The patch titled
Subject: test_maple_tree: test exhausted upper limit of mtree_alloc_cyclic()
has been added to the -mm mm-unstable branch. Its filename is
test_maple_tree-test-exhausted-upper-limit-of-mtree_alloc_cyclic.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/test_maple_tree-test-exhausted-upper-limit-of-mtree_alloc_cyclic.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
Subject: test_maple_tree: test exhausted upper limit of mtree_alloc_cyclic()
Date: Mon, 16 Dec 2024 14:01:13 -0500
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.
Link: https://lkml.kernel.org/r/20241216190113.1226145-3-Liam.Howlett@xxxxxxxxxx
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Reviewed-by: Yang Erkun <yangerkun@xxxxxxxxxx>
Cc: Christian Brauner <brauner@xxxxxxxxxx>
Cc: Chuck Lever <chuck.lever@xxxxxxxxxx> says:
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/test_maple_tree.c | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
--- a/lib/test_maple_tree.c~test_maple_tree-test-exhausted-upper-limit-of-mtree_alloc_cyclic
+++ a/lib/test_maple_tree.c
@@ -3738,6 +3738,34 @@ static noinline void __init alloc_cyclic
}
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);
_
Patches currently in -mm which might be from Liam.Howlett@xxxxxxxxxx are
maple_tree-fix-mas_alloc_cyclic-second-search.patch
test_maple_tree-test-exhausted-upper-limit-of-mtree_alloc_cyclic.patch
