Adding upstream version 6.1.76.upstream/6.1.76

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

1 files changed, 1041 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
new file mode 100644
index 000000000..8257f9d4f
--- /dev/null
+++ b/drivers/gpu/drm/drm_mm.c
@@ -0,0 +1,1041 @@
+/**************************************************************************
+ *
+ * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., USA.
+ * Copyright 2016 Intel Corporation
+ * 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.
+ *
+ *
+ **************************************************************************/
+
+/*
+ * Generic simple memory manager implementation. Intended to be used as a base
+ * class implementation for more advanced memory managers.
+ *
+ * Note that the algorithm used is quite simple and there might be substantial
+ * performance gains if a smarter free list is implemented. Currently it is
+ * just an unordered stack of free regions. This could easily be improved if
+ * an RB-tree is used instead. At least if we expect heavy fragmentation.
+ *
+ * Aligned allocations can also see improvement.
+ *
+ * Authors:
+ * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
+ */
+
+#include <linux/export.h>
+#include <linux/interval_tree_generic.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/stacktrace.h>
+
+#include <drm/drm_mm.h>
+
+/**
+ * DOC: Overview
+ *
+ * drm_mm provides a simple range allocator. The drivers are free to use the
+ * resource allocator from the linux core if it suits them, the upside of drm_mm
+ * is that it's in the DRM core. Which means that it's easier to extend for
+ * some of the crazier special purpose needs of gpus.
+ *
+ * The main data struct is &drm_mm, allocations are tracked in &drm_mm_node.
+ * Drivers are free to embed either of them into their own suitable
+ * datastructures. drm_mm itself will not do any memory allocations of its own,
+ * so if drivers choose not to embed nodes they need to still allocate them
+ * themselves.
+ *
+ * The range allocator also supports reservation of preallocated blocks. This is
+ * useful for taking over initial mode setting configurations from the firmware,
+ * where an object needs to be created which exactly matches the firmware's
+ * scanout target. As long as the range is still free it can be inserted anytime
+ * after the allocator is initialized, which helps with avoiding looped
+ * dependencies in the driver load sequence.
+ *
+ * drm_mm maintains a stack of most recently freed holes, which of all
+ * simplistic datastructures seems to be a fairly decent approach to clustering
+ * allocations and avoiding too much fragmentation. This means free space
+ * searches are O(num_holes). Given that all the fancy features drm_mm supports
+ * something better would be fairly complex and since gfx thrashing is a fairly
+ * steep cliff not a real concern. Removing a node again is O(1).
+ *
+ * drm_mm supports a few features: Alignment and range restrictions can be
+ * supplied. Furthermore every &drm_mm_node has a color value (which is just an
+ * opaque unsigned long) which in conjunction with a driver callback can be used
+ * to implement sophisticated placement restrictions. The i915 DRM driver uses
+ * this to implement guard pages between incompatible caching domains in the
+ * graphics TT.
+ *
+ * Two behaviors are supported for searching and allocating: bottom-up and
+ * top-down. The default is bottom-up. Top-down allocation can be used if the
+ * memory area has different restrictions, or just to reduce fragmentation.
+ *
+ * Finally iteration helpers to walk all nodes and all holes are provided as are
+ * some basic allocator dumpers for debugging.
+ *
+ * Note that this range allocator is not thread-safe, drivers need to protect
+ * modifications with their own locking. The idea behind this is that for a full
+ * memory manager additional data needs to be protected anyway, hence internal
+ * locking would be fully redundant.
