linux-kernel - [PATCH 14/28] maple_tree: Introduce ma_leaf_max

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Message-ID: <20260115193647.1695937-15-Liam.Howlett@oracle.com>
Date: Thu, 15 Jan 2026 14:36:33 -0500
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, Suren Baghdasaryan <surenb@...gle.com>,
        Matthew Wilcox <willy@...radead.org>,
        Sidhartha Kumar <sidhartha.kumar@...cle.com>,
        Vlastimil Babka <vbabka@...e.cz>, Alice Ryhl <aliceryhl@...gle.com>,
        Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Arnd Bergmann <arnd@...db.de>, Christian Kujau <lists@...dbynature.de>,
        "Liam R. Howlett" <Liam.Howlett@...cle.com>
Subject: [PATCH 14/28] maple_tree: Introduce ma_leaf_max_gap()

This is the same as mas_leaf_max_gap(), but the information necessary is
known without a maple state in future code.  Adding this function now
simplifies the review for a subsequent patch.

Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com>
---
 lib/maple_tree.c | 48 ++++++++++++++++++++++++++++--------------------
 1 file changed, 28 insertions(+), 20 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 4dd1cc73cd27c..366202dc22343 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -1315,26 +1315,14 @@ void wr_mas_setup(struct ma_wr_state *wr_mas, struct ma_state *mas)
 	wr_mas->r_max = mas_safe_pivot(mas, wr_mas->pivots, mas->offset,
 				       wr_mas->type);
 }
-
-/*
- * mas_leaf_max_gap() - Returns the largest gap in a leaf node
- * @mas: the maple state
- *
- * Return: The maximum gap in the leaf.
- */
-static unsigned long mas_leaf_max_gap(struct ma_state *mas)
+static inline unsigned long ma_leaf_max_gap(struct maple_node *mn,
+		enum maple_type mt, unsigned long min, unsigned long max,
+		unsigned long *pivots, void __rcu **slots)
 {
-	enum maple_type mt;
 	unsigned long pstart, gap, max_gap;
-	struct maple_node *mn;
-	unsigned long *pivots;
-	void __rcu **slots;
 	unsigned char i;
 	unsigned char max_piv;
 
-	mt = mte_node_type(mas->node);
-	mn = mas_mn(mas);
-	slots = ma_slots(mn, mt);
 	max_gap = 0;
 	if (unlikely(ma_is_dense(mt))) {
 		gap = 0;
@@ -1356,26 +1344,25 @@ static unsigned long mas_leaf_max_gap(struct ma_state *mas)
 	 * Check the first implied pivot optimizes the loop below and slot 1 may
 	 * be skipped if there is a gap in slot 0.
 	 */
-	pivots = ma_pivots(mn, mt);
 	if (likely(!slots[0])) {
-		max_gap = pivots[0] - mas->min + 1;
+		max_gap = pivots[0] - min + 1;
 		i = 2;
 	} else {
 		i = 1;
 	}
 
 	/* reduce max_piv as the special case is checked before the loop */
-	max_piv = ma_data_end(mn, mt, pivots, mas->max) - 1;
+	max_piv = ma_data_end(mn, mt, pivots, max) - 1;
 	/*
 	 * Check end implied pivot which can only be a gap on the right most
 	 * node.
 	 */
-	if (unlikely(mas->max == ULONG_MAX) && !slots[max_piv + 1]) {
+	if (unlikely(max == ULONG_MAX) && !slots[max_piv + 1]) {
 		gap = ULONG_MAX - pivots[max_piv];
 		if (gap > max_gap)
 			max_gap = gap;
 
-		if (max_gap > pivots[max_piv] - mas->min)
+		if (max_gap > pivots[max_piv] - min)
 			return max_gap;
 	}
 
@@ -1395,6 +1382,27 @@ static unsigned long mas_leaf_max_gap(struct ma_state *mas)
 	return max_gap;
 }
 
+/*
+ * mas_leaf_max_gap() - Returns the largest gap in a leaf node
+ * @mas: the maple state
+ *
+ * Return: The maximum gap in the leaf.
+ */
+static inline unsigned long mas_leaf_max_gap(struct ma_state *mas)
+{
+	enum maple_type mt;
+	struct maple_node *mn;
+	unsigned long *pivots;
+	void __rcu **slots;
+
+	mn = mas_mn(mas);
+	mt = mte_node_type(mas->node);
+	slots = ma_slots(mn, mt);
+	pivots = ma_pivots(mn, mt);
+
+	return ma_leaf_max_gap(mn, mt, mas->min, mas->max, pivots, slots);
+}
+
 /*
  * ma_max_gap() - Get the maximum gap in a maple node (non-leaf)
  * @node: The maple node
-- 
2.47.3