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From: Peng Zhang <zhangpeng.00@bytedance.com>
To: Liam.Howlett@oracle.com
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	maple-tree@lists.infradead.org,
	Peng Zhang <zhangpeng.00@bytedance.com>
Subject: [PATCH v2 1/3] maple_tree: Fix get wrong data_end in mtree_lookup_walk()
Date: Tue, 14 Mar 2023 20:42:01 +0800	[thread overview]
Message-ID: <20230314124203.91572-2-zhangpeng.00@bytedance.com> (raw)
In-Reply-To: <20230314124203.91572-1-zhangpeng.00@bytedance.com>

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.

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>
---
 lib/maple_tree.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 646297cae5d1..b3164266cfde 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -3875,18 +3875,13 @@ 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)))
-- 
2.20.1



  reply	other threads:[~2023-03-14 12:42 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-14 12:42 [PATCH v2 0/3] Some fixes and cleanup for maple tree Peng Zhang
2023-03-14 12:42 ` Peng Zhang [this message]
2023-03-14 12:42 ` [PATCH v2 2/3] maple_tree: Simplify mas_wr_node_walk() Peng Zhang
2023-03-14 12:42 ` [PATCH v2 3/3] maple_tree: Fix a potential concurrency bug in RCU mode Peng Zhang
2023-04-04  7:56 ` [PATCH v2 0/3] Some fixes and cleanup for maple tree Peng Zhang
2023-04-04 20:27 ` Andrew Morton
2023-04-05  0:49   ` Liam R. Howlett
2023-04-05  9:53   ` Peng Zhang
2023-04-05 17:49     ` Liam R. Howlett

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