linux-kernel - [PATCH 23/28] maple_tree: Add cp

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Message-ID: <20260115193647.1695937-24-Liam.Howlett@oracle.com>
Date: Thu, 15 Jan 2026 14:36:42 -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 23/28] maple_tree: Add cp_converged() helper

When the maple copy node converges into a single entry, then certain
operations can stop ascending the tree.

This is used more later.

Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com>
---
 lib/maple_tree.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index a6f4a1c8549b5..46daa1ef32084 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -3462,6 +3462,16 @@ static inline bool cp_is_new_root(struct maple_copy *cp, struct ma_state *mas)
 	return true;
 }
 
+static inline bool cp_converged(struct maple_copy *cp, struct ma_state *mas,
+				struct ma_state *sib)
+{
+	if (cp->d_count != 1 || sib->end)
+		return false;
+
+	cp->dst[0].node->parent = ma_parent_ptr(mas_mn(mas)->parent);
+	return true;
+}
+
 /*
  * spanning_ascend() - See if a spanning store operation has to keep walking up
  * the tree
@@ -3544,10 +3554,8 @@ static inline bool rebalance_ascend(struct maple_copy *cp,
 	if (cp_is_new_root(cp, mas))
 		return false;
 
-	if (cp->d_count == 1 && !sib->end) {
-		cp->dst[0].node->parent = ma_parent_ptr(mas_mn(mas)->parent);
+	if (cp_converged(cp, mas, sib))
 		return false;
-	}
 
 	cp->height++;
 	copy_tree_location(parent, mas);
-- 
2.47.3