maple_tree: Fix splitting causing deficient nodes.

When splitting a node, ensure a deficient node is not created when a
NULL in encountered at the split.  Also adjust the checking of the limit
when incrementing to ensure both the min and the number on the right are
zero based.

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

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index fb28b36cd79e962a1061838169d92955bef2a9dc..1bf8b7a8d6448eacc085d165c03fcc8864d6fd87 100644 (file)
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -1487,7 +1487,7 @@ static inline int mab_no_null_split(struct maple_big_node *b_node,
                /* If the split is less than the max slot && the right side will
                 * still be sufficient, then increment the split on NULL.
                 */
-               if ((split < slot_cnt - 1) &&
+               if ((split < mt_slots[b_node->type] - 1) &&
                    (b_node->b_end - split) < (mt_min_slots[b_node->type]))
                        split++;
                else
@@ -1521,7 +1521,7 @@ static inline int mab_calc_split(struct maple_big_node *b_node,
                 */
                while (((b_node->pivot[split] - b_node->min) < slot_cnt - 1) &&
                       (split < slot_cnt - 1) &&
-                      (b_node->b_end - split > mt_min_slots[b_node->type]))
+                      (b_node->b_end - split > mt_min_slots[b_node->type] - 1))
                        split++;
        }