From: Matthew Wilcox (Oracle) <willy@infradead.org>
Date: Sun, 13 Oct 2019 03:21:36 +0000 (-0400)
Subject: maple_tree: Fix mas_dead_node for a trivial tree
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=58e87d397110e9de6f098175f5897d45a79afff8;p=users%2Fjedix%2Flinux-maple.git

maple_tree: Fix mas_dead_node for a trivial tree

For a tree with no entries, or an entry only at 0, mas_dead_node()
can be called with a mas->node of NULL.  This node is, by definition,
not dead.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 350551179c33..3283ce5cb3c9 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -3303,7 +3303,9 @@ static inline int mas_safe_slot(struct ma_state *mas, unsigned char *slot,
 
 static inline int mas_dead_node(struct ma_state *mas, unsigned long index)
 {
-	if (!mte_dead_node(mas->node))
+	if (!mas->node)
+		return 0;
+	if (!mt_dead_node(mas->node))
 		return 0;
 
 	mas->index = index;