maple_tree: should get pivots boundary by type

[ Upstream commit ab6ef70a8b0d314c2160af70b0de984664d675e0 ]

We should get pivots boundary by type.  Fixes a potential overindexing of
mt_pivots[].

Link: https://lkml.kernel.org/r/20221112234308.23823-1-richard.weiyang@gmail.com
Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index fe21bf2..5bfaae6 100644 (file)
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -665,12 +665,13 @@ static inline unsigned long mte_pivot(const struct maple_enode *mn,
                                 unsigned char piv)
 {
        struct maple_node *node = mte_to_node(mn);
+       enum maple_type type = mte_node_type(mn);
 
-       if (piv >= mt_pivots[piv]) {
+       if (piv >= mt_pivots[type]) {
                WARN_ON(1);
                return 0;
        }
-       switch (mte_node_type(mn)) {
+       switch (type) {
        case maple_arange_64:
                return node->ma64.pivot[piv];
        case maple_range_64: