New subject: [PATCH v3 2/6] drm: improve drm_buddy_alloc function

16 Nov 2021

Move the base i915 buddy allocator code into drm
- Move i915_buddy.h to include/drm
- Move i915_buddy.c to drm root folder
- Rename "i915" string with "drm" string wherever applicable
- Rename "I915" string with "DRM" string wherever applicable
- Fix header file dependencies
- Fix alignment issues
- add Makefile support for drm buddy
- export functions and write kerneldoc description
- Remove i915 selftest config check condition as buddy selftest
  will be moved to drm selftest folder
cleanup i915 buddy references in i915 driver module
and replace with drm buddy
v2:
  - include header file in alphabetical order (Thomas)
  - merged changes listed in the body section into a single patch
    to keep the build intact (Christian, Jani)
Signed-off-by: Arunpravin Arunpravin.PaneerSelvam@amd.com
---
 drivers/gpu/drm/Makefile                      |   2 +-
 drivers/gpu/drm/drm_buddy.c                   | 521 ++++++++++++++++++
 drivers/gpu/drm/drm_drv.c                     |   3 +
 drivers/gpu/drm/i915/Makefile                 |   1 -
 drivers/gpu/drm/i915/i915_buddy.c             | 466 ----------------
 drivers/gpu/drm/i915/i915_buddy.h             | 143 -----
 drivers/gpu/drm/i915/i915_module.c            |   3 -
 drivers/gpu/drm/i915/i915_scatterlist.c       |  11 +-
 drivers/gpu/drm/i915/i915_ttm_buddy_manager.c |  33 +-
 drivers/gpu/drm/i915/i915_ttm_buddy_manager.h |   4 +-
 include/drm/drm_buddy.h                       | 153 +++++
 11 files changed, 702 insertions(+), 638 deletions(-)
 create mode 100644 drivers/gpu/drm/drm_buddy.c
 delete mode 100644 drivers/gpu/drm/i915/i915_buddy.c
 delete mode 100644 drivers/gpu/drm/i915/i915_buddy.h
 create mode 100644 include/drm/drm_buddy.h

diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 0dff40bb863c..dc61e91a3154 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -18,7 +18,7 @@ drm-y       :=	drm_aperture.o drm_auth.o drm_cache.o \
    	drm_dumb_buffers.o drm_mode_config.o drm_vblank.o \
    	drm_syncobj.o drm_lease.o drm_writeback.o drm_client.o \
    	drm_client_modeset.o drm_atomic_uapi.o drm_hdcp.o \
-		drm_managed.o drm_vblank_work.o
+		drm_managed.o drm_vblank_work.o drm_buddy.o
drm-$(CONFIG_DRM_LEGACY) += drm_agpsupport.o drm_bufs.o drm_context.o drm_dma.o \
    		    drm_legacy_misc.o drm_lock.o drm_memory.o drm_scatter.o \
diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c
new file mode 100644
index 000000000000..39eb1d224bec
--- /dev/null
+++ b/drivers/gpu/drm/drm_buddy.c
@@ -0,0 +1,521 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2021 Intel Corporation
+ */
+
+#include <linux/kmemleak.h>
+#include <linux/sizes.h>
+
+#include <drm/drm_buddy.h>
+
+static struct kmem_cache *slab_blocks;
+
+static struct drm_buddy_block *drm_block_alloc(struct drm_buddy_mm *mm,
+					       struct drm_buddy_block *parent,
+					       unsigned int order,
+					       u64 offset)
+{
+	struct drm_buddy_block *block;
+
+	BUG_ON(order > DRM_BUDDY_MAX_ORDER);
+
+	block = kmem_cache_zalloc(slab_blocks, GFP_KERNEL);
+	if (!block)
+		return NULL;
+
+	block->header = offset;
+	block->header |= order;
+	block->parent = parent;
+
+	BUG_ON(block->header & DRM_BUDDY_HEADER_UNUSED);
+	return block;
+}
+
+static void drm_block_free(struct drm_buddy_mm *mm,
+			   struct drm_buddy_block *block)
+{
+	kmem_cache_free(slab_blocks, block);
+}
+
+static void mark_allocated(struct drm_buddy_block *block)
+{
+	block->header &= ~DRM_BUDDY_HEADER_STATE;
+	block->header |= DRM_BUDDY_ALLOCATED;
+
+	list_del(&block->link);
+}
+
+static void mark_free(struct drm_buddy_mm *mm,
+		      struct drm_buddy_block *block)
+{
+	block->header &= ~DRM_BUDDY_HEADER_STATE;
+	block->header |= DRM_BUDDY_FREE;
+
+	list_add(&block->link,
+		 &mm->free_list[drm_buddy_block_order(block)]);
+}
+
+static void mark_split(struct drm_buddy_block *block)
+{
+	block->header &= ~DRM_BUDDY_HEADER_STATE;
+	block->header |= DRM_BUDDY_SPLIT;
+
+	list_del(&block->link);
+}
+
+/**
+ * drm_buddy_init - init memory manager
+ *
+ * @mm: DRM buddy manager to initialize
+ * @size: size in bytes to manage
+ * @chunk_size: minimum page size in bytes for our allocations
+ *
+ * Initializes the memory manager and its resources.
+ *
+ * Returns:
+ * 0 on success, error code on failure.
+ */
+int drm_buddy_init(struct drm_buddy_mm *mm, u64 size, u64 chunk_size)
+{
+	unsigned int i;
+	u64 offset;
+
+	if (size < chunk_size)
+		return -EINVAL;
+
+	if (chunk_size < PAGE_SIZE)
+		return -EINVAL;
+
+	if (!is_power_of_2(chunk_size))
+		return -EINVAL;
+
+	size = round_down(size, chunk_size);
+
+	mm->size = size;
+	mm->avail = size;
+	mm->chunk_size = chunk_size;
+	mm->max_order = ilog2(size) - ilog2(chunk_size);
+
+	BUG_ON(mm->max_order > DRM_BUDDY_MAX_ORDER);
+
+	mm->free_list = kmalloc_array(mm->max_order + 1,
+				      sizeof(struct list_head),
+				      GFP_KERNEL);
+	if (!mm->free_list)
+		return -ENOMEM;
+
+	for (i = 0; i <= mm->max_order; ++i)
+		INIT_LIST_HEAD(&mm->free_list[i]);
+
+	mm->n_roots = hweight64(size);
+
+	mm->roots = kmalloc_array(mm->n_roots,
+				  sizeof(struct drm_buddy_block *),
+				  GFP_KERNEL);
+	if (!mm->roots)
+		goto out_free_list;
+
+	offset = 0;
+	i = 0;
+
+	/*
+	 * Split into power-of-two blocks, in case we are given a size that is
+	 * not itself a power-of-two.
