From: Liam R. Howlett <Liam.Howlett@Oracle.com>
Date: Thu, 7 Mar 2019 14:47:48 +0000 (-0500)
Subject: maple: Fix off by one error when walking.
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=4dc3a35d3a5878377c881cc56067cf042029ed68;p=users%2Fjedix%2Flinux-maple.git

maple: Fix off by one error when walking.

When going to the next slot, the minimum value is actually pivot + 1 and
not just the pivot value.

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

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index b2f7cbddf7e1..7229bc460be8 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -504,7 +504,7 @@ static inline void mas_update_limits(struct ma_state *ms, unsigned char slot,
 		enum maple_type type)
 {
 	if (slot > 0)
-		ms->min = _ma_get_pivot(ms->node, slot - 1, type);
+		ms->min = _ma_get_pivot(ms->node, slot - 1, type) + 1;
 
 	if (slot < mt_slots[type] - 1)
 		ms->max = _ma_get_pivot(ms->node, slot, type);
@@ -1061,8 +1061,6 @@ static inline int _ma_insert(struct ma_state *mas, void *entry,
 	/* Linear node type */
 	if (!pivot_cnt) {
 		min = mas->index - mas->min;
-		if (mas->min)
-			min--;
 		max = mas->last - mas->min;
 		do
 			ma_update_rcu_slot(mas->node, min++, entry);
@@ -1079,13 +1077,13 @@ static inline int _ma_insert(struct ma_state *mas, void *entry,
 		slot = o_end + 1; // Append.
 
 	if (slot > 0)
-		min = ma_get_pivot(mas->node, slot - 1);
+		min = ma_get_pivot(mas->node, slot - 1) + 1;
 
 	/* Figure out how many slots are needed for the entry. */
 	if (max != mas->last)
 		n_end++;
 
-	if (mas->index && min != mas->index - 1)
+	if (mas->index && min != mas->index)
 		n_end++;
 
 	if (n_end > slot_cnt - 1 ||
@@ -1153,7 +1151,7 @@ static inline int _ma_insert(struct ma_state *mas, void *entry,
 
 
 
-	if (mas->index && min != mas->index - 1) {
+	if (mas->index && min != mas->index) {
 		/* When writing a NULL entry, the order must be reversed to
 		 * ensure readers don't get incorrect data on appends
 		 */
@@ -1308,7 +1306,7 @@ static inline bool _mas_walk(struct ma_state *mas)
 					max = pivot;
 					break;
 				}
-				min = pivot;
+				min = pivot + 1;
 			}
 
 			if ((i == pivot_cnt - 1) && (mas->index > pivot))
@@ -1321,8 +1319,6 @@ static inline bool _mas_walk(struct ma_state *mas)
 		case maple_dense:
 			// Linear node.
 			i = mas->index - mas->min;
-			if (mas->min)
-				i--;
 			goto done;
 			break;
 		}