diff --git a/drivers/atm/nicstar.c b/drivers/atm/nicstar.c
index cb28579e8a946f6820fdff21433fd715870a6436..d879f3bca1076dbbcfe1d3313f8286d984e1bbd5 100644
--- a/drivers/atm/nicstar.c
+++ b/drivers/atm/nicstar.c
@@ -1980,13 +1980,12 @@ static void dequeue_rx(ns_dev * card, ns_rsqe * rsqe)
 	card->lbfqc = ns_stat_lfbqc_get(stat);
 
 	id = le32_to_cpu(rsqe->buffer_handle);
-	skb = idr_find(&card->idr, id);
+	skb = idr_remove(&card->idr, id);
 	if (!skb) {
 		RXPRINTK(KERN_ERR
-			 "nicstar%d: idr_find() failed!\n", card->index);
+			 "nicstar%d: skb not found!\n", card->index);
 		return;
 	}
-	idr_remove(&card->idr, id);
 	dma_sync_single_for_cpu(&card->pcidev->dev,
 				NS_PRV_DMA(skb),
 				(NS_PRV_BUFTYPE(skb) == BUF_SM
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 615e5b5178a0541852820e67698d7a8b41cc268d..116509852a34da5730402edfedd025afd1b4a934 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2915,11 +2915,9 @@ enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsig
 	idr_remove(&connection->peer_devices, vnr);
 out_idr_remove_from_resource:
 	for_each_connection(connection, resource) {
-		peer_device = idr_find(&connection->peer_devices, vnr);
-		if (peer_device) {
-			idr_remove(&connection->peer_devices, vnr);
+		peer_device = idr_remove(&connection->peer_devices, vnr);
+		if (peer_device)
 			kref_put(&connection->kref, drbd_destroy_connection);
-		}
 	}
 	for_each_peer_device_safe(peer_device, tmp_peer_device, device) {
 		list_del(&peer_device->peer_devices);
diff --git a/drivers/firewire/core-cdev.c b/drivers/firewire/core-cdev.c
index aee149bdf4c0339169d939eed797ef9e6ab521bf..a301fcf46e8821ba7d605582703df532f27f24b5 100644
--- a/drivers/firewire/core-cdev.c
+++ b/drivers/firewire/core-cdev.c
@@ -1307,8 +1307,7 @@ static void iso_resource_work(struct work_struct *work)
 	 */
 	if (r->todo == ISO_RES_REALLOC && !success &&
 	    !client->in_shutdown &&
-	    idr_find(&client->resource_idr, r->resource.handle)) {
-		idr_remove(&client->resource_idr, r->resource.handle);
+	    idr_remove(&client->resource_idr, r->resource.handle)) {
 		client_put(client);
 		free = true;
 	}
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
index c02db01f6583e620d885542f37a0da6f1780152e..0218cea6be4d23ff500e17e9372085198e893efa 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
@@ -70,10 +70,10 @@ static void amdgpu_bo_list_destroy(struct amdgpu_fpriv *fpriv, int id)
 	struct amdgpu_bo_list *list;
 
 	mutex_lock(&fpriv->bo_list_lock);
-	list = idr_find(&fpriv->bo_list_handles, id);
+	list = idr_remove(&fpriv->bo_list_handles, id);
 	if (list) {
+		/* Another user may have a reference to this list still */
 		mutex_lock(&list->lock);
-		idr_remove(&fpriv->bo_list_handles, id);
 		mutex_unlock(&list->lock);
 		amdgpu_bo_list_free(list);
 	}
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
index 400c66ba4c6bdc49ecdf30a3cb9deb9a79dffa71..cf05006713531ce920c62ca105929907b7457fcd 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
@@ -135,15 +135,11 @@ static int amdgpu_ctx_free(struct amdgpu_fpriv *fpriv, uint32_t id)
 	struct amdgpu_ctx *ctx;
 
 	mutex_lock(&mgr->lock);
-	ctx = idr_find(&mgr->ctx_handles, id);
-	if (ctx) {
-		idr_remove(&mgr->ctx_handles, id);
+	ctx = idr_remove(&mgr->ctx_handles, id);
+	if (ctx)
 		kref_put(&ctx->refcount, amdgpu_ctx_do_release);
-		mutex_unlock(&mgr->lock);
-		return 0;
-	}
 	mutex_unlock(&mgr->lock);
-	return -EINVAL;
+	return ctx ? 0 : -EINVAL;
 }
 
 static int amdgpu_ctx_query(struct amdgpu_device *adev,
diff --git a/drivers/net/wireless/marvell/mwifiex/txrx.c b/drivers/net/wireless/marvell/mwifiex/txrx.c
index abdd0cf710bf6df2440595dfbe879debf208be9a..fac28bd8fbee49bac450a7af32b7c6c71b4e95b6 100644
--- a/drivers/net/wireless/marvell/mwifiex/txrx.c
+++ b/drivers/net/wireless/marvell/mwifiex/txrx.c
@@ -346,9 +346,7 @@ void mwifiex_parse_tx_status_event(struct mwifiex_private *priv,
 		return;
 
 	spin_lock_irqsave(&priv->ack_status_lock, flags);
-	ack_skb = idr_find(&priv->ack_status_frames, tx_status->tx_token_id);
-	if (ack_skb)
-		idr_remove(&priv->ack_status_frames, tx_status->tx_token_id);
+	ack_skb = idr_remove(&priv->ack_status_frames, tx_status->tx_token_id);
 	spin_unlock_irqrestore(&priv->ack_status_lock, flags);
 
 	if (ack_skb) {
diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
index 5c1cb2df3a548b354a712dd12bba926eb2786bdd..c3adefe95e50f7f7054e272e15fc5e37663d11c9 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -642,9 +642,7 @@ static unsigned int tcmu_handle_completions(struct tcmu_dev *udev)
 		WARN_ON(tcmu_hdr_get_op(entry->hdr.len_op) != TCMU_OP_CMD);
 
 		spin_lock(&udev->commands_lock);
-		cmd = idr_find(&udev->commands, entry->hdr.cmd_id);
-		if (cmd)
-			idr_remove(&udev->commands, cmd->cmd_id);
+		cmd = idr_remove(&udev->commands, entry->hdr.cmd_id);
 		spin_unlock(&udev->commands_lock);
 
 		if (!cmd) {
diff --git a/include/linux/idr.h b/include/linux/idr.h
index 3c01b89aed67623ca22e10c3b70e913197620cd4..bf70b3ef0a073bbcb301ddf0141d90e8ac6fa018 100644
--- a/include/linux/idr.h
+++ b/include/linux/idr.h
@@ -12,47 +12,29 @@
 #ifndef __IDR_H__
 #define __IDR_H__
 
-#include <linux/types.h>
-#include <linux/bitops.h>
-#include <linux/init.h>
-#include <linux/rcupdate.h>
+#include <linux/radix-tree.h>
+#include <linux/gfp.h>
+#include <linux/percpu.h>
+
+struct idr {
+	struct radix_tree_root	idr_rt;
+	unsigned int		idr_next;
+};
 
 /*
- * Using 6 bits at each layer allows us to allocate 7 layers out of each page.
- * 8 bits only gave us 3 layers out of every pair of pages, which is less
- * efficient except for trees with a largest element between 192-255 inclusive.
+ * The IDR API does not expose the tagging functionality of the radix tree
+ * to users.  Use tag 0 to track whether a node has free space below it.
  */
-#define IDR_BITS 6
-#define IDR_SIZE (1 << IDR_BITS)
-#define IDR_MASK ((1 << IDR_BITS)-1)
-
-struct idr_layer {
-	int			prefix;	/* the ID prefix of this idr_layer */
-	int			layer;	/* distance from leaf */
-	struct idr_layer __rcu	*ary[1<<IDR_BITS];
-	int			count;	/* When zero, we can release it */
-	union {
-		/* A zero bit means "space here" */
-		DECLARE_BITMAP(bitmap, IDR_SIZE);
-		struct rcu_head		rcu_head;
-	};
-};
+#define IDR_FREE	0
 
-struct idr {
-	struct idr_layer __rcu	*hint;	/* the last layer allocated from */
-	struct idr_layer __rcu	*top;
-	int			layers;	/* only valid w/o concurrent changes */
-	int			cur;	/* current pos for cyclic allocation */
-	spinlock_t		lock;
-	int			id_free_cnt;
-	struct idr_layer	*id_free;
-};
+/* Set the IDR flag and the IDR_FREE tag */
+#define IDR_RT_MARKER		((__force gfp_t)(3 << __GFP_BITS_SHIFT))
 
-#define IDR_INIT(name)							\
+#define IDR_INIT							\
 {									\
-	.lock			= __SPIN_LOCK_UNLOCKED(name.lock),	\
+	.idr_rt = RADIX_TREE_INIT(IDR_RT_MARKER)			\
 }
-#define DEFINE_IDR(name)	struct idr name = IDR_INIT(name)
+#define DEFINE_IDR(name)	struct idr name = IDR_INIT
 
 /**
  * idr_get_cursor - Return the current position of the cyclic allocator
@@ -62,9 +44,9 @@ struct idr {
  * idr_alloc_cyclic() if it is free (otherwise the search will start from
  * this position).
  */
-static inline unsigned int idr_get_cursor(struct idr *idr)
+static inline unsigned int idr_get_cursor(const struct idr *idr)
 {
-	return READ_ONCE(idr->cur);
+	return READ_ONCE(idr->idr_next);
 }
 
 /**
@@ -77,7 +59,7 @@ static inline unsigned int idr_get_cursor(struct idr *idr)
  */
 static inline void idr_set_cursor(struct idr *idr, unsigned int val)
 {
-	WRITE_ONCE(idr->cur, val);
+	WRITE_ONCE(idr->idr_next, val);
 }
 
 /**
@@ -97,22 +79,31 @@ static inline void idr_set_cursor(struct idr *idr, unsigned int val)
  * period).
  */
 
-/*
- * This is what we export.
- */
-
-void *idr_find_slowpath(struct idr *idp, int id);
 void idr_preload(gfp_t gfp_mask);
-int idr_alloc(struct idr *idp, void *ptr, int start, int end, gfp_t gfp_mask);
-int idr_alloc_cyclic(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask);
-int idr_for_each(struct idr *idp,
+int idr_alloc(struct idr *, void *entry, int start, int end, gfp_t);
+int idr_alloc_cyclic(struct idr *, void *entry, int start, int end, gfp_t);
+int idr_for_each(const struct idr *,
 		 int (*fn)(int id, void *p, void *data), void *data);
-void *idr_get_next(struct idr *idp, int *nextid);
-void *idr_replace(struct idr *idp, void *ptr, int id);
-void idr_remove(struct idr *idp, int id);
-void idr_destroy(struct idr *idp);
-void idr_init(struct idr *idp);
-bool idr_is_empty(struct idr *idp);
+void *idr_get_next(struct idr *, int *nextid);
+void *idr_replace(struct idr *, void *, int id);
+void idr_destroy(struct idr *);
+
+static inline void *idr_remove(struct idr *idr, int id)
+{
+	return radix_tree_delete_item(&idr->idr_rt, id, NULL);
+}
+
+static inline void idr_init(struct idr *idr)
+{
+	INIT_RADIX_TREE(&idr->idr_rt, IDR_RT_MARKER);
+	idr->idr_next = 0;
+}
+
+static inline bool idr_is_empty(const struct idr *idr)
+{
+	return radix_tree_empty(&idr->idr_rt) &&
+		radix_tree_tagged(&idr->idr_rt, IDR_FREE);
+}
 
 /**
  * idr_preload_end - end preload section started with idr_preload()
@@ -137,19 +128,14 @@ static inline void idr_preload_end(void)
  * This function can be called under rcu_read_lock(), given that the leaf
  * pointers lifetimes are correctly managed.
  */
-static inline void *idr_find(struct idr *idr, int id)
+static inline void *idr_find(const struct idr *idr, int id)
 {
-	struct idr_layer *hint = rcu_dereference_raw(idr->hint);
-
-	if (hint && (id & ~IDR_MASK) == hint->prefix)
-		return rcu_dereference_raw(hint->ary[id & IDR_MASK]);
-
-	return idr_find_slowpath(idr, id);
+	return radix_tree_lookup(&idr->idr_rt, id);
 }
 
 /**
  * idr_for_each_entry - iterate over an idr's elements of a given type
- * @idp:     idr handle
+ * @idr:     idr handle
  * @entry:   the type * to use as cursor
  * @id:      id entry's key
  *
@@ -157,57 +143,60 @@ static inline void *idr_find(struct idr *idr, int id)
  * after normal terminatinon @entry is left with the value NULL.  This
  * is convenient for a "not found" value.
  */
-#define idr_for_each_entry(idp, entry, id)			\
-	for (id = 0; ((entry) = idr_get_next(idp, &(id))) != NULL; ++id)
+#define idr_for_each_entry(idr, entry, id)			\
+	for (id = 0; ((entry) = idr_get_next(idr, &(id))) != NULL; ++id)
 
 /**
- * idr_for_each_entry - continue iteration over an idr's elements of a given type
- * @idp:     idr handle
+ * idr_for_each_entry_continue - continue iteration over an idr's elements of a given type
+ * @idr:     idr handle
  * @entry:   the type * to use as cursor
  * @id:      id entry's key
  *
  * Continue to iterate over list of given type, continuing after
  * the current position.
  */
-#define idr_for_each_entry_continue(idp, entry, id)			\
-	for ((entry) = idr_get_next((idp), &(id));			\
+#define idr_for_each_entry_continue(idr, entry, id)			\
+	for ((entry) = idr_get_next((idr), &(id));			\
 	     entry;							\
-	     ++id, (entry) = idr_get_next((idp), &(id)))
+	     ++id, (entry) = idr_get_next((idr), &(id)))
 
 /*
  * IDA - IDR based id allocator, use when translation from id to
  * pointer isn't necessary.
- *
- * IDA_BITMAP_LONGS is calculated to be one less to accommodate
- * ida_bitmap->nr_busy so that the whole struct fits in 128 bytes.
  */
 #define IDA_CHUNK_SIZE		128	/* 128 bytes per chunk */
-#define IDA_BITMAP_LONGS	(IDA_CHUNK_SIZE / sizeof(long) - 1)
+#define IDA_BITMAP_LONGS	(IDA_CHUNK_SIZE / sizeof(long))
 #define IDA_BITMAP_BITS 	(IDA_BITMAP_LONGS * sizeof(long) * 8)
 
 struct ida_bitmap {
-	long			nr_busy;
 	unsigned long		bitmap[IDA_BITMAP_LONGS];
 };
 
+DECLARE_PER_CPU(struct ida_bitmap *, ida_bitmap);
+
 struct ida {
-	struct idr		idr;
-	struct ida_bitmap	*free_bitmap;
+	struct radix_tree_root	ida_rt;
 };
 
-#define IDA_INIT(name)		{ .idr = IDR_INIT((name).idr), .free_bitmap = NULL, }
-#define DEFINE_IDA(name)	struct ida name = IDA_INIT(name)
+#define IDA_INIT	{						\
+	.ida_rt = RADIX_TREE_INIT(IDR_RT_MARKER | GFP_NOWAIT),		\
+}
+#define DEFINE_IDA(name)	struct ida name = IDA_INIT
 
 int ida_pre_get(struct ida *ida, gfp_t gfp_mask);
 int ida_get_new_above(struct ida *ida, int starting_id, int *p_id);
 void ida_remove(struct ida *ida, int id);
 void ida_destroy(struct ida *ida);
-void ida_init(struct ida *ida);
 
 int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end,
 		   gfp_t gfp_mask);
 void ida_simple_remove(struct ida *ida, unsigned int id);
 
+static inline void ida_init(struct ida *ida)
+{
+	INIT_RADIX_TREE(&ida->ida_rt, IDR_RT_MARKER | GFP_NOWAIT);
+}
+
 /**
  * ida_get_new - allocate new ID
  * @ida:	idr handle
@@ -220,11 +209,8 @@ static inline int ida_get_new(struct ida *ida, int *p_id)
 	return ida_get_new_above(ida, 0, p_id);
 }
 
-static inline bool ida_is_empty(struct ida *ida)
+static inline bool ida_is_empty(const struct ida *ida)
 {
-	return idr_is_empty(&ida->idr);
+	return radix_tree_empty(&ida->ida_rt);
 }
-
-void __init idr_init_cache(void);
-
 #endif /* __IDR_H__ */
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index 52bda854593b4a9eae9bad2d9990f9dd166ed609..3e5735064b7166837e7eae615a4cde2d3a9cd727 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -22,11 +22,13 @@
 #define _LINUX_RADIX_TREE_H
 
 #include <linux/bitops.h>
-#include <linux/preempt.h>
-#include <linux/types.h>
 #include <linux/bug.h>
 #include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/preempt.h>
 #include <linux/rcupdate.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
 
 /*
  * The bottom two bits of the slot determine how the remaining bits in the
@@ -94,7 +96,7 @@ struct radix_tree_node {
 	unsigned char	count;		/* Total entry count */
 	unsigned char	exceptional;	/* Exceptional entry count */
 	struct radix_tree_node *parent;		/* Used when ascending tree */
-	void *private_data;			/* For tree user */
+	struct radix_tree_root *root;		/* The tree we belong to */
 	union {
 		struct list_head private_list;	/* For tree user */
 		struct rcu_head	rcu_head;	/* Used when freeing node */
@@ -103,7 +105,10 @@ struct radix_tree_node {
 	unsigned long	tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS];
 };
 
-/* root tags are stored in gfp_mask, shifted by __GFP_BITS_SHIFT */
+/* The top bits of gfp_mask are used to store the root tags and the IDR flag */
+#define ROOT_IS_IDR	((__force gfp_t)(1 << __GFP_BITS_SHIFT))
+#define ROOT_TAG_SHIFT	(__GFP_BITS_SHIFT + 1)
+
 struct radix_tree_root {
 	gfp_t			gfp_mask;
 	struct radix_tree_node	__rcu *rnode;
@@ -123,7 +128,7 @@ do {									\
 	(root)->rnode = NULL;						\
 } while (0)
 
-static inline bool radix_tree_empty(struct radix_tree_root *root)
+static inline bool radix_tree_empty(const struct radix_tree_root *root)
 {
 	return root->rnode == NULL;
 }
@@ -216,10 +221,8 @@ static inline unsigned int iter_shift(const struct radix_tree_iter *iter)
  */
 
 /**
- * radix_tree_deref_slot	- dereference a slot
- * @pslot:	pointer to slot, returned by radix_tree_lookup_slot
- * Returns:	item that was stored in that slot with any direct pointer flag
- *		removed.
+ * radix_tree_deref_slot - dereference a slot
+ * @slot: slot pointer, returned by radix_tree_lookup_slot
  *
  * For use with radix_tree_lookup_slot().  Caller must hold tree at least read
  * locked across slot lookup and dereference. Not required if write lock is
@@ -227,26 +230,27 @@ static inline unsigned int iter_shift(const struct radix_tree_iter *iter)
  *
  * radix_tree_deref_retry must be used to confirm validity of the pointer if
  * only the read lock is held.
+ *
+ * Return: entry stored in that slot.
  */
-static inline void *radix_tree_deref_slot(void **pslot)
+static inline void *radix_tree_deref_slot(void __rcu **slot)
 {
-	return rcu_dereference(*pslot);
+	return rcu_dereference(*slot);
 }
 
 /**
- * radix_tree_deref_slot_protected	- dereference a slot without RCU lock but with tree lock held
- * @pslot:	pointer to slot, returned by radix_tree_lookup_slot
- * Returns:	item that was stored in that slot with any direct pointer flag
- *		removed.
- *
- * Similar to radix_tree_deref_slot but only used during migration when a pages
- * mapping is being moved. The caller does not hold the RCU read lock but it
- * must hold the tree lock to prevent parallel updates.
+ * radix_tree_deref_slot_protected - dereference a slot with tree lock held
+ * @slot: slot pointer, returned by radix_tree_lookup_slot
+ *
+ * Similar to radix_tree_deref_slot.  The caller does not hold the RCU read
+ * lock but it must hold the tree lock to prevent parallel updates.
+ *
+ * Return: entry stored in that slot.
  */
-static inline void *radix_tree_deref_slot_protected(void **pslot,
+static inline void *radix_tree_deref_slot_protected(void __rcu **slot,
 							spinlock_t *treelock)
 {
-	return rcu_dereference_protected(*pslot, lockdep_is_held(treelock));
+	return rcu_dereference_protected(*slot, lockdep_is_held(treelock));
 }
 
 /**
@@ -282,9 +286,9 @@ static inline int radix_tree_exception(void *arg)
 	return unlikely((unsigned long)arg & RADIX_TREE_ENTRY_MASK);
 }
 
