From: Liam R. Howlett <Liam.Howlett@Oracle.com>
Date: Mon, 1 Mar 2021 19:36:59 +0000 (-0500)
Subject: maple_tree: Fix mas_find for a single entry, add test
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=ad359a8dd84bee478b3bdc2263340d2ab44c901f;p=users%2Fjedix%2Flinux-maple.git

maple_tree: Fix mas_find for a single entry, add test

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
---

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 70846dbeb796..40e3321a43f8 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -4214,7 +4214,7 @@ static inline int mas_dead_node(struct ma_state *mas, unsigned long index)
 {
 	unsigned long range_max, range_min;
 
-	if (unlikely(!mas_searchable(mas)))
+	if (unlikely(!mas_searchable(mas) || mas_is_start(mas)))
 		return 0;
 
 	if (likely(!mte_dead_node(mas->node)))
@@ -4580,7 +4580,13 @@ retry:
 static inline bool mas_search_cont(struct ma_state *mas, unsigned long index,
 		unsigned long max, void *entry)
 {
-	if (index >= max)
+	if (index > max)
+		return false;
+
+	if (mas_is_start(mas))
+		return true;
+
+	if (index == max)
 		return false;
 
 	if (!mas_searchable(mas))
@@ -4589,9 +4595,6 @@ static inline bool mas_search_cont(struct ma_state *mas, unsigned long index,
 	if (mas_is_err(mas))
 		return false;
 
-	if (mas_is_start(mas))
-		return true;
-
 	if (entry)
 		return false;
 
@@ -5413,21 +5416,20 @@ void *mas_find(struct ma_state *mas, unsigned long max)
 {
 	void *entry = NULL;
 	bool first = false;
+	unsigned long index = mas->index;
 
-	if (mas_is_start(mas))
+	if (mas_is_start(mas) && (mas->index <= max))
 		first = true;
 
 retry:
-	while (mas_search_cont(mas, mas->index, max, entry)) {
+	while (mas_search_cont(mas, mas->index, max, entry))
 		entry = _mas_next(mas, max);
 
-		if (unlikely(mas_dead_node(mas, mas->index))) {
-			if (first)
-				mas->node = MAS_START;
+	if (unlikely(mas_dead_node(mas, index))) {
+		if (first)
+			mas->node = MAS_START;
 
-			goto retry;
-		}
-		first = false;
+		goto retry;
 	}
 
 	return entry;
diff --git a/lib/test_maple_tree.c b/lib/test_maple_tree.c
index 0f5548cd4bca..315f54693669 100644
--- a/lib/test_maple_tree.c
+++ b/lib/test_maple_tree.c
@@ -812,6 +812,12 @@ static noinline void check_find(struct maple_tree *mt)
 	}
 	mas_unlock(&mas);
 
+	mas_set(&mas, 1048576);
+	mas_lock(&mas);
+	entry = mas_find(&mas, 1048576);
+	mas_unlock(&mas);
+	MT_BUG_ON(mas.tree, entry == NULL);
+
 	/* Find last value.
 	 * 1. get the expected value, leveraging the existence of an end entry
 	 * 2. delete end entry