  		return ret;
  	}
  
  	if (bo->deleted) {
  		ret = ttm_bo_cleanup_refs(bo, ctx->interruptible,
  					  ctx->no_wait_gpu, locked);
  		ttm_bo_put(bo);
  		return ret;
  	}
  
  	spin_unlock(&ttm_bo_glob.lru_lock);
  
  	ret = ttm_bo_evict(bo, ctx);
  	if (locked)
  		ttm_bo_unreserve(bo);
  
  	ttm_bo_put(bo);
  	return ret;
  }
  
  void ttm_bo_mem_put(struct ttm_buffer_object *bo, struct ttm_mem_reg *mem)
  {
  	struct ttm_mem_type_manager *man = &bo->bdev->man[mem->mem_type];
  
  	if (mem->mm_node)
  		(*man->func->put_node)(man, mem);
  }
  EXPORT_SYMBOL(ttm_bo_mem_put);
  
  /**
   * Add the last move fence to the BO and reserve a new shared slot.
   */
  static int ttm_bo_add_move_fence(struct ttm_buffer_object *bo,
  				 struct ttm_mem_type_manager *man,
  				 struct ttm_mem_reg *mem,
  				 bool no_wait_gpu)
  {
  	struct dma_fence *fence;
  	int ret;
  
  	spin_lock(&man->move_lock);
  	fence = dma_fence_get(man->move);
  	spin_unlock(&man->move_lock);
  
  	if (!fence)
  		return 0;
  
  	if (no_wait_gpu) {
  		dma_fence_put(fence);
  		return -EBUSY;
  	}
  
  	dma_resv_add_shared_fence(bo->base.resv, fence);
  
  	ret = dma_resv_reserve_shared(bo->base.resv, 1);
  	if (unlikely(ret)) {
  		dma_fence_put(fence);
  		return ret;
  	}
  
  	dma_fence_put(bo->moving);
  	bo->moving = fence;
  	return 0;
  }
  
  /**
   * Repeatedly evict memory from the LRU for @mem_type until we create enough
   * space, or we've evicted everything and there isn't enough space.
   */
  static int ttm_bo_mem_force_space(struct ttm_buffer_object *bo,
  				  const struct ttm_place *place,
  				  struct ttm_mem_reg *mem,
  				  struct ttm_operation_ctx *ctx)
  {
  	struct ttm_bo_device *bdev = bo->bdev;
  	struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type];
  	struct ww_acquire_ctx *ticket;
  	int ret;
  
  	ticket = dma_resv_locking_ctx(bo->base.resv);
  	do {
  		ret = (*man->func->get_node)(man, bo, place, mem);
  		if (unlikely(ret != 0))
  			return ret;
  		if (mem->mm_node)
  			break;
  		ret = ttm_mem_evict_first(bdev, mem->mem_type, place, ctx,
  					  ticket);
  		if (unlikely(ret != 0))
  			return ret;
  	} while (1);
  
  	return ttm_bo_add_move_fence(bo, man, mem, ctx->no_wait_gpu);
  }
  
  static uint32_t ttm_bo_select_caching(struct ttm_mem_type_manager *man,
  				      uint32_t cur_placement,
  				      uint32_t proposed_placement)
  {
  	uint32_t caching = proposed_placement & TTM_PL_MASK_CACHING;
  	uint32_t result = proposed_placement & ~TTM_PL_MASK_CACHING;
  
  	/**
  	 * Keep current caching if possible.
  	 */
  
  	if ((cur_placement & caching) != 0)
  		result |= (cur_placement & caching);
  	else if ((man->default_caching & caching) != 0)
  		result |= man->default_caching;
  	else if ((TTM_PL_FLAG_CACHED & caching) != 0)
  		result |= TTM_PL_FLAG_CACHED;
  	else if ((TTM_PL_FLAG_WC & caching) != 0)
  		result |= TTM_PL_FLAG_WC;
  	else if ((TTM_PL_FLAG_UNCACHED & caching) != 0)
  		result |= TTM_PL_FLAG_UNCACHED;
  
  	return result;
  }
  
  static bool ttm_bo_mt_compatible(struct ttm_mem_type_manager *man,
  				 uint32_t mem_type,
  				 const struct ttm_place *place,
  				 uint32_t *masked_placement)
  {
  	uint32_t cur_flags = ttm_bo_type_flags(mem_type);
  
  	if ((cur_flags & place->flags & TTM_PL_MASK_MEM) == 0)
  		return false;
  
  	if ((place->flags & man->available_caching) == 0)
  		return false;
  
  	cur_flags |= (place->flags & man->available_caching);
  
