Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1219 insertions, 0 deletions

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
new file mode 100644
index 000000000..db332de13
--- /dev/null
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -0,0 +1,1219 @@
+/* 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_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>
+
+#include "ttm_module.h"
+
+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);
+	struct ttm_resource_manager *man;
+	int i, mem_type;
+
+	drm_printf(&p, "No space for %p (%lu pages, %zuK, %zuM)\n",
+		   bo, bo->resource->num_pages, bo->base.size >> 10,
+		   bo->base.size >> 20);
+	for (i = 0; i < placement->num_placement; i++) {
+		mem_type = placement->placement[i].mem_type;
+		drm_printf(&p, "  placement[%d]=0x%08X (%d)\n",
+			   i, placement->placement[i].flags, mem_type);
+		man = ttm_manager_type(bo->bdev, mem_type);
+		ttm_resource_manager_debug(man, &p);
+	}
+}
+
+/**
+ * ttm_bo_move_to_lru_tail
+ *
+ * @bo: The buffer object.
+ *
+ * Move this BO to the tail of all lru lists used to lookup and reserve an
+ * object. This function must be called with struct ttm_global::lru_lock
+ * held, and is used to make a BO less likely to be considered for eviction.
+ */
+void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo)
+{
+	dma_resv_assert_held(bo->base.resv);
+
+	if (bo->resource)
+		ttm_resource_move_to_lru_tail(bo->resource);
+}
+EXPORT_SYMBOL(ttm_bo_move_to_lru_tail);
+
+/**
+ * ttm_bo_set_bulk_move - update BOs bulk move object
+ *
+ * @bo: The buffer object.
+ *
+ * Update the BOs bulk move object, making sure that resources are added/removed
+ * as well. A bulk move allows to move many resource on the LRU at once,
+ * resulting in much less overhead of maintaining the LRU.
+ * The only requirement is that the resources stay together on the LRU and are
+ * never separated. This is enforces by setting the bulk_move structure on a BO.
+ * ttm_lru_bulk_move_tail() should be used to move all resources to the tail of
+ * their LRU list.
+ */
+void ttm_bo_set_bulk_move(struct ttm_buffer_object *bo,
+			  struct ttm_lru_bulk_move *bulk)
+{
+	dma_resv_assert_held(bo->base.resv);
+
+	if (bo->bulk_move == bulk)
+		return;
+
+	spin_lock(&bo->bdev->lru_lock);
+	if (bo->resource)
+		ttm_resource_del_bulk_move(bo->resource, bo);
+	bo->bulk_move = bulk;
+	if (bo->resource)
+		ttm_resource_add_bulk_move(bo->resource, bo);
+	spin_unlock(&bo->bdev->lru_lock);
+}
+EXPORT_SYMBOL(ttm_bo_set_bulk_move);
+
+static int ttm_bo_handle_move_mem(struct ttm_buffer_object *bo,
+				  struct ttm_resource *mem, bool evict,
+				  struct ttm_operation_ctx *ctx,
+				  struct ttm_place *hop)
+{
+	struct ttm_device *bdev = bo->bdev;
+	bool old_use_tt, new_use_tt;
+	int ret;
+
+	old_use_tt = bo->resource &&
+		ttm_manager_type(bdev, bo->resource->mem_type)->use_tt;
+	new_use_tt = ttm_manager_type(bdev, mem->mem_type)->use_tt;
+
+	ttm_bo_unmap_virtual(bo);
+
+	/*
+	 * Create and bind a ttm if required.
+	 */
+
+	if (new_use_tt) {
+		/* Zero init the new TTM structure if the old location should
+		 * have used one as well.
