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://lore.kernel.org/linux-mm/CAMuHMdV4T53fOw7VPoBgPR7fP6RYqf=CBhD_y_vOg5... 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 Cc: stable@vger.kernel.org Cc: Geert Uytterhoeven geert@linux-m68k.org --- lib/maple_tree.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/lib/maple_tree.c b/lib/maple_tree.c index d3072858c280..f55e59bd9122 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);