-int __radix_tree_create(struct radix_tree_root *root, unsigned long index,
+int __radix_tree_create(struct radix_tree_root *, unsigned long index,
 			unsigned order, struct radix_tree_node **nodep,
-			void ***slotp);
+			void __rcu ***slotp);
 int __radix_tree_insert(struct radix_tree_root *, unsigned long index,
 			unsigned order, void *);
 static inline int radix_tree_insert(struct radix_tree_root *root,
@@ -292,55 +296,56 @@ static inline int radix_tree_insert(struct radix_tree_root *root,
 {
 	return __radix_tree_insert(root, index, 0, entry);
 }
-void *__radix_tree_lookup(struct radix_tree_root *root, unsigned long index,
-			  struct radix_tree_node **nodep, void ***slotp);
-void *radix_tree_lookup(struct radix_tree_root *, unsigned long);
-void **radix_tree_lookup_slot(struct radix_tree_root *, unsigned long);
+void *__radix_tree_lookup(const struct radix_tree_root *, unsigned long index,
+			  struct radix_tree_node **nodep, void __rcu ***slotp);
+void *radix_tree_lookup(const struct radix_tree_root *, unsigned long);
+void __rcu **radix_tree_lookup_slot(const struct radix_tree_root *,
+					unsigned long index);
 typedef void (*radix_tree_update_node_t)(struct radix_tree_node *, void *);
-void __radix_tree_replace(struct radix_tree_root *root,
-			  struct radix_tree_node *node,
-			  void **slot, void *item,
+void __radix_tree_replace(struct radix_tree_root *, struct radix_tree_node *,
+			  void __rcu **slot, void *entry,
 			  radix_tree_update_node_t update_node, void *private);
 void radix_tree_iter_replace(struct radix_tree_root *,
-		const struct radix_tree_iter *, void **slot, void *item);
-void radix_tree_replace_slot(struct radix_tree_root *root,
-			     void **slot, void *item);
-void __radix_tree_delete_node(struct radix_tree_root *root,
-			      struct radix_tree_node *node,
+		const struct radix_tree_iter *, void __rcu **slot, void *entry);
+void radix_tree_replace_slot(struct radix_tree_root *,
+			     void __rcu **slot, void *entry);
+void __radix_tree_delete_node(struct radix_tree_root *,
+			      struct radix_tree_node *,
 			      radix_tree_update_node_t update_node,
 			      void *private);
+void radix_tree_iter_delete(struct radix_tree_root *,
+			struct radix_tree_iter *iter, void __rcu **slot);
 void *radix_tree_delete_item(struct radix_tree_root *, unsigned long, void *);
 void *radix_tree_delete(struct radix_tree_root *, unsigned long);
-void radix_tree_clear_tags(struct radix_tree_root *root,
-			   struct radix_tree_node *node,
-			   void **slot);
-unsigned int radix_tree_gang_lookup(struct radix_tree_root *root,
+void radix_tree_clear_tags(struct radix_tree_root *, struct radix_tree_node *,
+			   void __rcu **slot);
+unsigned int radix_tree_gang_lookup(const struct radix_tree_root *,
 			void **results, unsigned long first_index,
 			unsigned int max_items);
-unsigned int radix_tree_gang_lookup_slot(struct radix_tree_root *root,
-			void ***results, unsigned long *indices,
+unsigned int radix_tree_gang_lookup_slot(const struct radix_tree_root *,
+			void __rcu ***results, unsigned long *indices,
 			unsigned long first_index, unsigned int max_items);
 int radix_tree_preload(gfp_t gfp_mask);
 int radix_tree_maybe_preload(gfp_t gfp_mask);
 int radix_tree_maybe_preload_order(gfp_t gfp_mask, int order);
 void radix_tree_init(void);
-void *radix_tree_tag_set(struct radix_tree_root *root,
+void *radix_tree_tag_set(struct radix_tree_root *,
 			unsigned long index, unsigned int tag);
-void *radix_tree_tag_clear(struct radix_tree_root *root,
+void *radix_tree_tag_clear(struct radix_tree_root *,
 			unsigned long index, unsigned int tag);
-int radix_tree_tag_get(struct radix_tree_root *root,
+int radix_tree_tag_get(const struct radix_tree_root *,
 			unsigned long index, unsigned int tag);
-void radix_tree_iter_tag_set(struct radix_tree_root *root,
+void radix_tree_iter_tag_set(struct radix_tree_root *,
+		const struct radix_tree_iter *iter, unsigned int tag);
+void radix_tree_iter_tag_clear(struct radix_tree_root *,
 		const struct radix_tree_iter *iter, unsigned int tag);
-unsigned int
-radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results,
-		unsigned long first_index, unsigned int max_items,
-		unsigned int tag);
-unsigned int
-radix_tree_gang_lookup_tag_slot(struct radix_tree_root *root, void ***results,
-		unsigned long first_index, unsigned int max_items,
-		unsigned int tag);
-int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag);
+unsigned int radix_tree_gang_lookup_tag(const struct radix_tree_root *,
+		void **results, unsigned long first_index,
+		unsigned int max_items, unsigned int tag);
+unsigned int radix_tree_gang_lookup_tag_slot(const struct radix_tree_root *,
+		void __rcu ***results, unsigned long first_index,
+		unsigned int max_items, unsigned int tag);
+int radix_tree_tagged(const struct radix_tree_root *, unsigned int tag);
 
 static inline void radix_tree_preload_end(void)
 {
@@ -352,10 +357,14 @@ int radix_tree_split(struct radix_tree_root *, unsigned long index,
 			unsigned new_order);
 int radix_tree_join(struct radix_tree_root *, unsigned long index,
 			unsigned new_order, void *);
+void __rcu **idr_get_free(struct radix_tree_root *, struct radix_tree_iter *,
+			gfp_t, int end);
 
-#define RADIX_TREE_ITER_TAG_MASK	0x00FF	/* tag index in lower byte */
-#define RADIX_TREE_ITER_TAGGED		0x0100	/* lookup tagged slots */
-#define RADIX_TREE_ITER_CONTIG		0x0200	/* stop at first hole */
+enum {
+	RADIX_TREE_ITER_TAG_MASK = 0x0f,	/* tag index in lower nybble */
+	RADIX_TREE_ITER_TAGGED   = 0x10,	/* lookup tagged slots */
+	RADIX_TREE_ITER_CONTIG   = 0x20,	/* stop at first hole */
+};
 
 /**
  * radix_tree_iter_init - initialize radix tree iterator
@@ -364,7 +373,7 @@ int radix_tree_join(struct radix_tree_root *, unsigned long index,
  * @start:	iteration starting index
  * Returns:	NULL
  */
-static __always_inline void **
+static __always_inline void __rcu **
 radix_tree_iter_init(struct radix_tree_iter *iter, unsigned long start)
 {
 	/*
@@ -393,9 +402,45 @@ radix_tree_iter_init(struct radix_tree_iter *iter, unsigned long start)
  * Also it fills @iter with data about chunk: position in the tree (index),
  * its end (next_index), and constructs a bit mask for tagged iterating (tags).
  */
-void **radix_tree_next_chunk(struct radix_tree_root *root,
+void __rcu **radix_tree_next_chunk(const struct radix_tree_root *,
 			     struct radix_tree_iter *iter, unsigned flags);
 
+/**
+ * radix_tree_iter_lookup - look up an index in the radix tree
+ * @root: radix tree root
+ * @iter: iterator state
+ * @index: key to look up
+ *
+ * If @index is present in the radix tree, this function returns the slot
+ * containing it and updates @iter to describe the entry.  If @index is not
+ * present, it returns NULL.
+ */
+static inline void __rcu **
+radix_tree_iter_lookup(const struct radix_tree_root *root,
+			struct radix_tree_iter *iter, unsigned long index)
+{
+	radix_tree_iter_init(iter, index);
+	return radix_tree_next_chunk(root, iter, RADIX_TREE_ITER_CONTIG);
+}
+
+/**
+ * radix_tree_iter_find - find a present entry
+ * @root: radix tree root
+ * @iter: iterator state
+ * @index: start location
+ *
+ * This function returns the slot containing the entry with the lowest index
+ * which is at least @index.  If @index is larger than any present entry, this
+ * function returns NULL.  The @iter is updated to describe the entry found.
+ */
+static inline void __rcu **
+radix_tree_iter_find(const struct radix_tree_root *root,
+			struct radix_tree_iter *iter, unsigned long index)
+{
+	radix_tree_iter_init(iter, index);
+	return radix_tree_next_chunk(root, iter, 0);
+}
+
 /**
  * radix_tree_iter_retry - retry this chunk of the iteration
  * @iter:	iterator state
@@ -406,7 +451,7 @@ void **radix_tree_next_chunk(struct radix_tree_root *root,
  * and continue the iteration.
  */
 static inline __must_check
-void **radix_tree_iter_retry(struct radix_tree_iter *iter)
+void __rcu **radix_tree_iter_retry(struct radix_tree_iter *iter)
 {
 	iter->next_index = iter->index;
 	iter->tags = 0;
@@ -429,7 +474,7 @@ __radix_tree_iter_add(struct radix_tree_iter *iter, unsigned long slots)
  * have been invalidated by an insertion or deletion.  Call this function
  * before releasing the lock to continue the iteration from the next index.
  */
-void **__must_check radix_tree_iter_resume(void **slot,
+void __rcu **__must_check radix_tree_iter_resume(void __rcu **slot,
 					struct radix_tree_iter *iter);
 
 /**
@@ -445,11 +490,11 @@ radix_tree_chunk_size(struct radix_tree_iter *iter)
 }
 
 #ifdef CONFIG_RADIX_TREE_MULTIORDER
-void ** __radix_tree_next_slot(void **slot, struct radix_tree_iter *iter,
-				unsigned flags);
+void __rcu **__radix_tree_next_slot(void __rcu **slot,
+				struct radix_tree_iter *iter, unsigned flags);
 #else
 /* Can't happen without sibling entries, but the compiler can't tell that */
-static inline void ** __radix_tree_next_slot(void **slot,
+static inline void __rcu **__radix_tree_next_slot(void __rcu **slot,
 				struct radix_tree_iter *iter, unsigned flags)
 {
 	return slot;
@@ -475,8 +520,8 @@ static inline void ** __radix_tree_next_slot(void **slot,
  * b) we are doing non-tagged iteration, and iter->index and iter->next_index
  *    have been set up so that radix_tree_chunk_size() returns 1 or 0.
  */
-static __always_inline void **
-radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, unsigned flags)
+static __always_inline void __rcu **radix_tree_next_slot(void __rcu **slot,
+				struct radix_tree_iter *iter, unsigned flags)
 {
 	if (flags & RADIX_TREE_ITER_TAGGED) {
 		iter->tags >>= 1;
@@ -514,7 +559,7 @@ radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, unsigned flags)
 	return NULL;
 
  found:
-	if (unlikely(radix_tree_is_internal_node(*slot)))
+	if (unlikely(radix_tree_is_internal_node(rcu_dereference_raw(*slot))))
 		return __radix_tree_next_slot(slot, iter, flags);
 	return slot;
 }
diff --git a/init/main.c b/init/main.c
index 47ea22d181effd47af32f8a908d39b0e5d3c4629..ae9f2008fb86834f20d8160936601ee908740a66 100644
--- a/init/main.c
+++ b/init/main.c
@@ -554,7 +554,7 @@ asmlinkage __visible void __init start_kernel(void)
 	if (WARN(!irqs_disabled(),
 		 "Interrupts were enabled *very* early, fixing it\n"))
 		local_irq_disable();
-	idr_init_cache();
+	radix_tree_init();
 
 	/*
 	 * Allow workqueue creation and work item queueing/cancelling
@@ -569,7 +569,6 @@ asmlinkage __visible void __init start_kernel(void)
 	trace_init();
 
 	context_tracking_init();
-	radix_tree_init();
 	/* init some links before init_ISA_irqs() */
 	early_irq_init();
 	init_IRQ();
diff --git a/lib/Makefile b/lib/Makefile
index 469b2392893ab080b8529e2ef5a7d2993035ca90..320ac46a8725b6f9dac0726767a4976a2bd8907c 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -25,6 +25,9 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \
 	 earlycpio.o seq_buf.o siphash.o \
 	 nmi_backtrace.o nodemask.o win_minmax.o
 
+CFLAGS_radix-tree.o += -DCONFIG_SPARSE_RCU_POINTER
+CFLAGS_idr.o += -DCONFIG_SPARSE_RCU_POINTER
+
 lib-$(CONFIG_MMU) += ioremap.o
 lib-$(CONFIG_SMP) += cpumask.o
 lib-$(CONFIG_DMA_NOOP_OPS) += dma-noop.o
diff --git a/lib/idr.c b/lib/idr.c
index 52d2979a05e808432389f73fd77f180a8e5415a5..b13682bb0a1c67432092ffb6f3f23071e9cd15dd 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -1,1068 +1,409 @@
-/*
- * 2002-10-18  written by Jim Houston jim.houston@ccur.com
- *	Copyright (C) 2002 by Concurrent Computer Corporation
- *	Distributed under the GNU GPL license version 2.
- *
- * Modified by George Anzinger to reuse immediately and to use
- * find bit instructions.  Also removed _irq on spinlocks.
- *
- * Modified by Nadia Derbey to make it RCU safe.
- *
- * Small id to pointer translation service.
- *
- * It uses a radix tree like structure as a sparse array indexed
- * by the id to obtain the pointer.  The bitmap makes allocating
- * a new id quick.
- *
- * You call it to allocate an id (an int) an associate with that id a
- * pointer or what ever, we treat it as a (void *).  You can pass this
- * id to a user for him to pass back at a later time.  You then pass
- * that id to this code and it returns your pointer.
- */
-
-#ifndef TEST                        // to test in user space...
-#include <linux/slab.h>
-#include <linux/init.h>
+#include <linux/bitmap.h>
 #include <linux/export.h>
-#endif
-#include <linux/err.h>
-#include <linux/string.h>
 #include <linux/idr.h>
+#include <linux/slab.h>
 #include <linux/spinlock.h>
-#include <linux/percpu.h>
-
-#define MAX_IDR_SHIFT		(sizeof(int) * 8 - 1)
-#define MAX_IDR_BIT		(1U << MAX_IDR_SHIFT)
-
-/* Leave the possibility of an incomplete final layer */
-#define MAX_IDR_LEVEL ((MAX_IDR_SHIFT + IDR_BITS - 1) / IDR_BITS)
 
-/* Number of id_layer structs to leave in free list */
-#define MAX_IDR_FREE (MAX_IDR_LEVEL * 2)
-
-static struct kmem_cache *idr_layer_cache;
-static DEFINE_PER_CPU(struct idr_layer *, idr_preload_head);
-static DEFINE_PER_CPU(int, idr_preload_cnt);
+DEFINE_PER_CPU(struct ida_bitmap *, ida_bitmap);
 static DEFINE_SPINLOCK(simple_ida_lock);
 
-/* the maximum ID which can be allocated given idr->layers */
-static int idr_max(int layers)
-{
-	int bits = min_t(int, layers * IDR_BITS, MAX_IDR_SHIFT);
-
-	return (1 << bits) - 1;
-}
-
-/*
- * Prefix mask for an idr_layer at @layer.  For layer 0, the prefix mask is
- * all bits except for the lower IDR_BITS.  For layer 1, 2 * IDR_BITS, and
- * so on.
- */
-static int idr_layer_prefix_mask(int layer)
-{
-	return ~idr_max(layer + 1);
-}
-
-static struct idr_layer *get_from_free_list(struct idr *idp)
-{
-	struct idr_layer *p;
-	unsigned long flags;
-
-	spin_lock_irqsave(&idp->lock, flags);
-	if ((p = idp->id_free)) {
-		idp->id_free = p->ary[0];
-		idp->id_free_cnt--;
-		p->ary[0] = NULL;
-	}
-	spin_unlock_irqrestore(&idp->lock, flags);
-	return(p);
-}
-
 /**
- * idr_layer_alloc - allocate a new idr_layer
- * @gfp_mask: allocation mask
- * @layer_idr: optional idr to allocate from
- *
- * If @layer_idr is %NULL, directly allocate one using @gfp_mask or fetch
- * one from the per-cpu preload buffer.  If @layer_idr is not %NULL, fetch
- * an idr_layer from @idr->id_free.
- *
- * @layer_idr is to maintain backward compatibility with the old alloc
- * interface - idr_pre_get() and idr_get_new*() - and will be removed
- * together with per-pool preload buffer.
- */
-static struct idr_layer *idr_layer_alloc(gfp_t gfp_mask, struct idr *layer_idr)
-{
-	struct idr_layer *new;
-
-	/* this is the old path, bypass to get_from_free_list() */
-	if (layer_idr)
-		return get_from_free_list(layer_idr);
-
-	/*
-	 * Try to allocate directly from kmem_cache.  We want to try this
-	 * before preload buffer; otherwise, non-preloading idr_alloc()
-	 * users will end up taking advantage of preloading ones.  As the
-	 * following is allowed to fail for preloaded cases, suppress
-	 * warning this time.
-	 */
-	new = kmem_cache_zalloc(idr_layer_cache, gfp_mask | __GFP_NOWARN);
-	if (new)
-		return new;
-
-	/*
-	 * Try to fetch one from the per-cpu preload buffer if in process
-	 * context.  See idr_preload() for details.
-	 */
-	if (!in_interrupt()) {
-		preempt_disable();
-		new = __this_cpu_read(idr_preload_head);
-		if (new) {
-			__this_cpu_write(idr_preload_head, new->ary[0]);
-			__this_cpu_dec(idr_preload_cnt);
-			new->ary[0] = NULL;
-		}
-		preempt_enable();
-		if (new)
-			return new;
-	}
-
-	/*
-	 * Both failed.  Try kmem_cache again w/o adding __GFP_NOWARN so
-	 * that memory allocation failure warning is printed as intended.
-	 */
-	return kmem_cache_zalloc(idr_layer_cache, gfp_mask);
-}
-
-static void idr_layer_rcu_free(struct rcu_head *head)
-{
-	struct idr_layer *layer;
-
-	layer = container_of(head, struct idr_layer, rcu_head);
-	kmem_cache_free(idr_layer_cache, layer);
-}
-
-static inline void free_layer(struct idr *idr, struct idr_layer *p)
-{
-	if (idr->hint == p)
-		RCU_INIT_POINTER(idr->hint, NULL);
-	call_rcu(&p->rcu_head, idr_layer_rcu_free);
-}
-
-/* only called when idp->lock is held */
-static void __move_to_free_list(struct idr *idp, struct idr_layer *p)
-{
-	p->ary[0] = idp->id_free;
-	idp->id_free = p;
-	idp->id_free_cnt++;
-}
-
-static void move_to_free_list(struct idr *idp, struct idr_layer *p)
-{
-	unsigned long flags;
-
-	/*
-	 * Depends on the return element being zeroed.
-	 */
-	spin_lock_irqsave(&idp->lock, flags);
-	__move_to_free_list(idp, p);
-	spin_unlock_irqrestore(&idp->lock, flags);
-}
-
-static void idr_mark_full(struct idr_layer **pa, int id)
-{
-	struct idr_layer *p = pa[0];
-	int l = 0;
-
-	__set_bit(id & IDR_MASK, p->bitmap);
-	/*
-	 * If this layer is full mark the bit in the layer above to
-	 * show that this part of the radix tree is full.  This may
-	 * complete the layer above and require walking up the radix
-	 * tree.
-	 */
-	while (bitmap_full(p->bitmap, IDR_SIZE)) {
-		if (!(p = pa[++l]))
-			break;
-		id = id >> IDR_BITS;
-		__set_bit((id & IDR_MASK), p->bitmap);
-	}
-}
-
-static int __idr_pre_get(struct idr *idp, gfp_t gfp_mask)
-{
-	while (idp->id_free_cnt < MAX_IDR_FREE) {
-		struct idr_layer *new;
-		new = kmem_cache_zalloc(idr_layer_cache, gfp_mask);
-		if (new == NULL)
-			return (0);
-		move_to_free_list(idp, new);
-	}
-	return 1;
-}
-
-/**
- * sub_alloc - try to allocate an id without growing the tree depth
- * @idp: idr handle
- * @starting_id: id to start search at
- * @pa: idr_layer[MAX_IDR_LEVEL] used as backtrack buffer
- * @gfp_mask: allocation mask for idr_layer_alloc()
- * @layer_idr: optional idr passed to idr_layer_alloc()
- *
- * Allocate an id in range [@starting_id, INT_MAX] from @idp without
- * growing its depth.  Returns
- *
- *  the allocated id >= 0 if successful,
- *  -EAGAIN if the tree needs to grow for allocation to succeed,
- *  -ENOSPC if the id space is exhausted,
- *  -ENOMEM if more idr_layers need to be allocated.
- */
-static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa,
-		     gfp_t gfp_mask, struct idr *layer_idr)
-{
-	int n, m, sh;
-	struct idr_layer *p, *new;
-	int l, id, oid;
-
-	id = *starting_id;
- restart:
-	p = idp->top;
-	l = idp->layers;
-	pa[l--] = NULL;
-	while (1) {
-		/*
-		 * We run around this while until we reach the leaf node...
-		 */
-		n = (id >> (IDR_BITS*l)) & IDR_MASK;
-		m = find_next_zero_bit(p->bitmap, IDR_SIZE, n);
-		if (m == IDR_SIZE) {
-			/* no space available go back to previous layer. */
-			l++;
-			oid = id;
-			id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1;
-
-			/* if already at the top layer, we need to grow */
-			if (id > idr_max(idp->layers)) {
-				*starting_id = id;
-				return -EAGAIN;
-			}
-			p = pa[l];
-			BUG_ON(!p);
-
-			/* If we need to go up one layer, continue the
-			 * loop; otherwise, restart from the top.
-			 */
-			sh = IDR_BITS * (l + 1);
-			if (oid >> sh == id >> sh)
-				continue;
-			else
-				goto restart;
-		}
-		if (m != n) {
-			sh = IDR_BITS*l;
-			id = ((id >> sh) ^ n ^ m) << sh;
-		}
-		if ((id >= MAX_IDR_BIT) || (id < 0))
-			return -ENOSPC;
-		if (l == 0)
-			break;
-		/*
-		 * Create the layer below if it is missing.
-		 */
-		if (!p->ary[m]) {
-			new = idr_layer_alloc(gfp_mask, layer_idr);
-			if (!new)
-				return -ENOMEM;
-			new->layer = l-1;
-			new->prefix = id & idr_layer_prefix_mask(new->layer);
-			rcu_assign_pointer(p->ary[m], new);
-			p->count++;
-		}
-		pa[l--] = p;
-		p = p->ary[m];
-	}
-
-	pa[l] = p;
-	return id;
-}
-
-static int idr_get_empty_slot(struct idr *idp, int starting_id,
-			      struct idr_layer **pa, gfp_t gfp_mask,
-			      struct idr *layer_idr)
-{
-	struct idr_layer *p, *new;
-	int layers, v, id;
-	unsigned long flags;
-
-	id = starting_id;
-build_up:
-	p = idp->top;
-	layers = idp->layers;
-	if (unlikely(!p)) {
-		if (!(p = idr_layer_alloc(gfp_mask, layer_idr)))
-			return -ENOMEM;
-		p->layer = 0;
-		layers = 1;
-	}
-	/*
-	 * Add a new layer to the top of the tree if the requested
-	 * id is larger than the currently allocated space.
-	 */
-	while (id > idr_max(layers)) {
-		layers++;
-		if (!p->count) {
-			/* special case: if the tree is currently empty,
-			 * then we grow the tree by moving the top node
-			 * upwards.
-			 */
-			p->layer++;
-			WARN_ON_ONCE(p->prefix);
-			continue;
-		}
-		if (!(new = idr_layer_alloc(gfp_mask, layer_idr))) {
-			/*
-			 * The allocation failed.  If we built part of
-			 * the structure tear it down.
-			 */
-			spin_lock_irqsave(&idp->lock, flags);
-			for (new = p; p && p != idp->top; new = p) {
-				p = p->ary[0];
-				new->ary[0] = NULL;
-				new->count = 0;
-				bitmap_clear(new->bitmap, 0, IDR_SIZE);
-				__move_to_free_list(idp, new);
-			}
-			spin_unlock_irqrestore(&idp->lock, flags);
-			return -ENOMEM;
-		}
-		new->ary[0] = p;
-		new->count = 1;
-		new->layer = layers-1;
-		new->prefix = id & idr_layer_prefix_mask(new->layer);
-		if (bitmap_full(p->bitmap, IDR_SIZE))
-			__set_bit(0, new->bitmap);
-		p = new;
-	}
-	rcu_assign_pointer(idp->top, p);
-	idp->layers = layers;
-	v = sub_alloc(idp, &id, pa, gfp_mask, layer_idr);
-	if (v == -EAGAIN)
-		goto build_up;
-	return(v);
-}
-
-/*
- * @id and @pa are from a successful allocation from idr_get_empty_slot().
- * Install the user pointer @ptr and mark the slot full.
- */
-static void idr_fill_slot(struct idr *idr, void *ptr, int id,
-			  struct idr_layer **pa)
-{
-	/* update hint used for lookup, cleared from free_layer() */
-	rcu_assign_pointer(idr->hint, pa[0]);
-
-	rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], (struct idr_layer *)ptr);
-	pa[0]->count++;
-	idr_mark_full(pa, id);
-}
-
-
-/**
- * idr_preload - preload for idr_alloc()
- * @gfp_mask: allocation mask to use for preloading
- *
- * Preload per-cpu layer buffer for idr_alloc().  Can only be used from
- * process context and each idr_preload() invocation should be matched with
- * idr_preload_end().  Note that preemption is disabled while preloaded.
- *
- * The first idr_alloc() in the preloaded section can be treated as if it
- * were invoked with @gfp_mask used for preloading.  This allows using more
- * permissive allocation masks for idrs protected by spinlocks.
- *
- * For example, if idr_alloc() below fails, the failure can be treated as
- * if idr_alloc() were called with GFP_KERNEL rather than GFP_NOWAIT.
- *
- *	idr_preload(GFP_KERNEL);
- *	spin_lock(lock);
- *
- *	id = idr_alloc(idr, ptr, start, end, GFP_NOWAIT);
- *
- *	spin_unlock(lock);
- *	idr_preload_end();
- *	if (id < 0)
- *		error;
- */
-void idr_preload(gfp_t gfp_mask)
-{
-	/*
-	 * Consuming preload buffer from non-process context breaks preload
-	 * allocation guarantee.  Disallow usage from those contexts.
-	 */
-	WARN_ON_ONCE(in_interrupt());
-	might_sleep_if(gfpflags_allow_blocking(gfp_mask));
-
-	preempt_disable();
-
-	/*
-	 * idr_alloc() is likely to succeed w/o full idr_layer buffer and
-	 * return value from idr_alloc() needs to be checked for failure
-	 * anyway.  Silently give up if allocation fails.  The caller can
-	 * treat failures from idr_alloc() as if idr_alloc() were called
-	 * with @gfp_mask which should be enough.
-	 */
-	while (__this_cpu_read(idr_preload_cnt) < MAX_IDR_FREE) {
-		struct idr_layer *new;
-
-		preempt_enable();
-		new = kmem_cache_zalloc(idr_layer_cache, gfp_mask);
-		preempt_disable();
-		if (!new)
-			break;
-
-		/* link the new one to per-cpu preload list */
-		new->ary[0] = __this_cpu_read(idr_preload_head);
-		__this_cpu_write(idr_preload_head, new);
-		__this_cpu_inc(idr_preload_cnt);
-	}
-}
-EXPORT_SYMBOL(idr_preload);
-
-/**
- * idr_alloc - allocate new idr entry
- * @idr: the (initialized) idr
+ * idr_alloc - allocate an id
+ * @idr: idr handle
  * @ptr: pointer to be associated with the new id
  * @start: the minimum id (inclusive)
- * @end: the maximum id (exclusive, <= 0 for max)
- * @gfp_mask: memory allocation flags
+ * @end: the maximum id (exclusive)
+ * @gfp: memory allocation flags
  *
- * Allocate an id in [start, end) and associate it with @ptr.  If no ID is
- * available in the specified range, returns -ENOSPC.  On memory allocation
- * failure, returns -ENOMEM.
+ * Allocates an unused ID in the range [start, end).  Returns -ENOSPC
+ * if there are no unused IDs in that range.
  *
  * Note that @end is treated as max when <= 0.  This is to always allow
  * using @start + N as @end as long as N is inside integer range.
  *
- * The user is responsible for exclusively synchronizing all operations
- * which may modify @idr.  However, read-only accesses such as idr_find()
- * or iteration can be performed under RCU read lock provided the user
- * destroys @ptr in RCU-safe way after removal from idr.
+ * Simultaneous modifications to the @idr are not allowed and should be
+ * prevented by the user, usually with a lock.  idr_alloc() may be called
+ * concurrently with read-only accesses to the @idr, such as idr_find() and
+ * idr_for_each_entry().
  */
-int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask)
+int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp)
 {
-	int max = end > 0 ? end - 1 : INT_MAX;	/* inclusive upper limit */
-	struct idr_layer *pa[MAX_IDR_LEVEL + 1];
-	int id;
+	void __rcu **slot;
+	struct radix_tree_iter iter;
 