  	*masked_placement = cur_flags;
  	return true;
  }
  
  /**
   * ttm_bo_mem_placement - check if placement is compatible
   * @bo: BO to find memory for
   * @place: where to search
   * @mem: the memory object to fill in
   * @ctx: operation context
   *
   * Check if placement is compatible and fill in mem structure.
   * Returns -EBUSY if placement won't work or negative error code.
   * 0 when placement can be used.
   */
  static int ttm_bo_mem_placement(struct ttm_buffer_object *bo,
  				const struct ttm_place *place,
  				struct ttm_mem_reg *mem,
  				struct ttm_operation_ctx *ctx)
  {
  	struct ttm_bo_device *bdev = bo->bdev;
  	uint32_t mem_type = TTM_PL_SYSTEM;
  	struct ttm_mem_type_manager *man;
  	uint32_t cur_flags = 0;
  	int ret;
  
  	ret = ttm_mem_type_from_place(place, &mem_type);
  	if (ret)
  		return ret;
  
  	man = &bdev->man[mem_type];
  	if (!man->has_type || !man->use_type)
  		return -EBUSY;
  
  	if (!ttm_bo_mt_compatible(man, mem_type, place, &cur_flags))
  		return -EBUSY;
  
  	cur_flags = ttm_bo_select_caching(man, bo->mem.placement, cur_flags);
  	/*
  	 * Use the access and other non-mapping-related flag bits from
  	 * the memory placement flags to the current flags
  	 */
  	ttm_flag_masked(&cur_flags, place->flags, ~TTM_PL_MASK_MEMTYPE);
  
  	mem->mem_type = mem_type;
  	mem->placement = cur_flags;
  
  	spin_lock(&ttm_bo_glob.lru_lock);
  	ttm_bo_del_from_lru(bo);
  	ttm_bo_add_mem_to_lru(bo, mem);
  	spin_unlock(&ttm_bo_glob.lru_lock);
  
  	return 0;
  }
  
  /**
   * Creates space for memory region @mem according to its type.
   *
   * This function first searches for free space in compatible memory types in
   * the priority order defined by the driver.  If free space isn't found, then
   * ttm_bo_mem_force_space is attempted in priority order to evict and find
   * space.
   */
  int ttm_bo_mem_space(struct ttm_buffer_object *bo,
  			struct ttm_placement *placement,
  			struct ttm_mem_reg *mem,
  			struct ttm_operation_ctx *ctx)
  {
  	struct ttm_bo_device *bdev = bo->bdev;
  	bool type_found = false;
  	int i, ret;
  
  	ret = dma_resv_reserve_shared(bo->base.resv, 1);
  	if (unlikely(ret))
  		return ret;
  
  	mem->mm_node = NULL;
  	for (i = 0; i < placement->num_placement; ++i) {
  		const struct ttm_place *place = &placement->placement[i];
  		struct ttm_mem_type_manager *man;
  
  		ret = ttm_bo_mem_placement(bo, place, mem, ctx);
  		if (ret == -EBUSY)
  			continue;
  		if (ret)
  			goto error;
  
  		type_found = true;
  		mem->mm_node = NULL;
  		if (mem->mem_type == TTM_PL_SYSTEM)
  			return 0;
  
  		man = &bdev->man[mem->mem_type];
  		ret = (*man->func->get_node)(man, bo, place, mem);
  		if (unlikely(ret))
  			goto error;
  
  		if (!mem->mm_node)
  			continue;
  
  		ret = ttm_bo_add_move_fence(bo, man, mem, ctx->no_wait_gpu);
  		if (unlikely(ret)) {
  			(*man->func->put_node)(man, mem);
  			if (ret == -EBUSY)
  				continue;
  
  			goto error;
  		}
  		return 0;
  	}
  
  	for (i = 0; i < placement->num_busy_placement; ++i) {
  		const struct ttm_place *place = &placement->busy_placement[i];
  
  		ret = ttm_bo_mem_placement(bo, place, mem, ctx);
  		if (ret == -EBUSY)
  			continue;
  		if (ret)
  			goto error;
  
  		type_found = true;
  		mem->mm_node = NULL;
  		if (mem->mem_type == TTM_PL_SYSTEM)
  			return 0;
  
  		ret = ttm_bo_mem_force_space(bo, place, mem, ctx);
  		if (ret == 0 && mem->mm_node)
  			return 0;
  