+		 */
+		ret = ttm_tt_create(bo, old_use_tt);
+		if (ret)
+			goto out_err;
+
+		if (mem->mem_type != TTM_PL_SYSTEM) {
+			ret = ttm_tt_populate(bo->bdev, bo->ttm, ctx);
+			if (ret)
+				goto out_err;
+		}
+	}
+
+	ret = dma_resv_reserve_fences(bo->base.resv, 1);
+	if (ret)
+		goto out_err;
+
+	ret = bdev->funcs->move(bo, evict, ctx, mem, hop);
+	if (ret) {
+		if (ret == -EMULTIHOP)
+			return ret;
+		goto out_err;
+	}
+
+	ctx->bytes_moved += bo->base.size;
+	return 0;
+
+out_err:
+	if (!old_use_tt)
+		ttm_bo_tt_destroy(bo);
+
+	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->funcs->delete_mem_notify)
+		bo->bdev->funcs->delete_mem_notify(bo);
+
+	ttm_bo_tt_destroy(bo);
+	ttm_resource_free(bo, &bo->resource);
+}
+
+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(&bo->bdev->lru_lock);
+		bo->base.resv = &bo->base._resv;
+		spin_unlock(&bo->bdev->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_iter cursor;
+	struct dma_fence *fence;
+
+	dma_resv_iter_begin(&cursor, resv, DMA_RESV_USAGE_BOOKKEEP);
+	dma_resv_for_each_fence_unlocked(&cursor, fence) {
+		if (!fence->ops->signaled)
+			dma_fence_enable_sw_signaling(fence);
+	}
+	dma_resv_iter_end(&cursor);
+}
+
+/**
+ * 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.
+ *
+ * @bo:                    The buffer object to clean-up
+ * @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(resv, DMA_RESV_USAGE_BOOKKEEP))
+		ret = 0;
+	else
+		ret = -EBUSY;
+
+	if (ret && !no_wait_gpu) {
+		long lret;
+
+		if (unlock_resv)
+			dma_resv_unlock(bo->base.resv);
+		spin_unlock(&bo->bdev->lru_lock);
+
+		lret = dma_resv_wait_timeout(resv, DMA_RESV_USAGE_BOOKKEEP,
+					     interruptible,
+					     30 * HZ);
+
+		if (lret < 0)
+			return lret;
+		else if (lret == 0)
+			return -EBUSY;
+
+		spin_lock(&bo->bdev->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(&bo->bdev->lru_lock);
+			return 0;
+		}
+		ret = 0;
+	}
+
+	if (ret || unlikely(list_empty(&bo->ddestroy))) {
+		if (unlock_resv)
+			dma_resv_unlock(bo->base.resv);
+		spin_unlock(&bo->bdev->lru_lock);
+		return ret;
+	}
+
+	list_del_init(&bo->ddestroy);
+	spin_unlock(&bo->bdev->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.
+ */
+bool ttm_bo_delayed_delete(struct ttm_device *bdev, bool remove_all)
+{
+	struct list_head removed;
+	bool empty;
+
+	INIT_LIST_HEAD(&removed);
+
+	spin_lock(&bdev->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(&bdev->lru_lock);
+			dma_resv_lock(bo->base.resv, NULL);
+
+			spin_lock(&bdev->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(&bdev->lru_lock);
+		}
+
+		ttm_bo_put(bo);
+		spin_lock(&bdev->lru_lock);
+	}
+	list_splice_tail(&removed, &bdev->ddestroy);
+	empty = list_empty(&bdev->ddestroy);
+	spin_unlock(&bdev->lru_lock);
+
+	return empty;
+}
+
+static void ttm_bo_release(struct kref *kref)
+{
+	struct ttm_buffer_object *bo =
+	    container_of(kref, struct ttm_buffer_object, kref);
+	struct ttm_device *bdev = bo->bdev;
+	int ret;
+
+	WARN_ON_ONCE(bo->pin_count);
+	WARN_ON_ONCE(bo->bulk_move);
+
+	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(bo->base.resv,
+					      DMA_RESV_USAGE_BOOKKEEP, false,
+					      30 * HZ);
+		}
+
+		if (bo->bdev->funcs->release_notify)
+			bo->bdev->funcs->release_notify(bo);
+
+		drm_vma_offset_remove(bdev->vma_manager, &bo->base.vma_node);
+		ttm_mem_io_free(bdev, bo->resource);
+	}
+
+	if (!dma_resv_test_signaled(bo->base.resv, DMA_RESV_USAGE_BOOKKEEP) ||
+	    !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(&bo->bdev->lru_lock);
+
+		/*
+		 * Make pinned bos immediately available to
+		 * shrinkers, now that they are queued for
+		 * destruction.
+		 *
+		 * FIXME: QXL is triggering this. Can be removed when the
+		 * driver is fixed.
+		 */
+		if (bo->pin_count) {
+			bo->pin_count = 0;
+			ttm_resource_move_to_lru_tail(bo->resource);
+		}
+
+		kref_init(&bo->kref);
+		list_add_tail(&bo->ddestroy, &bdev->ddestroy);
+		spin_unlock(&bo->bdev->lru_lock);
+
+		schedule_delayed_work(&bdev->wq,
+				      ((HZ / 100) < 1) ? 1 : HZ / 100);
+		return;
+	}
+
+	spin_lock(&bo->bdev->lru_lock);
+	list_del(&bo->ddestroy);
+	spin_unlock(&bo->bdev->lru_lock);
+
+	ttm_bo_cleanup_memtype_use(bo);
+	dma_resv_unlock(bo->base.resv);
+
+	atomic_dec(&ttm_glob.bo_count);
+	bo->destroy(bo);
+}
+
+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_device *bdev)
+{
+	return cancel_delayed_work_sync(&bdev->wq);
+}
+EXPORT_SYMBOL(ttm_bo_lock_delayed_workqueue);
+
+void ttm_bo_unlock_delayed_workqueue(struct ttm_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_bounce_temp_buffer(struct ttm_buffer_object *bo,
+				     struct ttm_resource **mem,
+				     struct ttm_operation_ctx *ctx,
+				     struct ttm_place *hop)
+{
+	struct ttm_placement hop_placement;
+	struct ttm_resource *hop_mem;
+	int ret;
+
+	hop_placement.num_placement = hop_placement.num_busy_placement = 1;
+	hop_placement.placement = hop_placement.busy_placement = hop;
+
+	/* find space in the bounce domain */
+	ret = ttm_bo_mem_space(bo, &hop_placement, &hop_mem, ctx);
+	if (ret)
+		return ret;
+	/* move to the bounce domain */
+	ret = ttm_bo_handle_move_mem(bo, hop_mem, false, ctx, NULL);
+	if (ret) {
+		ttm_resource_free(bo, &hop_mem);
+		return ret;
+	}
+	return 0;
+}
+
+static int ttm_bo_evict(struct ttm_buffer_object *bo,
+			struct ttm_operation_ctx *ctx)
+{
+	struct ttm_device *bdev = bo->bdev;
+	struct ttm_resource *evict_mem;
+	struct ttm_placement placement;
+	struct ttm_place hop;
+	int ret = 0;
+
+	memset(&hop, 0, sizeof(hop));
+
+	dma_resv_assert_held(bo->base.resv);
+
+	placement.num_placement = 0;
+	placement.num_busy_placement = 0;
+	bdev->funcs->evict_flags(bo, &placement);
+
+	if (!placement.num_placement && !placement.num_busy_placement) {
+		ret = ttm_bo_wait(bo, true, false);
+		if (ret)
+			return ret;
+
+		/*
+		 * Since we've already synced, this frees backing store
+		 * immediately.
+		 */
+		return ttm_bo_pipeline_gutting(bo);
+	}
+
+	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;
+	}
+
+	do {
+		ret = ttm_bo_handle_move_mem(bo, evict_mem, true, ctx, &hop);
+		if (ret != -EMULTIHOP)
+			break;
+
+		ret = ttm_bo_bounce_temp_buffer(bo, &evict_mem, ctx, &hop);
+	} while (!ret);
+
+	if (ret) {
+		ttm_resource_free(bo, &evict_mem);
+		if (ret != -ERESTARTSYS && ret != -EINTR)
+			pr_err("Buffer eviction failed\n");
+	}
+out:
+	return ret;
+}
+
+bool ttm_bo_eviction_valuable(struct ttm_buffer_object *bo,
+			      const struct ttm_place *place)
+{
+	struct ttm_resource *res = bo->resource;
+	struct ttm_device *bdev = bo->bdev;
+
+	dma_resv_assert_held(bo->base.resv);
+	if (bo->resource->mem_type == TTM_PL_SYSTEM)
+		return true;
+
+	/* Don't evict this BO if it's outside of the
+	 * requested placement range
+	 */
+	return ttm_resource_intersects(bdev, res, place, bo->base.size);
+}
+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,
+					   const struct ttm_place *place,
+					   bool *locked, bool *busy)
+{
+	bool ret = false;
+
+	if (bo->pin_count) {
+		*locked = false;
+		if (busy)
+			*busy = false;
+		return false;
+	}
+
+	if (bo->base.resv == ctx->resv) {
+		dma_resv_assert_held(bo->base.resv);
+		if (ctx->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;
+	}
+
+	if (ret && place && (bo->resource->mem_type != place->mem_type ||
+		!bo->bdev->funcs->eviction_valuable(bo, place))) {
+		ret = false;
+		if (*locked) {
+			dma_resv_unlock(bo->base.resv);
+			*locked = false;
+		}
+	}
+
+	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;
+}
+
+int ttm_mem_evict_first(struct ttm_device *bdev,
+			struct ttm_resource_manager *man,
+			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_resource_cursor cursor;
+	struct ttm_resource *res;
+	bool locked = false;
+	int ret;
+
+	spin_lock(&bdev->lru_lock);
+	ttm_resource_manager_for_each_res(man, &cursor, res) {
+		bool busy;
+
+		if (!ttm_bo_evict_swapout_allowable(res->bo, ctx, place,
+						    &locked, &busy)) {
+			if (busy && !busy_bo && ticket !=
+			    dma_resv_locking_ctx(res->bo->base.resv))
+				busy_bo = res->bo;
+			continue;
+		}
+
+		if (ttm_bo_get_unless_zero(res->bo)) {
+			bo = res->bo;
+			break;
+		}
+		if (locked)
+			dma_resv_unlock(res->bo->base.resv);
+	}
+
+	if (!bo) {
+		if (busy_bo && !ttm_bo_get_unless_zero(busy_bo))
+			busy_bo = NULL;
+		spin_unlock(&bdev->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(&bdev->lru_lock);
+
+	ret = ttm_bo_evict(bo, ctx);
+	if (locked)
+		ttm_bo_unreserve(bo);
+	else
+		ttm_bo_move_to_lru_tail_unlocked(bo);
+
+	ttm_bo_put(bo);
+	return ret;
+}
+
+/**
+ * ttm_bo_pin - Pin the buffer object.
+ * @bo: The buffer object to pin
+ *
+ * Make sure the buffer is not evicted any more during memory pressure.
+ * @bo must be unpinned again by calling ttm_bo_unpin().
+ */
+void ttm_bo_pin(struct ttm_buffer_object *bo)
+{
+	dma_resv_assert_held(bo->base.resv);
+	WARN_ON_ONCE(!kref_read(&bo->kref));
+	spin_lock(&bo->bdev->lru_lock);
+	if (bo->resource)
+		ttm_resource_del_bulk_move(bo->resource, bo);
+	++bo->pin_count;
+	spin_unlock(&bo->bdev->lru_lock);
+}
+EXPORT_SYMBOL(ttm_bo_pin);
+
+/**
+ * ttm_bo_unpin - Unpin the buffer object.
+ * @bo: The buffer object to unpin
+ *
+ * Allows the buffer object to be evicted again during memory pressure.
+ */
+void ttm_bo_unpin(struct ttm_buffer_object *bo)
+{
+	dma_resv_assert_held(bo->base.resv);
+	WARN_ON_ONCE(!kref_read(&bo->kref));
+	if (WARN_ON_ONCE(!bo->pin_count))
+		return;
+
+	spin_lock(&bo->bdev->lru_lock);
+	--bo->pin_count;
+	if (bo->resource)
+		ttm_resource_add_bulk_move(bo->resource, bo);
+	spin_unlock(&bo->bdev->lru_lock);
+}
+EXPORT_SYMBOL(ttm_bo_unpin);
+
+/*
+ * Add the last move fence to the BO as kernel dependency and reserve a new
+ * fence slot.