-	might_sleep_if(gfpflags_allow_blocking(gfp_mask));
-
-	/* sanity checks */
 	if (WARN_ON_ONCE(start < 0))
 		return -EINVAL;
-	if (unlikely(max < start))
-		return -ENOSPC;
+	if (WARN_ON_ONCE(radix_tree_is_internal_node(ptr)))
+		return -EINVAL;
 
-	/* allocate id */
-	id = idr_get_empty_slot(idr, start, pa, gfp_mask, NULL);
-	if (unlikely(id < 0))
-		return id;
-	if (unlikely(id > max))
-		return -ENOSPC;
+	radix_tree_iter_init(&iter, start);
+	slot = idr_get_free(&idr->idr_rt, &iter, gfp, end);
+	if (IS_ERR(slot))
+		return PTR_ERR(slot);
 
-	idr_fill_slot(idr, ptr, id, pa);
-	return id;
+	radix_tree_iter_replace(&idr->idr_rt, &iter, slot, ptr);
+	radix_tree_iter_tag_clear(&idr->idr_rt, &iter, IDR_FREE);
+	return iter.index;
 }
 EXPORT_SYMBOL_GPL(idr_alloc);
 
 /**
  * idr_alloc_cyclic - allocate new idr entry in a cyclical fashion
- * @idr: the (initialized) idr
+ * @idr: idr handle
  * @ptr: pointer to be associated with the new id
  * @start: the minimum id (inclusive)
- * @end: the maximum id (exclusive, <= 0 for max)
- * @gfp_mask: memory allocation flags
- *
- * Essentially the same as idr_alloc, but prefers to allocate progressively
- * higher ids if it can. If the "cur" counter wraps, then it will start again
- * at the "start" end of the range and allocate one that has already been used.
- */
-int idr_alloc_cyclic(struct idr *idr, void *ptr, int start, int end,
-			gfp_t gfp_mask)
-{
-	int id;
-
-	id = idr_alloc(idr, ptr, max(start, idr->cur), end, gfp_mask);
-	if (id == -ENOSPC)
-		id = idr_alloc(idr, ptr, start, end, gfp_mask);
-
-	if (likely(id >= 0))
-		idr->cur = id + 1;
-	return id;
-}
-EXPORT_SYMBOL(idr_alloc_cyclic);
-
-static void idr_remove_warning(int id)
-{
-	WARN(1, "idr_remove called for id=%d which is not allocated.\n", id);
-}
-
-static void sub_remove(struct idr *idp, int shift, int id)
-{
-	struct idr_layer *p = idp->top;
-	struct idr_layer **pa[MAX_IDR_LEVEL + 1];
-	struct idr_layer ***paa = &pa[0];
-	struct idr_layer *to_free;
-	int n;
-
-	*paa = NULL;
-	*++paa = &idp->top;
-
-	while ((shift > 0) && p) {
-		n = (id >> shift) & IDR_MASK;
-		__clear_bit(n, p->bitmap);
-		*++paa = &p->ary[n];
-		p = p->ary[n];
-		shift -= IDR_BITS;
-	}
-	n = id & IDR_MASK;
-	if (likely(p != NULL && test_bit(n, p->bitmap))) {
-		__clear_bit(n, p->bitmap);
-		RCU_INIT_POINTER(p->ary[n], NULL);
-		to_free = NULL;
-		while(*paa && ! --((**paa)->count)){
-			if (to_free)
-				free_layer(idp, to_free);
-			to_free = **paa;
-			**paa-- = NULL;
-		}
-		if (!*paa)
-			idp->layers = 0;
-		if (to_free)
-			free_layer(idp, to_free);
-	} else
-		idr_remove_warning(id);
-}
-
-/**
- * idr_remove - remove the given id and free its slot
- * @idp: idr handle
- * @id: unique key
- */
-void idr_remove(struct idr *idp, int id)
-{
-	struct idr_layer *p;
-	struct idr_layer *to_free;
-
-	if (id < 0)
-		return;
-
-	if (id > idr_max(idp->layers)) {
-		idr_remove_warning(id);
-		return;
-	}
-
-	sub_remove(idp, (idp->layers - 1) * IDR_BITS, id);
-	if (idp->top && idp->top->count == 1 && (idp->layers > 1) &&
-	    idp->top->ary[0]) {
-		/*
-		 * Single child at leftmost slot: we can shrink the tree.
-		 * This level is not needed anymore since when layers are
-		 * inserted, they are inserted at the top of the existing
-		 * tree.
-		 */
-		to_free = idp->top;
-		p = idp->top->ary[0];
-		rcu_assign_pointer(idp->top, p);
-		--idp->layers;
-		to_free->count = 0;
-		bitmap_clear(to_free->bitmap, 0, IDR_SIZE);
-		free_layer(idp, to_free);
-	}
-}
-EXPORT_SYMBOL(idr_remove);
-
-static void __idr_remove_all(struct idr *idp)
-{
-	int n, id, max;
-	int bt_mask;
-	struct idr_layer *p;
-	struct idr_layer *pa[MAX_IDR_LEVEL + 1];
-	struct idr_layer **paa = &pa[0];
-
-	n = idp->layers * IDR_BITS;
-	*paa = idp->top;
-	RCU_INIT_POINTER(idp->top, NULL);
-	max = idr_max(idp->layers);
-
-	id = 0;
-	while (id >= 0 && id <= max) {
-		p = *paa;
-		while (n > IDR_BITS && p) {
-			n -= IDR_BITS;
-			p = p->ary[(id >> n) & IDR_MASK];
-			*++paa = p;
-		}
-
-		bt_mask = id;
-		id += 1 << n;
-		/* Get the highest bit that the above add changed from 0->1. */
-		while (n < fls(id ^ bt_mask)) {
-			if (*paa)
-				free_layer(idp, *paa);
-			n += IDR_BITS;
-			--paa;
-		}
-	}
-	idp->layers = 0;
-}
-
-/**
- * idr_destroy - release all cached layers within an idr tree
- * @idp: idr handle
- *
- * Free all id mappings and all idp_layers.  After this function, @idp is
- * completely unused and can be freed / recycled.  The caller is
- * responsible for ensuring that no one else accesses @idp during or after
- * idr_destroy().
+ * @end: the maximum id (exclusive)
+ * @gfp: memory allocation flags
  *
- * A typical clean-up sequence for objects stored in an idr tree will use
- * idr_for_each() to free all objects, if necessary, then idr_destroy() to
- * free up the id mappings and cached idr_layers.
+ * Allocates an ID larger than the last ID allocated if one is available.
+ * If not, it will attempt to allocate the smallest ID that is larger or
+ * equal to @start.
  */
-void idr_destroy(struct idr *idp)
+int idr_alloc_cyclic(struct idr *idr, void *ptr, int start, int end, gfp_t gfp)
 {
-	__idr_remove_all(idp);
+	int id, curr = idr->idr_next;
 
-	while (idp->id_free_cnt) {
-		struct idr_layer *p = get_from_free_list(idp);
-		kmem_cache_free(idr_layer_cache, p);
-	}
-}
-EXPORT_SYMBOL(idr_destroy);
+	if (curr < start)
+		curr = start;
 
-void *idr_find_slowpath(struct idr *idp, int id)
-{
-	int n;
-	struct idr_layer *p;
-
-	if (id < 0)
-		return NULL;
-
-	p = rcu_dereference_raw(idp->top);
-	if (!p)
-		return NULL;
-	n = (p->layer+1) * IDR_BITS;
+	id = idr_alloc(idr, ptr, curr, end, gfp);
+	if ((id == -ENOSPC) && (curr > start))
+		id = idr_alloc(idr, ptr, start, curr, gfp);
 
-	if (id > idr_max(p->layer + 1))
-		return NULL;
-	BUG_ON(n == 0);
+	if (id >= 0)
+		idr->idr_next = id + 1U;
 
-	while (n > 0 && p) {
-		n -= IDR_BITS;
-		BUG_ON(n != p->layer*IDR_BITS);
-		p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]);
-	}
-	return((void *)p);
+	return id;
 }
-EXPORT_SYMBOL(idr_find_slowpath);
+EXPORT_SYMBOL(idr_alloc_cyclic);
 
 /**
  * idr_for_each - iterate through all stored pointers
- * @idp: idr handle
+ * @idr: idr handle
  * @fn: function to be called for each pointer
- * @data: data passed back to callback function
+ * @data: data passed to callback function
  *
- * Iterate over the pointers registered with the given idr.  The
- * callback function will be called for each pointer currently
- * registered, passing the id, the pointer and the data pointer passed
- * to this function.  It is not safe to modify the idr tree while in
- * the callback, so functions such as idr_get_new and idr_remove are
- * not allowed.
+ * The callback function will be called for each entry in @idr, passing
+ * the id, the pointer and the data pointer passed to this function.
  *
- * We check the return of @fn each time. If it returns anything other
- * than %0, we break out and return that value.
+ * If @fn returns anything other than %0, the iteration stops and that
+ * value is returned from this function.
  *
- * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove().
+ * idr_for_each() can be called concurrently with idr_alloc() and
+ * idr_remove() if protected by RCU.  Newly added entries may not be
+ * seen and deleted entries may be seen, but adding and removing entries
+ * will not cause other entries to be skipped, nor spurious ones to be seen.
  */
-int idr_for_each(struct idr *idp,
-		 int (*fn)(int id, void *p, void *data), void *data)
+int idr_for_each(const struct idr *idr,
+		int (*fn)(int id, void *p, void *data), void *data)
 {
-	int n, id, max, error = 0;
-	struct idr_layer *p;
-	struct idr_layer *pa[MAX_IDR_LEVEL + 1];
-	struct idr_layer **paa = &pa[0];
-
-	n = idp->layers * IDR_BITS;
-	*paa = rcu_dereference_raw(idp->top);
-	max = idr_max(idp->layers);
+	struct radix_tree_iter iter;
+	void __rcu **slot;
 
-	id = 0;
-	while (id >= 0 && id <= max) {
-		p = *paa;
-		while (n > 0 && p) {
-			n -= IDR_BITS;
-			p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]);
-			*++paa = p;
-		}
-
-		if (p) {
-			error = fn(id, (void *)p, data);
-			if (error)
-				break;
-		}
-
-		id += 1 << n;
-		while (n < fls(id)) {
-			n += IDR_BITS;
-			--paa;
-		}
+	radix_tree_for_each_slot(slot, &idr->idr_rt, &iter, 0) {
+		int ret = fn(iter.index, rcu_dereference_raw(*slot), data);
+		if (ret)
+			return ret;
 	}
 
-	return error;
+	return 0;
 }
 EXPORT_SYMBOL(idr_for_each);
 
 /**
- * idr_get_next - lookup next object of id to given id.
- * @idp: idr handle
- * @nextidp:  pointer to lookup key
- *
- * Returns pointer to registered object with id, which is next number to
- * given id. After being looked up, *@nextidp will be updated for the next
- * iteration.
- *
- * This function can be called under rcu_read_lock(), given that the leaf
- * pointers lifetimes are correctly managed.
+ * idr_get_next - Find next populated entry
+ * @idr: idr handle
+ * @nextid: Pointer to lowest possible ID to return
+ *
+ * Returns the next populated entry in the tree with an ID greater than
+ * or equal to the value pointed to by @nextid.  On exit, @nextid is updated
+ * to the ID of the found value.  To use in a loop, the value pointed to by
+ * nextid must be incremented by the user.
  */
-void *idr_get_next(struct idr *idp, int *nextidp)
+void *idr_get_next(struct idr *idr, int *nextid)
 {
-	struct idr_layer *p, *pa[MAX_IDR_LEVEL + 1];
-	struct idr_layer **paa = &pa[0];
-	int id = *nextidp;
-	int n, max;
+	struct radix_tree_iter iter;
+	void __rcu **slot;
 
-	/* find first ent */
-	p = *paa = rcu_dereference_raw(idp->top);
-	if (!p)
+	slot = radix_tree_iter_find(&idr->idr_rt, &iter, *nextid);
+	if (!slot)
 		return NULL;
-	n = (p->layer + 1) * IDR_BITS;
-	max = idr_max(p->layer + 1);
-
-	while (id >= 0 && id <= max) {
-		p = *paa;
-		while (n > 0 && p) {
-			n -= IDR_BITS;
-			p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]);
-			*++paa = p;
-		}
-
-		if (p) {
-			*nextidp = id;
-			return p;
-		}
 
-		/*
-		 * Proceed to the next layer at the current level.  Unlike
-		 * idr_for_each(), @id isn't guaranteed to be aligned to
-		 * layer boundary at this point and adding 1 << n may
-		 * incorrectly skip IDs.  Make sure we jump to the
-		 * beginning of the next layer using round_up().
-		 */
-		id = round_up(id + 1, 1 << n);
-		while (n < fls(id)) {
-			n += IDR_BITS;
-			--paa;
-		}
-	}
-	return NULL;
+	*nextid = iter.index;
+	return rcu_dereference_raw(*slot);
 }
 EXPORT_SYMBOL(idr_get_next);
 
-
 /**
  * idr_replace - replace pointer for given id
- * @idp: idr handle
- * @ptr: pointer you want associated with the id
- * @id: lookup key
+ * @idr: idr handle
+ * @ptr: New pointer to associate with the ID
+ * @id: Lookup key
  *
- * Replace the pointer registered with an id and return the old value.
- * A %-ENOENT return indicates that @id was not found.
- * A %-EINVAL return indicates that @id was not within valid constraints.
+ * Replace the pointer registered with an ID and return the old value.
+ * This function can be called under the RCU read lock concurrently with
+ * idr_alloc() and idr_remove() (as long as the ID being removed is not
+ * the one being replaced!).
  *
- * The caller must serialize with writers.
+ * Returns: 0 on success.  %-ENOENT indicates that @id was not found.
+ * %-EINVAL indicates that @id or @ptr were not valid.
  */
-void *idr_replace(struct idr *idp, void *ptr, int id)
+void *idr_replace(struct idr *idr, void *ptr, int id)
 {
-	int n;
-	struct idr_layer *p, *old_p;
+	struct radix_tree_node *node;
+	void __rcu **slot = NULL;
+	void *entry;
 
-	if (id < 0)
+	if (WARN_ON_ONCE(id < 0))
+		return ERR_PTR(-EINVAL);
+	if (WARN_ON_ONCE(radix_tree_is_internal_node(ptr)))
 		return ERR_PTR(-EINVAL);
 
-	p = idp->top;
-	if (!p)
-		return ERR_PTR(-ENOENT);
-
-	if (id > idr_max(p->layer + 1))
-		return ERR_PTR(-ENOENT);
-
-	n = p->layer * IDR_BITS;
-	while ((n > 0) && p) {
-		p = p->ary[(id >> n) & IDR_MASK];
-		n -= IDR_BITS;
-	}
-
-	n = id & IDR_MASK;
-	if (unlikely(p == NULL || !test_bit(n, p->bitmap)))
+	entry = __radix_tree_lookup(&idr->idr_rt, id, &node, &slot);
+	if (!slot || radix_tree_tag_get(&idr->idr_rt, id, IDR_FREE))
 		return ERR_PTR(-ENOENT);
 