+ */
+
+#ifdef CONFIG_DRM_DEBUG_MM
+#include <linux/stackdepot.h>
+
+#define STACKDEPTH 32
+#define BUFSZ 4096
+
+static noinline void save_stack(struct drm_mm_node *node)
+{
+	unsigned long entries[STACKDEPTH];
+	unsigned int n;
+
+	n = stack_trace_save(entries, ARRAY_SIZE(entries), 1);
+
+	/* May be called under spinlock, so avoid sleeping */
+	node->stack = stack_depot_save(entries, n, GFP_NOWAIT);
+}
+
+static void show_leaks(struct drm_mm *mm)
+{
+	struct drm_mm_node *node;
+	char *buf;
+
+	buf = kmalloc(BUFSZ, GFP_KERNEL);
+	if (!buf)
+		return;
+
+	list_for_each_entry(node, drm_mm_nodes(mm), node_list) {
+		if (!node->stack) {
+			DRM_ERROR("node [%08llx + %08llx]: unknown owner\n",
+				  node->start, node->size);
+			continue;
+		}
+
+		stack_depot_snprint(node->stack, buf, BUFSZ, 0);
+		DRM_ERROR("node [%08llx + %08llx]: inserted at\n%s",
+			  node->start, node->size, buf);
+	}
+
+	kfree(buf);
+}
+
+#undef STACKDEPTH
+#undef BUFSZ
+#else
+static void save_stack(struct drm_mm_node *node) { }
+static void show_leaks(struct drm_mm *mm) { }
+#endif
+
+#define START(node) ((node)->start)
+#define LAST(node)  ((node)->start + (node)->size - 1)
+
+INTERVAL_TREE_DEFINE(struct drm_mm_node, rb,
+		     u64, __subtree_last,
+		     START, LAST, static inline, drm_mm_interval_tree)
+
+struct drm_mm_node *
+__drm_mm_interval_first(const struct drm_mm *mm, u64 start, u64 last)
+{
+	return drm_mm_interval_tree_iter_first((struct rb_root_cached *)&mm->interval_tree,
+					       start, last) ?: (struct drm_mm_node *)&mm->head_node;
+}
+EXPORT_SYMBOL(__drm_mm_interval_first);
+
+static void drm_mm_interval_tree_add_node(struct drm_mm_node *hole_node,
+					  struct drm_mm_node *node)
+{
+	struct drm_mm *mm = hole_node->mm;
+	struct rb_node **link, *rb;
+	struct drm_mm_node *parent;
+	bool leftmost;
+
+	node->__subtree_last = LAST(node);
+
+	if (drm_mm_node_allocated(hole_node)) {
+		rb = &hole_node->rb;
+		while (rb) {
+			parent = rb_entry(rb, struct drm_mm_node, rb);
+			if (parent->__subtree_last >= node->__subtree_last)
+				break;
+
+			parent->__subtree_last = node->__subtree_last;
+			rb = rb_parent(rb);
+		}
+
+		rb = &hole_node->rb;
+		link = &hole_node->rb.rb_right;
+		leftmost = false;
+	} else {
+		rb = NULL;
+		link = &mm->interval_tree.rb_root.rb_node;
+		leftmost = true;
+	}
+
+	while (*link) {
+		rb = *link;
+		parent = rb_entry(rb, struct drm_mm_node, rb);
+		if (parent->__subtree_last < node->__subtree_last)
+			parent->__subtree_last = node->__subtree_last;
+		if (node->start < parent->start) {
+			link = &parent->rb.rb_left;
+		} else {
+			link = &parent->rb.rb_right;
+			leftmost = false;
+		}
+	}
+
+	rb_link_node(&node->rb, rb, link);
+	rb_insert_augmented_cached(&node->rb, &mm->interval_tree, leftmost,
+				   &drm_mm_interval_tree_augment);
+}
+
+#define HOLE_SIZE(NODE) ((NODE)->hole_size)
+#define HOLE_ADDR(NODE) (__drm_mm_hole_node_start(NODE))
+
+static u64 rb_to_hole_size(struct rb_node *rb)
+{
+	return rb_entry(rb, struct drm_mm_node, rb_hole_size)->hole_size;
+}
+
+static void insert_hole_size(struct rb_root_cached *root,
+			     struct drm_mm_node *node)
+{
+	struct rb_node **link = &root->rb_root.rb_node, *rb = NULL;
+	u64 x = node->hole_size;
+	bool first = true;
+
+	while (*link) {
+		rb = *link;
+		if (x > rb_to_hole_size(rb)) {
+			link = &rb->rb_left;
+		} else {
+			link = &rb->rb_right;
+			first = false;
+		}
+	}
+
+	rb_link_node(&node->rb_hole_size, rb, link);
+	rb_insert_color_cached(&node->rb_hole_size, root, first);
+}
+
+RB_DECLARE_CALLBACKS_MAX(static, augment_callbacks,
+			 struct drm_mm_node, rb_hole_addr,
+			 u64, subtree_max_hole, HOLE_SIZE)
+
+static void insert_hole_addr(struct rb_root *root, struct drm_mm_node *node)
+{
+	struct rb_node **link = &root->rb_node, *rb_parent = NULL;
+	u64 start = HOLE_ADDR(node), subtree_max_hole = node->subtree_max_hole;
+	struct drm_mm_node *parent;
+
+	while (*link) {
+		rb_parent = *link;
+		parent = rb_entry(rb_parent, struct drm_mm_node, rb_hole_addr);
+		if (parent->subtree_max_hole < subtree_max_hole)
+			parent->subtree_max_hole = subtree_max_hole;
+		if (start < HOLE_ADDR(parent))
+			link = &parent->rb_hole_addr.rb_left;
+		else
+			link = &parent->rb_hole_addr.rb_right;
+	}
+
+	rb_link_node(&node->rb_hole_addr, rb_parent, link);
+	rb_insert_augmented(&node->rb_hole_addr, root, &augment_callbacks);
+}
+
+static void add_hole(struct drm_mm_node *node)
+{
+	struct drm_mm *mm = node->mm;
+
+	node->hole_size =
+		__drm_mm_hole_node_end(node) - __drm_mm_hole_node_start(node);
+	node->subtree_max_hole = node->hole_size;
+	DRM_MM_BUG_ON(!drm_mm_hole_follows(node));
+
+	insert_hole_size(&mm->holes_size, node);
+	insert_hole_addr(&mm->holes_addr, node);
+
+	list_add(&node->hole_stack, &mm->hole_stack);
+}
+
+static void rm_hole(struct drm_mm_node *node)
+{
+	DRM_MM_BUG_ON(!drm_mm_hole_follows(node));
+
+	list_del(&node->hole_stack);
+	rb_erase_cached(&node->rb_hole_size, &node->mm->holes_size);
+	rb_erase_augmented(&node->rb_hole_addr, &node->mm->holes_addr,
+			   &augment_callbacks);
+	node->hole_size = 0;
+	node->subtree_max_hole = 0;
+
+	DRM_MM_BUG_ON(drm_mm_hole_follows(node));
+}
+
+static inline struct drm_mm_node *rb_hole_size_to_node(struct rb_node *rb)
+{
+	return rb_entry_safe(rb, struct drm_mm_node, rb_hole_size);
+}
+
+static inline struct drm_mm_node *rb_hole_addr_to_node(struct rb_node *rb)
+{
+	return rb_entry_safe(rb, struct drm_mm_node, rb_hole_addr);
+}
+
+static struct drm_mm_node *best_hole(struct drm_mm *mm, u64 size)
+{
+	struct rb_node *rb = mm->holes_size.rb_root.rb_node;
+	struct drm_mm_node *best = NULL;
+
+	do {
+		struct drm_mm_node *node =
+			rb_entry(rb, struct drm_mm_node, rb_hole_size);
+
+		if (size <= node->hole_size) {
+			best = node;
+			rb = rb->rb_right;
+		} else {
+			rb = rb->rb_left;
+		}
+	} while (rb);
+
+	return best;
+}
+
+static bool usable_hole_addr(struct rb_node *rb, u64 size)
+{
+	return rb && rb_hole_addr_to_node(rb)->subtree_max_hole >= size;
+}
+
+static struct drm_mm_node *find_hole_addr(struct drm_mm *mm, u64 addr, u64 size)
+{
+	struct rb_node *rb = mm->holes_addr.rb_node;
+	struct drm_mm_node *node = NULL;
+
+	while (rb) {
+		u64 hole_start;
+
+		if (!usable_hole_addr(rb, size))
+			break;
+
+		node = rb_hole_addr_to_node(rb);
+		hole_start = __drm_mm_hole_node_start(node);
+
+		if (addr < hole_start)
+			rb = node->rb_hole_addr.rb_left;
+		else if (addr > hole_start + node->hole_size)
+			rb = node->rb_hole_addr.rb_right;
+		else
+			break;
+	}
+
+	return node;
+}
+
+static struct drm_mm_node *
+first_hole(struct drm_mm *mm,
+	   u64 start, u64 end, u64 size,
+	   enum drm_mm_insert_mode mode)
+{
+	switch (mode) {
+	default:
+	case DRM_MM_INSERT_BEST:
+		return best_hole(mm, size);
+
+	case DRM_MM_INSERT_LOW:
+		return find_hole_addr(mm, start, size);
+
+	case DRM_MM_INSERT_HIGH:
+		return find_hole_addr(mm, end, size);
+
+	case DRM_MM_INSERT_EVICT:
+		return list_first_entry_or_null(&mm->hole_stack,
+						struct drm_mm_node,
+						hole_stack);
+	}
+}
+
+/**
+ * DECLARE_NEXT_HOLE_ADDR - macro to declare next hole functions
+ * @name: name of function to declare
+ * @first: first rb member to traverse (either rb_left or rb_right).
+ * @last: last rb member to traverse (either rb_right or rb_left).
+ *
+ * This macro declares a function to return the next hole of the addr rb tree.
+ * While traversing the tree we take the searched size into account and only
+ * visit branches with potential big enough holes.
+ */
+
+#define DECLARE_NEXT_HOLE_ADDR(name, first, last)			\
+static struct drm_mm_node *name(struct drm_mm_node *entry, u64 size)	\
+{									\
+	struct rb_node *parent, *node = &entry->rb_hole_addr;		\
+									\
+	if (!entry || RB_EMPTY_NODE(node))				\
+		return NULL;						\
+									\
+	if (usable_hole_addr(node->first, size)) {			\
+		node = node->first;					\
+		while (usable_hole_addr(node->last, size))		\
+			node = node->last;				\
+		return rb_hole_addr_to_node(node);			\
+	}								\
+									\
+	while ((parent = rb_parent(node)) && node == parent->first)	\
+		node = parent;						\
+									\
+	return rb_hole_addr_to_node(parent);				\
+}
+
+DECLARE_NEXT_HOLE_ADDR(next_hole_high_addr, rb_left, rb_right)
+DECLARE_NEXT_HOLE_ADDR(next_hole_low_addr, rb_right, rb_left)
+
+static struct drm_mm_node *
+next_hole(struct drm_mm *mm,
+	  struct drm_mm_node *node,
+	  u64 size,
+	  enum drm_mm_insert_mode mode)
+{
+	switch (mode) {
+	default:
+	case DRM_MM_INSERT_BEST:
+		return rb_hole_size_to_node(rb_prev(&node->rb_hole_size));
+
+	case DRM_MM_INSERT_LOW:
+		return next_hole_low_addr(node, size);
+
+	case DRM_MM_INSERT_HIGH:
+		return next_hole_high_addr(node, size);
+
+	case DRM_MM_INSERT_EVICT:
+		node = list_next_entry(node, hole_stack);
+		return &node->hole_stack == &mm->hole_stack ? NULL : node;
+	}
+}
+
+/**
+ * drm_mm_reserve_node - insert an pre-initialized node
+ * @mm: drm_mm allocator to insert @node into
+ * @node: drm_mm_node to insert
+ *
+ * This functions inserts an already set-up &drm_mm_node into the allocator,
+ * meaning that start, size and color must be set by the caller. All other
+ * fields must be cleared to 0. This is useful to initialize the allocator with
+ * preallocated objects which must be set-up before the range allocator can be
+ * set-up, e.g. when taking over a firmware framebuffer.
+ *
+ * Returns:
+ * 0 on success, -ENOSPC if there's no hole where @node is.
+ */
+int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node)
+{
+	struct drm_mm_node *hole;
+	u64 hole_start, hole_end;
+	u64 adj_start, adj_end;
+	u64 end;
+
+	end = node->start + node->size;
+	if (unlikely(end <= node->start))
+		return -ENOSPC;
+
+	/* Find the relevant hole to add our node to */
+	hole = find_hole_addr(mm, node->start, 0);
+	if (!hole)
+		return -ENOSPC;
+
+	adj_start = hole_start = __drm_mm_hole_node_start(hole);
+	adj_end = hole_end = hole_start + hole->hole_size;
+
+	if (mm->color_adjust)
+		mm->color_adjust(hole, node->color, &adj_start, &adj_end);
+
+	if (adj_start > node->start || adj_end < end)
+		return -ENOSPC;
+
+	node->mm = mm;
+
+	__set_bit(DRM_MM_NODE_ALLOCATED_BIT, &node->flags);
+	list_add(&node->node_list, &hole->node_list);
+	drm_mm_interval_tree_add_node(hole, node);
+	node->hole_size = 0;
+
+	rm_hole(hole);
+	if (node->start > hole_start)
+		add_hole(hole);
+	if (end < hole_end)
+		add_hole(node);
+
+	save_stack(node);
+	return 0;
+}
+EXPORT_SYMBOL(drm_mm_reserve_node);
+
+static u64 rb_to_hole_size_or_zero(struct rb_node *rb)
+{
+	return rb ? rb_to_hole_size(rb) : 0;
+}
+
+/**
+ * drm_mm_insert_node_in_range - ranged search for space and insert @node
+ * @mm: drm_mm to allocate from
+ * @node: preallocate node to insert
+ * @size: size of the allocation
+ * @alignment: alignment of the allocation
+ * @color: opaque tag value to use for this node
+ * @range_start: start of the allowed range for this node
+ * @range_end: end of the allowed range for this node
+ * @mode: fine-tune the allocation search and placement
+ *
+ * The preallocated @node must be cleared to 0.
+ *
+ * Returns:
+ * 0 on success, -ENOSPC if there's no suitable hole.