+ */
+static int ttm_bo_add_move_fence(struct ttm_buffer_object *bo,
+				 struct ttm_resource_manager *man,
+				 struct ttm_resource *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) {
+		ret = dma_fence_is_signaled(fence) ? 0 : -EBUSY;
+		dma_fence_put(fence);
+		return ret;
+	}
+
+	dma_resv_add_fence(bo->base.resv, fence, DMA_RESV_USAGE_KERNEL);
+
+	ret = dma_resv_reserve_fences(bo->base.resv, 1);
+	dma_fence_put(fence);
+	return ret;
+}
+
+/*
+ * 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_resource **mem,
+				  struct ttm_operation_ctx *ctx)
+{
+	struct ttm_device *bdev = bo->bdev;
+	struct ttm_resource_manager *man;
+	struct ww_acquire_ctx *ticket;
+	int ret;
+
+	man = ttm_manager_type(bdev, place->mem_type);
+	ticket = dma_resv_locking_ctx(bo->base.resv);
+	do {
+		ret = ttm_resource_alloc(bo, place, mem);
+		if (likely(!ret))
+			break;
+		if (unlikely(ret != -ENOSPC))
+			return ret;
+		ret = ttm_mem_evict_first(bdev, man, place, ctx,
+					  ticket);
+		if (unlikely(ret != 0))
+			return ret;
+	} while (1);
+
+	return ttm_bo_add_move_fence(bo, man, *mem, ctx->no_wait_gpu);
+}
+
+/*
+ * 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_resource **mem,
+			struct ttm_operation_ctx *ctx)
+{
+	struct ttm_device *bdev = bo->bdev;
+	bool type_found = false;
+	int i, ret;
+
+	ret = dma_resv_reserve_fences(bo->base.resv, 1);
+	if (unlikely(ret))
+		return ret;
+
+	for (i = 0; i < placement->num_placement; ++i) {
+		const struct ttm_place *place = &placement->placement[i];
+		struct ttm_resource_manager *man;
+
+		man = ttm_manager_type(bdev, place->mem_type);
+		if (!man || !ttm_resource_manager_used(man))
+			continue;
+
+		type_found = true;
+		ret = ttm_resource_alloc(bo, place, mem);
+		if (ret == -ENOSPC)
+			continue;
+		if (unlikely(ret))
+			goto error;
+
+		ret = ttm_bo_add_move_fence(bo, man, *mem, ctx->no_wait_gpu);
+		if (unlikely(ret)) {
+			ttm_resource_free(bo, 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];
+		struct ttm_resource_manager *man;
+
+		man = ttm_manager_type(bdev, place->mem_type);
+		if (!man || !ttm_resource_manager_used(man))
+			continue;
+
+		type_found = true;
+		ret = ttm_bo_mem_force_space(bo, place, mem, ctx);
+		if (likely(!ret))
+			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:
+	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)
+{
+	struct ttm_resource *mem;
+	struct ttm_place hop;
+	int ret;
+
+	dma_resv_assert_held(bo->base.resv);
+
+	/*
+	 * Determine where to move the buffer.
+	 *
+	 * If driver determines move is going to need
+	 * an extra step then it will return -EMULTIHOP
+	 * and the buffer will be moved to the temporary
+	 * stop and the driver will be called to make
+	 * the second hop.
+	 */
+	ret = ttm_bo_mem_space(bo, placement, &mem, ctx);
+	if (ret)
+		return ret;
+bounce:
+	ret = ttm_bo_handle_move_mem(bo, mem, false, ctx, &hop);
+	if (ret == -EMULTIHOP) {
+		ret = ttm_bo_bounce_temp_buffer(bo, &mem, ctx, &hop);
+		if (ret)
+			goto out;
+		/* try and move to final place now. */
+		goto bounce;
+	}
+out:
+	if (ret)
+		ttm_resource_free(bo, &mem);
+	return ret;
+}
+
+int ttm_bo_validate(struct ttm_buffer_object *bo,
+		    struct ttm_placement *placement,
+		    struct ttm_operation_ctx *ctx)
+{
+	int ret;
+
+	dma_resv_assert_held(bo->base.resv);
+
+	/*
+	 * Remove the backing store if no placement is given.
+	 */
+	if (!placement->num_placement && !placement->num_busy_placement)
+		return ttm_bo_pipeline_gutting(bo);
+
+	/*
+	 * Check whether we need to move buffer.
+	 */
+	if (!bo->resource || !ttm_resource_compat(bo->resource, placement)) {
+		ret = ttm_bo_move_buffer(bo, placement, ctx);
+		if (ret)
+			return ret;
+	}
+	/*
+	 * We might need to add a TTM.
+	 */
+	if (!bo->resource || bo->resource->mem_type == TTM_PL_SYSTEM) {
+		ret = ttm_tt_create(bo, true);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+EXPORT_SYMBOL(ttm_bo_validate);
+
+/**
+ * ttm_bo_init_reserved
+ *
+ * @bdev: Pointer to a ttm_device struct.
+ * @bo: Pointer to a ttm_buffer_object to be initialized.
+ * @type: Requested type of buffer object.
+ * @placement: Initial placement for buffer object.
+ * @alignment: Data alignment in pages.
+ * @ctx: TTM operation context for memory allocation.
+ * @sg: Scatter-gather table.
+ * @resv: Pointer to a dma_resv, or NULL to let ttm allocate one.
+ * @destroy: Destroy function. Use NULL for kfree().
+ *
+ * This function initializes a pre-allocated struct ttm_buffer_object.
+ * As this object may be part of a larger structure, this function,
+ * together with the @destroy function, enables driver-specific objects
+ * derived from a ttm_buffer_object.
