2023-04-25 11:07:22

by Peng Zhang

Subject: [PATCH 2/9] maple_tree: Make maple state reusable after mas_empty_area()

Make mas->min and mas->max point to a node range instead of a leaf entry
range. This allows mas to still be usable after mas_empty_area() returns.
This currently has no user impact because no one use mas after
mas_empty_area() now.

Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Peng Zhang <[email protected]>
---
lib/maple_tree.c | 9 +--------
1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 72099b4b32169..aa55c914818a0 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -5320,14 +5320,7 @@ int mas_empty_area(struct ma_state *mas, unsigned long min,

mt = mte_node_type(mas->node);
pivots = ma_pivots(mas_mn(mas), mt);
- if (offset)
- mas->min = pivots[offset - 1] + 1;
-
- if (offset < mt_pivots[mt])
- mas->max = pivots[offset];
-
- if (mas->index < mas->min)
- mas->index = mas->min;
+ mas->index = max(mas->index, mas_safe_min(mas, pivots, offset));

mas->last = mas->index + size - 1;
return 0;
--
2.20.1

2023-04-25 16:14:44

by Liam R. Howlett

Subject: Re: [PATCH 2/9] maple_tree: Make maple state reusable after mas_empty_area()

* Peng Zhang <[email protected]> [230425 07:05]:
> Make mas->min and mas->max point to a node range instead of a leaf entry
> range. This allows mas to still be usable after mas_empty_area() returns.
> This currently has no user impact because no one use mas after
> mas_empty_area() now.
>
> Fixes: 54a611b60590 ("Maple Tree: add new data structure")
> Signed-off-by: Peng Zhang <[email protected]>
> ---
> lib/maple_tree.c | 9 +--------
> 1 file changed, 1 insertion(+), 8 deletions(-)
>
> diff --git a/lib/maple_tree.c b/lib/maple_tree.c
> index 72099b4b32169..aa55c914818a0 100644
> --- a/lib/maple_tree.c
> +++ b/lib/maple_tree.c
> @@ -5320,14 +5320,7 @@ int mas_empty_area(struct ma_state *mas, unsigned long min,
>
> mt = mte_node_type(mas->node);
> pivots = ma_pivots(mas_mn(mas), mt);
> - if (offset)
> - mas->min = pivots[offset - 1] + 1;
> -
> - if (offset < mt_pivots[mt])
> - mas->max = pivots[offset];
> -
> - if (mas->index < mas->min)
> - mas->index = mas->min;
> + mas->index = max(mas->index, mas_safe_min(mas, pivots, offset));

It is better to have a few extra lines of code than a complex statement
combined into one line. Things tend to get missed this way.

>
> mas->last = mas->index + size - 1;
> return 0;
> --
> 2.20.1
>