maple_tree: fix get wrong data_end in mtree_lookup_walk()

if (likely(offset > end))
	max = pivots[offset];

The above code should be changed to if (likely(offset < end)), which is
correct.  This affects the correctness of ma_data_end().  Now it seems
that the final result will not be wrong, but it is best to change it.
This patch does not change the code as above, because it simplifies the
code by the way.

Link: https://lkml.kernel.org/r/20230314124203.91572-1-zhangpeng.00@bytedance.com
Link: https://lkml.kernel.org/r/20230314124203.91572-2-zhangpeng.00@bytedance.com
Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index b1db0bd71aedec6f538aa5727c5ffc557e83d406..b8a230f5d94e536b06e91bdbcea6cce86118fdfc 100644 (file)
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -3941,18 +3941,13 @@ static inline void *mtree_lookup_walk(struct ma_state *mas)
                end = ma_data_end(node, type, pivots, max);
                if (unlikely(ma_dead_node(node)))
                        goto dead_node;
-
-               if (pivots[offset] >= mas->index)
-                       goto next;
-
                do {
-                       offset++;
-               } while ((offset < end) && (pivots[offset] < mas->index));
-
-               if (likely(offset > end))
-                       max = pivots[offset];
+                       if (pivots[offset] >= mas->index) {
+                               max = pivots[offset];
+                               break;
+                       }
+               } while (++offset < end);
 
-next:
                slots = ma_slots(node, type);
                next = mt_slot(mas->tree, slots, offset);
                if (unlikely(ma_dead_node(node)))