-	old_p = p->ary[n];
-	rcu_assign_pointer(p->ary[n], ptr);
+	__radix_tree_replace(&idr->idr_rt, node, slot, ptr, NULL, NULL);
 
-	return old_p;
+	return entry;
 }
 EXPORT_SYMBOL(idr_replace);
 
-void __init idr_init_cache(void)
-{
-	idr_layer_cache = kmem_cache_create("idr_layer_cache",
-				sizeof(struct idr_layer), 0, SLAB_PANIC, NULL);
-}
-
-/**
- * idr_init - initialize idr handle
- * @idp:	idr handle
- *
- * This function is use to set up the handle (@idp) that you will pass
- * to the rest of the functions.
- */
-void idr_init(struct idr *idp)
-{
-	memset(idp, 0, sizeof(struct idr));
-	spin_lock_init(&idp->lock);
-}
-EXPORT_SYMBOL(idr_init);
-
-static int idr_has_entry(int id, void *p, void *data)
-{
-	return 1;
-}
-
-bool idr_is_empty(struct idr *idp)
-{
-	return !idr_for_each(idp, idr_has_entry, NULL);
-}
-EXPORT_SYMBOL(idr_is_empty);
-
 /**
  * DOC: IDA description
- * IDA - IDR based ID allocator
  *
- * This is id allocator without id -> pointer translation.  Memory
- * usage is much lower than full blown idr because each id only
- * occupies a bit.  ida uses a custom leaf node which contains
- * IDA_BITMAP_BITS slots.
- *
- * 2007-04-25  written by Tejun Heo <htejun@gmail.com>
+ * The IDA is an ID allocator which does not provide the ability to
+ * associate an ID with a pointer.  As such, it only needs to store one
+ * bit per ID, and so is more space efficient than an IDR.  To use an IDA,
+ * define it using DEFINE_IDA() (or embed a &struct ida in a data structure,
+ * then initialise it using ida_init()).  To allocate a new ID, call
+ * ida_simple_get().  To free an ID, call ida_simple_remove().
+ *
+ * If you have more complex locking requirements, use a loop around
+ * ida_pre_get() and ida_get_new() to allocate a new ID.  Then use
+ * ida_remove() to free an ID.  You must make sure that ida_get_new() and
+ * ida_remove() cannot be called at the same time as each other for the
+ * same IDA.
+ *
+ * You can also use ida_get_new_above() if you need an ID to be allocated
+ * above a particular number.  ida_destroy() can be used to dispose of an
+ * IDA without needing to free the individual IDs in it.  You can use
+ * ida_is_empty() to find out whether the IDA has any IDs currently allocated.
+ *
+ * IDs are currently limited to the range [0-INT_MAX].  If this is an awkward
+ * limitation, it should be quite straightforward to raise the maximum.
  */
 
-static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap)
-{
-	unsigned long flags;
-
-	if (!ida->free_bitmap) {
-		spin_lock_irqsave(&ida->idr.lock, flags);
-		if (!ida->free_bitmap) {
-			ida->free_bitmap = bitmap;
-			bitmap = NULL;
-		}
-		spin_unlock_irqrestore(&ida->idr.lock, flags);
-	}
-
-	kfree(bitmap);
-}
-
-/**
- * ida_pre_get - reserve resources for ida allocation
- * @ida:	ida handle
- * @gfp_mask:	memory allocation flag
- *
- * This function should be called prior to locking and calling the
- * following function.  It preallocates enough memory to satisfy the
- * worst possible allocation.
- *
- * If the system is REALLY out of memory this function returns %0,
- * otherwise %1.
+/*
+ * Developer's notes:
+ *
+ * The IDA uses the functionality provided by the IDR & radix tree to store
+ * bitmaps in each entry.  The IDR_FREE tag means there is at least one bit
+ * free, unlike the IDR where it means at least one entry is free.
+ *
+ * I considered telling the radix tree that each slot is an order-10 node
+ * and storing the bit numbers in the radix tree, but the radix tree can't
+ * allow a single multiorder entry at index 0, which would significantly
+ * increase memory consumption for the IDA.  So instead we divide the index
+ * by the number of bits in the leaf bitmap before doing a radix tree lookup.
+ *
+ * As an optimisation, if there are only a few low bits set in any given
+ * leaf, instead of allocating a 128-byte bitmap, we use the 'exceptional
+ * entry' functionality of the radix tree to store BITS_PER_LONG - 2 bits
+ * directly in the entry.  By being really tricksy, we could store
+ * BITS_PER_LONG - 1 bits, but there're diminishing returns after optimising
+ * for 0-3 allocated IDs.
+ *
+ * We allow the radix tree 'exceptional' count to get out of date.  Nothing
+ * in the IDA nor the radix tree code checks it.  If it becomes important
+ * to maintain an accurate exceptional count, switch the rcu_assign_pointer()
+ * calls to radix_tree_iter_replace() which will correct the exceptional
+ * count.
+ *
+ * The IDA always requires a lock to alloc/free.  If we add a 'test_bit'
+ * equivalent, it will still need locking.  Going to RCU lookup would require
+ * using RCU to free bitmaps, and that's not trivial without embedding an
+ * RCU head in the bitmap, which adds a 2-pointer overhead to each 128-byte
+ * bitmap, which is excessive.
  */
-int ida_pre_get(struct ida *ida, gfp_t gfp_mask)
-{
-	/* allocate idr_layers */
-	if (!__idr_pre_get(&ida->idr, gfp_mask))
-		return 0;
 
-	/* allocate free_bitmap */
-	if (!ida->free_bitmap) {
-		struct ida_bitmap *bitmap;
-
-		bitmap = kmalloc(sizeof(struct ida_bitmap), gfp_mask);
-		if (!bitmap)
-			return 0;
-
-		free_bitmap(ida, bitmap);
-	}
-
-	return 1;
-}
-EXPORT_SYMBOL(ida_pre_get);
+#define IDA_MAX (0x80000000U / IDA_BITMAP_BITS)
 
 /**
  * ida_get_new_above - allocate new ID above or equal to a start id
- * @ida:	ida handle
- * @starting_id: id to start search at
- * @p_id:	pointer to the allocated handle
+ * @ida: ida handle
+ * @start: id to start search at
+ * @id: pointer to the allocated handle
  *
- * Allocate new ID above or equal to @starting_id.  It should be called
- * with any required locks.
+ * Allocate new ID above or equal to @start.  It should be called
+ * with any required locks to ensure that concurrent calls to
+ * ida_get_new_above() / ida_get_new() / ida_remove() are not allowed.
+ * Consider using ida_simple_get() if you do not have complex locking
+ * requirements.
  *
  * If memory is required, it will return %-EAGAIN, you should unlock
  * and go back to the ida_pre_get() call.  If the ida is full, it will
- * return %-ENOSPC.
- *
- * Note that callers must ensure that concurrent access to @ida is not possible.
- * See ida_simple_get() for a varaint which takes care of locking.
+ * return %-ENOSPC.  On success, it will return 0.
  *
- * @p_id returns a value in the range @starting_id ... %0x7fffffff.
+ * @id returns a value in the range @start ... %0x7fffffff.
  */
-int ida_get_new_above(struct ida *ida, int starting_id, int *p_id)
+int ida_get_new_above(struct ida *ida, int start, int *id)
 {
-	struct idr_layer *pa[MAX_IDR_LEVEL + 1];
+	struct radix_tree_root *root = &ida->ida_rt;
+	void __rcu **slot;
+	struct radix_tree_iter iter;
 	struct ida_bitmap *bitmap;
-	unsigned long flags;
-	int idr_id = starting_id / IDA_BITMAP_BITS;
-	int offset = starting_id % IDA_BITMAP_BITS;
-	int t, id;
-
- restart:
-	/* get vacant slot */
-	t = idr_get_empty_slot(&ida->idr, idr_id, pa, 0, &ida->idr);
-	if (t < 0)
-		return t == -ENOMEM ? -EAGAIN : t;
-
-	if (t * IDA_BITMAP_BITS >= MAX_IDR_BIT)
-		return -ENOSPC;
-
-	if (t != idr_id)
-		offset = 0;
-	idr_id = t;
-
-	/* if bitmap isn't there, create a new one */
-	bitmap = (void *)pa[0]->ary[idr_id & IDR_MASK];
-	if (!bitmap) {
-		spin_lock_irqsave(&ida->idr.lock, flags);
-		bitmap = ida->free_bitmap;
-		ida->free_bitmap = NULL;
-		spin_unlock_irqrestore(&ida->idr.lock, flags);
-
-		if (!bitmap)
-			return -EAGAIN;
-
-		memset(bitmap, 0, sizeof(struct ida_bitmap));
-		rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK],
-				(void *)bitmap);
-		pa[0]->count++;
-	}
-
-	/* lookup for empty slot */
-	t = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, offset);
-	if (t == IDA_BITMAP_BITS) {
-		/* no empty slot after offset, continue to the next chunk */
-		idr_id++;
-		offset = 0;
-		goto restart;
-	}
-
-	id = idr_id * IDA_BITMAP_BITS + t;
-	if (id >= MAX_IDR_BIT)
-		return -ENOSPC;
+	unsigned long index;
+	unsigned bit, ebit;
+	int new;
+
+	index = start / IDA_BITMAP_BITS;
+	bit = start % IDA_BITMAP_BITS;
+	ebit = bit + RADIX_TREE_EXCEPTIONAL_SHIFT;
+
+	slot = radix_tree_iter_init(&iter, index);
+	for (;;) {
+		if (slot)
+			slot = radix_tree_next_slot(slot, &iter,
+						RADIX_TREE_ITER_TAGGED);
+		if (!slot) {
+			slot = idr_get_free(root, &iter, GFP_NOWAIT, IDA_MAX);
+			if (IS_ERR(slot)) {
+				if (slot == ERR_PTR(-ENOMEM))
+					return -EAGAIN;
+				return PTR_ERR(slot);
+			}
+		}
+		if (iter.index > index) {
+			bit = 0;
+			ebit = RADIX_TREE_EXCEPTIONAL_SHIFT;
+		}
+		new = iter.index * IDA_BITMAP_BITS;
+		bitmap = rcu_dereference_raw(*slot);
+		if (radix_tree_exception(bitmap)) {
+			unsigned long tmp = (unsigned long)bitmap;
+			ebit = find_next_zero_bit(&tmp, BITS_PER_LONG, ebit);
+			if (ebit < BITS_PER_LONG) {
+				tmp |= 1UL << ebit;
+				rcu_assign_pointer(*slot, (void *)tmp);
+				*id = new + ebit - RADIX_TREE_EXCEPTIONAL_SHIFT;
+				return 0;
+			}
+			bitmap = this_cpu_xchg(ida_bitmap, NULL);
+			if (!bitmap)
+				return -EAGAIN;
+			memset(bitmap, 0, sizeof(*bitmap));
+			bitmap->bitmap[0] = tmp >> RADIX_TREE_EXCEPTIONAL_SHIFT;
+			rcu_assign_pointer(*slot, bitmap);
+		}
 
-	__set_bit(t, bitmap->bitmap);
-	if (++bitmap->nr_busy == IDA_BITMAP_BITS)
-		idr_mark_full(pa, idr_id);
+		if (bitmap) {
+			bit = find_next_zero_bit(bitmap->bitmap,
+							IDA_BITMAP_BITS, bit);
+			new += bit;
+			if (new < 0)
+				return -ENOSPC;
+			if (bit == IDA_BITMAP_BITS)
+				continue;
 
-	*p_id = id;
+			__set_bit(bit, bitmap->bitmap);
+			if (bitmap_full(bitmap->bitmap, IDA_BITMAP_BITS))
+				radix_tree_iter_tag_clear(root, &iter,
+								IDR_FREE);
+		} else {
+			new += bit;
+			if (new < 0)
+				return -ENOSPC;
+			if (ebit < BITS_PER_LONG) {
+				bitmap = (void *)((1UL << ebit) |
+						RADIX_TREE_EXCEPTIONAL_ENTRY);
+				radix_tree_iter_replace(root, &iter, slot,
+						bitmap);
+				*id = new;
+				return 0;
+			}
+			bitmap = this_cpu_xchg(ida_bitmap, NULL);
+			if (!bitmap)
+				return -EAGAIN;
+			memset(bitmap, 0, sizeof(*bitmap));
+			__set_bit(bit, bitmap->bitmap);
+			radix_tree_iter_replace(root, &iter, slot, bitmap);
+		}
 
-	/* Each leaf node can handle nearly a thousand slots and the
-	 * whole idea of ida is to have small memory foot print.
-	 * Throw away extra resources one by one after each successful
-	 * allocation.
-	 */
-	if (ida->idr.id_free_cnt || ida->free_bitmap) {
-		struct idr_layer *p = get_from_free_list(&ida->idr);
-		if (p)
-			kmem_cache_free(idr_layer_cache, p);
+		*id = new;
+		return 0;
 	}
-
-	return 0;
 }
 EXPORT_SYMBOL(ida_get_new_above);
 
 /**
- * ida_remove - remove the given ID
- * @ida:	ida handle
- * @id:		ID to free
+ * ida_remove - Free the given ID
+ * @ida: ida handle
+ * @id: ID to free
+ *
+ * This function should not be called at the same time as ida_get_new_above().
  */
 void ida_remove(struct ida *ida, int id)
 {
-	struct idr_layer *p = ida->idr.top;
-	int shift = (ida->idr.layers - 1) * IDR_BITS;
-	int idr_id = id / IDA_BITMAP_BITS;
-	int offset = id % IDA_BITMAP_BITS;
-	int n;
+	unsigned long index = id / IDA_BITMAP_BITS;
+	unsigned offset = id % IDA_BITMAP_BITS;
 	struct ida_bitmap *bitmap;
+	unsigned long *btmp;
+	struct radix_tree_iter iter;
+	void __rcu **slot;
 
-	if (idr_id > idr_max(ida->idr.layers))
+	slot = radix_tree_iter_lookup(&ida->ida_rt, &iter, index);
+	if (!slot)
 		goto err;
 
-	/* clear full bits while looking up the leaf idr_layer */
-	while ((shift > 0) && p) {
-		n = (idr_id >> shift) & IDR_MASK;
-		__clear_bit(n, p->bitmap);
-		p = p->ary[n];
-		shift -= IDR_BITS;
+	bitmap = rcu_dereference_raw(*slot);
+	if (radix_tree_exception(bitmap)) {
+		btmp = (unsigned long *)slot;
+		offset += RADIX_TREE_EXCEPTIONAL_SHIFT;
+		if (offset >= BITS_PER_LONG)
+			goto err;
+	} else {
+		btmp = bitmap->bitmap;
 	}
-
-	if (p == NULL)
-		goto err;
-
-	n = idr_id & IDR_MASK;
-	__clear_bit(n, p->bitmap);
-
-	bitmap = (void *)p->ary[n];
-	if (!bitmap || !test_bit(offset, bitmap->bitmap))
+	if (!test_bit(offset, btmp))
 		goto err;
 
-	/* update bitmap and remove it if empty */
-	__clear_bit(offset, bitmap->bitmap);
-	if (--bitmap->nr_busy == 0) {
-		__set_bit(n, p->bitmap);	/* to please idr_remove() */
-		idr_remove(&ida->idr, idr_id);
-		free_bitmap(ida, bitmap);
+	__clear_bit(offset, btmp);
+	radix_tree_iter_tag_set(&ida->ida_rt, &iter, IDR_FREE);
+	if (radix_tree_exception(bitmap)) {
+		if (rcu_dereference_raw(*slot) ==
+					(void *)RADIX_TREE_EXCEPTIONAL_ENTRY)
+			radix_tree_iter_delete(&ida->ida_rt, &iter, slot);
+	} else if (bitmap_empty(btmp, IDA_BITMAP_BITS)) {
+		kfree(bitmap);
+		radix_tree_iter_delete(&ida->ida_rt, &iter, slot);
 	}
-
 	return;
-
  err:
 	WARN(1, "ida_remove called for id=%d which is not allocated.\n", id);
 }
 EXPORT_SYMBOL(ida_remove);
 
 /**
- * ida_destroy - release all cached layers within an ida tree
- * @ida:		ida handle
+ * ida_destroy - Free the contents of an ida
+ * @ida: ida handle
+ *
+ * Calling this function releases all resources associated with an IDA.  When
+ * this call returns, the IDA is empty and can be reused or freed.  The caller
+ * should not allow ida_remove() or ida_get_new_above() to be called at the
+ * same time.
  */
 void ida_destroy(struct ida *ida)
 {
-	idr_destroy(&ida->idr);
-	kfree(ida->free_bitmap);
+	struct radix_tree_iter iter;
+	void __rcu **slot;
+
+	radix_tree_for_each_slot(slot, &ida->ida_rt, &iter, 0) {
+		struct ida_bitmap *bitmap = rcu_dereference_raw(*slot);
+		if (!radix_tree_exception(bitmap))
+			kfree(bitmap);
+		radix_tree_iter_delete(&ida->ida_rt, &iter, slot);
+	}
 }
 EXPORT_SYMBOL(ida_destroy);
 
@@ -1141,18 +482,3 @@ void ida_simple_remove(struct ida *ida, unsigned int id)
 	spin_unlock_irqrestore(&simple_ida_lock, flags);
 }
 EXPORT_SYMBOL(ida_simple_remove);
-
-/**
- * ida_init - initialize ida handle
- * @ida:	ida handle
- *
- * This function is use to set up the handle (@ida) that you will pass
- * to the rest of the functions.
- */
-void ida_init(struct ida *ida)
-{
-	memset(ida, 0, sizeof(struct ida));
-	idr_init(&ida->idr);
-
-}
-EXPORT_SYMBOL(ida_init);
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 72fab4999c00662a187536ee66c6084eb69a8b11..5ed506d648c4e53ee955e9c19b942fd0d666eee1 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -22,20 +22,21 @@
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
+#include <linux/bitmap.h>
+#include <linux/bitops.h>
 #include <linux/cpu.h>
 #include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/idr.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
-#include <linux/export.h>
-#include <linux/radix-tree.h>
+#include <linux/kmemleak.h>
 #include <linux/percpu.h>
+#include <linux/preempt.h>		/* in_interrupt() */
+#include <linux/radix-tree.h>
+#include <linux/rcupdate.h>
 #include <linux/slab.h>
-#include <linux/kmemleak.h>
-#include <linux/cpu.h>
 #include <linux/string.h>
-#include <linux/bitops.h>
-#include <linux/rcupdate.h>
-#include <linux/preempt.h>		/* in_interrupt() */
 
 
 /* Number of nodes in fully populated tree of given height */
@@ -59,12 +60,29 @@ static struct kmem_cache *radix_tree_node_cachep;
  */
 #define RADIX_TREE_PRELOAD_SIZE (RADIX_TREE_MAX_PATH * 2 - 1)
 
+/*
+ * The IDR does not have to be as high as the radix tree since it uses
+ * signed integers, not unsigned longs.
+ */
+#define IDR_INDEX_BITS		(8 /* CHAR_BIT */ * sizeof(int) - 1)
+#define IDR_MAX_PATH		(DIV_ROUND_UP(IDR_INDEX_BITS, \
+						RADIX_TREE_MAP_SHIFT))
+#define IDR_PRELOAD_SIZE	(IDR_MAX_PATH * 2 - 1)
+
+/*
+ * The IDA is even shorter since it uses a bitmap at the last level.
+ */
+#define IDA_INDEX_BITS		(8 * sizeof(int) - 1 - ilog2(IDA_BITMAP_BITS))
+#define IDA_MAX_PATH		(DIV_ROUND_UP(IDA_INDEX_BITS, \
+						RADIX_TREE_MAP_SHIFT))
+#define IDA_PRELOAD_SIZE	(IDA_MAX_PATH * 2 - 1)
+
 /*
  * Per-cpu pool of preloaded nodes
  */
 struct radix_tree_preload {
 	unsigned nr;
-	/* nodes->private_data points to next preallocated node */
+	/* nodes->parent points to next preallocated node */
 	struct radix_tree_node *nodes;
 };
 static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, };
@@ -83,35 +101,38 @@ static inline void *node_to_entry(void *ptr)
 
 #ifdef CONFIG_RADIX_TREE_MULTIORDER
 /* Sibling slots point directly to another slot in the same node */
-static inline bool is_sibling_entry(struct radix_tree_node *parent, void *node)
+static inline
+bool is_sibling_entry(const struct radix_tree_node *parent, void *node)
 {
-	void **ptr = node;
+	void __rcu **ptr = node;
 	return (parent->slots <= ptr) &&
 			(ptr < parent->slots + RADIX_TREE_MAP_SIZE);
 }
 #else
-static inline bool is_sibling_entry(struct radix_tree_node *parent, void *node)
+static inline
+bool is_sibling_entry(const struct radix_tree_node *parent, void *node)
 {
 	return false;
 }
 #endif
 
-static inline unsigned long get_slot_offset(struct radix_tree_node *parent,
-						 void **slot)
+static inline unsigned long
+get_slot_offset(const struct radix_tree_node *parent, void __rcu **slot)
 {
 	return slot - parent->slots;
 }
 
-static unsigned int radix_tree_descend(struct radix_tree_node *parent,
+static unsigned int radix_tree_descend(const struct radix_tree_node *parent,
 			struct radix_tree_node **nodep, unsigned long index)
 {
 	unsigned int offset = (index >> parent->shift) & RADIX_TREE_MAP_MASK;
-	void **entry = rcu_dereference_raw(parent->slots[offset]);
+	void __rcu **entry = rcu_dereference_raw(parent->slots[offset]);
 