+ */
+int drm_mm_insert_node_in_range(struct drm_mm * const mm,
+				struct drm_mm_node * const node,
+				u64 size, u64 alignment,
+				unsigned long color,
+				u64 range_start, u64 range_end,
+				enum drm_mm_insert_mode mode)
+{
+	struct drm_mm_node *hole;
+	u64 remainder_mask;
+	bool once;
+
+	DRM_MM_BUG_ON(range_start > range_end);
+
+	if (unlikely(size == 0 || range_end - range_start < size))
+		return -ENOSPC;
+
+	if (rb_to_hole_size_or_zero(rb_first_cached(&mm->holes_size)) < size)
+		return -ENOSPC;
+
+	if (alignment <= 1)
+		alignment = 0;
+
+	once = mode & DRM_MM_INSERT_ONCE;
+	mode &= ~DRM_MM_INSERT_ONCE;
+
+	remainder_mask = is_power_of_2(alignment) ? alignment - 1 : 0;
+	for (hole = first_hole(mm, range_start, range_end, size, mode);
+	     hole;
+	     hole = once ? NULL : next_hole(mm, hole, size, mode)) {
+		u64 hole_start = __drm_mm_hole_node_start(hole);
+		u64 hole_end = hole_start + hole->hole_size;
+		u64 adj_start, adj_end;
+		u64 col_start, col_end;
+
+		if (mode == DRM_MM_INSERT_LOW && hole_start >= range_end)
+			break;
+
+		if (mode == DRM_MM_INSERT_HIGH && hole_end <= range_start)
+			break;
+
+		col_start = hole_start;
+		col_end = hole_end;
+		if (mm->color_adjust)
+			mm->color_adjust(hole, color, &col_start, &col_end);
+
+		adj_start = max(col_start, range_start);
+		adj_end = min(col_end, range_end);
+
+		if (adj_end <= adj_start || adj_end - adj_start < size)
+			continue;
+
+		if (mode == DRM_MM_INSERT_HIGH)
+			adj_start = adj_end - size;
+
+		if (alignment) {
+			u64 rem;
+
+			if (likely(remainder_mask))
+				rem = adj_start & remainder_mask;
+			else
+				div64_u64_rem(adj_start, alignment, &rem);
+			if (rem) {
+				adj_start -= rem;
+				if (mode != DRM_MM_INSERT_HIGH)
+					adj_start += alignment;
+
+				if (adj_start < max(col_start, range_start) ||
+				    min(col_end, range_end) - adj_start < size)
+					continue;
+
+				if (adj_end <= adj_start ||
+				    adj_end - adj_start < size)
+					continue;
+			}
+		}
+
+		node->mm = mm;
+		node->size = size;
+		node->start = adj_start;
+		node->color = color;
+		node->hole_size = 0;
+
+		__set_bit(DRM_MM_NODE_ALLOCATED_BIT, &node->flags);
+		list_add(&node->node_list, &hole->node_list);
+		drm_mm_interval_tree_add_node(hole, node);
+
+		rm_hole(hole);
+		if (adj_start > hole_start)
+			add_hole(hole);
+		if (adj_start + size < hole_end)
+			add_hole(node);
+
+		save_stack(node);
+		return 0;
+	}
+
+	return -ENOSPC;
+}
+EXPORT_SYMBOL(drm_mm_insert_node_in_range);
+
+static inline bool drm_mm_node_scanned_block(const struct drm_mm_node *node)
+{
+	return test_bit(DRM_MM_NODE_SCANNED_BIT, &node->flags);
+}
+
+/**
+ * drm_mm_remove_node - Remove a memory node from the allocator.
+ * @node: drm_mm_node to remove
+ *
+ * This just removes a node from its drm_mm allocator. The node does not need to
+ * be cleared again before it can be re-inserted into this or any other drm_mm
+ * allocator. It is a bug to call this function on a unallocated node.
+ */
+void drm_mm_remove_node(struct drm_mm_node *node)
+{
+	struct drm_mm *mm = node->mm;
+	struct drm_mm_node *prev_node;
+
+	DRM_MM_BUG_ON(!drm_mm_node_allocated(node));
+	DRM_MM_BUG_ON(drm_mm_node_scanned_block(node));
+
+	prev_node = list_prev_entry(node, node_list);
+
+	if (drm_mm_hole_follows(node))
+		rm_hole(node);
+
+	drm_mm_interval_tree_remove(node, &mm->interval_tree);
+	list_del(&node->node_list);
+
+	if (drm_mm_hole_follows(prev_node))
+		rm_hole(prev_node);
+	add_hole(prev_node);
+
+	clear_bit_unlock(DRM_MM_NODE_ALLOCATED_BIT, &node->flags);
+}
+EXPORT_SYMBOL(drm_mm_remove_node);
+
+/**
+ * drm_mm_replace_node - move an allocation from @old to @new
+ * @old: drm_mm_node to remove from the allocator
+ * @new: drm_mm_node which should inherit @old's allocation
+ *
+ * This is useful for when drivers embed the drm_mm_node structure and hence
+ * can't move allocations by reassigning pointers. It's a combination of remove
+ * and insert with the guarantee that the allocation start will match.