+	 */
+	do {
+		struct drm_buddy_block *root;
+		unsigned int order;
+		u64 root_size;
+
+		root_size = rounddown_pow_of_two(size);
+		order = ilog2(root_size) - ilog2(chunk_size);
+
+		root = drm_block_alloc(mm, NULL, order, offset);
+		if (!root)
+			goto out_free_roots;
+
+		mark_free(mm, root);
+
+		BUG_ON(i > mm->max_order);
+		BUG_ON(drm_buddy_block_size(mm, root) < chunk_size);
+
+		mm->roots[i] = root;
+
+		offset += root_size;
+		size -= root_size;
+		i++;
+	} while (size);
+
+	return 0;
+
+out_free_roots:
+	while (i--)
+		drm_block_free(mm, mm->roots[i]);
+	kfree(mm->roots);
+out_free_list:
+	kfree(mm->free_list);
+	return -ENOMEM;
+}
+EXPORT_SYMBOL(drm_buddy_init);
+
+/**
+ * drm_buddy_fini - tear down the memory manager
+ *
+ * @mm: DRM buddy manager to free
+ *
+ * Cleanup memory manager resources and the freelist
+ */
+void drm_buddy_fini(struct drm_buddy_mm *mm)
+{
+	int i;
+
+	for (i = 0; i < mm->n_roots; ++i) {
+		WARN_ON(!drm_buddy_block_is_free(mm->roots[i]));
+		drm_block_free(mm, mm->roots[i]);
+	}
+
+	WARN_ON(mm->avail != mm->size);
+
+	kfree(mm->roots);
+	kfree(mm->free_list);
+}
+EXPORT_SYMBOL(drm_buddy_fini);
+
+static int split_block(struct drm_buddy_mm *mm,
+		       struct drm_buddy_block *block)
+{
+	unsigned int block_order = drm_buddy_block_order(block) - 1;
+	u64 offset = drm_buddy_block_offset(block);
+
+	BUG_ON(!drm_buddy_block_is_free(block));
+	BUG_ON(!drm_buddy_block_order(block));
+
+	block->left = drm_block_alloc(mm, block, block_order, offset);
+	if (!block->left)
+		return -ENOMEM;
+
+	block->right = drm_block_alloc(mm, block, block_order,
+					offset + (mm->chunk_size << block_order));
+	if (!block->right) {
+		drm_block_free(mm, block->left);
+		return -ENOMEM;
+	}
+
+	mark_free(mm, block->left);
+	mark_free(mm, block->right);
+
+	mark_split(block);
+
+	return 0;
+}
+
+static struct drm_buddy_block *
+get_buddy(struct drm_buddy_block *block)
+{
+	struct drm_buddy_block *parent;
+
+	parent = block->parent;
+	if (!parent)
+		return NULL;
+
+	if (parent->left == block)
+		return parent->right;
+
+	return parent->left;
+}
+
+static void __drm_buddy_free(struct drm_buddy_mm *mm,
+			     struct drm_buddy_block *block)
+{
+	struct drm_buddy_block *parent;
+
+	while ((parent = block->parent)) {
+		struct drm_buddy_block *buddy;
+
+		buddy = get_buddy(block);
+
+		if (!drm_buddy_block_is_free(buddy))
+			break;
+
+		list_del(&buddy->link);
+
+		drm_block_free(mm, block);
+		drm_block_free(mm, buddy);
+
+		block = parent;
+	}
+
+	mark_free(mm, block);
+}
+
+void drm_buddy_free(struct drm_buddy_mm *mm,
+		    struct drm_buddy_block *block)
+{
+	BUG_ON(!drm_buddy_block_is_allocated(block));
+	mm->avail += drm_buddy_block_size(mm, block);
+	__drm_buddy_free(mm, block);
+}
+
+/**
+ * drm_buddy_free_list - free blocks
+ *
+ * @mm: DRM buddy manager
+ * @objects: input list head to free blocks
+ */
+void drm_buddy_free_list(struct drm_buddy_mm *mm, struct list_head *objects)
+{
+	struct drm_buddy_block *block, *on;
+
+	list_for_each_entry_safe(block, on, objects, link) {
+		drm_buddy_free(mm, block);
+		cond_resched();
+	}
+	INIT_LIST_HEAD(objects);
+}
+EXPORT_SYMBOL(drm_buddy_free_list);
+
+/**
+ * drm_buddy_alloc - allocate power-of-two blocks
+ *
+ * @mm: DRM buddy manager to allocate from
+ * @order: size of the allocation
+ *
+ * The order value here translates to:
+ *
+ * 0 = 2^0 * mm->chunk_size
+ * 1 = 2^1 * mm->chunk_size
+ * 2 = 2^2 * mm->chunk_size
+ *
+ * Returns:
+ * allocated ptr to the &drm_buddy_block on success
+ */
+struct drm_buddy_block *
+drm_buddy_alloc(struct drm_buddy_mm *mm, unsigned int order)
+{
+	struct drm_buddy_block *block = NULL;
+	unsigned int i;
+	int err;
+
+	for (i = order; i <= mm->max_order; ++i) {
+		block = list_first_entry_or_null(&mm->free_list[i],
+						 struct drm_buddy_block,
+						 link);
+		if (block)
+			break;
+	}
+
+	if (!block)
+		return ERR_PTR(-ENOSPC);
+
+	BUG_ON(!drm_buddy_block_is_free(block));
+
+	while (i != order) {
+		err = split_block(mm, block);
+		if (unlikely(err))
+			goto out_free;
+
+		/* Go low */
+		block = block->left;
+		i--;
+	}
+
+	mark_allocated(block);
+	mm->avail -= drm_buddy_block_size(mm, block);
+	kmemleak_update_trace(block);
+	return block;
+
+out_free:
+	if (i != order)
+		__drm_buddy_free(mm, block);
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL(drm_buddy_alloc);
+
+static inline bool overlaps(u64 s1, u64 e1, u64 s2, u64 e2)
+{
+	return s1 <= e2 && e1 >= s2;
+}
+
+static inline bool contains(u64 s1, u64 e1, u64 s2, u64 e2)
+{
+	return s1 <= s2 && e1 >= e2;
+}
+
+/**
+ * drm_buddy_alloc_range - allocate range
+ *
+ * @mm: DRM buddy manager to allocate from
+ * @blocks: output list head to add allocated blocks
+ * @start: start of the allowed range for this block
+ * @size: size of the allocation
+ *
+ * Intended for pre-allocating portions of the address space, for example to
+ * reserve a block for the initial framebuffer or similar, hence the expectation
+ * here is that drm_buddy_alloc() is still the main vehicle for
+ * allocations, so if that's not the case then the drm_mm range allocator is
+ * probably a much better fit, and so you should probably go use that instead.