 #ifdef CONFIG_RADIX_TREE_MULTIORDER
 	if (radix_tree_is_internal_node(entry)) {
 		if (is_sibling_entry(parent, entry)) {
-			void **sibentry = (void **) entry_to_node(entry);
+			void __rcu **sibentry;
+			sibentry = (void __rcu **) entry_to_node(entry);
 			offset = get_slot_offset(parent, sibentry);
 			entry = rcu_dereference_raw(*sibentry);
 		}
@@ -122,7 +143,7 @@ static unsigned int radix_tree_descend(struct radix_tree_node *parent,
 	return offset;
 }
 
-static inline gfp_t root_gfp_mask(struct radix_tree_root *root)
+static inline gfp_t root_gfp_mask(const struct radix_tree_root *root)
 {
 	return root->gfp_mask & __GFP_BITS_MASK;
 }
@@ -139,42 +160,48 @@ static inline void tag_clear(struct radix_tree_node *node, unsigned int tag,
 	__clear_bit(offset, node->tags[tag]);
 }
 
-static inline int tag_get(struct radix_tree_node *node, unsigned int tag,
+static inline int tag_get(const struct radix_tree_node *node, unsigned int tag,
 		int offset)
 {
 	return test_bit(offset, node->tags[tag]);
 }
 
-static inline void root_tag_set(struct radix_tree_root *root, unsigned int tag)
+static inline void root_tag_set(struct radix_tree_root *root, unsigned tag)
 {
-	root->gfp_mask |= (__force gfp_t)(1 << (tag + __GFP_BITS_SHIFT));
+	root->gfp_mask |= (__force gfp_t)(1 << (tag + ROOT_TAG_SHIFT));
 }
 
 static inline void root_tag_clear(struct radix_tree_root *root, unsigned tag)
 {
-	root->gfp_mask &= (__force gfp_t)~(1 << (tag + __GFP_BITS_SHIFT));
+	root->gfp_mask &= (__force gfp_t)~(1 << (tag + ROOT_TAG_SHIFT));
 }
 
 static inline void root_tag_clear_all(struct radix_tree_root *root)
 {
-	root->gfp_mask &= __GFP_BITS_MASK;
+	root->gfp_mask &= (1 << ROOT_TAG_SHIFT) - 1;
+}
+
+static inline int root_tag_get(const struct radix_tree_root *root, unsigned tag)
+{
+	return (__force int)root->gfp_mask & (1 << (tag + ROOT_TAG_SHIFT));
 }
 
-static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag)
+static inline unsigned root_tags_get(const struct radix_tree_root *root)
 {
-	return (__force int)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT));
+	return (__force unsigned)root->gfp_mask >> ROOT_TAG_SHIFT;
 }
 
-static inline unsigned root_tags_get(struct radix_tree_root *root)
+static inline bool is_idr(const struct radix_tree_root *root)
 {
-	return (__force unsigned)root->gfp_mask >> __GFP_BITS_SHIFT;
+	return !!(root->gfp_mask & ROOT_IS_IDR);
 }
 
 /*
  * Returns 1 if any slot in the node has this tag set.
  * Otherwise returns 0.
  */
-static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag)
+static inline int any_tag_set(const struct radix_tree_node *node,
+							unsigned int tag)
 {
 	unsigned idx;
 	for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) {
@@ -184,6 +211,11 @@ static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag)
 	return 0;
 }
 
+static inline void all_tag_set(struct radix_tree_node *node, unsigned int tag)
+{
+	bitmap_fill(node->tags[tag], RADIX_TREE_MAP_SIZE);
+}
+
 /**
  * radix_tree_find_next_bit - find the next set bit in a memory region
  *
@@ -232,11 +264,18 @@ static inline unsigned long shift_maxindex(unsigned int shift)
 	return (RADIX_TREE_MAP_SIZE << shift) - 1;
 }
 
-static inline unsigned long node_maxindex(struct radix_tree_node *node)
+static inline unsigned long node_maxindex(const struct radix_tree_node *node)
 {
 	return shift_maxindex(node->shift);
 }
 
+static unsigned long next_index(unsigned long index,
+				const struct radix_tree_node *node,
+				unsigned long offset)
+{
+	return (index & ~node_maxindex(node)) + (offset << node->shift);
+}
+
 #ifndef __KERNEL__
 static void dump_node(struct radix_tree_node *node, unsigned long index)
 {
@@ -275,11 +314,59 @@ static void radix_tree_dump(struct radix_tree_root *root)
 {
 	pr_debug("radix root: %p rnode %p tags %x\n",
 			root, root->rnode,
-			root->gfp_mask >> __GFP_BITS_SHIFT);
+			root->gfp_mask >> ROOT_TAG_SHIFT);
 	if (!radix_tree_is_internal_node(root->rnode))
 		return;
 	dump_node(entry_to_node(root->rnode), 0);
 }
+
+static void dump_ida_node(void *entry, unsigned long index)
+{
+	unsigned long i;
+
+	if (!entry)
+		return;
+
+	if (radix_tree_is_internal_node(entry)) {
+		struct radix_tree_node *node = entry_to_node(entry);
+
+		pr_debug("ida node: %p offset %d indices %lu-%lu parent %p free %lx shift %d count %d\n",
+			node, node->offset, index * IDA_BITMAP_BITS,
+			((index | node_maxindex(node)) + 1) *
+				IDA_BITMAP_BITS - 1,
+			node->parent, node->tags[0][0], node->shift,
+			node->count);
+		for (i = 0; i < RADIX_TREE_MAP_SIZE; i++)
+			dump_ida_node(node->slots[i],
+					index | (i << node->shift));
+	} else if (radix_tree_exceptional_entry(entry)) {
+		pr_debug("ida excp: %p offset %d indices %lu-%lu data %lx\n",
+				entry, (int)(index & RADIX_TREE_MAP_MASK),
+				index * IDA_BITMAP_BITS,
+				index * IDA_BITMAP_BITS + BITS_PER_LONG -
+					RADIX_TREE_EXCEPTIONAL_SHIFT,
+				(unsigned long)entry >>
+					RADIX_TREE_EXCEPTIONAL_SHIFT);
+	} else {
+		struct ida_bitmap *bitmap = entry;
+
+		pr_debug("ida btmp: %p offset %d indices %lu-%lu data", bitmap,
+				(int)(index & RADIX_TREE_MAP_MASK),
+				index * IDA_BITMAP_BITS,
+				(index + 1) * IDA_BITMAP_BITS - 1);
+		for (i = 0; i < IDA_BITMAP_LONGS; i++)
+			pr_cont(" %lx", bitmap->bitmap[i]);
+		pr_cont("\n");
+	}
+}
+
+static void ida_dump(struct ida *ida)
+{
+	struct radix_tree_root *root = &ida->ida_rt;
+	pr_debug("ida: %p node %p free %d\n", ida, root->rnode,
+				root->gfp_mask >> ROOT_TAG_SHIFT);
+	dump_ida_node(root->rnode, 0);
+}
 #endif
 
 /*
@@ -287,13 +374,12 @@ static void radix_tree_dump(struct radix_tree_root *root)
  * that the caller has pinned this thread of control to the current CPU.
  */
 static struct radix_tree_node *
-radix_tree_node_alloc(struct radix_tree_root *root,
-			struct radix_tree_node *parent,
+radix_tree_node_alloc(gfp_t gfp_mask, struct radix_tree_node *parent,
+			struct radix_tree_root *root,
 			unsigned int shift, unsigned int offset,
 			unsigned int count, unsigned int exceptional)
 {
 	struct radix_tree_node *ret = NULL;
-	gfp_t gfp_mask = root_gfp_mask(root);
 
 	/*
 	 * Preload code isn't irq safe and it doesn't make sense to use
@@ -321,8 +407,7 @@ radix_tree_node_alloc(struct radix_tree_root *root,
 		rtp = this_cpu_ptr(&radix_tree_preloads);
 		if (rtp->nr) {
 			ret = rtp->nodes;
-			rtp->nodes = ret->private_data;
-			ret->private_data = NULL;
+			rtp->nodes = ret->parent;
 			rtp->nr--;
 		}
 		/*
@@ -336,11 +421,12 @@ radix_tree_node_alloc(struct radix_tree_root *root,
 out:
 	BUG_ON(radix_tree_is_internal_node(ret));
 	if (ret) {
-		ret->parent = parent;
 		ret->shift = shift;
 		ret->offset = offset;
 		ret->count = count;
 		ret->exceptional = exceptional;
+		ret->parent = parent;
+		ret->root = root;
 	}
 	return ret;
 }
@@ -399,7 +485,7 @@ static int __radix_tree_preload(gfp_t gfp_mask, unsigned nr)
 		preempt_disable();
 		rtp = this_cpu_ptr(&radix_tree_preloads);
 		if (rtp->nr < nr) {
-			node->private_data = rtp->nodes;
+			node->parent = rtp->nodes;
 			rtp->nodes = node;
 			rtp->nr++;
 		} else {
@@ -510,7 +596,7 @@ int radix_tree_maybe_preload_order(gfp_t gfp_mask, int order)
 	return __radix_tree_preload(gfp_mask, nr_nodes);
 }
 
-static unsigned radix_tree_load_root(struct radix_tree_root *root,
+static unsigned radix_tree_load_root(const struct radix_tree_root *root,
 		struct radix_tree_node **nodep, unsigned long *maxindex)
 {
 	struct radix_tree_node *node = rcu_dereference_raw(root->rnode);
@@ -530,10 +616,10 @@ static unsigned radix_tree_load_root(struct radix_tree_root *root,
 /*
  *	Extend a radix tree so it can store key @index.
  */
-static int radix_tree_extend(struct radix_tree_root *root,
+static int radix_tree_extend(struct radix_tree_root *root, gfp_t gfp,
 				unsigned long index, unsigned int shift)
 {
-	struct radix_tree_node *slot;
+	void *entry;
 	unsigned int maxshift;
 	int tag;
 
@@ -542,32 +628,44 @@ static int radix_tree_extend(struct radix_tree_root *root,
 	while (index > shift_maxindex(maxshift))
 		maxshift += RADIX_TREE_MAP_SHIFT;
 
-	slot = root->rnode;
-	if (!slot)
+	entry = rcu_dereference_raw(root->rnode);
+	if (!entry && (!is_idr(root) || root_tag_get(root, IDR_FREE)))
 		goto out;
 
 	do {
-		struct radix_tree_node *node = radix_tree_node_alloc(root,
-							NULL, shift, 0, 1, 0);
+		struct radix_tree_node *node = radix_tree_node_alloc(gfp, NULL,
+							root, shift, 0, 1, 0);
 		if (!node)
 			return -ENOMEM;
 
-		/* Propagate the aggregated tag info into the new root */
-		for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
-			if (root_tag_get(root, tag))
-				tag_set(node, tag, 0);
+		if (is_idr(root)) {
+			all_tag_set(node, IDR_FREE);
+			if (!root_tag_get(root, IDR_FREE)) {
+				tag_clear(node, IDR_FREE, 0);
+				root_tag_set(root, IDR_FREE);
+			}
+		} else {
+			/* Propagate the aggregated tag info to the new child */
+			for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
+				if (root_tag_get(root, tag))
+					tag_set(node, tag, 0);
+			}
 		}
 
 		BUG_ON(shift > BITS_PER_LONG);
-		if (radix_tree_is_internal_node(slot)) {
-			entry_to_node(slot)->parent = node;
-		} else if (radix_tree_exceptional_entry(slot)) {
+		if (radix_tree_is_internal_node(entry)) {
+			entry_to_node(entry)->parent = node;
+		} else if (radix_tree_exceptional_entry(entry)) {
 			/* Moving an exceptional root->rnode to a node */
 			node->exceptional = 1;
 		}
-		node->slots[0] = slot;
-		slot = node_to_entry(node);
-		rcu_assign_pointer(root->rnode, slot);
+		/*
+		 * entry was already in the radix tree, so we do not need
+		 * rcu_assign_pointer here
+		 */
+		node->slots[0] = (void __rcu *)entry;
+		entry = node_to_entry(node);
+		rcu_assign_pointer(root->rnode, entry);
 		shift += RADIX_TREE_MAP_SHIFT;
 	} while (shift <= maxshift);
 out:
@@ -578,12 +676,14 @@ static int radix_tree_extend(struct radix_tree_root *root,
  *	radix_tree_shrink    -    shrink radix tree to minimum height
  *	@root		radix tree root
  */
-static inline void radix_tree_shrink(struct radix_tree_root *root,
+static inline bool radix_tree_shrink(struct radix_tree_root *root,
 				     radix_tree_update_node_t update_node,
 				     void *private)
 {
+	bool shrunk = false;
+
 	for (;;) {
-		struct radix_tree_node *node = root->rnode;
+		struct radix_tree_node *node = rcu_dereference_raw(root->rnode);
 		struct radix_tree_node *child;
 
 		if (!radix_tree_is_internal_node(node))
@@ -597,7 +697,7 @@ static inline void radix_tree_shrink(struct radix_tree_root *root,
 		 */
 		if (node->count != 1)
 			break;
-		child = node->slots[0];
+		child = rcu_dereference_raw(node->slots[0]);
 		if (!child)
 			break;
 		if (!radix_tree_is_internal_node(child) && node->shift)
@@ -613,7 +713,9 @@ static inline void radix_tree_shrink(struct radix_tree_root *root,
 		 * (node->slots[0]), it will be safe to dereference the new
 		 * one (root->rnode) as far as dependent read barriers go.
 		 */
-		root->rnode = child;
+		root->rnode = (void __rcu *)child;
+		if (is_idr(root) && !tag_get(node, IDR_FREE, 0))
+			root_tag_clear(root, IDR_FREE);
 
 		/*
 		 * We have a dilemma here. The node's slot[0] must not be
@@ -635,27 +737,34 @@ static inline void radix_tree_shrink(struct radix_tree_root *root,
 		 */
 		node->count = 0;
 		if (!radix_tree_is_internal_node(child)) {
-			node->slots[0] = RADIX_TREE_RETRY;
+			node->slots[0] = (void __rcu *)RADIX_TREE_RETRY;
 			if (update_node)
 				update_node(node, private);
 		}
 
 		WARN_ON_ONCE(!list_empty(&node->private_list));
 		radix_tree_node_free(node);
+		shrunk = true;
 	}
+
+	return shrunk;
 }
 
-static void delete_node(struct radix_tree_root *root,
+static bool delete_node(struct radix_tree_root *root,
 			struct radix_tree_node *node,
 			radix_tree_update_node_t update_node, void *private)
 {
+	bool deleted = false;
+
 	do {
 		struct radix_tree_node *parent;
 
 		if (node->count) {
-			if (node == entry_to_node(root->rnode))
-				radix_tree_shrink(root, update_node, private);
-			return;
+			if (node_to_entry(node) ==
+					rcu_dereference_raw(root->rnode))
+				deleted |= radix_tree_shrink(root, update_node,
+								private);
+			return deleted;
 		}
 
 		parent = node->parent;
@@ -663,15 +772,23 @@ static void delete_node(struct radix_tree_root *root,
 			parent->slots[node->offset] = NULL;
 			parent->count--;
 		} else {
-			root_tag_clear_all(root);
+			/*
+			 * Shouldn't the tags already have all been cleared
+			 * by the caller?
+			 */
+			if (!is_idr(root))
+				root_tag_clear_all(root);
 			root->rnode = NULL;
 		}
 
 		WARN_ON_ONCE(!list_empty(&node->private_list));
 		radix_tree_node_free(node);
+		deleted = true;
 
 		node = parent;
 	} while (node);
+
+	return deleted;
 }
 
 /**
@@ -693,13 +810,14 @@ static void delete_node(struct radix_tree_root *root,
  */
 int __radix_tree_create(struct radix_tree_root *root, unsigned long index,
 			unsigned order, struct radix_tree_node **nodep,
-			void ***slotp)
+			void __rcu ***slotp)
 {
 	struct radix_tree_node *node = NULL, *child;
-	void **slot = (void **)&root->rnode;
+	void __rcu **slot = (void __rcu **)&root->rnode;
 	unsigned long maxindex;
 	unsigned int shift, offset = 0;
 	unsigned long max = index | ((1UL << order) - 1);
+	gfp_t gfp = root_gfp_mask(root);
 
 	shift = radix_tree_load_root(root, &child, &maxindex);
 
@@ -707,18 +825,18 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index,
 	if (order > 0 && max == ((1UL << order) - 1))
 		max++;
 	if (max > maxindex) {
-		int error = radix_tree_extend(root, max, shift);
+		int error = radix_tree_extend(root, gfp, max, shift);
 		if (error < 0)
 			return error;
 		shift = error;
-		child = root->rnode;
+		child = rcu_dereference_raw(root->rnode);
 	}
 
 	while (shift > order) {
 		shift -= RADIX_TREE_MAP_SHIFT;
 		if (child == NULL) {
 			/* Have to add a child node.  */
-			child = radix_tree_node_alloc(root, node, shift,
+			child = radix_tree_node_alloc(gfp, node, root, shift,
 							offset, 0, 0);
 			if (!child)
 				return -ENOMEM;
@@ -741,7 +859,6 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index,
 	return 0;
 }
 
-#ifdef CONFIG_RADIX_TREE_MULTIORDER
 /*
  * Free any nodes below this node.  The tree is presumed to not need
  * shrinking, and any user data in the tree is presumed to not need a
@@ -757,7 +874,7 @@ static void radix_tree_free_nodes(struct radix_tree_node *node)
 	struct radix_tree_node *child = entry_to_node(node);
 
 	for (;;) {
-		void *entry = child->slots[offset];
+		void *entry = rcu_dereference_raw(child->slots[offset]);
 		if (radix_tree_is_internal_node(entry) &&
 					!is_sibling_entry(child, entry)) {
 			child = entry_to_node(entry);
@@ -777,8 +894,9 @@ static void radix_tree_free_nodes(struct radix_tree_node *node)
 	}
 }
 
-static inline int insert_entries(struct radix_tree_node *node, void **slot,
-				void *item, unsigned order, bool replace)
+#ifdef CONFIG_RADIX_TREE_MULTIORDER
+static inline int insert_entries(struct radix_tree_node *node,
+		void __rcu **slot, void *item, unsigned order, bool replace)
 {
 	struct radix_tree_node *child;
 	unsigned i, n, tag, offset, tags = 0;
@@ -813,7 +931,7 @@ static inline int insert_entries(struct radix_tree_node *node, void **slot,
 	}
 
 	for (i = 0; i < n; i++) {
-		struct radix_tree_node *old = slot[i];
+		struct radix_tree_node *old = rcu_dereference_raw(slot[i]);
 		if (i) {
 			rcu_assign_pointer(slot[i], child);
 			for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
@@ -840,8 +958,8 @@ static inline int insert_entries(struct radix_tree_node *node, void **slot,
 	return n;
 }
 #else
-static inline int insert_entries(struct radix_tree_node *node, void **slot,
-				void *item, unsigned order, bool replace)
+static inline int insert_entries(struct radix_tree_node *node,
+		void __rcu **slot, void *item, unsigned order, bool replace)
 {
 	if (*slot)
 		return -EEXIST;
@@ -868,7 +986,7 @@ int __radix_tree_insert(struct radix_tree_root *root, unsigned long index,
 			unsigned order, void *item)
 {
 	struct radix_tree_node *node;
-	void **slot;
+	void __rcu **slot;
 	int error;
 
 	BUG_ON(radix_tree_is_internal_node(item));
@@ -908,16 +1026,17 @@ EXPORT_SYMBOL(__radix_tree_insert);
  *	allocated and @root->rnode is used as a direct slot instead of
  *	pointing to a node, in which case *@nodep will be NULL.
  */
-void *__radix_tree_lookup(struct radix_tree_root *root, unsigned long index,
-			  struct radix_tree_node **nodep, void ***slotp)
+void *__radix_tree_lookup(const struct radix_tree_root *root,
+			  unsigned long index, struct radix_tree_node **nodep,
+			  void __rcu ***slotp)
 {
 	struct radix_tree_node *node, *parent;
 	unsigned long maxindex;
-	void **slot;
+	void __rcu **slot;
 
  restart:
 	parent = NULL;
-	slot = (void **)&root->rnode;
+	slot = (void __rcu **)&root->rnode;
 	radix_tree_load_root(root, &node, &maxindex);
 	if (index > maxindex)
 		return NULL;
@@ -952,9 +1071,10 @@ void *__radix_tree_lookup(struct radix_tree_root *root, unsigned long index,
  *	exclusive from other writers. Any dereference of the slot must be done
  *	using radix_tree_deref_slot.
  */
-void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index)
+void __rcu **radix_tree_lookup_slot(const struct radix_tree_root *root,
+				unsigned long index)
 {
-	void **slot;
+	void __rcu **slot;
 
 	if (!__radix_tree_lookup(root, index, NULL, &slot))
 		return NULL;
@@ -974,75 +1094,76 @@ EXPORT_SYMBOL(radix_tree_lookup_slot);
  *	them safely). No RCU barriers are required to access or modify the
  *	returned item, however.
  */
-void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index)
+void *radix_tree_lookup(const struct radix_tree_root *root, unsigned long index)
 {
 	return __radix_tree_lookup(root, index, NULL, NULL);
 }
 EXPORT_SYMBOL(radix_tree_lookup);
 
