linux-kernel - [PATCH v2 2/3] maple_tree: Simplify mas_wr_node

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Date:   Tue, 14 Mar 2023 20:42:02 +0800
From:   Peng Zhang <zhangpeng.00@...edance.com>
To:     Liam.Howlett@...cle.com
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        maple-tree@...ts.infradead.org,
        Peng Zhang <zhangpeng.00@...edance.com>
Subject: [PATCH v2 2/3] maple_tree: Simplify mas_wr_node_walk()

Simplify code of mas_wr_node_walk() without changing functionality,
and improve readability. Remove some special judgments. Instead of
dynamically recording the min and max in the loop, get the final min
and max directly at the end.

Signed-off-by: Peng Zhang <zhangpeng.00@...edance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@...cle.com>
---
 lib/maple_tree.c | 34 +++++-----------------------------
 1 file changed, 5 insertions(+), 29 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index b3164266cfde..4d15202a0692 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -2251,9 +2251,7 @@ static inline struct maple_enode *mte_node_or_none(struct maple_enode *enode)
 static inline void mas_wr_node_walk(struct ma_wr_state *wr_mas)
 {
 	struct ma_state *mas = wr_mas->mas;
-	unsigned char count;
-	unsigned char offset;
-	unsigned long index, min, max;
+	unsigned char count, offset;
 
 	if (unlikely(ma_is_dense(wr_mas->type))) {
 		wr_mas->r_max = wr_mas->r_min = mas->index;
@@ -2266,34 +2264,12 @@ static inline void mas_wr_node_walk(struct ma_wr_state *wr_mas)
 	count = wr_mas->node_end = ma_data_end(wr_mas->node, wr_mas->type,
 					       wr_mas->pivots, mas->max);
 	offset = mas->offset;
-	min = mas_safe_min(mas, wr_mas->pivots, offset);
-	if (unlikely(offset == count))
-		goto max;
-
-	max = wr_mas->pivots[offset];
-	index = mas->index;
-	if (unlikely(index <= max))
-		goto done;
-
-	if (unlikely(!max && offset))
-		goto max;
 
-	min = max + 1;
-	while (++offset < count) {
-		max = wr_mas->pivots[offset];
-		if (index <= max)
-			goto done;
-		else if (unlikely(!max))
-			break;
-
-		min = max + 1;
-	}
+	while (offset < count && mas->index > wr_mas->pivots[offset])
+		offset++;
 
-max:
-	max = mas->max;
-done:
-	wr_mas->r_max = max;
-	wr_mas->r_min = min;
+	wr_mas->r_max = offset < count ? wr_mas->pivots[offset] : mas->max;
+	wr_mas->r_min = mas_safe_min(mas, wr_mas->pivots, offset);
 	wr_mas->offset_end = mas->offset = offset;
 }
 
-- 
2.20.1