radix tree test suite: free preallocated nodes

It can be a source of mild concern when the test suite shows that we're
leaking nodes.  While poring over the source code looking for leaks can
lead to some fascinating bugs being discovered, sometimes the leak is
simply that these nodes were preallocated and are sitting on the per-CPU
list.  Free them by calling the CPU dead callback.

Link: http://lkml.kernel.org/r/1480369871-5271-40-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

tools/testing/radix-tree/main.c

@@ -344,6 +344,9 @@ int main(int argc, char **argv)
 	iteration_test();
 	single_thread_tests(long_run);
 
+	/* Free any remaining preallocated nodes */
+	radix_tree_cpu_dead(0);
+
 	sleep(1);
 	printf("after sleep(1): %d allocated, preempt %d\n",
 		nr_allocated, preempt_count);

tools/testing/radix-tree/test.h

@@ -44,3 +44,4 @@ void radix_tree_dump(struct radix_tree_root *root);
 int root_tag_get(struct radix_tree_root *root, unsigned int tag);
 unsigned long node_maxindex(struct radix_tree_node *);
 unsigned long shift_maxindex(unsigned int shift);
+int radix_tree_cpu_dead(unsigned int cpu);