+ *
+ * On successful return, the caller owns an object kref to @bo. The kref and
+ * list_kref are usually set to 1, but note that in some situations, other
+ * tasks may already be holding references to @bo as well.
+ * Furthermore, if resv == NULL, the buffer's reservation lock will be held,
+ * and it is the caller's responsibility to call ttm_bo_unreserve.
+ *
+ * If a failure occurs, the function will call the @destroy function. Thus,
+ * after a failure, dereferencing @bo is illegal and will likely cause memory
+ * corruption.
+ *
+ * Returns
+ * -ENOMEM: Out of memory.
+ * -EINVAL: Invalid placement flags.
+ * -ERESTARTSYS: Interrupted by signal while sleeping waiting for resources.
+ */
+int ttm_bo_init_reserved(struct ttm_device *bdev, struct ttm_buffer_object *bo,
+			 enum ttm_bo_type type, struct ttm_placement *placement,
+			 uint32_t alignment, struct ttm_operation_ctx *ctx,
+			 struct sg_table *sg, struct dma_resv *resv,
+			 void (*destroy) (struct ttm_buffer_object *))
+{
+	static const struct ttm_place sys_mem = { .mem_type = TTM_PL_SYSTEM };
+	int ret;
+
+	kref_init(&bo->kref);
+	INIT_LIST_HEAD(&bo->ddestroy);
+	bo->bdev = bdev;
+	bo->type = type;
+	bo->page_alignment = alignment;
+	bo->destroy = destroy;
+	bo->pin_count = 0;
+	bo->sg = sg;
+	bo->bulk_move = NULL;
+	if (resv)
+		bo->base.resv = resv;
+	else
+		bo->base.resv = &bo->base._resv;
+	atomic_inc(&ttm_glob.bo_count);
+
+	ret = ttm_resource_alloc(bo, &sys_mem, &bo->resource);
+	if (unlikely(ret)) {
+		ttm_bo_put(bo);
+		return ret;
+	}
+
+	/*
+	 * 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,
+					 PFN_UP(bo->base.size));
+		if (ret)
+			goto err_put;
+	}
+
+	/* passed reservation objects should already be locked,
+	 * since otherwise lockdep will be angered in radeon.
+	 */
+	if (!resv)
+		WARN_ON(!dma_resv_trylock(bo->base.resv));
+	else
+		dma_resv_assert_held(resv);
+
+	ret = ttm_bo_validate(bo, placement, ctx);
+	if (unlikely(ret))
+		goto err_unlock;
+
+	return 0;
+
+err_unlock:
+	if (!resv)
+		dma_resv_unlock(bo->base.resv);
+
+err_put:
+	ttm_bo_put(bo);
+	return ret;
+}
+EXPORT_SYMBOL(ttm_bo_init_reserved);
+
+/**
+ * ttm_bo_init_validate
+ *
+ * @bdev: Pointer to a ttm_device struct.
+ * @bo: Pointer to a ttm_buffer_object to be initialized.
+ * @type: Requested type of buffer object.
+ * @placement: Initial placement for buffer object.
+ * @alignment: Data alignment in pages.
+ * @interruptible: If needing to sleep to wait for GPU resources,
+ * sleep interruptible.
+ * pinned in physical memory. If this behaviour is not desired, this member
+ * holds a pointer to a persistent shmem object. Typically, this would
+ * point to the shmem object backing a GEM object if TTM is used to back a
+ * GEM user interface.
+ * @sg: Scatter-gather table.
+ * @resv: Pointer to a dma_resv, or NULL to let ttm allocate one.
+ * @destroy: Destroy function. Use NULL for kfree().
+ *
+ * This function initializes a pre-allocated struct ttm_buffer_object.
+ * As this object may be part of a larger structure, this function,
+ * together with the @destroy function,
+ * enables driver-specific objects derived from a ttm_buffer_object.
+ *
+ * On successful return, the caller owns an object kref to @bo. The kref and
+ * list_kref are usually set to 1, but note that in some situations, other
+ * tasks may already be holding references to @bo as well.
+ *
+ * If a failure occurs, the function will call the @destroy function, Thus,
+ * after a failure, dereferencing @bo is illegal and will likely cause memory
+ * corruption.
+ *
+ * Returns
+ * -ENOMEM: Out of memory.
+ * -EINVAL: Invalid placement flags.
