radix tree test harness

This code is mostly from Andrew Morton and Nick Piggin; tarball downloaded
from http://ozlabs.org/~akpm/rtth.tar.gz with sha1sum
0ce679db9ec047296b5d1ff7a1dfaa03a7bef1bd

Some small modifications were necessary to the test harness to fix the
build with the current Linux source code.

I also made minor modifications to automatically test the radix-tree.c
and radix-tree.h files that are in the current source tree, as opposed
to a copied and slightly modified version.  I am sure more could be done
to tidy up the harness, as well as adding more tests.

[koct9i@gmail.com: fix compilation]
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

tools/testing/radix-tree/linux.c

@@ -0,0 +1,60 @@
+#include <stdlib.h>
+#include <string.h>
+#include <malloc.h>
+#include <unistd.h>
+#include <assert.h>
+
+#include <linux/mempool.h>
+#include <linux/slab.h>
+#include <urcu/uatomic.h>
+
+int nr_allocated;
+
+void *mempool_alloc(mempool_t *pool, int gfp_mask)
+{
+	return pool->alloc(gfp_mask, pool->data);
+}
+
+void mempool_free(void *element, mempool_t *pool)
+{
+	pool->free(element, pool->data);
+}
+
+mempool_t *mempool_create(int min_nr, mempool_alloc_t *alloc_fn,
+			mempool_free_t *free_fn, void *pool_data)
+{
+	mempool_t *ret = malloc(sizeof(*ret));
+
+	ret->alloc = alloc_fn;
+	ret->free = free_fn;
+	ret->data = pool_data;
+	return ret;
+}
+
+void *kmem_cache_alloc(struct kmem_cache *cachep, int flags)
+{
+	void *ret = malloc(cachep->size);
+	if (cachep->ctor)
+		cachep->ctor(ret);
+	uatomic_inc(&nr_allocated);
+	return ret;
+}
+
+void kmem_cache_free(struct kmem_cache *cachep, void *objp)
+{
+	assert(objp);
+	uatomic_dec(&nr_allocated);
+	memset(objp, 0, cachep->size);
+	free(objp);
+}
+
+struct kmem_cache *
+kmem_cache_create(const char *name, size_t size, size_t offset,
+	unsigned long flags, void (*ctor)(void *))
+{
+	struct kmem_cache *ret = malloc(sizeof(*ret));
+
+	ret->size = size;
+	ret->ctor = ctor;
+	return ret;
+}