diff --git a/lib/idr.c b/lib/idr.c
index 99ec5bc..823b813 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -36,8 +36,8 @@ int idr_alloc_u32(struct idr *idr, void *ptr, u32 *nextid,
 {
 	struct radix_tree_iter iter;
 	void __rcu **slot;
-	int base = idr->idr_base;
-	int id = *nextid;
+	unsigned int base = idr->idr_base;
+	unsigned int id = *nextid;
 
 	if (WARN_ON_ONCE(radix_tree_is_internal_node(ptr)))
 		return -EINVAL;
@@ -204,10 +204,11 @@ int idr_for_each(const struct idr *idr,
 
 	radix_tree_for_each_slot(slot, &idr->idr_rt, &iter, 0) {
 		int ret;
+		unsigned long id = iter.index + base;
 
-		if (WARN_ON_ONCE(iter.index > INT_MAX))
+		if (WARN_ON_ONCE(id > INT_MAX))
 			break;
-		ret = fn(iter.index + base, rcu_dereference_raw(*slot), data);
+		ret = fn(id, rcu_dereference_raw(*slot), data);
 		if (ret)
 			return ret;
 	}
@@ -230,8 +231,8 @@ void *idr_get_next(struct idr *idr, int *nextid)
 {
 	struct radix_tree_iter iter;
 	void __rcu **slot;
-	int base = idr->idr_base;
-	int id = *nextid;
+	unsigned long base = idr->idr_base;
+	unsigned long id = *nextid;
 
 	id = (id < base) ? 0 : id - base;
 	slot = radix_tree_iter_find(&idr->idr_rt, &iter, id);
diff --git a/tools/testing/radix-tree/idr-test.c b/tools/testing/radix-tree/idr-test.c
index 44ef9eb..6c645eb 100644
--- a/tools/testing/radix-tree/idr-test.c
+++ b/tools/testing/radix-tree/idr-test.c
@@ -178,6 +178,55 @@ void idr_get_next_test(int base)
 	idr_destroy(&idr);
 }
 
+int idr_u32_cb(int id, void *ptr, void *data)
+{
+	BUG_ON(id < 0);
+	BUG_ON(ptr != DUMMY_PTR);
+	return 0;
+}
+
+void idr_u32_test1(struct idr *idr, u32 handle)
+{
+	static bool warned = false;
+	u32 id = handle;
+	int sid = 0;
+	void *ptr;
+
+	BUG_ON(idr_alloc_u32(idr, DUMMY_PTR, &id, id, GFP_KERNEL));
+	BUG_ON(id != handle);
+	BUG_ON(idr_alloc_u32(idr, DUMMY_PTR, &id, id, GFP_KERNEL) != -ENOSPC);
+	BUG_ON(id != handle);
+	if (!warned && id > INT_MAX)
+		printk("vvv Ignore these warnings\n");
+	ptr = idr_get_next(idr, &sid);
+	if (id > INT_MAX) {
+		BUG_ON(ptr != NULL);
+		BUG_ON(sid != 0);
+	} else {
+		BUG_ON(ptr != DUMMY_PTR);
+		BUG_ON(sid != id);
+	}
+	idr_for_each(idr, idr_u32_cb, NULL);
+	if (!warned && id > INT_MAX) {
+		printk("^^^ Warnings over\n");
+		warned = true;
+	}
+	BUG_ON(idr_remove(idr, id) != DUMMY_PTR);
+	BUG_ON(!idr_is_empty(idr));
+}
+
+void idr_u32_test(int base)
+{
+	DEFINE_IDR(idr);
+	idr_init_base(&idr, base);
+	idr_u32_test1(&idr, 10);
+	idr_u32_test1(&idr, 0x7fffffff);
+	idr_u32_test1(&idr, 0x80000000);
+	idr_u32_test1(&idr, 0x80000001);
+	idr_u32_test1(&idr, 0xffe00000);
+	idr_u32_test1(&idr, 0xffffffff);
+}
+
 void idr_checks(void)
 {
 	unsigned long i;
@@ -248,6 +297,9 @@ void idr_checks(void)
 	idr_get_next_test(0);
 	idr_get_next_test(1);
 	idr_get_next_test(4);
+	idr_u32_test(4);
+	idr_u32_test(1);
+	idr_u32_test(0);
 }
 
 /*
diff --git a/tools/testing/radix-tree/linux.c b/tools/testing/radix-tree/linux.c
index 6903ccf..44a0d1ad 100644
--- a/tools/testing/radix-tree/linux.c
+++ b/tools/testing/radix-tree/linux.c
@@ -29,7 +29,7 @@ void *kmem_cache_alloc(struct kmem_cache *cachep, int flags)
 {
 	struct radix_tree_node *node;
 
-	if (flags & __GFP_NOWARN)
+	if (!(flags & __GFP_DIRECT_RECLAIM))
 		return NULL;
 
 	pthread_mutex_lock(&cachep->lock);
@@ -73,10 +73,17 @@ void kmem_cache_free(struct kmem_cache *cachep, void *objp)
 
 void *kmalloc(size_t size, gfp_t gfp)
 {
-	void *ret = malloc(size);
+	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;
 }
 
diff --git a/tools/testing/radix-tree/linux/compiler_types.h b/tools/testing/radix-tree/linux/compiler_types.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/tools/testing/radix-tree/linux/compiler_types.h
diff --git a/tools/testing/radix-tree/linux/gfp.h b/tools/testing/radix-tree/linux/gfp.h
index e9fff59..e3201cc 100644
--- a/tools/testing/radix-tree/linux/gfp.h
+++ b/tools/testing/radix-tree/linux/gfp.h
@@ -11,6 +11,7 @@
 #define __GFP_IO		0x40u
 #define __GFP_FS		0x80u
 #define __GFP_NOWARN		0x200u
+#define __GFP_ZERO		0x8000u
 #define __GFP_ATOMIC		0x80000u
 #define __GFP_ACCOUNT		0x100000u
 #define __GFP_DIRECT_RECLAIM	0x400000u
diff --git a/tools/testing/radix-tree/linux/slab.h b/tools/testing/radix-tree/linux/slab.h
index 979baee..a037def 100644
--- a/tools/testing/radix-tree/linux/slab.h
+++ b/tools/testing/radix-tree/linux/slab.h
@@ -3,6 +3,7 @@
 #define SLAB_H
 
 #include <linux/types.h>
+#include <linux/gfp.h>
 
 #define SLAB_HWCACHE_ALIGN 1
 #define SLAB_PANIC 2
@@ -11,6 +12,11 @@
 void *kmalloc(size_t size, gfp_t);
 void kfree(void *);
 
+static inline void *kzalloc(size_t size, gfp_t gfp)
+{
+        return kmalloc(size, gfp | __GFP_ZERO);
+}
+
 void *kmem_cache_alloc(struct kmem_cache *cachep, int flags);
 void kmem_cache_free(struct kmem_cache *cachep, void *objp);