+ */
+void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new)
+{
+	struct drm_mm *mm = old->mm;
+
+	DRM_MM_BUG_ON(!drm_mm_node_allocated(old));
+
+	*new = *old;
+
+	__set_bit(DRM_MM_NODE_ALLOCATED_BIT, &new->flags);
+	list_replace(&old->node_list, &new->node_list);
+	rb_replace_node_cached(&old->rb, &new->rb, &mm->interval_tree);
+
+	if (drm_mm_hole_follows(old)) {
+		list_replace(&old->hole_stack, &new->hole_stack);
+		rb_replace_node_cached(&old->rb_hole_size,
+				       &new->rb_hole_size,
+				       &mm->holes_size);
+		rb_replace_node(&old->rb_hole_addr,
+				&new->rb_hole_addr,
+				&mm->holes_addr);
+	}
+
+	clear_bit_unlock(DRM_MM_NODE_ALLOCATED_BIT, &old->flags);
+}
+EXPORT_SYMBOL(drm_mm_replace_node);
+
+/**
+ * DOC: lru scan roster
+ *
+ * Very often GPUs need to have continuous allocations for a given object. When
+ * evicting objects to make space for a new one it is therefore not most
+ * efficient when we simply start to select all objects from the tail of an LRU
+ * until there's a suitable hole: Especially for big objects or nodes that
+ * otherwise have special allocation constraints there's a good chance we evict
+ * lots of (smaller) objects unnecessarily.
+ *
+ * The DRM range allocator supports this use-case through the scanning
+ * interfaces. First a scan operation needs to be initialized with
+ * drm_mm_scan_init() or drm_mm_scan_init_with_range(). The driver adds
+ * objects to the roster, probably by walking an LRU list, but this can be
+ * freely implemented. Eviction candidates are added using
+ * drm_mm_scan_add_block() until a suitable hole is found or there are no
+ * further evictable objects. Eviction roster metadata is tracked in &struct
+ * drm_mm_scan.
+ *
+ * The driver must walk through all objects again in exactly the reverse
+ * order to restore the allocator state. Note that while the allocator is used
+ * in the scan mode no other operation is allowed.
+ *
+ * Finally the driver evicts all objects selected (drm_mm_scan_remove_block()
+ * reported true) in the scan, and any overlapping nodes after color adjustment
+ * (drm_mm_scan_color_evict()). Adding and removing an object is O(1), and
+ * since freeing a node is also O(1) the overall complexity is
+ * O(scanned_objects). So like the free stack which needs to be walked before a
+ * scan operation even begins this is linear in the number of objects. It
+ * doesn't seem to hurt too badly.
+ */
+
+/**
+ * drm_mm_scan_init_with_range - initialize range-restricted lru scanning
+ * @scan: scan state
+ * @mm: drm_mm to scan
+ * @size: size of the allocation
+ * @alignment: alignment of the allocation
+ * @color: opaque tag value to use for the allocation
+ * @start: start of the allowed range for the allocation
+ * @end: end of the allowed range for the allocation
+ * @mode: fine-tune the allocation search and placement
+ *
+ * This simply sets up the scanning routines with the parameters for the desired
+ * hole.
+ *
+ * Warning:
+ * As long as the scan list is non-empty, no other operations than
+ * adding/removing nodes to/from the scan list are allowed.
+ */
+void drm_mm_scan_init_with_range(struct drm_mm_scan *scan,
+				 struct drm_mm *mm,
+				 u64 size,
+				 u64 alignment,
+				 unsigned long color,
+				 u64 start,
+				 u64 end,
+				 enum drm_mm_insert_mode mode)
+{
+	DRM_MM_BUG_ON(start >= end);
+	DRM_MM_BUG_ON(!size || size > end - start);
+	DRM_MM_BUG_ON(mm->scan_active);
+
+	scan->mm = mm;
+
+	if (alignment <= 1)
+		alignment = 0;
+
+	scan->color = color;
+	scan->alignment = alignment;
+	scan->remainder_mask = is_power_of_2(alignment) ? alignment - 1 : 0;
+	scan->size = size;
+	scan->mode = mode;
+
+	DRM_MM_BUG_ON(end <= start);
+	scan->range_start = start;
+	scan->range_end = end;
+
+	scan->hit_start = U64_MAX;
+	scan->hit_end = 0;
+}
+EXPORT_SYMBOL(drm_mm_scan_init_with_range);
+
+/**
+ * drm_mm_scan_add_block - add a node to the scan list
+ * @scan: the active drm_mm scanner
+ * @node: drm_mm_node to add
+ *
+ * Add a node to the scan list that might be freed to make space for the desired
+ * hole.
+ *
+ * Returns:
+ * True if a hole has been found, false otherwise.
+ */
+bool drm_mm_scan_add_block(struct drm_mm_scan *scan,
+			   struct drm_mm_node *node)
+{
+	struct drm_mm *mm = scan->mm;
+	struct drm_mm_node *hole;
+	u64 hole_start, hole_end;
+	u64 col_start, col_end;
+	u64 adj_start, adj_end;
+
+	DRM_MM_BUG_ON(node->mm != mm);
+	DRM_MM_BUG_ON(!drm_mm_node_allocated(node));
+	DRM_MM_BUG_ON(drm_mm_node_scanned_block(node));
+	__set_bit(DRM_MM_NODE_SCANNED_BIT, &node->flags);
+	mm->scan_active++;
+
+	/* Remove this block from the node_list so that we enlarge the hole
+	 * (distance between the end of our previous node and the start of
+	 * or next), without poisoning the link so that we can restore it
+	 * later in drm_mm_scan_remove_block().
