v4.19.13 snapshot.
diff --git a/tools/testing/radix-tree/linux.c b/tools/testing/radix-tree/linux.c
new file mode 100644
index 0000000..44a0d1a
--- /dev/null
+++ b/tools/testing/radix-tree/linux.c
@@ -0,0 +1,112 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdlib.h>
+#include <string.h>
+#include <malloc.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <assert.h>
+
+#include <linux/gfp.h>
+#include <linux/poison.h>
+#include <linux/slab.h>
+#include <linux/radix-tree.h>
+#include <urcu/uatomic.h>
+
+int nr_allocated;
+int preempt_count;
+int kmalloc_verbose;
+int test_verbose;
+
+struct kmem_cache {
+ pthread_mutex_t lock;
+ int size;
+ int nr_objs;
+ void *objs;
+ void (*ctor)(void *);
+};
+
+void *kmem_cache_alloc(struct kmem_cache *cachep, int flags)
+{
+ struct radix_tree_node *node;
+
+ if (!(flags & __GFP_DIRECT_RECLAIM))
+ return NULL;
+
+ pthread_mutex_lock(&cachep->lock);
+ if (cachep->nr_objs) {
+ cachep->nr_objs--;
+ node = cachep->objs;
+ cachep->objs = node->parent;
+ pthread_mutex_unlock(&cachep->lock);
+ node->parent = NULL;
+ } else {
+ pthread_mutex_unlock(&cachep->lock);
+ node = malloc(cachep->size);
+ if (cachep->ctor)
+ cachep->ctor(node);
+ }
+
+ uatomic_inc(&nr_allocated);
+ if (kmalloc_verbose)
+ printf("Allocating %p from slab\n", node);
+ return node;
+}
+
+void kmem_cache_free(struct kmem_cache *cachep, void *objp)
+{
+ assert(objp);
+ uatomic_dec(&nr_allocated);
+ if (kmalloc_verbose)
+ printf("Freeing %p to slab\n", objp);
+ pthread_mutex_lock(&cachep->lock);
+ if (cachep->nr_objs > 10) {
+ memset(objp, POISON_FREE, cachep->size);
+ free(objp);
+ } else {
+ struct radix_tree_node *node = objp;
+ cachep->nr_objs++;
+ node->parent = cachep->objs;
+ cachep->objs = node;
+ }
+ pthread_mutex_unlock(&cachep->lock);
+}
+
+void *kmalloc(size_t size, gfp_t gfp)
+{
+ void *ret;
+
+ if (!(gfp & __GFP_DIRECT_RECLAIM))
+ return NULL;
+
+ ret = malloc(size);
+ uatomic_inc(&nr_allocated);
+ if (kmalloc_verbose)
+ printf("Allocating %p from malloc\n", ret);
+ if (gfp & __GFP_ZERO)
+ memset(ret, 0, size);
+ return ret;
+}
+
+void kfree(void *p)
+{
+ if (!p)
+ return;
+ uatomic_dec(&nr_allocated);
+ if (kmalloc_verbose)
+ printf("Freeing %p to malloc\n", p);
+ free(p);
+}
+
+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));
+
+ pthread_mutex_init(&ret->lock, NULL);
+ ret->size = size;
+ ret->nr_objs = 0;
+ ret->objs = NULL;
+ ret->ctor = ctor;
+ return ret;
+}