  		if (ret && ret != -EBUSY)
  			goto error;
  	}
  
  	ret = -ENOMEM;
  	if (!type_found) {
  		pr_err(TTM_PFX "No compatible memory type found\n");
  		ret = -EINVAL;
  	}
  
  error:
  	if (bo->mem.mem_type == TTM_PL_SYSTEM && !list_empty(&bo->lru)) {
  		spin_lock(&ttm_bo_glob.lru_lock);
  		ttm_bo_move_to_lru_tail(bo, NULL);
  		spin_unlock(&ttm_bo_glob.lru_lock);
  	}
  
  	return ret;
  }
  EXPORT_SYMBOL(ttm_bo_mem_space);
  
  static int ttm_bo_move_buffer(struct ttm_buffer_object *bo,
  			      struct ttm_placement *placement,
  			      struct ttm_operation_ctx *ctx)
  {
  	int ret = 0;
  	struct ttm_mem_reg mem;
  
  	dma_resv_assert_held(bo->base.resv);
  
  	mem.num_pages = bo->num_pages;
  	mem.size = mem.num_pages << PAGE_SHIFT;
  	mem.page_alignment = bo->mem.page_alignment;
  	mem.bus.io_reserved_vm = false;
  	mem.bus.io_reserved_count = 0;
  	/*
  	 * Determine where to move the buffer.
  	 */
  	ret = ttm_bo_mem_space(bo, placement, &mem, ctx);
  	if (ret)
  		goto out_unlock;
  	ret = ttm_bo_handle_move_mem(bo, &mem, false, ctx);
  out_unlock:
  	if (ret && mem.mm_node)
  		ttm_bo_mem_put(bo, &mem);
  	return ret;
  }
  
  static bool ttm_bo_places_compat(const struct ttm_place *places,
  				 unsigned num_placement,
  				 struct ttm_mem_reg *mem,
  				 uint32_t *new_flags)
  {
  	unsigned i;
  
  	for (i = 0; i < num_placement; i++) {
  		const struct ttm_place *heap = &places[i];
  
  		if (mem->mm_node && (mem->start < heap->fpfn ||
  		     (heap->lpfn != 0 && (mem->start + mem->num_pages) > heap->lpfn)))
  			continue;
  
  		*new_flags = heap->flags;
  		if ((*new_flags & mem->placement & TTM_PL_MASK_CACHING) &&
  		    (*new_flags & mem->placement & TTM_PL_MASK_MEM) &&
  		    (!(*new_flags & TTM_PL_FLAG_CONTIGUOUS) ||
  		     (mem->placement & TTM_PL_FLAG_CONTIGUOUS)))
  			return true;
  	}
  	return false;
  }
  
  bool ttm_bo_mem_compat(struct ttm_placement *placement,
  		       struct ttm_mem_reg *mem,
  		       uint32_t *new_flags)
  {
  	if (ttm_bo_places_compat(placement->placement, placement->num_placement,
  				 mem, new_flags))
  		return true;
  
  	if ((placement->busy_placement != placement->placement ||
  	     placement->num_busy_placement > placement->num_placement) &&
  	    ttm_bo_places_compat(placement->busy_placement,
  				 placement->num_busy_placement,
  				 mem, new_flags))
  		return true;
  
  	return false;
  }
  EXPORT_SYMBOL(ttm_bo_mem_compat);
  
  int ttm_bo_validate(struct ttm_buffer_object *bo,
  		    struct ttm_placement *placement,
  		    struct ttm_operation_ctx *ctx)
  {
  	int ret;
  	uint32_t new_flags;
  
  	dma_resv_assert_held(bo->base.resv);
  
  	/*
  	 * Remove the backing store if no placement is given.
  	 */
  	if (!placement->num_placement && !placement->num_busy_placement) {
  		ret = ttm_bo_pipeline_gutting(bo);
  		if (ret)
  			return ret;
  
  		return ttm_tt_create(bo, false);
  	}
  
  	/*
  	 * Check whether we need to move buffer.
  	 */
  	if (!ttm_bo_mem_compat(placement, &bo->mem, &new_flags)) {
  		ret = ttm_bo_move_buffer(bo, placement, ctx);
  		if (ret)
  			return ret;
  	} else {
  		/*
  		 * Use the access and other non-mapping-related flag bits from
  		 * the compatible memory placement flags to the active flags
  		 */
  		ttm_flag_masked(&bo->mem.placement, new_flags,
  				~TTM_PL_MASK_MEMTYPE);
  	}
  	/*
  	 * We might need to add a TTM.
  	 */
  	if (bo->mem.mem_type == TTM_PL_SYSTEM && bo->ttm == NULL) {
  		ret = ttm_tt_create(bo, true);
  		if (ret)
  			return ret;
  	}
  	return 0;
  }
  EXPORT_SYMBOL(ttm_bo_validate);
  