+	 */
+	hole = list_prev_entry(node, node_list);
+	DRM_MM_BUG_ON(list_next_entry(hole, node_list) != node);
+	__list_del_entry(&node->node_list);
+
+	hole_start = __drm_mm_hole_node_start(hole);
+	hole_end = __drm_mm_hole_node_end(hole);
+
+	col_start = hole_start;
+	col_end = hole_end;
+	if (mm->color_adjust)
+		mm->color_adjust(hole, scan->color, &col_start, &col_end);
+
+	adj_start = max(col_start, scan->range_start);
+	adj_end = min(col_end, scan->range_end);
+	if (adj_end <= adj_start || adj_end - adj_start < scan->size)
+		return false;
+
+	if (scan->mode == DRM_MM_INSERT_HIGH)
+		adj_start = adj_end - scan->size;
+
+	if (scan->alignment) {
+		u64 rem;
+
+		if (likely(scan->remainder_mask))
+			rem = adj_start & scan->remainder_mask;
+		else
+			div64_u64_rem(adj_start, scan->alignment, &rem);
+		if (rem) {
+			adj_start -= rem;
+			if (scan->mode != DRM_MM_INSERT_HIGH)
+				adj_start += scan->alignment;
+			if (adj_start < max(col_start, scan->range_start) ||
+			    min(col_end, scan->range_end) - adj_start < scan->size)
+				return false;
+
+			if (adj_end <= adj_start ||
+			    adj_end - adj_start < scan->size)
+				return false;
+		}
+	}
+
+	scan->hit_start = adj_start;
+	scan->hit_end = adj_start + scan->size;
+
+	DRM_MM_BUG_ON(scan->hit_start >= scan->hit_end);
+	DRM_MM_BUG_ON(scan->hit_start < hole_start);
+	DRM_MM_BUG_ON(scan->hit_end > hole_end);
+
+	return true;
+}
+EXPORT_SYMBOL(drm_mm_scan_add_block);
+
+/**
+ * drm_mm_scan_remove_block - remove a node from the scan list
+ * @scan: the active drm_mm scanner
+ * @node: drm_mm_node to remove
+ *
+ * Nodes **must** be removed in exactly the reverse order from the scan list as
+ * they have been added (e.g. using list_add() as they are added and then
+ * list_for_each() over that eviction list to remove), otherwise the internal
+ * state of the memory manager will be corrupted.
+ *
+ * When the scan list is empty, the selected memory nodes can be freed. An
+ * immediately following drm_mm_insert_node_in_range_generic() or one of the
+ * simpler versions of that function with !DRM_MM_SEARCH_BEST will then return
+ * the just freed block (because it's at the top of the free_stack list).
+ *
+ * Returns:
+ * True if this block should be evicted, false otherwise. Will always
+ * return false when no hole has been found.
+ */
+bool drm_mm_scan_remove_block(struct drm_mm_scan *scan,
+			      struct drm_mm_node *node)
+{
+	struct drm_mm_node *prev_node;
+
+	DRM_MM_BUG_ON(node->mm != scan->mm);
+	DRM_MM_BUG_ON(!drm_mm_node_scanned_block(node));
+	__clear_bit(DRM_MM_NODE_SCANNED_BIT, &node->flags);
+
+	DRM_MM_BUG_ON(!node->mm->scan_active);
+	node->mm->scan_active--;
+
+	/* During drm_mm_scan_add_block() we decoupled this node leaving
+	 * its pointers intact. Now that the caller is walking back along
+	 * the eviction list we can restore this block into its rightful
+	 * place on the full node_list. To confirm that the caller is walking
+	 * backwards correctly we check that prev_node->next == node->next,
+	 * i.e. both believe the same node should be on the other side of the
+	 * hole.
+	 */
+	prev_node = list_prev_entry(node, node_list);
+	DRM_MM_BUG_ON(list_next_entry(prev_node, node_list) !=
+		      list_next_entry(node, node_list));
+	list_add(&node->node_list, &prev_node->node_list);
+
+	return (node->start + node->size > scan->hit_start &&
+		node->start < scan->hit_end);
+}
+EXPORT_SYMBOL(drm_mm_scan_remove_block);
+
+/**
+ * drm_mm_scan_color_evict - evict overlapping nodes on either side of hole
+ * @scan: drm_mm scan with target hole
+ *
+ * After completing an eviction scan and removing the selected nodes, we may
+ * need to remove a few more nodes from either side of the target hole if
+ * mm.color_adjust is being used.
+ *
+ * Returns:
+ * A node to evict, or NULL if there are no overlapping nodes.