-static inline int slot_count(struct radix_tree_node *node,
-						void **slot)
+static inline void replace_sibling_entries(struct radix_tree_node *node,
+				void __rcu **slot, int count, int exceptional)
 {
-	int n = 1;
 #ifdef CONFIG_RADIX_TREE_MULTIORDER
 	void *ptr = node_to_entry(slot);
-	unsigned offset = get_slot_offset(node, slot);
-	int i;
+	unsigned offset = get_slot_offset(node, slot) + 1;
 
-	for (i = 1; offset + i < RADIX_TREE_MAP_SIZE; i++) {
-		if (node->slots[offset + i] != ptr)
+	while (offset < RADIX_TREE_MAP_SIZE) {
+		if (rcu_dereference_raw(node->slots[offset]) != ptr)
 			break;
-		n++;
+		if (count < 0) {
+			node->slots[offset] = NULL;
+			node->count--;
+		}
+		node->exceptional += exceptional;
+		offset++;
 	}
 #endif
-	return n;
 }
 
-static void replace_slot(struct radix_tree_root *root,
-			 struct radix_tree_node *node,
-			 void **slot, void *item,
-			 bool warn_typeswitch)
+static void replace_slot(void __rcu **slot, void *item,
+		struct radix_tree_node *node, int count, int exceptional)
 {
-	void *old = rcu_dereference_raw(*slot);
-	int count, exceptional;
-
-	WARN_ON_ONCE(radix_tree_is_internal_node(item));
-
-	count = !!item - !!old;
-	exceptional = !!radix_tree_exceptional_entry(item) -
-		      !!radix_tree_exceptional_entry(old);
-
-	WARN_ON_ONCE(warn_typeswitch && (count || exceptional));
+	if (WARN_ON_ONCE(radix_tree_is_internal_node(item)))
+		return;
 
-	if (node) {
+	if (node && (count || exceptional)) {
 		node->count += count;
-		if (exceptional) {
-			exceptional *= slot_count(node, slot);
-			node->exceptional += exceptional;
-		}
+		node->exceptional += exceptional;
+		replace_sibling_entries(node, slot, count, exceptional);
 	}
 
 	rcu_assign_pointer(*slot, item);
 }
 
-static inline void delete_sibling_entries(struct radix_tree_node *node,
-						void **slot)
+static bool node_tag_get(const struct radix_tree_root *root,
+				const struct radix_tree_node *node,
+				unsigned int tag, unsigned int offset)
 {
-#ifdef CONFIG_RADIX_TREE_MULTIORDER
-	bool exceptional = radix_tree_exceptional_entry(*slot);
-	void *ptr = node_to_entry(slot);
-	unsigned offset = get_slot_offset(node, slot);
-	int i;
+	if (node)
+		return tag_get(node, tag, offset);
+	return root_tag_get(root, tag);
+}
 
-	for (i = 1; offset + i < RADIX_TREE_MAP_SIZE; i++) {
-		if (node->slots[offset + i] != ptr)
-			break;
-		node->slots[offset + i] = NULL;
-		node->count--;
-		if (exceptional)
-			node->exceptional--;
+/*
+ * IDR users want to be able to store NULL in the tree, so if the slot isn't
+ * free, don't adjust the count, even if it's transitioning between NULL and
+ * non-NULL.  For the IDA, we mark slots as being IDR_FREE while they still
+ * have empty bits, but it only stores NULL in slots when they're being
+ * deleted.
+ */
+static int calculate_count(struct radix_tree_root *root,
+				struct radix_tree_node *node, void __rcu **slot,
+				void *item, void *old)
+{
+	if (is_idr(root)) {
+		unsigned offset = get_slot_offset(node, slot);
+		bool free = node_tag_get(root, node, IDR_FREE, offset);
+		if (!free)
+			return 0;
+		if (!old)
+			return 1;
 	}
-#endif
+	return !!item - !!old;
 }
 
 /**
@@ -1059,18 +1180,22 @@ static inline void delete_sibling_entries(struct radix_tree_node *node,
  */
 void __radix_tree_replace(struct radix_tree_root *root,
 			  struct radix_tree_node *node,
-			  void **slot, void *item,
+			  void __rcu **slot, void *item,
 			  radix_tree_update_node_t update_node, void *private)
 {
-	if (!item)
-		delete_sibling_entries(node, slot);
+	void *old = rcu_dereference_raw(*slot);
+	int exceptional = !!radix_tree_exceptional_entry(item) -
+				!!radix_tree_exceptional_entry(old);
+	int count = calculate_count(root, node, slot, item, old);
+
 	/*
 	 * This function supports replacing exceptional entries and
 	 * deleting entries, but that needs accounting against the
 	 * node unless the slot is root->rnode.
 	 */
-	replace_slot(root, node, slot, item,
-		     !node && slot != (void **)&root->rnode);
+	WARN_ON_ONCE(!node && (slot != (void __rcu **)&root->rnode) &&
+			(count || exceptional));
+	replace_slot(slot, item, node, count, exceptional);
 
 	if (!node)
 		return;
@@ -1098,9 +1223,9 @@ void __radix_tree_replace(struct radix_tree_root *root,
  * radix_tree_iter_replace().
  */
 void radix_tree_replace_slot(struct radix_tree_root *root,
-			     void **slot, void *item)
+			     void __rcu **slot, void *item)
 {
-	replace_slot(root, NULL, slot, item, true);
+	__radix_tree_replace(root, NULL, slot, item, NULL, NULL);
 }
 EXPORT_SYMBOL(radix_tree_replace_slot);
 
@@ -1114,7 +1239,8 @@ EXPORT_SYMBOL(radix_tree_replace_slot);
  * Caller must hold tree write locked across split and replacement.
  */
 void radix_tree_iter_replace(struct radix_tree_root *root,
-		const struct radix_tree_iter *iter, void **slot, void *item)
+				const struct radix_tree_iter *iter,
+				void __rcu **slot, void *item)
 {
 	__radix_tree_replace(root, iter->node, slot, item, NULL, NULL);
 }
@@ -1138,7 +1264,7 @@ int radix_tree_join(struct radix_tree_root *root, unsigned long index,
 			unsigned order, void *item)
 {
 	struct radix_tree_node *node;
-	void **slot;
+	void __rcu **slot;
 	int error;
 
 	BUG_ON(radix_tree_is_internal_node(item));
@@ -1173,9 +1299,10 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index,
 				unsigned order)
 {
 	struct radix_tree_node *parent, *node, *child;
-	void **slot;
+	void __rcu **slot;
 	unsigned int offset, end;
 	unsigned n, tag, tags = 0;
+	gfp_t gfp = root_gfp_mask(root);
 
 	if (!__radix_tree_lookup(root, index, &parent, &slot))
 		return -ENOENT;
@@ -1189,7 +1316,8 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index,
 			tags |= 1 << tag;
 
 	for (end = offset + 1; end < RADIX_TREE_MAP_SIZE; end++) {
-		if (!is_sibling_entry(parent, parent->slots[end]))
+		if (!is_sibling_entry(parent,
+				rcu_dereference_raw(parent->slots[end])))
 			break;
 		for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
 			if (tags & (1 << tag))
@@ -1213,14 +1341,15 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index,
 
 	for (;;) {
 		if (node->shift > order) {
-			child = radix_tree_node_alloc(root, node,
+			child = radix_tree_node_alloc(gfp, node, root,
 					node->shift - RADIX_TREE_MAP_SHIFT,
 					offset, 0, 0);
 			if (!child)
 				goto nomem;
 			if (node != parent) {
 				node->count++;
-				node->slots[offset] = node_to_entry(child);
+				rcu_assign_pointer(node->slots[offset],
+							node_to_entry(child));
 				for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
 					if (tags & (1 << tag))
 						tag_set(node, tag, offset);
@@ -1262,6 +1391,22 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index,
 }
 #endif
 
+static void node_tag_set(struct radix_tree_root *root,
+				struct radix_tree_node *node,
+				unsigned int tag, unsigned int offset)
+{
+	while (node) {
+		if (tag_get(node, tag, offset))
+			return;
+		tag_set(node, tag, offset);
+		offset = node->offset;
+		node = node->parent;
+	}
+
+	if (!root_tag_get(root, tag))
+		root_tag_set(root, tag);
+}
+
 /**
  *	radix_tree_tag_set - set a tag on a radix tree node
  *	@root:		radix tree root
@@ -1303,6 +1448,18 @@ void *radix_tree_tag_set(struct radix_tree_root *root,
 }
 EXPORT_SYMBOL(radix_tree_tag_set);
 
+/**
+ * radix_tree_iter_tag_set - set a tag on the current iterator entry
+ * @root:	radix tree root
+ * @iter:	iterator state
+ * @tag:	tag to set
+ */
+void radix_tree_iter_tag_set(struct radix_tree_root *root,
+			const struct radix_tree_iter *iter, unsigned int tag)
+{
+	node_tag_set(root, iter->node, tag, iter_offset(iter));
+}
+
 static void node_tag_clear(struct radix_tree_root *root,
 				struct radix_tree_node *node,
 				unsigned int tag, unsigned int offset)
@@ -1323,34 +1480,6 @@ static void node_tag_clear(struct radix_tree_root *root,
 		root_tag_clear(root, tag);
 }
 
-static void node_tag_set(struct radix_tree_root *root,
-				struct radix_tree_node *node,
-				unsigned int tag, unsigned int offset)
-{
-	while (node) {
-		if (tag_get(node, tag, offset))
-			return;
-		tag_set(node, tag, offset);
-		offset = node->offset;
-		node = node->parent;
-	}
-
-	if (!root_tag_get(root, tag))
-		root_tag_set(root, tag);
-}
-
-/**
- * radix_tree_iter_tag_set - set a tag on the current iterator entry
- * @root:	radix tree root
- * @iter:	iterator state
- * @tag:	tag to set
- */
-void radix_tree_iter_tag_set(struct radix_tree_root *root,
-			const struct radix_tree_iter *iter, unsigned int tag)
-{
-	node_tag_set(root, iter->node, tag, iter_offset(iter));
-}
-
 /**
  *	radix_tree_tag_clear - clear a tag on a radix tree node
  *	@root:		radix tree root
@@ -1390,6 +1519,18 @@ void *radix_tree_tag_clear(struct radix_tree_root *root,
 }
 EXPORT_SYMBOL(radix_tree_tag_clear);
 
+/**
+  * radix_tree_iter_tag_clear - clear a tag on the current iterator entry
+  * @root: radix tree root
+  * @iter: iterator state
+  * @tag: tag to clear
+  */
+void radix_tree_iter_tag_clear(struct radix_tree_root *root,
+			const struct radix_tree_iter *iter, unsigned int tag)
+{
+	node_tag_clear(root, iter->node, tag, iter_offset(iter));
+}
+
 /**
  * radix_tree_tag_get - get a tag on a radix tree node
  * @root:		radix tree root
@@ -1405,7 +1546,7 @@ EXPORT_SYMBOL(radix_tree_tag_clear);
  * the RCU lock is held, unless tag modification and node deletion are excluded
  * from concurrency.
  */
-int radix_tree_tag_get(struct radix_tree_root *root,
+int radix_tree_tag_get(const struct radix_tree_root *root,
 			unsigned long index, unsigned int tag)
 {
 	struct radix_tree_node *node, *parent;
@@ -1417,8 +1558,6 @@ int radix_tree_tag_get(struct radix_tree_root *root,
 	radix_tree_load_root(root, &node, &maxindex);
 	if (index > maxindex)
 		return 0;
-	if (node == NULL)
-		return 0;
 
 	while (radix_tree_is_internal_node(node)) {
 		unsigned offset;
@@ -1426,8 +1565,6 @@ int radix_tree_tag_get(struct radix_tree_root *root,
 		parent = entry_to_node(node);
 		offset = radix_tree_descend(parent, &node, index);
 
-		if (!node)
-			return 0;
 		if (!tag_get(parent, tag, offset))
 			return 0;
 		if (node == RADIX_TREE_RETRY)
@@ -1454,6 +1591,11 @@ static void set_iter_tags(struct radix_tree_iter *iter,
 	unsigned tag_long = offset / BITS_PER_LONG;
 	unsigned tag_bit  = offset % BITS_PER_LONG;
 
+	if (!node) {
+		iter->tags = 1;
+		return;
+	}
+
 	iter->tags = node->tags[tag][tag_long] >> tag_bit;
 
 	/* This never happens if RADIX_TREE_TAG_LONGS == 1 */
@@ -1468,8 +1610,8 @@ static void set_iter_tags(struct radix_tree_iter *iter,
 }
 
 #ifdef CONFIG_RADIX_TREE_MULTIORDER
-static void **skip_siblings(struct radix_tree_node **nodep,
-			void **slot, struct radix_tree_iter *iter)
+static void __rcu **skip_siblings(struct radix_tree_node **nodep,
+			void __rcu **slot, struct radix_tree_iter *iter)
 {
 	void *sib = node_to_entry(slot - 1);
 
@@ -1486,8 +1628,8 @@ static void **skip_siblings(struct radix_tree_node **nodep,
 	return NULL;
 }
 
-void ** __radix_tree_next_slot(void **slot, struct radix_tree_iter *iter,
-					unsigned flags)
+void __rcu **__radix_tree_next_slot(void __rcu **slot,
+				struct radix_tree_iter *iter, unsigned flags)
 {
 	unsigned tag = flags & RADIX_TREE_ITER_TAG_MASK;
 	struct radix_tree_node *node = rcu_dereference_raw(*slot);
@@ -1540,20 +1682,20 @@ void ** __radix_tree_next_slot(void **slot, struct radix_tree_iter *iter,
 }
 EXPORT_SYMBOL(__radix_tree_next_slot);
 #else
-static void **skip_siblings(struct radix_tree_node **nodep,
-			void **slot, struct radix_tree_iter *iter)
+static void __rcu **skip_siblings(struct radix_tree_node **nodep,
+			void __rcu **slot, struct radix_tree_iter *iter)
 {
 	return slot;
 }
 #endif
 
-void **radix_tree_iter_resume(void **slot, struct radix_tree_iter *iter)
+void __rcu **radix_tree_iter_resume(void __rcu **slot,
+					struct radix_tree_iter *iter)
 {
 	struct radix_tree_node *node;
 
 	slot++;
 	iter->index = __radix_tree_iter_add(iter, 1);
-	node = rcu_dereference_raw(*slot);
 	skip_siblings(&node, slot, iter);
 	iter->next_index = iter->index;
 	iter->tags = 0;
@@ -1569,7 +1711,7 @@ EXPORT_SYMBOL(radix_tree_iter_resume);
  * @flags:	RADIX_TREE_ITER_* flags and tag index
  * Returns:	pointer to chunk first slot, or NULL if iteration is over
  */
-void **radix_tree_next_chunk(struct radix_tree_root *root,
+void __rcu **radix_tree_next_chunk(const struct radix_tree_root *root,
 			     struct radix_tree_iter *iter, unsigned flags)
 {
 	unsigned tag = flags & RADIX_TREE_ITER_TAG_MASK;
@@ -1606,7 +1748,7 @@ void **radix_tree_next_chunk(struct radix_tree_root *root,
 		iter->tags = 1;
 		iter->node = NULL;
 		__set_iter_shift(iter, 0);
-		return (void **)&root->rnode;
+		return (void __rcu **)&root->rnode;
 	}
 
 	do {
@@ -1624,7 +1766,8 @@ void **radix_tree_next_chunk(struct radix_tree_root *root,
 						offset + 1);
 			else
 				while (++offset	< RADIX_TREE_MAP_SIZE) {
-					void *slot = node->slots[offset];
+					void *slot = rcu_dereference_raw(
+							node->slots[offset]);
 					if (is_sibling_entry(node, slot))
 						continue;
 					if (slot)
@@ -1680,11 +1823,11 @@ EXPORT_SYMBOL(radix_tree_next_chunk);
  *	stored in 'results'.
  */
 unsigned int
-radix_tree_gang_lookup(struct radix_tree_root *root, void **results,
+radix_tree_gang_lookup(const struct radix_tree_root *root, void **results,
 			unsigned long first_index, unsigned int max_items)
 {
 	struct radix_tree_iter iter;
-	void **slot;
+	void __rcu **slot;
 	unsigned int ret = 0;
 
 	if (unlikely(!max_items))
@@ -1725,12 +1868,12 @@ EXPORT_SYMBOL(radix_tree_gang_lookup);
  *	protection, radix_tree_deref_slot may fail requiring a retry.
  */
 unsigned int
-radix_tree_gang_lookup_slot(struct radix_tree_root *root,
-			void ***results, unsigned long *indices,
+radix_tree_gang_lookup_slot(const struct radix_tree_root *root,
+			void __rcu ***results, unsigned long *indices,
 			unsigned long first_index, unsigned int max_items)
 {
 	struct radix_tree_iter iter;
-	void **slot;
+	void __rcu **slot;
 	unsigned int ret = 0;
 
 	if (unlikely(!max_items))
@@ -1762,12 +1905,12 @@ EXPORT_SYMBOL(radix_tree_gang_lookup_slot);
  *	returns the number of items which were placed at *@results.
  */
 unsigned int
-radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results,
+radix_tree_gang_lookup_tag(const struct radix_tree_root *root, void **results,
 		unsigned long first_index, unsigned int max_items,
 		unsigned int tag)
 {
 	struct radix_tree_iter iter;
-	void **slot;
+	void __rcu **slot;
 	unsigned int ret = 0;
 
 	if (unlikely(!max_items))
@@ -1803,12 +1946,12 @@ EXPORT_SYMBOL(radix_tree_gang_lookup_tag);
  *	returns the number of slots which were placed at *@results.
  */
 unsigned int
-radix_tree_gang_lookup_tag_slot(struct radix_tree_root *root, void ***results,
-		unsigned long first_index, unsigned int max_items,
-		unsigned int tag)
+radix_tree_gang_lookup_tag_slot(const struct radix_tree_root *root,
+		void __rcu ***results, unsigned long first_index,
+		unsigned int max_items, unsigned int tag)
 {
 	struct radix_tree_iter iter;
-	void **slot;
+	void __rcu **slot;
 	unsigned int ret = 0;
 
 	if (unlikely(!max_items))
@@ -1843,59 +1986,83 @@ void __radix_tree_delete_node(struct radix_tree_root *root,
 	delete_node(root, node, update_node, private);
 }
 
+static bool __radix_tree_delete(struct radix_tree_root *root,
+				struct radix_tree_node *node, void __rcu **slot)
+{
+	void *old = rcu_dereference_raw(*slot);
+	int exceptional = radix_tree_exceptional_entry(old) ? -1 : 0;
+	unsigned offset = get_slot_offset(node, slot);
+	int tag;
+
+	if (is_idr(root))
+		node_tag_set(root, node, IDR_FREE, offset);
+	else
+		for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
+			node_tag_clear(root, node, tag, offset);
+
+	replace_slot(slot, NULL, node, -1, exceptional);
+	return node && delete_node(root, node, NULL, NULL);
+}
+
 /**
- *	radix_tree_delete_item    -    delete an item from a radix tree
- *	@root:		radix tree root
- *	@index:		index key
- *	@item:		expected item
+ * radix_tree_iter_delete - delete the entry at this iterator position
+ * @root: radix tree root
+ * @iter: iterator state
+ * @slot: pointer to slot
  *
- *	Remove @item at @index from the radix tree rooted at @root.
+ * Delete the entry at the position currently pointed to by the iterator.
+ * This may result in the current node being freed; if it is, the iterator
+ * is advanced so that it will not reference the freed memory.  This
+ * function may be called without any locking if there are no other threads
+ * which can access this tree.
+ */
+void radix_tree_iter_delete(struct radix_tree_root *root,
+				struct radix_tree_iter *iter, void __rcu **slot)
+{
+	if (__radix_tree_delete(root, iter->node, slot))
+		iter->index = iter->next_index;
+}
+
+/**
+ * radix_tree_delete_item - delete an item from a radix tree
+ * @root: radix tree root
+ * @index: index key
+ * @item: expected item
  *
- *	Returns the address of the deleted item, or NULL if it was not present
- *	or the entry at the given @index was not @item.
+ * Remove @item at @index from the radix tree rooted at @root.
+ *
+ * Return: the deleted entry, or %NULL if it was not present
+ * or the entry at the given @index was not @item.
  */
 void *radix_tree_delete_item(struct radix_tree_root *root,
 			     unsigned long index, void *item)
 {
-	struct radix_tree_node *node;
-	unsigned int offset;
-	void **slot;
+	struct radix_tree_node *node = NULL;
+	void __rcu **slot;
 	void *entry;
-	int tag;
 
 	entry = __radix_tree_lookup(root, index, &node, &slot);
-	if (!entry)
+	if (!entry && (!is_idr(root) || node_tag_get(root, node, IDR_FREE,
+						get_slot_offset(node, slot))))
 		return NULL;
 
 	if (item && entry != item)
 		return NULL;
 
-	if (!node) {
-		root_tag_clear_all(root);
-		root->rnode = NULL;
-		return entry;
-	}
-
-	offset = get_slot_offset(node, slot);
-
-	/* Clear all tags associated with the item to be deleted.  */
-	for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
-		node_tag_clear(root, node, tag, offset);
-
-	__radix_tree_replace(root, node, slot, NULL, NULL, NULL);
+	__radix_tree_delete(root, node, slot);
 
 	return entry;
 }
 EXPORT_SYMBOL(radix_tree_delete_item);
 
