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From:   "Liam R. Howlett" <Liam.Howlett@oracle.com>
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     maple-tree@lists.infradead.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        "Liam R. Howlett" <Liam.Howlett@oracle.com>,
        Peng Zhang <zhangpeng.00@bytedance.com>
Subject: [PATCH v3 32/35] maple_tree: Clear up index and last setting in single entry tree
Date:   Fri, 12 May 2023 14:20:33 -0400
Message-Id: <20230512182036.359030-33-Liam.Howlett@oracle.com>
In-Reply-To: <20230512182036.359030-1-Liam.Howlett@oracle.com>
References: <20230512182036.359030-1-Liam.Howlett@oracle.com>
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When there is a single entry tree (range of 0-0 pointing to an entry),
then ensure the limit is either 0-0 or 1-oo, depending on where the user
walks.  Ensure the correct node setting as well; either MAS_ROOT or
MAS_NONE.

Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
---
 lib/maple_tree.c | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index fd4f9f766cf23..ec4285e141d53 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -5022,24 +5022,25 @@ void *mas_walk(struct ma_state *mas)
 {
 	void *entry;
 
+	if (mas_is_none(mas) || mas_is_paused(mas) || mas_is_ptr(mas))
+		mas->node = MAS_START;
 retry:
 	entry = mas_state_walk(mas);
-	if (mas_is_start(mas))
+	if (mas_is_start(mas)) {
 		goto retry;
-
-	if (mas_is_ptr(mas)) {
+	} else if (mas_is_none(mas)) {
+		mas->index = 0;
+		mas->last = ULONG_MAX;
+	} else if (mas_is_ptr(mas)) {
 		if (!mas->index) {
 			mas->last = 0;
-		} else {
-			mas->index = 1;
-			mas->last = ULONG_MAX;
+			return entry;
 		}
-		return entry;
-	}
 
-	if (mas_is_none(mas)) {
-		mas->index = 0;
+		mas->index = 1;
 		mas->last = ULONG_MAX;
+		mas->node = MAS_NONE;
+		return NULL;
 	}
 
 	return entry;
-- 
2.39.2