Round up the size value to the min_page_size and trim the last block to the required size.
This solves a bug detected when size is not aligned with the min_page_size. Unigine Heaven has allocation requests for example required pages are 257 and alignment request is 256. To allocate the left over 1 page, continues the iteration to find the order value which is 0 and when it compares with min_order = 8, triggers the BUG_ON(order < min_order). To avoid this issue we round_up the size value to the min_page_size and trim the last block to the computed required size value.
Signed-off-by: Arunpravin Paneer Selvam Arunpravin.PaneerSelvam@amd.com --- drivers/gpu/drm/drm_buddy.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+)
diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c index 72f52f293249..98d7ec359b08 100644 --- a/drivers/gpu/drm/drm_buddy.c +++ b/drivers/gpu/drm/drm_buddy.c @@ -641,6 +641,7 @@ int drm_buddy_alloc_blocks(struct drm_buddy *mm, unsigned int min_order, order; unsigned long pages; LIST_HEAD(allocated); + u64 cur_size; int err;
if (size < mm->chunk_size) @@ -665,6 +666,11 @@ int drm_buddy_alloc_blocks(struct drm_buddy *mm, if (start + size == end) return __drm_buddy_alloc_range(mm, start, size, blocks);
+ cur_size = size; + + if (!IS_ALIGNED(size, min_page_size)) + size = round_up(size, min_page_size); + pages = size >> ilog2(mm->chunk_size); order = fls(pages) - 1; min_order = ilog2(min_page_size) - ilog2(mm->chunk_size); @@ -702,6 +708,31 @@ int drm_buddy_alloc_blocks(struct drm_buddy *mm, break; } while (1);
+ + /* + * If size value rounded up to min_page_size, trim the last block + * to the required size + */ + if (cur_size != size) { + struct drm_buddy_block *trim_block; + LIST_HEAD(trim_list); + u64 required_size; + + trim_block = list_last_entry(&allocated, typeof(*trim_block), link); + list_move_tail(&trim_block->link, &trim_list); + /* + * Compute the required_size value by subtracting the last block size + * with (aligned size - original size) + */ + required_size = drm_buddy_block_size(mm, trim_block) - (size - cur_size); + + drm_buddy_block_trim(mm, + required_size, + &trim_list); + + list_splice_tail(&trim_list, &allocated); + } + list_splice_tail(&allocated, blocks); return 0;
base-commit: ec57376fba5abc0e571617ff88e2ade7970c2e4b