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authorPeng Zhang <zhangpeng.00@bytedance.com>2023-07-11 11:54:37 +0800
committerAndrew Morton <akpm@linux-foundation.org>2023-07-17 12:53:22 -0700
commit3c769fd88b9742954763a968e84de09f7ad78cfe (patch)
tree64538363b4982c99bd6af953e02c8e09d6d26991 /lib
parent2658f94d679243209889cdfa8de3743cde1abea9 (diff)
maple_tree: set the node limit when creating a new root node
Set the node limit of the root node so that the last pivot of all nodes is the node limit (if the node is not full). This patch also fixes a bug in mas_rev_awalk(). Effectively, always setting a maximum makes mas_logical_pivot() behave as mas_safe_pivot(). Without this fix, it is possible that very small tasks would fail to find the correct gap. Although this has not been observed with real tasks, it has been reported to happen in m68k nommu running the maple tree tests. Link: https://lkml.kernel.org/r/20230711035444.526-1-zhangpeng.00@bytedance.com Link: https://lore.kernel.org/linux-mm/CAMuHMdV4T53fOw7VPoBgPR7fP6RYqf=CBhD_y_vOg53zZX_DnA@mail.gmail.com/ Link: https://lkml.kernel.org/r/20230711035444.526-2-zhangpeng.00@bytedance.com Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/maple_tree.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index bfffbb7cab26..4dd73cf936a6 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -3692,7 +3692,8 @@ static inline int mas_root_expand(struct ma_state *mas, void *entry)
mas->offset = slot;
pivots[slot] = mas->last;
if (mas->last != ULONG_MAX)
- slot++;
+ pivots[++slot] = ULONG_MAX;
+
mas->depth = 1;
mas_set_height(mas);
ma_set_meta(node, maple_leaf_64, 0, slot);