maple_tree: fix get wrong data_end in mtree_lookup_walk()

commit ec07967d7523adb3670f9dfee0232e3bc868f3de upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 96be96a1f35dcf3d1bb2e9d6911d050e02d1e79a..08e41a993eb61f56fba8977fcb0c7f1b298e452d 100644 (file)
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -3870,18 +3870,13 @@ 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)))