1 files changed, 335 insertions, 85 deletions

diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c
index d60878bc9c20..72f52f293249 100644
--- a/drivers/gpu/drm/drm_buddy.c
+++ b/drivers/gpu/drm/drm_buddy.c
@@ -211,7 +211,7 @@ static int split_block(struct drm_buddy *mm,
 }
 
 static struct drm_buddy_block *
-get_buddy(struct drm_buddy_block *block)
+__get_buddy(struct drm_buddy_block *block)
 {
 	struct drm_buddy_block *parent;
 
@@ -225,6 +225,23 @@ get_buddy(struct drm_buddy_block *block)
 	return parent->left;
 }
 
+/**
+ * drm_get_buddy - get buddy address
+ *
+ * @block: DRM buddy block
+ *
+ * Returns the corresponding buddy block for @block, or NULL
+ * if this is a root block and can't be merged further.
+ * Requires some kind of locking to protect against
+ * any concurrent allocate and free operations.
+ */
+struct drm_buddy_block *
+drm_get_buddy(struct drm_buddy_block *block)
+{
+	return __get_buddy(block);
+}
+EXPORT_SYMBOL(drm_get_buddy);
+
 static void __drm_buddy_free(struct drm_buddy *mm,
 			     struct drm_buddy_block *block)
 {
@@ -233,7 +250,7 @@ static void __drm_buddy_free(struct drm_buddy *mm,
 	while ((parent = block->parent)) {
 		struct drm_buddy_block *buddy;
 
-		buddy = get_buddy(block);
+		buddy = __get_buddy(block);
 
 		if (!drm_buddy_block_is_free(buddy))
 			break;
@@ -282,34 +299,134 @@ void drm_buddy_free_list(struct drm_buddy *mm, struct list_head *objects)
 }
 EXPORT_SYMBOL(drm_buddy_free_list);
 
-/**
- * drm_buddy_alloc_blocks - 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_blocks(struct drm_buddy *mm, unsigned int order)
+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;
+}
+
+static struct drm_buddy_block *
+alloc_range_bias(struct drm_buddy *mm,
+		 u64 start, u64 end,
+		 unsigned int order)
+{
+	struct drm_buddy_block *block;
+	struct drm_buddy_block *buddy;
+	LIST_HEAD(dfs);
+	int err;
+	int i;
+
+	end = end - 1;
+
+	for (i = 0; i < mm->n_roots; ++i)
+		list_add_tail(&mm->roots[i]->tmp_link, &dfs);
+
+	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);
+
+		if (drm_buddy_block_order(block) < order)
+			continue;
+
+		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))
+			continue;
+
+		if (contains(start, end, block_start, block_end) &&
+		    order == drm_buddy_block_order(block)) {
+			/*
+			 * Find the free block within the range.
+			 */
+			if (drm_buddy_block_is_free(block))
+				return block;
+
+			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);
+
+	return ERR_PTR(-ENOSPC);
+
+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);
+	return ERR_PTR(err);
+}
+
+static struct drm_buddy_block *
+get_maxblock(struct list_head *head)
+{
+	struct drm_buddy_block *max_block = NULL, *node;
+
+	max_block = list_first_entry_or_null(head,
+					     struct drm_buddy_block,
+					     link);
+	if (!max_block)
+		return NULL;
+
+	list_for_each_entry(node, head, link) {
+		if (drm_buddy_block_offset(node) >
+		    drm_buddy_block_offset(max_block))
+			max_block = node;
+	}
+
+	return max_block;
+}
+
+static struct drm_buddy_block *
+alloc_from_freelist(struct drm_buddy *mm,
+		    unsigned int order,
+		    unsigned long flags)
 {
 	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 (flags & DRM_BUDDY_TOPDOWN_ALLOCATION) {
+			block = get_maxblock(&mm->free_list[i]);
+			if (block)
+				break;
+		} else {
+			block = list_first_entry_or_null(&mm->free_list[i],
+							 struct drm_buddy_block,
+							 link);
+			if (block)
+				break;
+		}
 	}
 
 	if (!block)
@@ -320,78 +437,29 @@ drm_buddy_alloc_blocks(struct drm_buddy *mm, unsigned int order)
 	while (i != order) {
 		err = split_block(mm, block);
 		if (unlikely(err))
-			goto out_free;
+			goto err_undo;
 