+ *
+ * Note that it's safe to chain together multiple alloc_ranges
+ * with the same blocks list
+ *
+ * Returns:
+ * 0 on success, error code on failure.
+ */
+int drm_buddy_alloc_range(struct drm_buddy_mm *mm,
+			  struct list_head *blocks,
+			  u64 start, u64 size)
+{
+	struct drm_buddy_block *block;
+	struct drm_buddy_block *buddy;
+	LIST_HEAD(allocated);
+	LIST_HEAD(dfs);
+	u64 end;
+	int err;
+	int i;
+
+	if (size < mm->chunk_size)
+		return -EINVAL;
+
+	if (!IS_ALIGNED(size | start, mm->chunk_size))
+		return -EINVAL;
+
+	if (range_overflows(start, size, mm->size))
+		return -EINVAL;
+
+	for (i = 0; i < mm->n_roots; ++i)
+		list_add_tail(&mm->roots[i]->tmp_link, &dfs);
+
+	end = start + size - 1;
+
+	do {
+		u64 block_start;
+		u64 block_end;
+
+		block = list_first_entry_or_null(&dfs,
+						 struct drm_buddy_block,
+						 tmp_link);
+		if (!block)
+			break;
+
+		list_del(&block->tmp_link);
+
+		block_start = drm_buddy_block_offset(block);
+		block_end = block_start + drm_buddy_block_size(mm, block) - 1;
+
+		if (!overlaps(start, end, block_start, block_end))
+			continue;
+
+		if (drm_buddy_block_is_allocated(block)) {
+			err = -ENOSPC;
+			goto err_free;
+		}
+
+		if (contains(start, end, block_start, block_end)) {
+			if (!drm_buddy_block_is_free(block)) {
+				err = -ENOSPC;
+				goto err_free;
+			}
+
+			mark_allocated(block);
+			mm->avail -= drm_buddy_block_size(mm, block);
+			list_add_tail(&block->link, &allocated);
+			continue;
+		}
+
+		if (!drm_buddy_block_is_split(block)) {
+			err = split_block(mm, block);
+			if (unlikely(err))
+				goto err_undo;
+		}
+
+		list_add(&block->right->tmp_link, &dfs);
+		list_add(&block->left->tmp_link, &dfs);
+	} while (1);
+
+	list_splice_tail(&allocated, blocks);
+	return 0;
+
+err_undo:
+	/*
+	 * We really don't want to leave around a bunch of split blocks, since
+	 * bigger is better, so make sure we merge everything back before we
+	 * free the allocated blocks.
+	 */
+	buddy = get_buddy(block);
+	if (buddy &&
+	    (drm_buddy_block_is_free(block) &&
+	     drm_buddy_block_is_free(buddy)))
+		__drm_buddy_free(mm, block);
+
+err_free:
+	drm_buddy_free_list(mm, &allocated);
+	return err;
+}
+EXPORT_SYMBOL(drm_buddy_alloc_range);
+
+/**
+ * drm_buddy_block_print - print block information
+ *
+ * @mm: DRM buddy manager
+ * @block: DRM buddy block
+ * @p: DRM printer to use
+ */
+void drm_buddy_block_print(struct drm_buddy_mm *mm,
+			   struct drm_buddy_block *block,
+			   struct drm_printer *p)
+{
+	u64 start = drm_buddy_block_offset(block);
+	u64 size = drm_buddy_block_size(mm, block);
+
+	drm_printf(p, "%#018llx-%#018llx: %llu\n", start, start + size, size);
+}
+EXPORT_SYMBOL(drm_buddy_block_print);
+
+/**
+ * drm_buddy_print - print allocator state
+ *
+ * @mm: DRM buddy manager
+ * @p: DRM printer to use
+ */
+void drm_buddy_print(struct drm_buddy_mm *mm, struct drm_printer *p)
+{
+	int order;
+
+	drm_printf(p, "chunk_size: %lluKiB, total: %lluMiB, free: %lluMiB\n",
+		   mm->chunk_size >> 10, mm->size >> 20, mm->avail >> 20);
+
+	for (order = mm->max_order; order >= 0; order--) {
+		struct drm_buddy_block *block;
+		u64 count = 0, free;
+
+		list_for_each_entry(block, &mm->free_list[order], link) {
+			BUG_ON(!drm_buddy_block_is_free(block));
+			count++;
+		}
+
+		drm_printf(p, "order-%d ", order);
+
+		free = count * (mm->chunk_size << order);
+		if (free < SZ_1M)
+			drm_printf(p, "free: %lluKiB", free >> 10);
+		else
+			drm_printf(p, "free: %lluMiB", free >> 20);
+
+		drm_printf(p, ", pages: %llu\n", count);
+	}
+}
+EXPORT_SYMBOL(drm_buddy_print);
+
+void drm_buddy_module_exit(void)
+{
+	kmem_cache_destroy(slab_blocks);
+}
+
+int __init drm_buddy_module_init(void)
+{
+	slab_blocks = KMEM_CACHE(drm_buddy_block, 0);
+	if (!slab_blocks)
+		return -ENOMEM;
+
+	return 0;
+}
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 7a5097467ba5..5d5e46e60586 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -35,6 +35,7 @@
 #include <linux/slab.h>
 #include <linux/srcu.h>
+#include <drm/drm_buddy.h>
 #include <drm/drm_cache.h>
 #include <drm/drm_client.h>
 #include <drm/drm_color_mgmt.h>
@@ -1034,6 +1035,7 @@ static void drm_core_exit(void)
    drm_sysfs_destroy();
    idr_destroy(&drm_minors_idr);
    drm_connector_ida_destroy();
+	drm_buddy_module_exit();
 }
static int __init drm_core_init(void)
@@ -1043,6 +1045,7 @@ static int __init drm_core_init(void)
    drm_connector_ida_init();
    idr_init(&drm_minors_idr);
    drm_memcpy_init_early();
+	drm_buddy_module_init();
ret = drm_sysfs_init();
    if (ret < 0) {
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 467872cca027..fc5ca8c4ccb2 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -161,7 +161,6 @@ gem-y += \
 i915-y += \
      $(gem-y) \
      i915_active.o \
-	  i915_buddy.o \
      i915_cmd_parser.o \
      i915_gem_evict.o \
      i915_gem_gtt.o \
diff --git a/drivers/gpu/drm/i915/i915_buddy.c b/drivers/gpu/drm/i915/i915_buddy.c
deleted file mode 100644
index 6e2ad68f8f3f..000000000000
--- a/drivers/gpu/drm/i915/i915_buddy.c
+++ /dev/null
@@ -1,466 +0,0 @@
-// SPDX-License-Identifier: MIT
-/*
- * Copyright © 2021 Intel Corporation
- */
-
-#include <linux/kmemleak.h>
-#include <linux/sizes.h>
-
-#include "i915_buddy.h"
-
-#include "i915_gem.h"
-#include "i915_utils.h"
-
-static struct kmem_cache *slab_blocks;
