The patch titled
Subject: maple_tree: goto complete directly on a pivot of 0
has been added to the -mm mm-unstable branch. Its filename is
maple_tree-goto-complete-directly-on-a-pivot-of-0.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/maple_tree-goto-complete-directly-on-a-pivot-of-0.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Wei Yang <richard.weiyang@xxxxxxxxx>
Subject: maple_tree: goto complete directly on a pivot of 0
Date: Wed, 11 Sep 2024 14:27:59 +0000
When we break the loop after assigning a pivot, the index i/j is not
changed. Then the following code assign pivot, which means we do the
assignment with same i/j by mas_safe_pivot.
Since the loop condition is (i < piv_end), from which we can get i is less
than mt_pivots[mt]. It implies mas_safe_pivot() return pivot[i] which is
the same value we get in loop.
Now we can conclude it does a redundant assignment on a pivot of 0. Let's
just go to complete to avoid it.
Link: https://lkml.kernel.org/r/20240911142759.20989-3-richard.weiyang@xxxxxxxxx
Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>
Reviewed-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/maple_tree.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/lib/maple_tree.c~maple_tree-goto-complete-directly-on-a-pivot-of-0
+++ a/lib/maple_tree.c
@@ -1943,7 +1943,7 @@ static inline void mas_mab_cp(struct ma_
for (; i < piv_end; i++, j++) {
b_node->pivot[j] = pivots[i];
if (unlikely(!b_node->pivot[j]))
- break;
+ goto complete;
if (unlikely(mas->max == b_node->pivot[j]))
goto complete;
_
Patches currently in -mm which might be from richard.weiyang@xxxxxxxxx are
maple_tree-i-is-always-less-than-or-equal-to-mas_end.patch
maple_tree-goto-complete-directly-on-a-pivot-of-0.patch