 /**
- *	radix_tree_delete    -    delete an item from a radix tree
- *	@root:		radix tree root
- *	@index:		index key
+ * radix_tree_delete - delete an entry from a radix tree
+ * @root: radix tree root
+ * @index: index key
  *
- *	Remove the item at @index from the radix tree rooted at @root.
+ * Remove the entry at @index from the radix tree rooted at @root.
  *
- *	Returns the address of the deleted item, or NULL if it was not present.
+ * Return: The deleted entry, or %NULL if it was not present.
  */
 void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
 {
@@ -1905,15 +2072,14 @@ EXPORT_SYMBOL(radix_tree_delete);
 
 void radix_tree_clear_tags(struct radix_tree_root *root,
 			   struct radix_tree_node *node,
-			   void **slot)
+			   void __rcu **slot)
 {
 	if (node) {
 		unsigned int tag, offset = get_slot_offset(node, slot);
 		for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
 			node_tag_clear(root, node, tag, offset);
 	} else {
-		/* Clear root node tags */
-		root->gfp_mask &= __GFP_BITS_MASK;
+		root_tag_clear_all(root);
 	}
 }
 
@@ -1922,12 +2088,147 @@ void radix_tree_clear_tags(struct radix_tree_root *root,
  *	@root:		radix tree root
  *	@tag:		tag to test
  */
-int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag)
+int radix_tree_tagged(const struct radix_tree_root *root, unsigned int tag)
 {
 	return root_tag_get(root, tag);
 }
 EXPORT_SYMBOL(radix_tree_tagged);
 
+/**
+ * idr_preload - preload for idr_alloc()
+ * @gfp_mask: allocation mask to use for preloading
+ *
+ * Preallocate memory to use for the next call to idr_alloc().  This function
+ * returns with preemption disabled.  It will be enabled by idr_preload_end().
+ */
+void idr_preload(gfp_t gfp_mask)
+{
+	__radix_tree_preload(gfp_mask, IDR_PRELOAD_SIZE);
+}
+EXPORT_SYMBOL(idr_preload);
+
+/**
+ * ida_pre_get - reserve resources for ida allocation
+ * @ida: ida handle
+ * @gfp: memory allocation flags
+ *
+ * This function should be called before calling ida_get_new_above().  If it
+ * is unable to allocate memory, it will return %0.  On success, it returns %1.
+ */
+int ida_pre_get(struct ida *ida, gfp_t gfp)
+{
+	__radix_tree_preload(gfp, IDA_PRELOAD_SIZE);
+	/*
+	 * The IDA API has no preload_end() equivalent.  Instead,
+	 * ida_get_new() can return -EAGAIN, prompting the caller
+	 * to return to the ida_pre_get() step.
+	 */
+	preempt_enable();
+
+	if (!this_cpu_read(ida_bitmap)) {
+		struct ida_bitmap *bitmap = kmalloc(sizeof(*bitmap), gfp);
+		if (!bitmap)
+			return 0;
+		bitmap = this_cpu_cmpxchg(ida_bitmap, NULL, bitmap);
+		kfree(bitmap);
+	}
+
+	return 1;
+}
+EXPORT_SYMBOL(ida_pre_get);
+
+void __rcu **idr_get_free(struct radix_tree_root *root,
+			struct radix_tree_iter *iter, gfp_t gfp, int end)
+{
+	struct radix_tree_node *node = NULL, *child;
+	void __rcu **slot = (void __rcu **)&root->rnode;
+	unsigned long maxindex, start = iter->next_index;
+	unsigned long max = end > 0 ? end - 1 : INT_MAX;
+	unsigned int shift, offset = 0;
+
+ grow:
+	shift = radix_tree_load_root(root, &child, &maxindex);
+	if (!radix_tree_tagged(root, IDR_FREE))
+		start = max(start, maxindex + 1);
+	if (start > max)
+		return ERR_PTR(-ENOSPC);
+
+	if (start > maxindex) {
+		int error = radix_tree_extend(root, gfp, start, shift);
+		if (error < 0)
+			return ERR_PTR(error);
+		shift = error;
+		child = rcu_dereference_raw(root->rnode);
+	}
+
+	while (shift) {
+		shift -= RADIX_TREE_MAP_SHIFT;
+		if (child == NULL) {
+			/* Have to add a child node.  */
+			child = radix_tree_node_alloc(gfp, node, root, shift,
+							offset, 0, 0);
+			if (!child)
+				return ERR_PTR(-ENOMEM);
+			all_tag_set(child, IDR_FREE);
+			rcu_assign_pointer(*slot, node_to_entry(child));
+			if (node)
+				node->count++;
+		} else if (!radix_tree_is_internal_node(child))
+			break;
+
+		node = entry_to_node(child);
+		offset = radix_tree_descend(node, &child, start);
+		if (!tag_get(node, IDR_FREE, offset)) {
+			offset = radix_tree_find_next_bit(node, IDR_FREE,
+							offset + 1);
+			start = next_index(start, node, offset);
+			if (start > max)
+				return ERR_PTR(-ENOSPC);
+			while (offset == RADIX_TREE_MAP_SIZE) {
+				offset = node->offset + 1;
+				node = node->parent;
+				if (!node)
+					goto grow;
+				shift = node->shift;
+			}
+			child = rcu_dereference_raw(node->slots[offset]);
+		}
+		slot = &node->slots[offset];
+	}
+
+	iter->index = start;
+	if (node)
+		iter->next_index = 1 + min(max, (start | node_maxindex(node)));
+	else
+		iter->next_index = 1;
+	iter->node = node;
+	__set_iter_shift(iter, shift);
+	set_iter_tags(iter, node, offset, IDR_FREE);
+
+	return slot;
+}
+
+/**
+ * idr_destroy - release all internal memory from an IDR
+ * @idr: idr handle
+ *
+ * After this function is called, the IDR is empty, and may be reused or
+ * the data structure containing it may be freed.
+ *
+ * A typical clean-up sequence for objects stored in an idr tree will use
+ * idr_for_each() to free all objects, if necessary, then idr_destroy() to
+ * free the memory used to keep track of those objects.
+ */
+void idr_destroy(struct idr *idr)
+{
+	struct radix_tree_node *node = rcu_dereference_raw(idr->idr_rt.rnode);
+	if (radix_tree_is_internal_node(node))
+		radix_tree_free_nodes(node);
+	idr->idr_rt.rnode = NULL;
+	root_tag_set(&idr->idr_rt, IDR_FREE);
+}
+EXPORT_SYMBOL(idr_destroy);
+
 static void
 radix_tree_node_ctor(void *arg)
 {
@@ -1971,10 +2272,12 @@ static int radix_tree_cpu_dead(unsigned int cpu)
 	rtp = &per_cpu(radix_tree_preloads, cpu);
 	while (rtp->nr) {
 		node = rtp->nodes;
-		rtp->nodes = node->private_data;
+		rtp->nodes = node->parent;
 		kmem_cache_free(radix_tree_node_cachep, node);
 		rtp->nr--;
 	}
+	kfree(per_cpu(ida_bitmap, cpu));
+	per_cpu(ida_bitmap, cpu) = NULL;
 	return 0;
 }
 
diff --git a/mm/workingset.c b/mm/workingset.c
index 79ed5364375d3385824091b7a0d944e2f22539f7..ac839fca0e76ae3cc5a025684cb1516301922d92 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -355,10 +355,8 @@ void workingset_update_node(struct radix_tree_node *node, void *private)
 	 * as node->private_list is protected by &mapping->tree_lock.
 	 */
 	if (node->count && node->count == node->exceptional) {
-		if (list_empty(&node->private_list)) {
-			node->private_data = mapping;
+		if (list_empty(&node->private_list))
 			list_lru_add(&shadow_nodes, &node->private_list);
-		}
 	} else {
 		if (!list_empty(&node->private_list))
 			list_lru_del(&shadow_nodes, &node->private_list);
@@ -436,7 +434,7 @@ static enum lru_status shadow_lru_isolate(struct list_head *item,
 	 */
 
 	node = container_of(item, struct radix_tree_node, private_list);
-	mapping = node->private_data;
+	mapping = container_of(node->root, struct address_space, page_tree);
 
 	/* Coming from the list, invert the lock order */
 	if (!spin_trylock(&mapping->tree_lock)) {
diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index a3af6e1bfd984d3548b3f48dad508028b7958bae..0dd7c351002dbe909b973b5b048ec9652be00b1b 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -462,9 +462,7 @@ static void ieee80211_report_ack_skb(struct ieee80211_local *local,
 	unsigned long flags;
 
 	spin_lock_irqsave(&local->ack_status_lock, flags);
-	skb = idr_find(&local->ack_status_frames, info->ack_frame_id);
-	if (skb)
-		idr_remove(&local->ack_status_frames, info->ack_frame_id);
+	skb = idr_remove(&local->ack_status_frames, info->ack_frame_id);
 	spin_unlock_irqrestore(&local->ack_status_lock, flags);
 
 	if (!skb)
diff --git a/tools/include/asm-generic/bitops/atomic.h b/tools/include/asm-generic/bitops/atomic.h
index 18663f59d72f7c221286da025be45ac08b590165..68b8c1516c5a719b9fd422849e4431bafdaf8065 100644
--- a/tools/include/asm-generic/bitops/atomic.h
+++ b/tools/include/asm-generic/bitops/atomic.h
@@ -20,4 +20,7 @@ static __always_inline int test_bit(unsigned int nr, const unsigned long *addr)
 		(((unsigned long *)addr)[nr / __BITS_PER_LONG])) != 0;
 }
 
+#define __set_bit(nr, addr)	set_bit(nr, addr)
+#define __clear_bit(nr, addr)	clear_bit(nr, addr)
+
 #endif /* _TOOLS_LINUX_ASM_GENERIC_BITOPS_ATOMIC_H_ */
diff --git a/tools/include/asm/bug.h b/tools/include/asm/bug.h
index beda1a884b50f0465ace7e3f01ca6014e5d3e755..4790f047a89c476624975d51514698f210900a19 100644
--- a/tools/include/asm/bug.h
+++ b/tools/include/asm/bug.h
@@ -12,6 +12,14 @@
 	unlikely(__ret_warn_on);		\
 })
 
+#define WARN_ON(condition) ({					\
+	int __ret_warn_on = !!(condition);			\
+	if (unlikely(__ret_warn_on))				\
+		__WARN_printf("assertion failed at %s:%d\n",	\
+				__FILE__, __LINE__);		\
+	unlikely(__ret_warn_on);				\
+})
+
 #define WARN_ON_ONCE(condition) ({			\
 	static int __warned;				\
 	int __ret_warn_once = !!(condition);		\
diff --git a/tools/include/linux/bitmap.h b/tools/include/linux/bitmap.h
index eef41d500e9e5497b21532980bc1be180a02eefe..e8b9f518e36b2cddfbd415db8cde2f9a8581d876 100644
--- a/tools/include/linux/bitmap.h
+++ b/tools/include/linux/bitmap.h
@@ -4,6 +4,7 @@
 #include <string.h>
 #include <linux/bitops.h>
 #include <stdlib.h>
+#include <linux/kernel.h>
 
 #define DECLARE_BITMAP(name,bits) \
 	unsigned long name[BITS_TO_LONGS(bits)]
diff --git a/tools/include/linux/bitops.h b/tools/include/linux/bitops.h
index fc446343ff417760dc8e3d98ebd0e33e5deb3dad..1aecad369af57f07cfc32db53dfd414cc6f5433c 100644
--- a/tools/include/linux/bitops.h
+++ b/tools/include/linux/bitops.h
@@ -2,7 +2,6 @@
 #define _TOOLS_LINUX_BITOPS_H_
 
 #include <asm/types.h>
-#include <linux/kernel.h>
 #include <linux/compiler.h>
 
 #ifndef __WORDSIZE
diff --git a/tools/include/linux/compiler.h b/tools/include/linux/compiler.h
index 6326ede9aecef7f6b417f67990894032e79b3f4a..8de163b17c0d00011d33083d247936d8265465e7 100644
--- a/tools/include/linux/compiler.h
+++ b/tools/include/linux/compiler.h
@@ -25,6 +25,8 @@
 #endif
 
 #define __user
+#define __rcu
+#define __read_mostly
 
 #ifndef __attribute_const__
 # define __attribute_const__
@@ -54,6 +56,8 @@
 # define unlikely(x)		__builtin_expect(!!(x), 0)
 #endif
 
+#define uninitialized_var(x) x = *(&(x))
+
 #define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
 
 #include <linux/types.h>
diff --git a/tools/include/linux/spinlock.h b/tools/include/linux/spinlock.h
new file mode 100644
index 0000000000000000000000000000000000000000..58397dcb19d6092a607478d070a850f162e49bed
--- /dev/null
+++ b/tools/include/linux/spinlock.h
@@ -0,0 +1,5 @@
+#define spinlock_t		pthread_mutex_t
+#define DEFINE_SPINLOCK(x)	pthread_mutex_t x = PTHREAD_MUTEX_INITIALIZER;
+
+#define spin_lock_irqsave(x, f)		(void)f, pthread_mutex_lock(x)
+#define spin_unlock_irqrestore(x, f)	(void)f, pthread_mutex_unlock(x)
diff --git a/tools/testing/radix-tree/.gitignore b/tools/testing/radix-tree/.gitignore
index 11d888ca6a9237392607cf99e3e767878c5716ec..d4706c0ffcebdead866851aa98fcb9323e394fe5 100644
--- a/tools/testing/radix-tree/.gitignore
+++ b/tools/testing/radix-tree/.gitignore
@@ -1,2 +1,6 @@
+generated/map-shift.h
+idr.c
+idr-test
 main
+multiorder
 radix-tree.c
diff --git a/tools/testing/radix-tree/Makefile b/tools/testing/radix-tree/Makefile
index 3635e4d3eca7fcd8dae99f740c587b7ac02162b9..f11315bedefc3d68152bef22da0f8ab60f8c5be6 100644
--- a/tools/testing/radix-tree/Makefile
+++ b/tools/testing/radix-tree/Makefile
@@ -1,29 +1,47 @@
 
-CFLAGS += -I. -I../../include -g -O2 -Wall -D_LGPL_SOURCE
+CFLAGS += -I. -I../../include -g -O2 -Wall -D_LGPL_SOURCE -fsanitize=address
 LDFLAGS += -lpthread -lurcu
-TARGETS = main
-OFILES = main.o radix-tree.o linux.o test.o tag_check.o find_next_bit.o \
-	 regression1.o regression2.o regression3.o multiorder.o \
-	 iteration_check.o benchmark.o
+TARGETS = main idr-test multiorder
+CORE_OFILES := radix-tree.o idr.o linux.o test.o find_bit.o
+OFILES = main.o $(CORE_OFILES) regression1.o regression2.o regression3.o \
+	 tag_check.o multiorder.o idr-test.o iteration_check.o benchmark.o
 
-ifdef BENCHMARK
-	CFLAGS += -DBENCHMARK=1
+ifndef SHIFT
+	SHIFT=3
 endif
 
-targets: $(TARGETS)
+targets: mapshift $(TARGETS)
 
 main:	$(OFILES)
-	$(CC) $(CFLAGS) $(LDFLAGS) $(OFILES) -o main
+	$(CC) $(CFLAGS) $(LDFLAGS) $^ -o main
+
+idr-test: idr-test.o $(CORE_OFILES)
+	$(CC) $(CFLAGS) $(LDFLAGS) $^ -o idr-test
+
+multiorder: multiorder.o $(CORE_OFILES)
+	$(CC) $(CFLAGS) $(LDFLAGS) $^ -o multiorder
 
 clean:
-	$(RM) -f $(TARGETS) *.o radix-tree.c
+	$(RM) $(TARGETS) *.o radix-tree.c idr.c generated/map-shift.h
 
-find_next_bit.o: ../../lib/find_bit.c
-	$(CC) $(CFLAGS) -c -o $@ $<
+vpath %.c ../../lib
 
-$(OFILES): *.h */*.h \
+$(OFILES): *.h */*.h generated/map-shift.h \
 	../../include/linux/*.h \
-	../../../include/linux/radix-tree.h
+	../../include/asm/*.h \
+	../../../include/linux/radix-tree.h \
+	../../../include/linux/idr.h
 
 radix-tree.c: ../../../lib/radix-tree.c
 	sed -e 's/^static //' -e 's/__always_inline //' -e 's/inline //' < $< > $@
+
+idr.c: ../../../lib/idr.c
+	sed -e 's/^static //' -e 's/__always_inline //' -e 's/inline //' < $< > $@
+
+.PHONY: mapshift
+
+mapshift:
+	@if ! grep -qw $(SHIFT) generated/map-shift.h; then		\
+		echo "#define RADIX_TREE_MAP_SHIFT $(SHIFT)" >		\
+				generated/map-shift.h;			\
+	fi
diff --git a/tools/testing/radix-tree/benchmark.c b/tools/testing/radix-tree/benchmark.c
index 215ca86c7605527d59a208cb8b34f686a5ac4ba4..9b09ddfe462fd3b2ea782805560c349e720a4637 100644
--- a/tools/testing/radix-tree/benchmark.c
+++ b/tools/testing/radix-tree/benchmark.c
@@ -71,7 +71,7 @@ static void benchmark_size(unsigned long size, unsigned long step, int order)
 	tagged = benchmark_iter(&tree, true);
 	normal = benchmark_iter(&tree, false);
 
-	printf("Size %ld, step %6ld, order %d tagged %10lld ns, normal %10lld ns\n",
+	printv(2, "Size %ld, step %6ld, order %d tagged %10lld ns, normal %10lld ns\n",
 		size, step, order, tagged, normal);
 
 	item_kill_tree(&tree);
@@ -85,8 +85,8 @@ void benchmark(void)
 				128, 256, 512, 12345, 0};
 	int c, s;
 
-	printf("starting benchmarks\n");
-	printf("RADIX_TREE_MAP_SHIFT = %d\n", RADIX_TREE_MAP_SHIFT);
+	printv(1, "starting benchmarks\n");
+	printv(1, "RADIX_TREE_MAP_SHIFT = %d\n", RADIX_TREE_MAP_SHIFT);
 