+ * -ERESTARTSYS: Interrupted by signal while sleeping waiting for resources.
+ */
+int ttm_bo_init_validate(struct ttm_device *bdev, struct ttm_buffer_object *bo,
+			 enum ttm_bo_type type, struct ttm_placement *placement,
+			 uint32_t alignment, bool interruptible,
+			 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, type, placement, alignment, &ctx,
+				   sg, resv, destroy);
+	if (ret)
+		return ret;
+
+	if (!resv)
+		ttm_bo_unreserve(bo);
+
+	return 0;
+}
+EXPORT_SYMBOL(ttm_bo_init_validate);
+
+/*
+ * buffer object vm functions.
+ */
+
+void ttm_bo_unmap_virtual(struct ttm_buffer_object *bo)
+{
+	struct ttm_device *bdev = bo->bdev;
+
+	drm_vma_node_unmap(&bo->base.vma_node, bdev->dev_mapping);
+	ttm_mem_io_free(bdev, bo->resource);
+}
+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(bo->base.resv, DMA_RESV_USAGE_BOOKKEEP))
+			return 0;
+		else
+			return -EBUSY;
+	}
+
+	timeout = dma_resv_wait_timeout(bo->base.resv, DMA_RESV_USAGE_BOOKKEEP,
+					interruptible, timeout);
+	if (timeout < 0)
+		return timeout;
+
+	if (timeout == 0)
+		return -EBUSY;
+
+	return 0;
+}
+EXPORT_SYMBOL(ttm_bo_wait);
+
+int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
+		   gfp_t gfp_flags)
+{
+	struct ttm_place place;
+	bool locked;
+	int ret;
+
+	/*
+	 * While the bo may already reside in SYSTEM placement, set
+	 * SYSTEM as new placement to cover also the move further below.
+	 * The driver may use the fact that we're moving from SYSTEM
+	 * as an indication that we're about to swap out.
+	 */
+	memset(&place, 0, sizeof(place));
+	place.mem_type = bo->resource->mem_type;
+	if (!ttm_bo_evict_swapout_allowable(bo, ctx, &place, &locked, NULL))
+		return -EBUSY;
+
+	if (!bo->ttm || !ttm_tt_is_populated(bo->ttm) ||
+	    bo->ttm->page_flags & TTM_TT_FLAG_EXTERNAL ||
+	    bo->ttm->page_flags & TTM_TT_FLAG_SWAPPED ||
+	    !ttm_bo_get_unless_zero(bo)) {
+		if (locked)
+			dma_resv_unlock(bo->base.resv);
+		return -EBUSY;
+	}
+
+	if (bo->deleted) {
+		ret = ttm_bo_cleanup_refs(bo, false, false, locked);
+		ttm_bo_put(bo);
+		return ret == -EBUSY ? -ENOSPC : ret;
+	}
+
+	/* TODO: Cleanup the locking */
+	spin_unlock(&bo->bdev->lru_lock);
+
+	/*
+	 * Move to system cached
+	 */
+	if (bo->resource->mem_type != TTM_PL_SYSTEM) {
+		struct ttm_operation_ctx ctx = { false, false };
+		struct ttm_resource *evict_mem;
+		struct ttm_place hop;
+
+		memset(&hop, 0, sizeof(hop));
+		place.mem_type = TTM_PL_SYSTEM;
+		ret = ttm_resource_alloc(bo, &place, &evict_mem);
+		if (unlikely(ret))
+			goto out;
+
+		ret = ttm_bo_handle_move_mem(bo, evict_mem, true, &ctx, &hop);
+		if (unlikely(ret != 0)) {
+			WARN(ret == -EMULTIHOP, "Unexpected multihop in swaput - likely driver bug.\n");
+			ttm_resource_free(bo, &evict_mem);
+			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->funcs->swap_notify)
+		bo->bdev->funcs->swap_notify(bo);
+
+	if (ttm_tt_is_populated(bo->ttm))
+		ret = ttm_tt_swapout(bo->bdev, bo->ttm, gfp_flags);
+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 == -EBUSY ? -ENOSPC : ret;
+}
+
+void ttm_bo_tt_destroy(struct ttm_buffer_object *bo)
+{
+	if (bo->ttm == NULL)
+		return;
+
+	ttm_tt_unpopulate(bo->bdev, bo->ttm);
+	ttm_tt_destroy(bo->bdev, bo->ttm);
+	bo->ttm = NULL;
+}