  int ttm_bo_init_reserved(struct ttm_bo_device *bdev,
  			 struct ttm_buffer_object *bo,
  			 unsigned long size,
  			 enum ttm_bo_type type,
  			 struct ttm_placement *placement,
  			 uint32_t page_alignment,
  			 struct ttm_operation_ctx *ctx,
  			 size_t acc_size,
  			 struct sg_table *sg,
  			 struct dma_resv *resv,
  			 void (*destroy) (struct ttm_buffer_object *))
  {
  	struct ttm_mem_global *mem_glob = &ttm_mem_glob;
  	int ret = 0;
  	unsigned long num_pages;
  	bool locked;
  
  	ret = ttm_mem_global_alloc(mem_glob, acc_size, ctx);
  	if (ret) {
  		pr_err("Out of kernel memory\n");
  		if (destroy)
  			(*destroy)(bo);
  		else
  			kfree(bo);
  		return -ENOMEM;
  	}
  
  	num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
  	if (num_pages == 0) {
  		pr_err("Illegal buffer object size\n");
  		if (destroy)
  			(*destroy)(bo);
  		else
  			kfree(bo);
  		ttm_mem_global_free(mem_glob, acc_size);
  		return -EINVAL;
  	}
  	bo->destroy = destroy ? destroy : ttm_bo_default_destroy;
  
  	kref_init(&bo->kref);
  	INIT_LIST_HEAD(&bo->lru);
  	INIT_LIST_HEAD(&bo->ddestroy);
  	INIT_LIST_HEAD(&bo->swap);
  	INIT_LIST_HEAD(&bo->io_reserve_lru);
  	bo->bdev = bdev;
  	bo->type = type;
  	bo->num_pages = num_pages;
  	bo->mem.size = num_pages << PAGE_SHIFT;
  	bo->mem.mem_type = TTM_PL_SYSTEM;
  	bo->mem.num_pages = bo->num_pages;
  	bo->mem.mm_node = NULL;
  	bo->mem.page_alignment = page_alignment;
  	bo->mem.bus.io_reserved_vm = false;
  	bo->mem.bus.io_reserved_count = 0;
  	bo->moving = NULL;
  	bo->mem.placement = (TTM_PL_FLAG_SYSTEM | TTM_PL_FLAG_CACHED);
  	bo->acc_size = acc_size;
  	bo->sg = sg;
  	if (resv) {
  		bo->base.resv = resv;
  		dma_resv_assert_held(bo->base.resv);
  	} else {
  		bo->base.resv = &bo->base._resv;
  	}
  	if (!ttm_bo_uses_embedded_gem_object(bo)) {
  		/*
  		 * bo.gem is not initialized, so we have to setup the
  		 * struct elements we want use regardless.
  		 */
  		dma_resv_init(&bo->base._resv);
  		drm_vma_node_reset(&bo->base.vma_node);
  	}
  	atomic_inc(&ttm_bo_glob.bo_count);
  
  	/*
  	 * For ttm_bo_type_device buffers, allocate
  	 * address space from the device.
  	 */
  	if (bo->type == ttm_bo_type_device ||
  	    bo->type == ttm_bo_type_sg)
  		ret = drm_vma_offset_add(bdev->vma_manager, &bo->base.vma_node,
  					 bo->mem.num_pages);
  
  	/* passed reservation objects should already be locked,
  	 * since otherwise lockdep will be angered in radeon.
  	 */
  	if (!resv) {
  		locked = dma_resv_trylock(bo->base.resv);
  		WARN_ON(!locked);
  	}
  
  	if (likely(!ret))
  		ret = ttm_bo_validate(bo, placement, ctx);
  
  	if (unlikely(ret)) {
  		if (!resv)
  			ttm_bo_unreserve(bo);
  
  		ttm_bo_put(bo);
  		return ret;
  	}
  
  	spin_lock(&ttm_bo_glob.lru_lock);
  	ttm_bo_move_to_lru_tail(bo, NULL);
  	spin_unlock(&ttm_bo_glob.lru_lock);
  
  	return ret;
  }
  EXPORT_SYMBOL(ttm_bo_init_reserved);
  