-
-static struct i915_buddy_block *i915_block_alloc(struct i915_buddy_mm *mm,
-						 struct i915_buddy_block *parent,
-						 unsigned int order,
-						 u64 offset)
-{
-	struct i915_buddy_block *block;
-
-	GEM_BUG_ON(order > I915_BUDDY_MAX_ORDER);
-
-	block = kmem_cache_zalloc(slab_blocks, GFP_KERNEL);
-	if (!block)
-		return NULL;
-
-	block->header = offset;
-	block->header |= order;
-	block->parent = parent;
-
-	GEM_BUG_ON(block->header & I915_BUDDY_HEADER_UNUSED);
-	return block;
-}
-
-static void i915_block_free(struct i915_buddy_mm *mm,
-			    struct i915_buddy_block *block)
-{
-	kmem_cache_free(slab_blocks, block);
-}
-
-static void mark_allocated(struct i915_buddy_block *block)
-{
-	block->header &= ~I915_BUDDY_HEADER_STATE;
-	block->header |= I915_BUDDY_ALLOCATED;
-
-	list_del(&block->link);
-}
-
-static void mark_free(struct i915_buddy_mm *mm,
-		      struct i915_buddy_block *block)
-{
-	block->header &= ~I915_BUDDY_HEADER_STATE;
-	block->header |= I915_BUDDY_FREE;
-
-	list_add(&block->link,
-		 &mm->free_list[i915_buddy_block_order(block)]);
-}
-
-static void mark_split(struct i915_buddy_block *block)
-{
-	block->header &= ~I915_BUDDY_HEADER_STATE;
-	block->header |= I915_BUDDY_SPLIT;
-
-	list_del(&block->link);
-}
-
-int i915_buddy_init(struct i915_buddy_mm *mm, u64 size, u64 chunk_size)
-{
-	unsigned int i;
-	u64 offset;
-
-	if (size < chunk_size)
-		return -EINVAL;
-
-	if (chunk_size < PAGE_SIZE)
-		return -EINVAL;
-
-	if (!is_power_of_2(chunk_size))
-		return -EINVAL;
-
-	size = round_down(size, chunk_size);
-
-	mm->size = size;
-	mm->avail = size;
-	mm->chunk_size = chunk_size;
-	mm->max_order = ilog2(size) - ilog2(chunk_size);
-
-	GEM_BUG_ON(mm->max_order > I915_BUDDY_MAX_ORDER);
-
-	mm->free_list = kmalloc_array(mm->max_order + 1,
-				      sizeof(struct list_head),
-				      GFP_KERNEL);
-	if (!mm->free_list)
-		return -ENOMEM;
-
-	for (i = 0; i <= mm->max_order; ++i)
-		INIT_LIST_HEAD(&mm->free_list[i]);
-
-	mm->n_roots = hweight64(size);
-
-	mm->roots = kmalloc_array(mm->n_roots,
-				  sizeof(struct i915_buddy_block *),
-				  GFP_KERNEL);
-	if (!mm->roots)
-		goto out_free_list;
-
-	offset = 0;
-	i = 0;
-
-	/*
-	 * Split into power-of-two blocks, in case we are given a size that is
-	 * not itself a power-of-two.
-	 */
-	do {
-		struct i915_buddy_block *root;
-		unsigned int order;
-		u64 root_size;
-
-		root_size = rounddown_pow_of_two(size);
-		order = ilog2(root_size) - ilog2(chunk_size);
-
-		root = i915_block_alloc(mm, NULL, order, offset);
-		if (!root)
-			goto out_free_roots;
-
-		mark_free(mm, root);
-
-		GEM_BUG_ON(i > mm->max_order);
-		GEM_BUG_ON(i915_buddy_block_size(mm, root) < chunk_size);
-
-		mm->roots[i] = root;
-
-		offset += root_size;
-		size -= root_size;
-		i++;
-	} while (size);
-
-	return 0;
-
-out_free_roots:
-	while (i--)
-		i915_block_free(mm, mm->roots[i]);
-	kfree(mm->roots);
-out_free_list:
-	kfree(mm->free_list);
-	return -ENOMEM;
-}
-
-void i915_buddy_fini(struct i915_buddy_mm *mm)
-{
-	int i;
-
-	for (i = 0; i < mm->n_roots; ++i) {
-		GEM_WARN_ON(!i915_buddy_block_is_free(mm->roots[i]));
-		i915_block_free(mm, mm->roots[i]);
-	}
-
-	GEM_WARN_ON(mm->avail != mm->size);
-
-	kfree(mm->roots);
-	kfree(mm->free_list);
-}
-
-static int split_block(struct i915_buddy_mm *mm,
-		       struct i915_buddy_block *block)
-{
-	unsigned int block_order = i915_buddy_block_order(block) - 1;
-	u64 offset = i915_buddy_block_offset(block);
-
-	GEM_BUG_ON(!i915_buddy_block_is_free(block));
-	GEM_BUG_ON(!i915_buddy_block_order(block));
-
-	block->left = i915_block_alloc(mm, block, block_order, offset);
-	if (!block->left)
-		return -ENOMEM;
-
-	block->right = i915_block_alloc(mm, block, block_order,
-					offset + (mm->chunk_size << block_order));
-	if (!block->right) {
-		i915_block_free(mm, block->left);
-		return -ENOMEM;
-	}
-
-	mark_free(mm, block->left);
-	mark_free(mm, block->right);
-
-	mark_split(block);
-
-	return 0;
-}
-
-static struct i915_buddy_block *
-get_buddy(struct i915_buddy_block *block)
-{
-	struct i915_buddy_block *parent;
-
-	parent = block->parent;
-	if (!parent)
-		return NULL;
-
-	if (parent->left == block)
-		return parent->right;
-
-	return parent->left;
-}
-
-static void __i915_buddy_free(struct i915_buddy_mm *mm,
-			      struct i915_buddy_block *block)
-{
-	struct i915_buddy_block *parent;
-
-	while ((parent = block->parent)) {
-		struct i915_buddy_block *buddy;
-
-		buddy = get_buddy(block);
-
-		if (!i915_buddy_block_is_free(buddy))
-			break;
-
-		list_del(&buddy->link);
-
-		i915_block_free(mm, block);
-		i915_block_free(mm, buddy);
-
-		block = parent;
-	}
-
-	mark_free(mm, block);
-}
-
-void i915_buddy_free(struct i915_buddy_mm *mm,
-		     struct i915_buddy_block *block)
-{
-	GEM_BUG_ON(!i915_buddy_block_is_allocated(block));
-	mm->avail += i915_buddy_block_size(mm, block);
-	__i915_buddy_free(mm, block);
-}
-
-void i915_buddy_free_list(struct i915_buddy_mm *mm, struct list_head *objects)
-{
-	struct i915_buddy_block *block, *on;
-
-	list_for_each_entry_safe(block, on, objects, link) {
-		i915_buddy_free(mm, block);
-		cond_resched();
-	}
-	INIT_LIST_HEAD(objects);
-}
-
-/*
- * Allocate power-of-two block. The order value here translates to:
- *
- *   0 = 2^0 * mm->chunk_size
- *   1 = 2^1 * mm->chunk_size
- *   2 = 2^2 * mm->chunk_size
- *   ...
- */
-struct i915_buddy_block *
-i915_buddy_alloc(struct i915_buddy_mm *mm, unsigned int order)
-{
-	struct i915_buddy_block *block = NULL;
-	unsigned int i;
-	int err;
-
-	for (i = order; i <= mm->max_order; ++i) {
-		block = list_first_entry_or_null(&mm->free_list[i],
-						 struct i915_buddy_block,
-						 link);
-		if (block)
-			break;
-	}
-
-	if (!block)
-		return ERR_PTR(-ENOSPC);
-
-	GEM_BUG_ON(!i915_buddy_block_is_free(block));
-
-	while (i != order) {
-		err = split_block(mm, block);
-		if (unlikely(err))
-			goto out_free;
-
-		/* Go low */
-		block = block->left;
-		i--;
-	}
-
-	mark_allocated(block);
-	mm->avail -= i915_buddy_block_size(mm, block);
-	kmemleak_update_trace(block);
-	return block;
-
-out_free:
-	if (i != order)
-		__i915_buddy_free(mm, block);
-	return ERR_PTR(err);
-}
-
-static inline bool overlaps(u64 s1, u64 e1, u64 s2, u64 e2)
-{
-	return s1 <= e2 && e1 >= s2;
-}
-
-static inline bool contains(u64 s1, u64 e1, u64 s2, u64 e2)
-{
-	return s1 <= s2 && e1 >= e2;
-}
-
-/*
- * Allocate range. Note that it's safe to chain together multiple alloc_ranges
- * with the same blocks list.
- *
- * Intended for pre-allocating portions of the address space, for example to
- * reserve a block for the initial framebuffer or similar, hence the expectation
- * here is that i915_buddy_alloc() is still the main vehicle for
- * allocations, so if that's not the case then the drm_mm range allocator is
- * probably a much better fit, and so you should probably go use that instead.
- */
-int i915_buddy_alloc_range(struct i915_buddy_mm *mm,
-			   struct list_head *blocks,
-			   u64 start, u64 size)
-{
-	struct i915_buddy_block *block;
-	struct i915_buddy_block *buddy;
-	LIST_HEAD(allocated);
-	LIST_HEAD(dfs);
-	u64 end;
-	int err;
-	int i;
-
-	if (size < mm->chunk_size)
-		return -EINVAL;
-
-	if (!IS_ALIGNED(size | start, mm->chunk_size))
-		return -EINVAL;
-
-	if (range_overflows(start, size, mm->size))
-		return -EINVAL;
-
-	for (i = 0; i < mm->n_roots; ++i)
-		list_add_tail(&mm->roots[i]->tmp_link, &dfs);
-
-	end = start + size - 1;
-
-	do {
-		u64 block_start;
-		u64 block_end;
-
-		block = list_first_entry_or_null(&dfs,
-						 struct i915_buddy_block,
-						 tmp_link);
-		if (!block)
-			break;
-
-		list_del(&block->tmp_link);
-
-		block_start = i915_buddy_block_offset(block);
-		block_end = block_start + i915_buddy_block_size(mm, block) - 1;
-
-		if (!overlaps(start, end, block_start, block_end))
-			continue;
-
-		if (i915_buddy_block_is_allocated(block)) {
-			err = -ENOSPC;
-			goto err_free;
-		}
-
-		if (contains(start, end, block_start, block_end)) {
-			if (!i915_buddy_block_is_free(block)) {
-				err = -ENOSPC;
-				goto err_free;
-			}
-
-			mark_allocated(block);
-			mm->avail -= i915_buddy_block_size(mm, block);
-			list_add_tail(&block->link, &allocated);
-			continue;
-		}
-
-		if (!i915_buddy_block_is_split(block)) {
-			err = split_block(mm, block);
-			if (unlikely(err))
-				goto err_undo;
-		}
-
-		list_add(&block->right->tmp_link, &dfs);
-		list_add(&block->left->tmp_link, &dfs);
-	} while (1);
-
-	list_splice_tail(&allocated, blocks);
-	return 0;
-
-err_undo:
-	/*
-	 * We really don't want to leave around a bunch of split blocks, since
-	 * bigger is better, so make sure we merge everything back before we
-	 * free the allocated blocks.
-	 */
-	buddy = get_buddy(block);
-	if (buddy &&
-	    (i915_buddy_block_is_free(block) &&
-	     i915_buddy_block_is_free(buddy)))
-		__i915_buddy_free(mm, block);
-
-err_free:
-	i915_buddy_free_list(mm, &allocated);
-	return err;
-}
-
-void i915_buddy_block_print(struct i915_buddy_mm *mm,
-			    struct i915_buddy_block *block,
-			    struct drm_printer *p)
-{
-	u64 start = i915_buddy_block_offset(block);
-	u64 size = i915_buddy_block_size(mm, block);
-
-	drm_printf(p, "%#018llx-%#018llx: %llu\n", start, start + size, size);
-}
-
-void i915_buddy_print(struct i915_buddy_mm *mm, struct drm_printer *p)
-{
-	int order;
-
-	drm_printf(p, "chunk_size: %lluKiB, total: %lluMiB, free: %lluMiB\n",
-		   mm->chunk_size >> 10, mm->size >> 20, mm->avail >> 20);
-
-	for (order = mm->max_order; order >= 0; order--) {
-		struct i915_buddy_block *block;
-		u64 count = 0, free;
-
-		list_for_each_entry(block, &mm->free_list[order], link) {
-			GEM_BUG_ON(!i915_buddy_block_is_free(block));
-			count++;
-		}
-
-		drm_printf(p, "order-%d ", order);
-
-		free = count * (mm->chunk_size << order);
-		if (free < SZ_1M)
-			drm_printf(p, "free: %lluKiB", free >> 10);
-		else
-			drm_printf(p, "free: %lluMiB", free >> 20);
-
-		drm_printf(p, ", pages: %llu\n", count);
-	}
-}
-
-#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
-#include "selftests/i915_buddy.c"
-#endif
-
-void i915_buddy_module_exit(void)
-{
-	kmem_cache_destroy(slab_blocks);
-}
-
-int __init i915_buddy_module_init(void)
-{
-	slab_blocks = KMEM_CACHE(i915_buddy_block, 0);
-	if (!slab_blocks)
-		return -ENOMEM;
-
-	return 0;
-}
diff --git a/drivers/gpu/drm/i915/i915_buddy.h b/drivers/gpu/drm/i915/i915_buddy.h
deleted file mode 100644
index 7077742112ac..000000000000
--- a/drivers/gpu/drm/i915/i915_buddy.h
+++ /dev/null
@@ -1,143 +0,0 @@
-/* SPDX-License-Identifier: MIT */
-/*
- * Copyright © 2021 Intel Corporation
- */
-
-#ifndef __I915_BUDDY_H__
-#define __I915_BUDDY_H__
-
-#include <linux/bitops.h>
-#include <linux/list.h>
-#include <linux/slab.h>
-
-#include <drm/drm_print.h>
-
-struct i915_buddy_block {
-#define I915_BUDDY_HEADER_OFFSET GENMASK_ULL(63, 12)
-#define I915_BUDDY_HEADER_STATE  GENMASK_ULL(11, 10)
-#define   I915_BUDDY_ALLOCATED	   (1 << 10)
-#define   I915_BUDDY_FREE	   (2 << 10)
-#define   I915_BUDDY_SPLIT	   (3 << 10)
-/* Free to be used, if needed in the future */
-#define I915_BUDDY_HEADER_UNUSED GENMASK_ULL(9, 6)
-#define I915_BUDDY_HEADER_ORDER  GENMASK_ULL(5, 0)
-	u64 header;
-
-	struct i915_buddy_block *left;
-	struct i915_buddy_block *right;
-	struct i915_buddy_block *parent;
-
-	void *private; /* owned by creator */
-
-	/*
-	 * While the block is allocated by the user through i915_buddy_alloc*,
-	 * the user has ownership of the link, for example to maintain within
-	 * a list, if so desired. As soon as the block is freed with
-	 * i915_buddy_free* ownership is given back to the mm.
