radix-tree: test radix_tree_iter_retry

From: Konstantin Khlebnikov <koct9i@gmail.com>

Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
---
 lib/radix-tree.c |   62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 6b79e9026e24..f489334b9cb7 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -1491,6 +1491,66 @@ static int radix_tree_callback(struct notifier_block *nfb,
        return NOTIFY_OK;
 }
 
+static void test_iter_retry(void)
+{
+	RADIX_TREE(root, GFP_KERNEL);
+	void *ptr = (void *)4ul;
+	struct radix_tree_iter iter;
+	void **slot;
+	bool first;
+
+	radix_tree_insert(&root, 0, ptr);
+	radix_tree_tag_set(&root, 0, 0);
+
+	first = true;
+	radix_tree_for_each_tagged(slot, &root, &iter, 0, 0) {
+		printk("tagged %ld %p\n", iter.index, *slot);
+		if (first) {
+			radix_tree_insert(&root, 1, ptr);
+			radix_tree_tag_set(&root, 1, 0);
+			first = false;
+		}
+		if (radix_tree_deref_retry(*slot)) {
+			printk("retry %ld\n", iter.index);
+			slot = radix_tree_iter_retry(&iter);
+			continue;
+		}
+	}
+	radix_tree_delete(&root, 1);
+
+	first = true;
+	radix_tree_for_each_slot(slot, &root, &iter, 0) {
+		printk("slot %ld %p\n", iter.index, *slot);
+		if (first) {
+			radix_tree_insert(&root, 1, ptr);
+			first = false;
+		}
+		if (radix_tree_deref_retry(*slot)) {
+			printk("retry %ld\n", iter.index);
+			slot = radix_tree_iter_retry(&iter);
+			continue;
+		}
+	}
+	radix_tree_delete(&root, 1);
+
+	first = true;
+	radix_tree_for_each_contig(slot, &root, &iter, 0) {
+		printk("contig %ld %p\n", iter.index, *slot);
+		if (first) {
+			radix_tree_insert(&root, 1, ptr);
+			first = false;
+		}
+		if (radix_tree_deref_retry(*slot)) {
+			printk("retry %ld\n", iter.index);
+			slot = radix_tree_iter_retry(&iter);
+			continue;
+		}
+	}
+
+	radix_tree_delete(&root, 0);
+	radix_tree_delete(&root, 1);
+}
+
 void __init radix_tree_init(void)
 {
 	radix_tree_node_cachep = kmem_cache_create("radix_tree_node",
@@ -1499,4 +1559,6 @@ void __init radix_tree_init(void)
 			radix_tree_node_ctor);
 	radix_tree_init_maxindex();
 	hotcpu_notifier(radix_tree_callback, 0);
+
+	test_iter_retry();
 }