[merged mm-stable] maple_tree-add-mas_wr_new_end-to-calculate-new_end-accurately.patch removed from -mm tree

[Andrew Morton <akpm@linux-foundation.org>]

The quilt patch titled
     Subject: maple_tree: add mas_wr_new_end() to calculate new_end accurately
has been removed from the -mm tree.  Its filename was
     maple_tree-add-mas_wr_new_end-to-calculate-new_end-accurately.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Peng Zhang <zhangpeng.00@bytedance.com>
Subject: maple_tree: add mas_wr_new_end() to calculate new_end accurately
Date: Wed, 24 May 2023 11:12:43 +0800

The previous new_end calculation is inaccurate, because it assumes that
two new pivots must be added (this is inaccurate), and sometimes it will
miss the fast path and enter the slow path.  Add mas_wr_new_end() to
accurately calculate new_end to make the conditions for entering the fast
path more accurate.

Link: https://lkml.kernel.org/r/20230524031247.65949-7-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/maple_tree.c |   34 +++++++++++++++++++++++-----------
 1 file changed, 23 insertions(+), 11 deletions(-)

--- a/lib/maple_tree.c~maple_tree-add-mas_wr_new_end-to-calculate-new_end-accurately
+++ a/lib/maple_tree.c
@@ -4296,6 +4296,21 @@ static inline void mas_wr_extend_null(st
 	}
 }
 
+static inline unsigned char mas_wr_new_end(struct ma_wr_state *wr_mas)
+{
+	struct ma_state *mas = wr_mas->mas;
+	unsigned char new_end = wr_mas->node_end + 2;
+
+	new_end -= wr_mas->offset_end - mas->offset;
+	if (wr_mas->r_min == mas->index)
+		new_end--;
+
+	if (wr_mas->end_piv == mas->last)
+		new_end--;
+
+	return new_end;
+}
+
 static inline bool mas_wr_append(struct ma_wr_state *wr_mas)
 {
 	unsigned char end = wr_mas->node_end;
@@ -4351,9 +4366,8 @@ static void mas_wr_bnode(struct ma_wr_st
 
 static inline void mas_wr_modify(struct ma_wr_state *wr_mas)
 {
-	unsigned char node_slots;
-	unsigned char node_size;
 	struct ma_state *mas = wr_mas->mas;
+	unsigned char new_end;
 
 	/* Direct replacement */
 	if (wr_mas->r_min == mas->index && wr_mas->r_max == mas->last) {
@@ -4363,17 +4377,15 @@ static inline void mas_wr_modify(struct
 		return;
 	}
 
-	/* Attempt to append */
-	node_slots = mt_slots[wr_mas->type];
-	node_size = wr_mas->node_end - wr_mas->offset_end + mas->offset + 2;
-	if (mas->max == ULONG_MAX)
-		node_size++;
-
-	/* slot and node store will not fit, go to the slow path */
-	if (unlikely(node_size >= node_slots))
+	/*
+	 * new_end exceeds the size of the maple node and cannot enter the fast
+	 * path.
+	 */
+	new_end = mas_wr_new_end(wr_mas);
+	if (new_end >= mt_slots[wr_mas->type])
 		goto slow_path;
 
-	if (wr_mas->entry && (wr_mas->node_end < node_slots - 1) &&
+	if (wr_mas->entry && (wr_mas->node_end < mt_slots[wr_mas->type] - 1) &&
 	    (mas->offset == wr_mas->node_end) && mas_wr_append(wr_mas)) {
 		if (!wr_mas->content || !wr_mas->entry)
 			mas_update_gap(mas);
_

Patches currently in -mm which might be from zhangpeng.00@bytedance.com are