From: Peng Zhang <zhangpeng.00@bytedance.com>
Date: Mon, 20 Nov 2023 07:09:34 +0000 (+0800)
Subject: maple_tree: avoid ascending when mas->min is also the parent's minimum
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=4ee8154a22ec3f8de61841a75317b21730adb767;p=users%2Fjedix%2Flinux-maple.git

maple_tree: avoid ascending when mas->min is also the parent's minimum

When the child node is the first child of its parent node, mas->min does
not need to be updated. This can reduce the number of ascending times
in some cases.

Link: https://lkml.kernel.org/r/20231120070937.35481-3-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 067b186202d7..cc928b5f753d 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -1088,14 +1088,16 @@ static int mas_ascend(struct ma_state *mas)
 		return 0;
 	}
 
-	if (!mas->min)
+	min = 0;
+	max = ULONG_MAX;
+	if (!mas->offset) {
+		min = mas->min;
 		set_min = true;
+	}
 
 	if (mas->max == ULONG_MAX)
 		set_max = true;
 
-	min = 0;
-	max = ULONG_MAX;
 	do {
 		p_enode = a_enode;
 		a_type = mas_parent_type(mas, p_enode);