在 2024/12/17 3:01, Liam R. Howlett 写道:
From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
When the upper bound of the search is exhausted, the maple state may be
returned in an error state of -EBUSY. This means maple state needs to
be reset before the second search in mas_alloc_cylic() to ensure the
search happens. This test ensures the issue is not recreated.
Cc: Yang Erkun <yangerkun@xxxxxxxxxxxxxxx>
Cc: chuck.lever@xxxxxxxxxx
Cc: brauner@xxxxxxxxxx
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
---
lib/test_maple_tree.c | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
Thanks for the testcase!
Reviewed-by: Yang Erkun <yangerkun@xxxxxxxxxx>
diff --git a/lib/test_maple_tree.c b/lib/test_maple_tree.c
index 72bda304b5952..13e2a10d7554d 100644
--- a/lib/test_maple_tree.c
+++ b/lib/test_maple_tree.c
@@ -3738,6 +3738,34 @@ static noinline void __init alloc_cyclic_testing(struct maple_tree *mt)
}
mtree_destroy(mt);
+
+ /*
+ * Issue with reverse search was discovered
+ * https://lore.kernel.org/all/20241216060600.287B4C4CED0@xxxxxxxxxxxxxxx/
+ * Exhausting the allocation area and forcing the search to wrap needs a
+ * mas_reset() in mas_alloc_cyclic().
+ */
+ next = 0;
+ mt_init_flags(mt, MT_FLAGS_ALLOC_RANGE);
+ for (int i = 0; i < 1023; i++) {
+ mtree_alloc_cyclic(mt, &location, mt, 2, 1024, &next, GFP_KERNEL);
+ MT_BUG_ON(mt, i != location - 2);
+ MT_BUG_ON(mt, i != next - 3);
+ MT_BUG_ON(mt, mtree_load(mt, location) != mt);
+ }
+ mtree_erase(mt, 123);
+ MT_BUG_ON(mt, mtree_load(mt, 123) != NULL);
+ mtree_alloc_cyclic(mt, &location, mt, 2, 1024, &next, GFP_KERNEL);
+ MT_BUG_ON(mt, 123 != location);
+ MT_BUG_ON(mt, 124 != next);
+ MT_BUG_ON(mt, mtree_load(mt, location) != mt);
+ mtree_erase(mt, 100);
+ mtree_alloc_cyclic(mt, &location, mt, 2, 1024, &next, GFP_KERNEL);
+ MT_BUG_ON(mt, 100 != location);
+ MT_BUG_ON(mt, 101 != next);
+ MT_BUG_ON(mt, mtree_load(mt, location) != mt);
+ mtree_destroy(mt);
+
/* Overflow test */
next = ULONG_MAX - 1;
ret = mtree_alloc_cyclic(mt, &location, mt, 2, ULONG_MAX, &next, GFP_KERNEL);
