linux-kernel - [PATCH 05/12] maple_tree: Use cached node end in mas

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Date:   Wed,  1 Nov 2023 13:16:22 -0400
From:   "Liam R. Howlett" <Liam.Howlett@...cle.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     maple-tree@...ts.infradead.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org,
        "Liam R. Howlett" <Liam.Howlett@...cle.com>
Subject: [PATCH 05/12] maple_tree: Use cached node end in mas_next()

When looking for the next entry, don't recalculate the node end as it is
now tracked in the maple state.

Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com>
---
 lib/maple_tree.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 6634594c770a..6c0ed71844e6 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -4527,6 +4527,7 @@ static inline int mas_next_node(struct ma_state *mas, struct maple_node *node,
 	unsigned long min;
 	unsigned long *pivots;
 	struct maple_enode *enode;
+	struct maple_node *tmp;
 	int level = 0;
 	unsigned char node_end;
 	enum maple_type mt;
@@ -4579,6 +4580,10 @@ static inline int mas_next_node(struct ma_state *mas, struct maple_node *node,
 		pivots = ma_pivots(node, mt);
 
 	mas->max = mas_safe_pivot(mas, pivots, mas->offset, mt);
+	tmp = mte_to_node(enode);
+	mt = mte_node_type(enode);
+	pivots = ma_pivots(tmp, mt);
+	mas->end = ma_data_end(tmp, mt, pivots, mas->max);
 	if (unlikely(ma_dead_node(node)))
 		return 1;
 
@@ -4613,7 +4618,6 @@ static void *mas_next_slot(struct ma_state *mas, unsigned long max, bool empty,
 	unsigned long pivot;
 	enum maple_type type;
 	struct maple_node *node;
-	unsigned char data_end;
 	unsigned long save_point = mas->last;
 	void *entry;
 
@@ -4621,12 +4625,11 @@ static void *mas_next_slot(struct ma_state *mas, unsigned long max, bool empty,
 	node = mas_mn(mas);
 	type = mte_node_type(mas->node);
 	pivots = ma_pivots(node, type);
-	data_end = ma_data_end(node, type, pivots, mas->max);
 	if (unlikely(mas_rewalk_if_dead(mas, node, save_point)))
 		goto retry;
 
 	if (mas->max >= max) {
-		if (likely(mas->offset < data_end))
+		if (likely(mas->offset < mas->end))
 			pivot = pivots[mas->offset];
 		else
 			goto overflow;
@@ -4638,11 +4641,11 @@ static void *mas_next_slot(struct ma_state *mas, unsigned long max, bool empty,
 			goto overflow;
 	}
 
-	if (likely(mas->offset < data_end)) {
+	if (likely(mas->offset < mas->end)) {
 		mas->index = pivots[mas->offset] + 1;
 again:
 		mas->offset++;
-		if (likely(mas->offset < data_end))
+		if (likely(mas->offset < mas->end))
 			mas->last = pivots[mas->offset];
 		else
 			mas->last = mas->max;
@@ -4679,7 +4682,6 @@ static void *mas_next_slot(struct ma_state *mas, unsigned long max, bool empty,
 			goto overflow;
 
 		mas->index = mas->last + 1;
-		/* Node cannot end on NULL, so it's safe to short-cut here */
 		goto again;
 	}
 
-- 
2.40.1