radix-tree: add test for radix_tree_locate_item()

Add a unit test that provides coverage for the bug fixed in the commit entitled "radix-tree: rewrite radix_tree_locate_item fix" from Hugh Dickins. I've verified that this test fails before his patch due to miscalculated 'index' values in __locate() in lib/radix-tree.c, and passes with his fix. Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ross Zwisler <[email protected]> Cc: Hugh Dickins <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
ambv · May 21, 2016 · eb73f7f · eb73f7f
1 parent 0a2efc6
commit eb73f7f
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diff --git a/tools/testing/radix-tree/linux/init.h b/tools/testing/radix-tree/linux/init.h
@@ -0,0 +1 @@
+/* An empty file stub that allows radix-tree.c to compile. */
diff --git a/tools/testing/radix-tree/main.c b/tools/testing/radix-tree/main.c
@@ -232,7 +232,7 @@ void copy_tag_check(void)
 	item_kill_tree(&tree);
 }
 
-void __locate_check(struct radix_tree_root *tree, unsigned long index,
+static void __locate_check(struct radix_tree_root *tree, unsigned long index,
 			unsigned order)
 {
 	struct item *item;
@@ -248,12 +248,25 @@ void __locate_check(struct radix_tree_root *tree, unsigned long index,
 	}
 }
 
+static void __order_0_locate_check(void)
+{
+	RADIX_TREE(tree, GFP_KERNEL);
+	int i;
+
+	for (i = 0; i < 50; i++)
+		__locate_check(&tree, rand() % INT_MAX, 0);
+
+	item_kill_tree(&tree);
+}
+
 static void locate_check(void)
 {
 	RADIX_TREE(tree, GFP_KERNEL);
 	unsigned order;
 	unsigned long offset, index;
 
+	__order_0_locate_check();
+
 	for (order = 0; order < 20; order++) {
 		for (offset = 0; offset < (1 << (order + 3));
 		     offset += (1UL << order)) {
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		/* An empty file stub that allows radix-tree.c to compile. */