From: Liam R. Howlett <Liam.Howlett@Oracle.com>
Date: Tue, 4 Aug 2020 14:15:41 +0000 (-0400)
Subject: maple_tree: Fix splitting causing deficient nodes.
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=d78fffa43353f09e0b86ab3add91519a378780ed;p=users%2Fjedix%2Flinux-maple.git

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 fb28b36cd79e9..1bf8b7a8d6448 100644
--- 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++;
 	}