-	 */
-	struct list_head link;
-	struct list_head tmp_link;
-};
-
-/* Order-zero must be at least PAGE_SIZE */
-#define I915_BUDDY_MAX_ORDER (63 - PAGE_SHIFT)
-
-/*
- * Binary Buddy System.
- *
- * Locking should be handled by the user, a simple mutex around
- * i915_buddy_alloc* and i915_buddy_free* should suffice.
- */
-struct i915_buddy_mm {
-	/* Maintain a free list for each order. */
-	struct list_head *free_list;
-
-	/*
-	 * Maintain explicit binary tree(s) to track the allocation of the
-	 * address space. This gives us a simple way of finding a buddy block
-	 * and performing the potentially recursive merge step when freeing a
-	 * block.  Nodes are either allocated or free, in which case they will
-	 * also exist on the respective free list.
-	 */
-	struct i915_buddy_block **roots;
-
-	/*
-	 * Anything from here is public, and remains static for the lifetime of
-	 * the mm. Everything above is considered do-not-touch.
-	 */
-	unsigned int n_roots;
-	unsigned int max_order;
-
-	/* Must be at least PAGE_SIZE */
-	u64 chunk_size;
-	u64 size;
-	u64 avail;
-};
-
-static inline u64
-i915_buddy_block_offset(struct i915_buddy_block *block)
-{
-	return block->header & I915_BUDDY_HEADER_OFFSET;
-}
-
-static inline unsigned int
-i915_buddy_block_order(struct i915_buddy_block *block)
-{
-	return block->header & I915_BUDDY_HEADER_ORDER;
-}
-
-static inline unsigned int
-i915_buddy_block_state(struct i915_buddy_block *block)
-{
-	return block->header & I915_BUDDY_HEADER_STATE;
-}
-
-static inline bool
-i915_buddy_block_is_allocated(struct i915_buddy_block *block)
-{
-	return i915_buddy_block_state(block) == I915_BUDDY_ALLOCATED;
-}
-
-static inline bool
-i915_buddy_block_is_free(struct i915_buddy_block *block)
-{
-	return i915_buddy_block_state(block) == I915_BUDDY_FREE;
-}
-
-static inline bool
-i915_buddy_block_is_split(struct i915_buddy_block *block)
-{
-	return i915_buddy_block_state(block) == I915_BUDDY_SPLIT;
-}
-
-static inline u64
-i915_buddy_block_size(struct i915_buddy_mm *mm,
-		      struct i915_buddy_block *block)
-{
-	return mm->chunk_size << i915_buddy_block_order(block);
-}
-
-int i915_buddy_init(struct i915_buddy_mm *mm, u64 size, u64 chunk_size);
-
-void i915_buddy_fini(struct i915_buddy_mm *mm);
-
-struct i915_buddy_block *
-i915_buddy_alloc(struct i915_buddy_mm *mm, unsigned int order);
-
-int i915_buddy_alloc_range(struct i915_buddy_mm *mm,
-			   struct list_head *blocks,
-			   u64 start, u64 size);
-
-void i915_buddy_free(struct i915_buddy_mm *mm, struct i915_buddy_block *block);
-
-void i915_buddy_free_list(struct i915_buddy_mm *mm, struct list_head *objects);
-
-void i915_buddy_print(struct i915_buddy_mm *mm, struct drm_printer *p);
-void i915_buddy_block_print(struct i915_buddy_mm *mm,
-			    struct i915_buddy_block *block,
-			    struct drm_printer *p);
-
-void i915_buddy_module_exit(void);
-int i915_buddy_module_init(void);
-
-#endif
diff --git a/drivers/gpu/drm/i915/i915_module.c b/drivers/gpu/drm/i915/i915_module.c
index c7507266aa83..355681dbd7a8 100644
--- a/drivers/gpu/drm/i915/i915_module.c
+++ b/drivers/gpu/drm/i915/i915_module.c
@@ -9,7 +9,6 @@
 #include "gem/i915_gem_context.h"
 #include "gem/i915_gem_object.h"
 #include "i915_active.h"
-#include "i915_buddy.h"
 #include "i915_params.h"
 #include "i915_pci.h"
 #include "i915_perf.h"
@@ -50,8 +49,6 @@ static const struct {
    { .init = i915_check_nomodeset },
    { .init = i915_active_module_init,
      .exit = i915_active_module_exit },
-	{ .init = i915_buddy_module_init,
-	  .exit = i915_buddy_module_exit },
    { .init = i915_context_module_init,
      .exit = i915_context_module_exit },
    { .init = i915_gem_context_module_init,
diff --git a/drivers/gpu/drm/i915/i915_scatterlist.c b/drivers/gpu/drm/i915/i915_scatterlist.c
index 4a6712dca838..84d622aa32d2 100644
--- a/drivers/gpu/drm/i915/i915_scatterlist.c
+++ b/drivers/gpu/drm/i915/i915_scatterlist.c
@@ -5,10 +5,9 @@
  */
#include "i915_scatterlist.h"
-
-#include "i915_buddy.h"
 #include "i915_ttm_buddy_manager.h"
+#include <drm/drm_buddy.h>
 #include <drm/drm_mm.h>
#include <linux/slab.h>
@@ -126,9 +125,9 @@ struct sg_table *i915_sg_from_buddy_resource(struct ttm_resource *res,
    struct i915_ttm_buddy_resource *bman_res = to_ttm_buddy_resource(res);
    const u64 size = res->num_pages << PAGE_SHIFT;
    const u64 max_segment = rounddown(UINT_MAX, PAGE_SIZE);
-	struct i915_buddy_mm *mm = bman_res->mm;
+	struct drm_buddy_mm *mm = bman_res->mm;
    struct list_head *blocks = &bman_res->blocks;
-	struct i915_buddy_block *block;
+	struct drm_buddy_block *block;
    struct scatterlist *sg;
    struct sg_table *st;
    resource_size_t prev_end;
@@ -151,8 +150,8 @@ struct sg_table *i915_sg_from_buddy_resource(struct ttm_resource *res,
    list_for_each_entry(block, blocks, link) {
    	u64 block_size, offset;
-		block_size = min_t(u64, size, i915_buddy_block_size(mm, block));
-		offset = i915_buddy_block_offset(block);