  int ttm_bo_init(struct ttm_bo_device *bdev,
  		struct ttm_buffer_object *bo,
  		unsigned long size,
  		enum ttm_bo_type type,
  		struct ttm_placement *placement,
  		uint32_t page_alignment,
  		bool interruptible,
  		size_t acc_size,
  		struct sg_table *sg,
  		struct dma_resv *resv,
  		void (*destroy) (struct ttm_buffer_object *))
  {
  	struct ttm_operation_ctx ctx = { interruptible, false };
  	int ret;
  
  	ret = ttm_bo_init_reserved(bdev, bo, size, type, placement,
  				   page_alignment, &ctx, acc_size,
  				   sg, resv, destroy);
  	if (ret)
  		return ret;
  
  	if (!resv)
  		ttm_bo_unreserve(bo);
  
  	return 0;
  }
  EXPORT_SYMBOL(ttm_bo_init);
  
  size_t ttm_bo_acc_size(struct ttm_bo_device *bdev,
  		       unsigned long bo_size,
  		       unsigned struct_size)
  {
  	unsigned npages = (PAGE_ALIGN(bo_size)) >> PAGE_SHIFT;
  	size_t size = 0;
  
  	size += ttm_round_pot(struct_size);
  	size += ttm_round_pot(npages * sizeof(void *));
  	size += ttm_round_pot(sizeof(struct ttm_tt));
  	return size;
  }
  EXPORT_SYMBOL(ttm_bo_acc_size);
  
  size_t ttm_bo_dma_acc_size(struct ttm_bo_device *bdev,
  			   unsigned long bo_size,
  			   unsigned struct_size)
  {
  	unsigned npages = (PAGE_ALIGN(bo_size)) >> PAGE_SHIFT;
  	size_t size = 0;
  
  	size += ttm_round_pot(struct_size);
  	size += ttm_round_pot(npages * (2*sizeof(void *) + sizeof(dma_addr_t)));
  	size += ttm_round_pot(sizeof(struct ttm_dma_tt));
  	return size;
  }
  EXPORT_SYMBOL(ttm_bo_dma_acc_size);
  
  int ttm_bo_create(struct ttm_bo_device *bdev,
  			unsigned long size,
  			enum ttm_bo_type type,
  			struct ttm_placement *placement,
  			uint32_t page_alignment,
  			bool interruptible,
  			struct ttm_buffer_object **p_bo)
  {
  	struct ttm_buffer_object *bo;
  	size_t acc_size;
  	int ret;
  
  	bo = kzalloc(sizeof(*bo), GFP_KERNEL);
  	if (unlikely(bo == NULL))
  		return -ENOMEM;
  
  	acc_size = ttm_bo_acc_size(bdev, size, sizeof(struct ttm_buffer_object));
  	ret = ttm_bo_init(bdev, bo, size, type, placement, page_alignment,
  			  interruptible, acc_size,
  			  NULL, NULL, NULL);
  	if (likely(ret == 0))
  		*p_bo = bo;
  
  	return ret;
  }
  EXPORT_SYMBOL(ttm_bo_create);
  
  static int ttm_bo_force_list_clean(struct ttm_bo_device *bdev,
  				   unsigned mem_type)
  {
  	struct ttm_operation_ctx ctx = {
  		.interruptible = false,
  		.no_wait_gpu = false,
  		.flags = TTM_OPT_FLAG_FORCE_ALLOC
  	};
  	struct ttm_mem_type_manager *man = &bdev->man[mem_type];
  	struct ttm_bo_global *glob = &ttm_bo_glob;
  	struct dma_fence *fence;
  	int ret;
  	unsigned i;
  
  	/*
  	 * Can't use standard list traversal since we're unlocking.
  	 */
  
  	spin_lock(&glob->lru_lock);
  	for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
  		while (!list_empty(&man->lru[i])) {
  			spin_unlock(&glob->lru_lock);
  			ret = ttm_mem_evict_first(bdev, mem_type, NULL, &ctx,
  						  NULL);
  			if (ret)
  				return ret;
  			spin_lock(&glob->lru_lock);
  		}
  	}
  	spin_unlock(&glob->lru_lock);
  
  	spin_lock(&man->move_lock);
  	fence = dma_fence_get(man->move);
  	spin_unlock(&man->move_lock);
  
  	if (fence) {
  		ret = dma_fence_wait(fence, false);
  		dma_fence_put(fence);
  		if (ret)
  			return ret;
  	}
  
  	return 0;
  }
  
  int ttm_bo_clean_mm(struct ttm_bo_device *bdev, unsigned mem_type)
  {
  	struct ttm_mem_type_manager *man;
  	int ret = -EINVAL;
  