-		/* Go low */
-		block = block->left;
+		block = block->right;
 		i--;
 	}
-
-	mark_allocated(block);
-	mm->avail -= drm_buddy_block_size(mm, block);
-	kmemleak_update_trace(block);
 	return block;
 
-out_free:
+err_undo:
 	if (i != order)
 		__drm_buddy_free(mm, block);
 	return ERR_PTR(err);
 }
-EXPORT_SYMBOL(drm_buddy_alloc_blocks);
-
-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_blocks() 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,
-			  struct list_head *blocks,
-			  u64 start, u64 size)
+static int __alloc_range(struct drm_buddy *mm,
+			 struct list_head *dfs,
+			 u64 start, u64 size,
+			 struct list_head *blocks)
 {
 	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;
 
@@ -399,7 +467,7 @@ int drm_buddy_alloc_range(struct drm_buddy *mm,
 		u64 block_start;
 		u64 block_end;
 
-		block = list_first_entry_or_null(&dfs,
+		block = list_first_entry_or_null(dfs,
 						 struct drm_buddy_block,
 						 tmp_link);
 		if (!block)
@@ -436,8 +504,8 @@ int drm_buddy_alloc_range(struct drm_buddy *mm,
 				goto err_undo;
 		}
 
-		list_add(&block->right->tmp_link, &dfs);
-		list_add(&block->left->tmp_link, &dfs);
+		list_add(&block->right->tmp_link, dfs);
+		list_add(&block->left->tmp_link, dfs);
 	} while (1);
 