+		block_size = min_t(u64, size, drm_buddy_block_size(mm, block));
+		offset = drm_buddy_block_offset(block);
while (block_size) {
    		u64 len;
diff --git a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
index d59fbb019032..c4b70cb8c248 100644
--- a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
+++ b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
@@ -8,14 +8,15 @@
 #include <drm/ttm/ttm_bo_driver.h>
 #include <drm/ttm/ttm_placement.h>
+#include <drm/drm_buddy.h>
+
 #include "i915_ttm_buddy_manager.h"
-#include "i915_buddy.h"
 #include "i915_gem.h"
struct i915_ttm_buddy_manager {
    struct ttm_resource_manager manager;
-	struct i915_buddy_mm mm;
+	struct drm_buddy_mm mm;
    struct list_head reserved;
    struct mutex lock;
    u64 default_page_size;
@@ -34,7 +35,7 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,
 {
    struct i915_ttm_buddy_manager *bman = to_buddy_manager(man);
    struct i915_ttm_buddy_resource *bman_res;
-	struct i915_buddy_mm *mm = &bman->mm;
+	struct drm_buddy_mm *mm = &bman->mm;
    unsigned long n_pages;
    unsigned int min_order;
    u64 min_page_size;
@@ -73,7 +74,7 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,
    n_pages = size >> ilog2(mm->chunk_size);
do {
-		struct i915_buddy_block *block;
+		struct drm_buddy_block *block;
    	unsigned int order;
order = fls(n_pages) - 1;
@@ -82,7 +83,7 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,
do {
    		mutex_lock(&bman->lock);
-			block = i915_buddy_alloc(mm, order);
+			block = drm_buddy_alloc(mm, order);
    		mutex_unlock(&bman->lock);
    		if (!IS_ERR(block))
    			break;
@@ -106,7 +107,7 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,
err_free_blocks:
    mutex_lock(&bman->lock);
-	i915_buddy_free_list(mm, &bman_res->blocks);
+	drm_buddy_free_list(mm, &bman_res->blocks);
    mutex_unlock(&bman->lock);
 err_free_res:
    kfree(bman_res);
@@ -120,7 +121,7 @@ static void i915_ttm_buddy_man_free(struct ttm_resource_manager *man,
    struct i915_ttm_buddy_manager *bman = to_buddy_manager(man);
mutex_lock(&bman->lock);
-	i915_buddy_free_list(&bman->mm, &bman_res->blocks);
+	drm_buddy_free_list(&bman->mm, &bman_res->blocks);
    mutex_unlock(&bman->lock);
kfree(bman_res);
@@ -130,17 +131,17 @@ static void i915_ttm_buddy_man_debug(struct ttm_resource_manager *man,
    			     struct drm_printer *printer)
 {
    struct i915_ttm_buddy_manager *bman = to_buddy_manager(man);
-	struct i915_buddy_block *block;
+	struct drm_buddy_block *block;
mutex_lock(&bman->lock);
    drm_printf(printer, "default_page_size: %lluKiB\n",
    	   bman->default_page_size >> 10);
-	i915_buddy_print(&bman->mm, printer);
+	drm_buddy_print(&bman->mm, printer);
drm_printf(printer, "reserved:\n");
    list_for_each_entry(block, &bman->reserved, link)
-		i915_buddy_block_print(&bman->mm, block, printer);
+		drm_buddy_block_print(&bman->mm, block, printer);
    mutex_unlock(&bman->lock);
 }
@@ -190,7 +191,7 @@ int i915_ttm_buddy_man_init(struct ttm_device *bdev,
    if (!bman)
    	return -ENOMEM;
-	err = i915_buddy_init(&bman->mm, size, chunk_size);
+	err = drm_buddy_init(&bman->mm, size, chunk_size);
    if (err)
    	goto err_free_bman;
@@ -228,7 +229,7 @@ int i915_ttm_buddy_man_fini(struct ttm_device *bdev, unsigned int type)
 {
    struct ttm_resource_manager *man = ttm_manager_type(bdev, type);
    struct i915_ttm_buddy_manager *bman = to_buddy_manager(man);
-	struct i915_buddy_mm *mm = &bman->mm;
+	struct drm_buddy_mm *mm = &bman->mm;
    int ret;
ttm_resource_manager_set_used(man, false);
@@ -240,8 +241,8 @@ int i915_ttm_buddy_man_fini(struct ttm_device *bdev, unsigned int type)
    ttm_set_driver_manager(bdev, type, NULL);
mutex_lock(&bman->lock);
-	i915_buddy_free_list(mm, &bman->reserved);
-	i915_buddy_fini(mm);
+	drm_buddy_free_list(mm, &bman->reserved);
+	drm_buddy_fini(mm);
    mutex_unlock(&bman->lock);
ttm_resource_manager_cleanup(man);
@@ -264,11 +265,11 @@ int i915_ttm_buddy_man_reserve(struct ttm_resource_manager *man,
    		       u64 start, u64 size)
 {
    struct i915_ttm_buddy_manager *bman = to_buddy_manager(man);
-	struct i915_buddy_mm *mm = &bman->mm;
+	struct drm_buddy_mm *mm = &bman->mm;
    int ret;
mutex_lock(&bman->lock);
-	ret = i915_buddy_alloc_range(mm, &bman->reserved, start, size);
+	ret = drm_buddy_alloc_range(mm, &bman->reserved, start, size);
    mutex_unlock(&bman->lock);
return ret;
diff --git a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h
index 0722d33f3e14..fa644b512c2e 100644
--- a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h
+++ b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h
@@ -13,7 +13,7 @@
struct ttm_device;
 struct ttm_resource_manager;
-struct i915_buddy_mm;
+struct drm_buddy_mm;
/**
  * struct i915_ttm_buddy_resource
@@ -28,7 +28,7 @@ struct i915_buddy_mm;
 struct i915_ttm_buddy_resource {
    struct ttm_resource base;
    struct list_head blocks;