+ */
+struct drm_mm_node *drm_mm_scan_color_evict(struct drm_mm_scan *scan)
+{
+	struct drm_mm *mm = scan->mm;
+	struct drm_mm_node *hole;
+	u64 hole_start, hole_end;
+
+	DRM_MM_BUG_ON(list_empty(&mm->hole_stack));
+
+	if (!mm->color_adjust)
+		return NULL;
+
+	/*
+	 * The hole found during scanning should ideally be the first element
+	 * in the hole_stack list, but due to side-effects in the driver it
+	 * may not be.
+	 */
+	list_for_each_entry(hole, &mm->hole_stack, hole_stack) {
+		hole_start = __drm_mm_hole_node_start(hole);
+		hole_end = hole_start + hole->hole_size;
+
+		if (hole_start <= scan->hit_start &&
+		    hole_end >= scan->hit_end)
+			break;
+	}
+
+	/* We should only be called after we found the hole previously */
+	DRM_MM_BUG_ON(&hole->hole_stack == &mm->hole_stack);
+	if (unlikely(&hole->hole_stack == &mm->hole_stack))
+		return NULL;
+
+	DRM_MM_BUG_ON(hole_start > scan->hit_start);
+	DRM_MM_BUG_ON(hole_end < scan->hit_end);
+
+	mm->color_adjust(hole, scan->color, &hole_start, &hole_end);
+	if (hole_start > scan->hit_start)
+		return hole;
+	if (hole_end < scan->hit_end)
+		return list_next_entry(hole, node_list);
+
+	return NULL;
+}
+EXPORT_SYMBOL(drm_mm_scan_color_evict);
+
+/**
+ * drm_mm_init - initialize a drm-mm allocator
+ * @mm: the drm_mm structure to initialize
+ * @start: start of the range managed by @mm
+ * @size: end of the range managed by @mm
+ *
+ * Note that @mm must be cleared to 0 before calling this function.
+ */
+void drm_mm_init(struct drm_mm *mm, u64 start, u64 size)
+{
+	DRM_MM_BUG_ON(start + size <= start);
+
+	mm->color_adjust = NULL;
+
+	INIT_LIST_HEAD(&mm->hole_stack);
+	mm->interval_tree = RB_ROOT_CACHED;
+	mm->holes_size = RB_ROOT_CACHED;
+	mm->holes_addr = RB_ROOT;
+
+	/* Clever trick to avoid a special case in the free hole tracking. */
+	INIT_LIST_HEAD(&mm->head_node.node_list);
+	mm->head_node.flags = 0;
+	mm->head_node.mm = mm;
+	mm->head_node.start = start + size;
+	mm->head_node.size = -size;
+	add_hole(&mm->head_node);
+
+	mm->scan_active = 0;
+
+#ifdef CONFIG_DRM_DEBUG_MM
+	stack_depot_init();
+#endif
+}
+EXPORT_SYMBOL(drm_mm_init);
+
+/**
+ * drm_mm_takedown - clean up a drm_mm allocator
+ * @mm: drm_mm allocator to clean up
+ *
+ * Note that it is a bug to call this function on an allocator which is not
+ * clean.
+ */
+void drm_mm_takedown(struct drm_mm *mm)
+{
+	if (WARN(!drm_mm_clean(mm),
+		 "Memory manager not clean during takedown.\n"))
+		show_leaks(mm);
+}
+EXPORT_SYMBOL(drm_mm_takedown);
+
+static u64 drm_mm_dump_hole(struct drm_printer *p, const struct drm_mm_node *entry)
+{
+	u64 start, size;
+
+	size = entry->hole_size;
+	if (size) {
+		start = drm_mm_hole_node_start(entry);
+		drm_printf(p, "%#018llx-%#018llx: %llu: free\n",
+			   start, start + size, size);
+	}
+
+	return size;
+}
+/**
+ * drm_mm_print - print allocator state
+ * @mm: drm_mm allocator to print
+ * @p: DRM printer to use
+ */
+void drm_mm_print(const struct drm_mm *mm, struct drm_printer *p)
+{
+	const struct drm_mm_node *entry;
+	u64 total_used = 0, total_free = 0, total = 0;
+
+	total_free += drm_mm_dump_hole(p, &mm->head_node);
+
+	drm_mm_for_each_node(entry, mm) {
+		drm_printf(p, "%#018llx-%#018llx: %llu: used\n", entry->start,
+			   entry->start + entry->size, entry->size);
+		total_used += entry->size;
+		total_free += drm_mm_dump_hole(p, entry);
+	}
+	total = total_free + total_used;
+
+	drm_printf(p, "total: %llu, used %llu free %llu\n", total,
+		   total_used, total_free);
+}
+EXPORT_SYMBOL(drm_mm_print);