 	list_splice_tail(&allocated, blocks);
@@ -449,7 +517,7 @@ err_undo:
 	 * bigger is better, so make sure we merge everything back before we
 	 * free the allocated blocks.
 	 */
-	buddy = get_buddy(block);
+	buddy = __get_buddy(block);
 	if (buddy &&
 	    (drm_buddy_block_is_free(block) &&
 	     drm_buddy_block_is_free(buddy)))
@@ -459,7 +527,189 @@ err_free:
 	drm_buddy_free_list(mm, &allocated);
 	return err;
 }
-EXPORT_SYMBOL(drm_buddy_alloc_range);
+
+static int __drm_buddy_alloc_range(struct drm_buddy *mm,
+				   u64 start,
+				   u64 size,
+				   struct list_head *blocks)
+{
+	LIST_HEAD(dfs);
+	int i;
+
+	for (i = 0; i < mm->n_roots; ++i)
+		list_add_tail(&mm->roots[i]->tmp_link, &dfs);
+
+	return __alloc_range(mm, &dfs, start, size, blocks);
+}
+
+/**
+ * drm_buddy_block_trim - free unused pages
+ *
+ * @mm: DRM buddy manager
+ * @new_size: original size requested
+ * @blocks: Input and output list of allocated blocks.
+ * MUST contain single block as input to be trimmed.
+ * On success will contain the newly allocated blocks
+ * making up the @new_size. Blocks always appear in
+ * ascending order
+ *
+ * For contiguous allocation, we round up the size to the nearest
+ * power of two value, drivers consume *actual* size, so remaining
+ * portions are unused and can be optionally freed with this function
+ *
+ * Returns:
+ * 0 on success, error code on failure.
+ */
+int drm_buddy_block_trim(struct drm_buddy *mm,
+			 u64 new_size,
+			 struct list_head *blocks)
+{
+	struct drm_buddy_block *parent;
+	struct drm_buddy_block *block;
+	LIST_HEAD(dfs);
+	u64 new_start;
+	int err;
+
+	if (!list_is_singular(blocks))
+		return -EINVAL;
+
+	block = list_first_entry(blocks,
+				 struct drm_buddy_block,
+				 link);
+
+	if (WARN_ON(!drm_buddy_block_is_allocated(block)))
+		return -EINVAL;
+
+	if (new_size > drm_buddy_block_size(mm, block))
+		return -EINVAL;
+
+	if (!new_size || !IS_ALIGNED(new_size, mm->chunk_size))
+		return -EINVAL;
+
+	if (new_size == drm_buddy_block_size(mm, block))
+		return 0;
+
+	list_del(&block->link);
+	mark_free(mm, block);
+	mm->avail += drm_buddy_block_size(mm, block);
+
+	/* Prevent recursively freeing this node */
+	parent = block->parent;
+	block->parent = NULL;
+
+	new_start = drm_buddy_block_offset(block);
+	list_add(&block->tmp_link, &dfs);
+	err =  __alloc_range(mm, &dfs, new_start, new_size, blocks);
+	if (err) {
+		mark_allocated(block);
+		mm->avail -= drm_buddy_block_size(mm, block);
+		list_add(&block->link, blocks);
+	}
+
+	block->parent = parent;
+	return err;
+}
+EXPORT_SYMBOL(drm_buddy_block_trim);
+
+/**
+ * drm_buddy_alloc_blocks - allocate power-of-two blocks
+ *
+ * @mm: DRM buddy manager to allocate from
+ * @start: start of the allowed range for this block
+ * @end: end of the allowed range for this block
+ * @size: size of the allocation
+ * @min_page_size: alignment of the allocation
+ * @blocks: output list head to add allocated blocks
+ * @flags: DRM_BUDDY_*_ALLOCATION flags
+ *
+ * alloc_range_bias() called on range limitations, which traverses
+ * the tree and returns the desired block.
+ *
+ * alloc_from_freelist() called when *no* range restrictions
+ * are enforced, which picks the block from the freelist.
+ *
+ * Returns:
+ * 0 on success, error code on failure.
+ */
+int drm_buddy_alloc_blocks(struct drm_buddy *mm,
+			   u64 start, u64 end, u64 size,
+			   u64 min_page_size,
+			   struct list_head *blocks,
+			   unsigned long flags)
+{
+	struct drm_buddy_block *block = NULL;
+	unsigned int min_order, order;
+	unsigned long pages;
+	LIST_HEAD(allocated);
+	int err;
+
+	if (size < mm->chunk_size)
+		return -EINVAL;
+
+	if (min_page_size < mm->chunk_size)
+		return -EINVAL;
+
+	if (!is_power_of_2(min_page_size))
+		return -EINVAL;
+
+	if (!IS_ALIGNED(start | end | size, mm->chunk_size))
+		return -EINVAL;
+
+	if (end > mm->size)
+		return -EINVAL;
+
+	if (range_overflows(start, size, mm->size))
+		return -EINVAL;
+
+	/* Actual range allocation */
+	if (start + size == end)
+		return __drm_buddy_alloc_range(mm, start, size, blocks);
+
+	pages = size >> ilog2(mm->chunk_size);
+	order = fls(pages) - 1;
+	min_order = ilog2(min_page_size) - ilog2(mm->chunk_size);
+
+	do {
+		order = min(order, (unsigned int)fls(pages) - 1);
+		BUG_ON(order > mm->max_order);
+		BUG_ON(order < min_order);
+
+		do {
+			if (flags & DRM_BUDDY_RANGE_ALLOCATION)
+				/* Allocate traversing within the range */
+				block = alloc_range_bias(mm, start, end, order);
+			else
+				/* Allocate from freelist */
+				block = alloc_from_freelist(mm, order, flags);
+
+			if (!IS_ERR(block))
+				break;
+
+			if (order-- == min_order) {
+				err = -ENOSPC;
+				goto err_free;
+			}
+		} while (1);
+
+		mark_allocated(block);
+		mm->avail -= drm_buddy_block_size(mm, block);
+		kmemleak_update_trace(block);
+		list_add_tail(&block->link, &allocated);
+
+		pages -= BIT(order);
+
+		if (!pages)
+			break;
+	} while (1);
+
+	list_splice_tail(&allocated, blocks);
+	return 0;
+
+err_free:
+	drm_buddy_free_list(mm, &allocated);
+	return err;
+}
+EXPORT_SYMBOL(drm_buddy_alloc_blocks);
 
 /**
  * drm_buddy_block_print - print block information