From 5e476625fa8a36d7483ec3396a2bd124c2c02066 Mon Sep 17 00:00:00 2001 From: Matthew Auld Date: Mon, 19 Feb 2024 12:18:52 +0000 Subject: [PATCH] drm/buddy: fix range bias MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit f41900e4a6ef019d64a70394b0e0c3bd048d4ec8 upstream. There is a corner case here where start/end is after/before the block range we are currently checking. If so we need to be sure that splitting the block will eventually give use the block size we need. To do that we should adjust the block range to account for the start/end, and only continue with the split if the size/alignment will fit the requested size. Not doing so can result in leaving split blocks unmerged when it eventually fails. Fixes: afea229fe102 ("drm: improve drm_buddy_alloc function") Signed-off-by: Matthew Auld Cc: Arunpravin Paneer Selvam Cc: Christian König Cc: # v5.18+ Reviewed-by: Arunpravin Paneer Selvam Link: https://patchwork.freedesktop.org/patch/msgid/20240219121851.25774-4-matthew.auld@intel.com Signed-off-by: Christian König Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/drm_buddy.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c index e6f5ba5f4baf..d9cbf4e3327c 100644 --- a/drivers/gpu/drm/drm_buddy.c +++ b/drivers/gpu/drm/drm_buddy.c @@ -332,6 +332,7 @@ alloc_range_bias(struct drm_buddy *mm, u64 start, u64 end, unsigned int order) { + u64 req_size = mm->chunk_size << order; struct drm_buddy_block *block; struct drm_buddy_block *buddy; LIST_HEAD(dfs); @@ -367,6 +368,15 @@ alloc_range_bias(struct drm_buddy *mm, if (drm_buddy_block_is_allocated(block)) continue; + if (block_start < start || block_end > end) { + u64 adjusted_start = max(block_start, start); + u64 adjusted_end = min(block_end, end); + + if (round_down(adjusted_end + 1, req_size) <= + round_up(adjusted_start, req_size)) + continue; + } + if (contains(start, end, block_start, block_end) && order == drm_buddy_block_order(block)) { /*