  	if (mem_type >= TTM_NUM_MEM_TYPES) {
  		pr_err("Illegal memory type %d\n", mem_type);
  		return ret;
  	}
  	man = &bdev->man[mem_type];
  
  	if (!man->has_type) {
  		pr_err("Trying to take down uninitialized memory manager type %u\n",
  		       mem_type);
  		return ret;
  	}
  
  	man->use_type = false;
  	man->has_type = false;
  
  	ret = 0;
  	if (mem_type > 0) {
  		ret = ttm_bo_force_list_clean(bdev, mem_type);
  		if (ret) {
  			pr_err("Cleanup eviction failed\n");
  			return ret;
  		}
  
  		ret = (*man->func->takedown)(man);
  	}
  
  	dma_fence_put(man->move);
  	man->move = NULL;
  
  	return ret;
  }
  EXPORT_SYMBOL(ttm_bo_clean_mm);
  
  int ttm_bo_evict_mm(struct ttm_bo_device *bdev, unsigned mem_type)
  {
  	struct ttm_mem_type_manager *man = &bdev->man[mem_type];
  
  	if (mem_type == 0 || mem_type >= TTM_NUM_MEM_TYPES) {
  		pr_err("Illegal memory manager memory type %u\n", mem_type);
  		return -EINVAL;
  	}
  
  	if (!man->has_type) {
  		pr_err("Memory type %u has not been initialized\n", mem_type);
  		return 0;
  	}
  
  	return ttm_bo_force_list_clean(bdev, mem_type);
  }
  EXPORT_SYMBOL(ttm_bo_evict_mm);
  
  int ttm_bo_init_mm(struct ttm_bo_device *bdev, unsigned type,
  			unsigned long p_size)
  {
  	int ret;
  	struct ttm_mem_type_manager *man;
  	unsigned i;
  
  	BUG_ON(type >= TTM_NUM_MEM_TYPES);
  	man = &bdev->man[type];
  	BUG_ON(man->has_type);
  	man->io_reserve_fastpath = true;
  	man->use_io_reserve_lru = false;
  	mutex_init(&man->io_reserve_mutex);
  	spin_lock_init(&man->move_lock);
  	INIT_LIST_HEAD(&man->io_reserve_lru);
  
  	ret = bdev->driver->init_mem_type(bdev, type, man);
  	if (ret)
  		return ret;
  	man->bdev = bdev;
  
  	if (type != TTM_PL_SYSTEM) {
  		ret = (*man->func->init)(man, p_size);
  		if (ret)
  			return ret;
  	}
  	man->has_type = true;
  	man->use_type = true;
  	man->size = p_size;
  
  	for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i)
  		INIT_LIST_HEAD(&man->lru[i]);
  	man->move = NULL;
  
  	return 0;
  }
  EXPORT_SYMBOL(ttm_bo_init_mm);
  
  static void ttm_bo_global_kobj_release(struct kobject *kobj)
  {
  	struct ttm_bo_global *glob =
  		container_of(kobj, struct ttm_bo_global, kobj);
  
  	__free_page(glob->dummy_read_page);
  }
  
  static void ttm_bo_global_release(void)
  {
  	struct ttm_bo_global *glob = &ttm_bo_glob;
  
  	mutex_lock(&ttm_global_mutex);
  	if (--ttm_bo_glob_use_count > 0)
  		goto out;
  
  	kobject_del(&glob->kobj);
  	kobject_put(&glob->kobj);
  	ttm_mem_global_release(&ttm_mem_glob);
  	memset(glob, 0, sizeof(*glob));
  out:
  	mutex_unlock(&ttm_global_mutex);
  }
  
  static int ttm_bo_global_init(void)
  {
  	struct ttm_bo_global *glob = &ttm_bo_glob;
  	int ret = 0;
  	unsigned i;
  
  	mutex_lock(&ttm_global_mutex);
  	if (++ttm_bo_glob_use_count > 1)
  		goto out;
  
  	ret = ttm_mem_global_init(&ttm_mem_glob);
  	if (ret)
  		goto out;
  
  	spin_lock_init(&glob->lru_lock);
  	glob->dummy_read_page = alloc_page(__GFP_ZERO | GFP_DMA32);
  
  	if (unlikely(glob->dummy_read_page == NULL)) {
  		ret = -ENOMEM;
  		goto out;
  	}
  
