XArray: set the marks correctly when splitting an entry

If we created a new node to replace an entry which had search marks set,
we were setting the search mark on every entry in that node.  That works
fine when we're splitting to order 0, but when splitting to a larger
order, we must not set the search marks on the sibling entries.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: c010d47f107f ("mm: thp: split huge page to any lower order pages")
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Reported-by: Luis Chamberlain <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Tested-by: Luis Chamberlain <[email protected]>
Cc: Zi Yan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

1 files changed, 13 insertions, 1 deletions

diff --git a/lib/test_xarray.c b/lib/test_xarray.c
index 5ab35190aae3..928fc20337e6 100644
--- a/lib/test_xarray.c
+++ b/lib/test_xarray.c
@@ -1788,9 +1788,11 @@ static void check_split_1(struct xarray *xa, unsigned long index,
 				unsigned int order, unsigned int new_order)
 {
 	XA_STATE_ORDER(xas, xa, index, new_order);
-	unsigned int i;
+	unsigned int i, found;
+	void *entry;
 
 	xa_store_order(xa, index, order, xa, GFP_KERNEL);
+	xa_set_mark(xa, index, XA_MARK_1);
 
 	xas_split_alloc(&xas, xa, order, GFP_KERNEL);
 	xas_lock(&xas);
@@ -1807,6 +1809,16 @@ static void check_split_1(struct xarray *xa, unsigned long index,
 	xa_set_mark(xa, index, XA_MARK_0);
 	XA_BUG_ON(xa, !xa_get_mark(xa, index, XA_MARK_0));
 
+	xas_set_order(&xas, index, 0);
+	found = 0;
+	rcu_read_lock();
+	xas_for_each_marked(&xas, entry, ULONG_MAX, XA_MARK_1) {
+		found++;
+		XA_BUG_ON(xa, xa_is_internal(entry));
+	}
+	rcu_read_unlock();
+	XA_BUG_ON(xa, found != 1 << (order - new_order));
+
 	xa_destroy(xa);
 }