linux-kernel - [PATCH 06/14] maple_tree: Introduce __mas_set

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Message-Id: <20230601021605.2823123-7-Liam.Howlett@oracle.com>
Date:   Wed, 31 May 2023 22:15:57 -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 06/14] maple_tree: Introduce __mas_set_range()

mas_set_range() resets the node to MAS_START, which will cause a re-walk
of the tree to the range.  This is unnecessary when the maple state is
already at the correct location of the write.  Add a function that only
sets the range to avoid unnecessary re-walking of the tree.

Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com>
---
 include/linux/maple_tree.h | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/include/linux/maple_tree.h b/include/linux/maple_tree.h
index 295548cca8b3..ed50d8f459e6 100644
--- a/include/linux/maple_tree.h
+++ b/include/linux/maple_tree.h
@@ -531,6 +531,22 @@ static inline void mas_reset(struct ma_state *mas)
  */
 #define mas_for_each(__mas, __entry, __max) \
 	while (((__entry) = mas_find((__mas), (__max))) != NULL)
+/**
+ * __mas_set_range() - Set up Maple Tree operation state to a sub-range of the
+ * current location.
+ * @mas: Maple Tree operation state.
+ * @start: New start of range in the Maple Tree.
+ * @last: New end of range in the Maple Tree.
+ *
+ * set the internal maple state values to a sub-range.
+ * Please use mas_set_range() if you do not know where you are in the tree.
+ */
+static inline void __mas_set_range(struct ma_state *mas, unsigned long start,
+		unsigned long last)
+{
+       mas->index = start;
+       mas->last = last;
+}
 
 /**
  * mas_set_range() - Set up Maple Tree operation state for a different index.
@@ -545,9 +561,8 @@ static inline void mas_reset(struct ma_state *mas)
 static inline
 void mas_set_range(struct ma_state *mas, unsigned long start, unsigned long last)
 {
-	       mas->index = start;
-	       mas->last = last;
-	       mas->node = MAS_START;
+	__mas_set_range(mas, start, last);
+	mas->node = MAS_START;
 }
 
 /**
-- 
2.39.2