  	for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i)
  		INIT_LIST_HEAD(&glob->swap_lru[i]);
  	INIT_LIST_HEAD(&glob->device_list);
  	atomic_set(&glob->bo_count, 0);
  
  	ret = kobject_init_and_add(
  		&glob->kobj, &ttm_bo_glob_kobj_type, ttm_get_kobj(), "buffer_objects");
  	if (unlikely(ret != 0))
  		kobject_put(&glob->kobj);
  out:
  	mutex_unlock(&ttm_global_mutex);
  	return ret;
  }
  
  int ttm_bo_device_release(struct ttm_bo_device *bdev)
  {
  	struct ttm_bo_global *glob = &ttm_bo_glob;
  	int ret = 0;
  	unsigned i = TTM_NUM_MEM_TYPES;
  	struct ttm_mem_type_manager *man;
  
  	while (i--) {
  		man = &bdev->man[i];
  		if (man->has_type) {
  			man->use_type = false;
  			if ((i != TTM_PL_SYSTEM) && ttm_bo_clean_mm(bdev, i)) {
  				ret = -EBUSY;
  				pr_err("DRM memory manager type %d is not clean\n",
  				       i);
  			}
  			man->has_type = false;
  		}
  	}
  
  	mutex_lock(&ttm_global_mutex);
  	list_del(&bdev->device_list);
  	mutex_unlock(&ttm_global_mutex);
  
  	cancel_delayed_work_sync(&bdev->wq);
  
  	if (ttm_bo_delayed_delete(bdev, true))
  		pr_debug("Delayed destroy list was clean\n");
  
  	spin_lock(&glob->lru_lock);
  	for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i)
  		if (list_empty(&bdev->man[0].lru[0]))
  			pr_debug("Swap list %d was clean\n", i);
  	spin_unlock(&glob->lru_lock);
  
  	if (!ret)
  		ttm_bo_global_release();
  
  	return ret;
  }
  EXPORT_SYMBOL(ttm_bo_device_release);
  
  int ttm_bo_device_init(struct ttm_bo_device *bdev,
  		       struct ttm_bo_driver *driver,
  		       struct address_space *mapping,
  		       struct drm_vma_offset_manager *vma_manager,
  		       bool need_dma32)
  {
  	struct ttm_bo_global *glob = &ttm_bo_glob;
  	int ret;
  
  	if (WARN_ON(vma_manager == NULL))
  		return -EINVAL;
  
  	ret = ttm_bo_global_init();
  	if (ret)
  		return ret;
  
  	bdev->driver = driver;
  
  	memset(bdev->man, 0, sizeof(bdev->man));
  
  	/*
  	 * Initialize the system memory buffer type.
  	 * Other types need to be driver / IOCTL initialized.
  	 */
  	ret = ttm_bo_init_mm(bdev, TTM_PL_SYSTEM, 0);
  	if (unlikely(ret != 0))
  		goto out_no_sys;
  
  	bdev->vma_manager = vma_manager;
  	INIT_DELAYED_WORK(&bdev->wq, ttm_bo_delayed_workqueue);
  	INIT_LIST_HEAD(&bdev->ddestroy);
  	bdev->dev_mapping = mapping;
  	bdev->need_dma32 = need_dma32;
  	mutex_lock(&ttm_global_mutex);
  	list_add_tail(&bdev->device_list, &glob->device_list);
  	mutex_unlock(&ttm_global_mutex);
  
  	return 0;
  out_no_sys:
  	ttm_bo_global_release();
  	return ret;
  }
  EXPORT_SYMBOL(ttm_bo_device_init);
  
  /*
   * buffer object vm functions.
   */
  
  bool ttm_mem_reg_is_pci(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem)
  {
  	struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type];
  
  	if (!(man->flags & TTM_MEMTYPE_FLAG_FIXED)) {
  		if (mem->mem_type == TTM_PL_SYSTEM)
  			return false;
  
  		if (man->flags & TTM_MEMTYPE_FLAG_CMA)
  			return false;
  
  		if (mem->placement & TTM_PL_FLAG_CACHED)
  			return false;
  	}
  	return true;
  }
  
  void ttm_bo_unmap_virtual_locked(struct ttm_buffer_object *bo)
  {
  	struct ttm_bo_device *bdev = bo->bdev;
  
  	drm_vma_node_unmap(&bo->base.vma_node, bdev->dev_mapping);
  	ttm_mem_io_free_vm(bo);
  }
  
  void ttm_bo_unmap_virtual(struct ttm_buffer_object *bo)
  {
  	struct ttm_bo_device *bdev = bo->bdev;
  	struct ttm_mem_type_manager *man = &bdev->man[bo->mem.mem_type];
  
  	ttm_mem_io_lock(man, false);
  	ttm_bo_unmap_virtual_locked(bo);
  	ttm_mem_io_unlock(man);
  }
  
