The patch titled Subject: maple_tree: set the node limit when creating a new root node has been added to the -mm mm-hotfixes-unstable branch. Its filename is maple_tree-set-the-node-limit-when-creating-a-new-root-node.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: Peng Zhang zhangpeng.00@bytedance.com Subject: maple_tree: set the node limit when creating a new root node Date: Tue, 11 Jul 2023 11:54:37 +0800

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_vOg5... 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 ---

lib/maple_tree.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/lib/maple_tree.c~maple_tree-set-the-node-limit-when-creating-a-new-root-node +++ a/lib/maple_tree.c @@ -3692,7 +3692,8 @@ static inline int mas_root_expand(struct 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); _

Patches currently in -mm which might be from zhangpeng.00@bytedance.com are

maple_tree-set-the-node-limit-when-creating-a-new-root-node.patch maple_tree-add-test-for-mas_wr_modify-fast-path.patch maple_tree-add-test-for-expanding-range-in-rcu-mode.patch maple_tree-optimize-mas_wr_append-also-improve-duplicating-vmas.patch maple_tree-add-a-fast-path-case-in-mas_wr_slot_store.patch maple_tree-dont-use-maple_arange64_meta_max-to-indicate-no-gap.patch maple_tree-make-mas_validate_gaps-to-check-metadata.patch maple_tree-fix-mas_validate_child_slot-to-check-last-missed-slot.patch maple_tree-make-mas_validate_limits-check-root-node-and-node-limit.patch maple_tree-update-mt_validate.patch maple_tree-replace-mas_logical_pivot-with-mas_safe_pivot.patch maple_tree-drop-mas_first_entry.patch