-	struct i915_buddy_mm *mm;
+	struct drm_buddy_mm *mm;
 };
/**
diff --git a/include/drm/drm_buddy.h b/include/drm/drm_buddy.h
new file mode 100644
index 000000000000..5ce3fc702f80
--- /dev/null
+++ b/include/drm/drm_buddy.h
@@ -0,0 +1,153 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2021 Intel Corporation
+ */
+
+#ifndef __DRM_BUDDY_H__
+#define __DRM_BUDDY_H__
+
+#include <linux/bitops.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+
+#include <drm/drm_print.h>
+
+#define range_overflows(start, size, max) ({ \
+	typeof(start) start__ = (start); \
+	typeof(size) size__ = (size); \
+	typeof(max) max__ = (max); \
+	(void)(&start__ == &size__); \
+	(void)(&start__ == &max__); \
+	start__ >= max__ || size__ > max__ - start__; \
+})
+
+struct drm_buddy_block {
+#define DRM_BUDDY_HEADER_OFFSET GENMASK_ULL(63, 12)
+#define DRM_BUDDY_HEADER_STATE  GENMASK_ULL(11, 10)
+#define   DRM_BUDDY_ALLOCATED	   (1 << 10)
+#define   DRM_BUDDY_FREE	   (2 << 10)
+#define   DRM_BUDDY_SPLIT	   (3 << 10)
+/* Free to be used, if needed in the future */
+#define DRM_BUDDY_HEADER_UNUSED GENMASK_ULL(9, 6)
+#define DRM_BUDDY_HEADER_ORDER  GENMASK_ULL(5, 0)
+	u64 header;
+
+	struct drm_buddy_block *left;
+	struct drm_buddy_block *right;
+	struct drm_buddy_block *parent;
+
+	void *private; /* owned by creator */
+
+	/*
+	 * While the block is allocated by the user through drm_buddy_alloc*,
+	 * the user has ownership of the link, for example to maintain within
+	 * a list, if so desired. As soon as the block is freed with
+	 * drm_buddy_free* ownership is given back to the mm.
+	 */
+	struct list_head link;
+	struct list_head tmp_link;
+};
+
+/* Order-zero must be at least PAGE_SIZE */
+#define DRM_BUDDY_MAX_ORDER (63 - PAGE_SHIFT)
+
+/*
+ * Binary Buddy System.
+ *
+ * Locking should be handled by the user, a simple mutex around
+ * drm_buddy_alloc* and drm_buddy_free* should suffice.
+ */
+struct drm_buddy_mm {
+	/* Maintain a free list for each order. */
+	struct list_head *free_list;
+
+	/*
+	 * Maintain explicit binary tree(s) to track the allocation of the
+	 * address space. This gives us a simple way of finding a buddy block
+	 * and performing the potentially recursive merge step when freeing a
+	 * block.  Nodes are either allocated or free, in which case they will
+	 * also exist on the respective free list.
+	 */
+	struct drm_buddy_block **roots;
+
+	/*
+	 * Anything from here is public, and remains static for the lifetime of
+	 * the mm. Everything above is considered do-not-touch.
+	 */
+	unsigned int n_roots;
+	unsigned int max_order;
+
+	/* Must be at least PAGE_SIZE */
+	u64 chunk_size;
+	u64 size;
+	u64 avail;
+};
+
+static inline u64
+drm_buddy_block_offset(struct drm_buddy_block *block)
+{
+	return block->header & DRM_BUDDY_HEADER_OFFSET;
+}
+
+static inline unsigned int
+drm_buddy_block_order(struct drm_buddy_block *block)
+{
+	return block->header & DRM_BUDDY_HEADER_ORDER;
+}
+
+static inline unsigned int
+drm_buddy_block_state(struct drm_buddy_block *block)
+{
+	return block->header & DRM_BUDDY_HEADER_STATE;
+}
+
+static inline bool
+drm_buddy_block_is_allocated(struct drm_buddy_block *block)
+{
+	return drm_buddy_block_state(block) == DRM_BUDDY_ALLOCATED;
+}
+
+static inline bool
+drm_buddy_block_is_free(struct drm_buddy_block *block)
+{
+	return drm_buddy_block_state(block) == DRM_BUDDY_FREE;
+}
+
+static inline bool
+drm_buddy_block_is_split(struct drm_buddy_block *block)
+{
+	return drm_buddy_block_state(block) == DRM_BUDDY_SPLIT;
+}
+
+static inline u64
+drm_buddy_block_size(struct drm_buddy_mm *mm,
+		     struct drm_buddy_block *block)
+{
+	return mm->chunk_size << drm_buddy_block_order(block);
+}
+
+int drm_buddy_init(struct drm_buddy_mm *mm, u64 size, u64 chunk_size);
+
+void drm_buddy_fini(struct drm_buddy_mm *mm);
+
+struct drm_buddy_block *
+drm_buddy_alloc(struct drm_buddy_mm *mm, unsigned int order);
+
+int drm_buddy_alloc_range(struct drm_buddy_mm *mm,
+			  struct list_head *blocks,
+			  u64 start, u64 size);
+
+void drm_buddy_free(struct drm_buddy_mm *mm, struct drm_buddy_block *block);
+
+void drm_buddy_free_list(struct drm_buddy_mm *mm, struct list_head *objects);
+
+void drm_buddy_print(struct drm_buddy_mm *mm, struct drm_printer *p);
+void drm_buddy_block_print(struct drm_buddy_mm *mm,
+			   struct drm_buddy_block *block,
+			   struct drm_printer *p);
+
+void drm_buddy_module_exit(void);
+int drm_buddy_module_init(void);
+
+#endif
-- 
2.25.1


    

[PATCH v3 1/6] drm: move the buddy allocator from i915 into common drm

Signed-off-by: Arunpravin Arunpravin.PaneerSelvam@amd.com

Signed-off-by: Arunpravin Arunpravin.PaneerSelvam@amd.com

Signed-off-by: Arunpravin Arunpravin.PaneerSelvam@amd.com

Signed-off-by: Arunpravin Arunpravin.PaneerSelvam@amd.com

Signed-off-by: Arunpravin Arunpravin.PaneerSelvam@amd.com

Signed-off-by: Arunpravin Arunpravin.PaneerSelvam@amd.com

Signed-off-by: Arunpravin Arunpravin.PaneerSelvam@amd.com