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

Christian König ckoenig.leichtzumerken at gmail.com
Wed Nov 17 08:03:23 UTC 2021


I've looked a bit more into this and I think we should just follow 
Thomas Zimmermann's idea to make this a separate module.

Otherwise we just have the code around all the time even if it is unused 
and implementing this should be trivial.

See how DRM_GEM_CMA_HELPER or DRM_VRAM_HELPER are done in 
drivers/gpu/drm/Kconfig and then have the desired effect in 
drivers/gpu/drm/Makefile

Should be something like ~15 lines of additional configuration which 
saves a bit of memory on embedded systems which just need a fbdev 
replacement.

Thanks,
Christian.

Am 16.11.21 um 21:18 schrieb Arunpravin:
> 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 at 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



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