  
  EXPORT_SYMBOL(ttm_bo_unmap_virtual);
  
  int ttm_bo_wait(struct ttm_buffer_object *bo,
  		bool interruptible, bool no_wait)
  {
  	long timeout = 15 * HZ;
  
  	if (no_wait) {
  		if (dma_resv_test_signaled_rcu(bo->base.resv, true))
  			return 0;
  		else
  			return -EBUSY;
  	}
  
  	timeout = dma_resv_wait_timeout_rcu(bo->base.resv, true,
  						      interruptible, timeout);
  	if (timeout < 0)
  		return timeout;
  
  	if (timeout == 0)
  		return -EBUSY;
  
  	dma_resv_add_excl_fence(bo->base.resv, NULL);
  	return 0;
  }
  EXPORT_SYMBOL(ttm_bo_wait);
  
  /**
   * A buffer object shrink method that tries to swap out the first
   * buffer object on the bo_global::swap_lru list.
   */
  int ttm_bo_swapout(struct ttm_bo_global *glob, struct ttm_operation_ctx *ctx)
  {
  	struct ttm_buffer_object *bo;
  	int ret = -EBUSY;
  	bool locked;
  	unsigned i;
  
  	spin_lock(&glob->lru_lock);
  	for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
  		list_for_each_entry(bo, &glob->swap_lru[i], swap) {
  			if (!ttm_bo_evict_swapout_allowable(bo, ctx, &locked,
  							    NULL))
  				continue;
  
  			if (!ttm_bo_get_unless_zero(bo)) {
  				if (locked)
  					dma_resv_unlock(bo->base.resv);
  				continue;
  			}
  
  			ret = 0;
  			break;
  		}
  		if (!ret)
  			break;
  	}
  
  	if (ret) {
  		spin_unlock(&glob->lru_lock);
  		return ret;
  	}
  
  	if (bo->deleted) {
  		ret = ttm_bo_cleanup_refs(bo, false, false, locked);
  		ttm_bo_put(bo);
  		return ret;
  	}
  
  	ttm_bo_del_from_lru(bo);
  	spin_unlock(&glob->lru_lock);
  
  	/**
  	 * Move to system cached
  	 */
  
  	if (bo->mem.mem_type != TTM_PL_SYSTEM ||
  	    bo->ttm->caching_state != tt_cached) {
  		struct ttm_operation_ctx ctx = { false, false };
  		struct ttm_mem_reg evict_mem;
  
  		evict_mem = bo->mem;
  		evict_mem.mm_node = NULL;
  		evict_mem.placement = TTM_PL_FLAG_SYSTEM | TTM_PL_FLAG_CACHED;
  		evict_mem.mem_type = TTM_PL_SYSTEM;
  
  		ret = ttm_bo_handle_move_mem(bo, &evict_mem, true, &ctx);
  		if (unlikely(ret != 0))
  			goto out;
  	}
  
  	/**
  	 * Make sure BO is idle.
  	 */
  
  	ret = ttm_bo_wait(bo, false, false);
  	if (unlikely(ret != 0))
  		goto out;
  
  	ttm_bo_unmap_virtual(bo);
  
  	/**
  	 * Swap out. Buffer will be swapped in again as soon as
  	 * anyone tries to access a ttm page.
  	 */
  
  	if (bo->bdev->driver->swap_notify)
  		bo->bdev->driver->swap_notify(bo);
  
  	ret = ttm_tt_swapout(bo->ttm, bo->persistent_swap_storage);
  out:
  
  	/**
  	 *
  	 * Unreserve without putting on LRU to avoid swapping out an
  	 * already swapped buffer.
  	 */
  	if (locked)
  		dma_resv_unlock(bo->base.resv);
  	ttm_bo_put(bo);
  	return ret;
  }
  EXPORT_SYMBOL(ttm_bo_swapout);
  
  void ttm_bo_swapout_all(struct ttm_bo_device *bdev)
  {
  	struct ttm_operation_ctx ctx = {
  		.interruptible = false,
  		.no_wait_gpu = false
  	};
  
  	while (ttm_bo_swapout(&ttm_bo_glob, &ctx) == 0);
  }
  EXPORT_SYMBOL(ttm_bo_swapout_all);
  