radix tree test suite: add tests for radix_tree_locate_item()

Fairly simple tests; add various items to the tree, then make sure we
can find them again.  Also check that a pointer that we know isn't in
the tree is not found.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jan Kara <jack@suse.com>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/tools/testing/radix-tree/linux/kernel.h b/tools/testing/radix-tree/linux/kernel.h
index 6d0cdf6..76a88f3 100644
--- a/tools/testing/radix-tree/linux/kernel.h
+++ b/tools/testing/radix-tree/linux/kernel.h
@@ -9,6 +9,9 @@
 
 #include "../../include/linux/compiler.h"
 
+#define CONFIG_SHMEM
+#define CONFIG_SWAP
+
 #ifndef NULL
 #define NULL	0
 #endif