 	for (c = 0; size[c]; c++)
 		for (s = 0; step[s]; s++)
diff --git a/tools/testing/radix-tree/generated/autoconf.h b/tools/testing/radix-tree/generated/autoconf.h
index ad18cf5a2a3a1df8dfc34ec8ed7d0c18471e24ff..cf88dc5b8832a20b89e2130055f12e179233187f 100644
--- a/tools/testing/radix-tree/generated/autoconf.h
+++ b/tools/testing/radix-tree/generated/autoconf.h
@@ -1,3 +1 @@
 #define CONFIG_RADIX_TREE_MULTIORDER 1
-#define CONFIG_SHMEM 1
-#define CONFIG_SWAP 1
diff --git a/tools/testing/radix-tree/idr-test.c b/tools/testing/radix-tree/idr-test.c
new file mode 100644
index 0000000000000000000000000000000000000000..a26098c6123d1cf99ce2b6669a0e186bd22cedbe
--- /dev/null
+++ b/tools/testing/radix-tree/idr-test.c
@@ -0,0 +1,444 @@
+/*
+ * idr-test.c: Test the IDR API
+ * Copyright (c) 2016 Matthew Wilcox <willy@infradead.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ */
+#include <linux/bitmap.h>
+#include <linux/idr.h>
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+
+#include "test.h"
+
+#define DUMMY_PTR	((void *)0x12)
+
+int item_idr_free(int id, void *p, void *data)
+{
+	struct item *item = p;
+	assert(item->index == id);
+	free(p);
+
+	return 0;
+}
+
+void item_idr_remove(struct idr *idr, int id)
+{
+	struct item *item = idr_find(idr, id);
+	assert(item->index == id);
+	idr_remove(idr, id);
+	free(item);
+}
+
+void idr_alloc_test(void)
+{
+	unsigned long i;
+	DEFINE_IDR(idr);
+
+	assert(idr_alloc_cyclic(&idr, DUMMY_PTR, 0, 0x4000, GFP_KERNEL) == 0);
+	assert(idr_alloc_cyclic(&idr, DUMMY_PTR, 0x3ffd, 0x4000, GFP_KERNEL) == 0x3ffd);
+	idr_remove(&idr, 0x3ffd);
+	idr_remove(&idr, 0);
+
+	for (i = 0x3ffe; i < 0x4003; i++) {
+		int id;
+		struct item *item;
+
+		if (i < 0x4000)
+			item = item_create(i, 0);
+		else
+			item = item_create(i - 0x3fff, 0);
+
+		id = idr_alloc_cyclic(&idr, item, 1, 0x4000, GFP_KERNEL);
+		assert(id == item->index);
+	}
+
+	idr_for_each(&idr, item_idr_free, &idr);
+	idr_destroy(&idr);
+}
+
+void idr_replace_test(void)
+{
+	DEFINE_IDR(idr);
+
+	idr_alloc(&idr, (void *)-1, 10, 11, GFP_KERNEL);
+	idr_replace(&idr, &idr, 10);
+
+	idr_destroy(&idr);
+}
+
+/*
+ * Unlike the radix tree, you can put a NULL pointer -- with care -- into
+ * the IDR.  Some interfaces, like idr_find() do not distinguish between
+ * "present, value is NULL" and "not present", but that's exactly what some
+ * users want.
+ */
+void idr_null_test(void)
+{
+	int i;
+	DEFINE_IDR(idr);
+
+	assert(idr_is_empty(&idr));
+
+	assert(idr_alloc(&idr, NULL, 0, 0, GFP_KERNEL) == 0);
+	assert(!idr_is_empty(&idr));
+	idr_remove(&idr, 0);
+	assert(idr_is_empty(&idr));
+
+	assert(idr_alloc(&idr, NULL, 0, 0, GFP_KERNEL) == 0);
+	assert(!idr_is_empty(&idr));
+	idr_destroy(&idr);
+	assert(idr_is_empty(&idr));
+
+	for (i = 0; i < 10; i++) {
+		assert(idr_alloc(&idr, NULL, 0, 0, GFP_KERNEL) == i);
+	}
+
+	assert(idr_replace(&idr, DUMMY_PTR, 3) == NULL);
+	assert(idr_replace(&idr, DUMMY_PTR, 4) == NULL);
+	assert(idr_replace(&idr, NULL, 4) == DUMMY_PTR);
+	assert(idr_replace(&idr, DUMMY_PTR, 11) == ERR_PTR(-ENOENT));
+	idr_remove(&idr, 5);
+	assert(idr_alloc(&idr, NULL, 0, 0, GFP_KERNEL) == 5);
+	idr_remove(&idr, 5);
+
+	for (i = 0; i < 9; i++) {
+		idr_remove(&idr, i);
+		assert(!idr_is_empty(&idr));
+	}
+	idr_remove(&idr, 8);
+	assert(!idr_is_empty(&idr));
+	idr_remove(&idr, 9);
+	assert(idr_is_empty(&idr));
+
+	assert(idr_alloc(&idr, NULL, 0, 0, GFP_KERNEL) == 0);
+	assert(idr_replace(&idr, DUMMY_PTR, 3) == ERR_PTR(-ENOENT));
+	assert(idr_replace(&idr, DUMMY_PTR, 0) == NULL);
+	assert(idr_replace(&idr, NULL, 0) == DUMMY_PTR);
+
+	idr_destroy(&idr);
+	assert(idr_is_empty(&idr));
+
+	for (i = 1; i < 10; i++) {
+		assert(idr_alloc(&idr, NULL, 1, 0, GFP_KERNEL) == i);
+	}
+
+	idr_destroy(&idr);
+	assert(idr_is_empty(&idr));
+}
+
+void idr_nowait_test(void)
+{
+	unsigned int i;
+	DEFINE_IDR(idr);
+
+	idr_preload(GFP_KERNEL);
+
+	for (i = 0; i < 3; i++) {
+		struct item *item = item_create(i, 0);
+		assert(idr_alloc(&idr, item, i, i + 1, GFP_NOWAIT) == i);
+	}
+
+	idr_preload_end();
+
+	idr_for_each(&idr, item_idr_free, &idr);
+	idr_destroy(&idr);
+}
+
+void idr_checks(void)
+{
+	unsigned long i;
+	DEFINE_IDR(idr);
+
+	for (i = 0; i < 10000; i++) {
+		struct item *item = item_create(i, 0);
+		assert(idr_alloc(&idr, item, 0, 20000, GFP_KERNEL) == i);
+	}
+
+	assert(idr_alloc(&idr, DUMMY_PTR, 5, 30, GFP_KERNEL) < 0);
+
+	for (i = 0; i < 5000; i++)
+		item_idr_remove(&idr, i);
+
+	idr_remove(&idr, 3);
+
+	idr_for_each(&idr, item_idr_free, &idr);
+	idr_destroy(&idr);
+
+	assert(idr_is_empty(&idr));
+
+	idr_remove(&idr, 3);
+	idr_remove(&idr, 0);
+
+	for (i = INT_MAX - 3UL; i < INT_MAX + 1UL; i++) {
+		struct item *item = item_create(i, 0);
+		assert(idr_alloc(&idr, item, i, i + 10, GFP_KERNEL) == i);
+	}
+	assert(idr_alloc(&idr, DUMMY_PTR, i - 2, i, GFP_KERNEL) == -ENOSPC);
+
+	idr_for_each(&idr, item_idr_free, &idr);
+	idr_destroy(&idr);
+	idr_destroy(&idr);
+
+	assert(idr_is_empty(&idr));
+
+	for (i = 1; i < 10000; i++) {
+		struct item *item = item_create(i, 0);
+		assert(idr_alloc(&idr, item, 1, 20000, GFP_KERNEL) == i);
+	}
+
+	idr_for_each(&idr, item_idr_free, &idr);
+	idr_destroy(&idr);
+
+	idr_replace_test();
+	idr_alloc_test();
+	idr_null_test();
+	idr_nowait_test();
+}
+
+/*
+ * Check that we get the correct error when we run out of memory doing
+ * allocations.  To ensure we run out of memory, just "forget" to preload.
+ * The first test is for not having a bitmap available, and the second test
+ * is for not being able to allocate a level of the radix tree.
+ */
+void ida_check_nomem(void)
+{
+	DEFINE_IDA(ida);
+	int id, err;
+
+	err = ida_get_new_above(&ida, 256, &id);
+	assert(err == -EAGAIN);
+	err = ida_get_new_above(&ida, 1UL << 30, &id);
+	assert(err == -EAGAIN);
+}
+
+/*
+ * Check what happens when we fill a leaf and then delete it.  This may
+ * discover mishandling of IDR_FREE.
+ */
+void ida_check_leaf(void)
+{
+	DEFINE_IDA(ida);
+	int id;
+	unsigned long i;
+
+	for (i = 0; i < IDA_BITMAP_BITS; i++) {
+		assert(ida_pre_get(&ida, GFP_KERNEL));
+		assert(!ida_get_new(&ida, &id));
+		assert(id == i);
+	}
+
+	ida_destroy(&ida);
+	assert(ida_is_empty(&ida));
+
+	assert(ida_pre_get(&ida, GFP_KERNEL));
+	assert(!ida_get_new(&ida, &id));
+	assert(id == 0);
+	ida_destroy(&ida);
+	assert(ida_is_empty(&ida));
+}
+
+/*
+ * Check handling of conversions between exceptional entries and full bitmaps.
+ */
+void ida_check_conv(void)
+{
+	DEFINE_IDA(ida);
+	int id;
+	unsigned long i;
+
+	for (i = 0; i < IDA_BITMAP_BITS * 2; i += IDA_BITMAP_BITS) {
+		assert(ida_pre_get(&ida, GFP_KERNEL));
+		assert(!ida_get_new_above(&ida, i + 1, &id));
+		assert(id == i + 1);
+		assert(!ida_get_new_above(&ida, i + BITS_PER_LONG, &id));
+		assert(id == i + BITS_PER_LONG);
+		ida_remove(&ida, i + 1);
+		ida_remove(&ida, i + BITS_PER_LONG);
+		assert(ida_is_empty(&ida));
+	}
+
+	assert(ida_pre_get(&ida, GFP_KERNEL));
+
+	for (i = 0; i < IDA_BITMAP_BITS * 2; i++) {
+		assert(ida_pre_get(&ida, GFP_KERNEL));
+		assert(!ida_get_new(&ida, &id));
+		assert(id == i);
+	}
+
+	for (i = IDA_BITMAP_BITS * 2; i > 0; i--) {
+		ida_remove(&ida, i - 1);
+	}
+	assert(ida_is_empty(&ida));
+
+	for (i = 0; i < IDA_BITMAP_BITS + BITS_PER_LONG - 4; i++) {
+		assert(ida_pre_get(&ida, GFP_KERNEL));
+		assert(!ida_get_new(&ida, &id));
+		assert(id == i);
+	}
+
+	for (i = IDA_BITMAP_BITS + BITS_PER_LONG - 4; i > 0; i--) {
+		ida_remove(&ida, i - 1);
+	}
+	assert(ida_is_empty(&ida));
+
+	radix_tree_cpu_dead(1);
+	for (i = 0; i < 1000000; i++) {
+		int err = ida_get_new(&ida, &id);
+		if (err == -EAGAIN) {
+			assert((i % IDA_BITMAP_BITS) == (BITS_PER_LONG - 2));
+			assert(ida_pre_get(&ida, GFP_KERNEL));
+			err = ida_get_new(&ida, &id);
+		} else {
+			assert((i % IDA_BITMAP_BITS) != (BITS_PER_LONG - 2));
+		}
+		assert(!err);
+		assert(id == i);
+	}
+	ida_destroy(&ida);
+}
+
+/*
+ * Check allocations up to and slightly above the maximum allowed (2^31-1) ID.
+ * Allocating up to 2^31-1 should succeed, and then allocating the next one
+ * should fail.
+ */
+void ida_check_max(void)
+{
+	DEFINE_IDA(ida);
+	int id, err;
+	unsigned long i, j;
+
+	for (j = 1; j < 65537; j *= 2) {
+		unsigned long base = (1UL << 31) - j;
+		for (i = 0; i < j; i++) {
+			assert(ida_pre_get(&ida, GFP_KERNEL));
+			assert(!ida_get_new_above(&ida, base, &id));
+			assert(id == base + i);
+		}
+		assert(ida_pre_get(&ida, GFP_KERNEL));
+		err = ida_get_new_above(&ida, base, &id);
+		assert(err == -ENOSPC);
+		ida_destroy(&ida);
+		assert(ida_is_empty(&ida));
+		rcu_barrier();
+	}
+}
+
+void ida_check_random(void)
+{
+	DEFINE_IDA(ida);
+	DECLARE_BITMAP(bitmap, 2048);
+	int id;
+	unsigned int i;
+	time_t s = time(NULL);
+
+ repeat:
+	memset(bitmap, 0, sizeof(bitmap));
+	for (i = 0; i < 100000; i++) {
+		int i = rand();
+		int bit = i & 2047;
+		if (test_bit(bit, bitmap)) {
+			__clear_bit(bit, bitmap);
+			ida_remove(&ida, bit);
+		} else {
+			__set_bit(bit, bitmap);
+			ida_pre_get(&ida, GFP_KERNEL);
+			assert(!ida_get_new_above(&ida, bit, &id));
+			assert(id == bit);
+		}
+	}
+	ida_destroy(&ida);
+	if (time(NULL) < s + 10)
+		goto repeat;
+}
+
+void ida_checks(void)
+{
+	DEFINE_IDA(ida);
+	int id;
+	unsigned long i;
+
+	radix_tree_cpu_dead(1);
+	ida_check_nomem();
+
+	for (i = 0; i < 10000; i++) {
+		assert(ida_pre_get(&ida, GFP_KERNEL));
+		assert(!ida_get_new(&ida, &id));
+		assert(id == i);
+	}
+
+	ida_remove(&ida, 20);
+	ida_remove(&ida, 21);
+	for (i = 0; i < 3; i++) {
+		assert(ida_pre_get(&ida, GFP_KERNEL));
+		assert(!ida_get_new(&ida, &id));
+		if (i == 2)
+			assert(id == 10000);
+	}
+
+	for (i = 0; i < 5000; i++)
+		ida_remove(&ida, i);
+
+	assert(ida_pre_get(&ida, GFP_KERNEL));
+	assert(!ida_get_new_above(&ida, 5000, &id));
+	assert(id == 10001);
+
+	ida_destroy(&ida);
+
+	assert(ida_is_empty(&ida));
+
+	assert(ida_pre_get(&ida, GFP_KERNEL));
+	assert(!ida_get_new_above(&ida, 1, &id));
+	assert(id == 1);
+
+	ida_remove(&ida, id);
+	assert(ida_is_empty(&ida));
+	ida_destroy(&ida);
+	assert(ida_is_empty(&ida));
+
+	assert(ida_pre_get(&ida, GFP_KERNEL));
+	assert(!ida_get_new_above(&ida, 1, &id));
+	ida_destroy(&ida);
+	assert(ida_is_empty(&ida));
+
+	assert(ida_pre_get(&ida, GFP_KERNEL));
+	assert(!ida_get_new_above(&ida, 1, &id));
+	assert(id == 1);
+	assert(ida_pre_get(&ida, GFP_KERNEL));
+	assert(!ida_get_new_above(&ida, 1025, &id));
+	assert(id == 1025);
+	assert(ida_pre_get(&ida, GFP_KERNEL));
+	assert(!ida_get_new_above(&ida, 10000, &id));
+	assert(id == 10000);
+	ida_remove(&ida, 1025);
+	ida_destroy(&ida);
+	assert(ida_is_empty(&ida));
+
+	ida_check_leaf();
+	ida_check_max();
+	ida_check_conv();
+	ida_check_random();
+
+	radix_tree_cpu_dead(1);
+}
+
+int __weak main(void)
+{
+	radix_tree_init();
+	idr_checks();
+	ida_checks();
+	rcu_barrier();
+	if (nr_allocated)
+		printf("nr_allocated = %d\n", nr_allocated);
+	return 0;
+}
diff --git a/tools/testing/radix-tree/iteration_check.c b/tools/testing/radix-tree/iteration_check.c
index 7572b7ed930ecccbf043b6f9989f64b6cd27d0e7..a92bab51370139f673001cef8bf193463498bd98 100644
--- a/tools/testing/radix-tree/iteration_check.c
+++ b/tools/testing/radix-tree/iteration_check.c
@@ -177,7 +177,7 @@ void iteration_test(unsigned order, unsigned test_duration)
 {
 	int i;
 
-	printf("Running %siteration tests for %d seconds\n",
+	printv(1, "Running %siteration tests for %d seconds\n",
 			order > 0 ? "multiorder " : "", test_duration);
 
 	max_order = order;
diff --git a/tools/testing/radix-tree/linux.c b/tools/testing/radix-tree/linux.c
index d31ea7c9abec8231b37e6e61efbd56e7e7f09706..cf48c8473f4869a8205a9eaa94b6f423079b9be5 100644
--- a/tools/testing/radix-tree/linux.c
+++ b/tools/testing/radix-tree/linux.c
@@ -5,7 +5,7 @@
 #include <unistd.h>
 #include <assert.h>
 
-#include <linux/mempool.h>
+#include <linux/gfp.h>
 #include <linux/poison.h>
 #include <linux/slab.h>
 #include <linux/radix-tree.h>
@@ -13,6 +13,8 @@
 
 int nr_allocated;
 int preempt_count;
+int kmalloc_verbose;
+int test_verbose;
 
 struct kmem_cache {
 	pthread_mutex_t lock;
@@ -22,27 +24,6 @@ struct kmem_cache {
 	void (*ctor)(void *);
 };
 
-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)
 {
 	struct radix_tree_node *node;
@@ -54,9 +35,9 @@ void *kmem_cache_alloc(struct kmem_cache *cachep, int flags)
 	if (cachep->nr_objs) {
 		cachep->nr_objs--;
 		node = cachep->objs;
-		cachep->objs = node->private_data;
+		cachep->objs = node->parent;
 		pthread_mutex_unlock(&cachep->lock);
-		node->private_data = NULL;
+		node->parent = NULL;
 	} else {
 		pthread_mutex_unlock(&cachep->lock);
 		node = malloc(cachep->size);
@@ -65,6 +46,8 @@ void *kmem_cache_alloc(struct kmem_cache *cachep, int flags)
 	}
 
 	uatomic_inc(&nr_allocated);
+	if (kmalloc_verbose)
+		printf("Allocating %p from slab\n", node);
 	return node;
 }
 
@@ -72,6 +55,8 @@ 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);
@@ -79,7 +64,7 @@ void kmem_cache_free(struct kmem_cache *cachep, void *objp)
 	} else {
 		struct radix_tree_node *node = objp;
 		cachep->nr_objs++;
-		node->private_data = cachep->objs;
+		node->parent = cachep->objs;
 		cachep->objs = node;
 	}
 	pthread_mutex_unlock(&cachep->lock);
@@ -89,6 +74,8 @@ void *kmalloc(size_t size, gfp_t gfp)
 {
 	void *ret = malloc(size);
 	uatomic_inc(&nr_allocated);
+	if (kmalloc_verbose)
+		printf("Allocating %p from malloc\n", ret);
 	return ret;
 }
 
@@ -97,6 +84,8 @@ void kfree(void *p)
 	if (!p)
 		return;
 	uatomic_dec(&nr_allocated);
+	if (kmalloc_verbose)
+		printf("Freeing %p to malloc\n", p);
 	free(p);
 }
 
diff --git a/tools/testing/radix-tree/linux/bitops.h b/tools/testing/radix-tree/linux/bitops.h
deleted file mode 100644
index a13e9bc76eece8d29372ad0605f2bfd1f2383d9f..0000000000000000000000000000000000000000
--- a/tools/testing/radix-tree/linux/bitops.h
+++ /dev/null
@@ -1,160 +0,0 @@
-#ifndef _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
-#define _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
-
-#include <linux/types.h>
-#include <linux/bitops/find.h>
-#include <linux/bitops/hweight.h>
-#include <linux/kernel.h>
-
-#define BIT_MASK(nr)		(1UL << ((nr) % BITS_PER_LONG))
-#define BIT_WORD(nr)		((nr) / BITS_PER_LONG)
-#define BITS_PER_BYTE		8
-#define BITS_TO_LONGS(nr)	DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
-
-/**
- * __set_bit - Set a bit in memory
- * @nr: the bit to set
- * @addr: the address to start counting from
- *
- * Unlike set_bit(), this function is non-atomic and may be reordered.
- * If it's called on the same region of memory simultaneously, the effect
- * may be that only one operation succeeds.
- */
-static inline void __set_bit(int nr, volatile unsigned long *addr)
-{
-	unsigned long mask = BIT_MASK(nr);
-	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
-
-	*p  |= mask;
-}
-
-static inline void __clear_bit(int nr, volatile unsigned long *addr)
-{
-	unsigned long mask = BIT_MASK(nr);
-	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
-
-	*p &= ~mask;
-}
-
-/**
- * __change_bit - Toggle a bit in memory
- * @nr: the bit to change
- * @addr: the address to start counting from
- *
- * Unlike change_bit(), this function is non-atomic and may be reordered.
- * If it's called on the same region of memory simultaneously, the effect
- * may be that only one operation succeeds.
- */
-static inline void __change_bit(int nr, volatile unsigned long *addr)
-{
-	unsigned long mask = BIT_MASK(nr);
-	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
-
-	*p ^= mask;
-}
-
-/**
- * __test_and_set_bit - Set a bit and return its old value
- * @nr: Bit to set
- * @addr: Address to count from
- *
- * This operation is non-atomic and can be reordered.
- * If two examples of this operation race, one can appear to succeed
- * but actually fail.  You must protect multiple accesses with a lock.
- */
-static inline int __test_and_set_bit(int nr, volatile unsigned long *addr)
-{
-	unsigned long mask = BIT_MASK(nr);
-	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
-	unsigned long old = *p;
-
-	*p = old | mask;
-	return (old & mask) != 0;
-}
-
-/**
- * __test_and_clear_bit - Clear a bit and return its old value
- * @nr: Bit to clear
- * @addr: Address to count from
- *
- * This operation is non-atomic and can be reordered.
- * If two examples of this operation race, one can appear to succeed
- * but actually fail.  You must protect multiple accesses with a lock.
- */
-static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr)
-{
-	unsigned long mask = BIT_MASK(nr);
-	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
-	unsigned long old = *p;
-
-	*p = old & ~mask;
-	return (old & mask) != 0;
-}
-
-/* WARNING: non atomic and it can be reordered! */
-static inline int __test_and_change_bit(int nr,
-					    volatile unsigned long *addr)
-{
-	unsigned long mask = BIT_MASK(nr);
-	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
-	unsigned long old = *p;
-
-	*p = old ^ mask;
-	return (old & mask) != 0;
-}
-
-/**
- * test_bit - Determine whether a bit is set
- * @nr: bit number to test
- * @addr: Address to start counting from
- */
-static inline int test_bit(int nr, const volatile unsigned long *addr)
-{
-	return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
-}
-
-/**
- * __ffs - find first bit in word.
- * @word: The word to search
- *
- * Undefined if no bit exists, so code should check against 0 first.
- */
-static inline unsigned long __ffs(unsigned long word)
-{
-	int num = 0;
-
-	if ((word & 0xffffffff) == 0) {
-		num += 32;
-		word >>= 32;
-	}
-	if ((word & 0xffff) == 0) {
-		num += 16;
-		word >>= 16;
-	}
-	if ((word & 0xff) == 0) {
-		num += 8;
-		word >>= 8;
-	}
-	if ((word & 0xf) == 0) {
-		num += 4;
-		word >>= 4;
-	}
-	if ((word & 0x3) == 0) {
-		num += 2;
-		word >>= 2;
-	}
-	if ((word & 0x1) == 0)
-		num += 1;
-	return num;
-}
-
-unsigned long find_next_bit(const unsigned long *addr,
-			    unsigned long size,
-			    unsigned long offset);
-
-static inline unsigned long hweight_long(unsigned long w)
-{
-	return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
-}
-
-#endif /* _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ */
diff --git a/tools/testing/radix-tree/linux/bitops/__ffs.h b/tools/testing/radix-tree/linux/bitops/__ffs.h
deleted file mode 100644
index 9a3274aecf839562fef3e10c422615b6dee8e60b..0000000000000000000000000000000000000000
--- a/tools/testing/radix-tree/linux/bitops/__ffs.h
+++ /dev/null
@@ -1,43 +0,0 @@
-#ifndef _ASM_GENERIC_BITOPS___FFS_H_
-#define _ASM_GENERIC_BITOPS___FFS_H_
-
-#include <asm/types.h>
-
-/**
- * __ffs - find first bit in word.
- * @word: The word to search
- *
- * Undefined if no bit exists, so code should check against 0 first.
- */
-static inline unsigned long __ffs(unsigned long word)
-{
-	int num = 0;
-
-#if BITS_PER_LONG == 64
-	if ((word & 0xffffffff) == 0) {
-		num += 32;
-		word >>= 32;
-	}
-#endif
-	if ((word & 0xffff) == 0) {
-		num += 16;
-		word >>= 16;
-	}
-	if ((word & 0xff) == 0) {
-		num += 8;
-		word >>= 8;
-	}
-	if ((word & 0xf) == 0) {
-		num += 4;
-		word >>= 4;
-	}
-	if ((word & 0x3) == 0) {
-		num += 2;
-		word >>= 2;
-	}
-	if ((word & 0x1) == 0)
-		num += 1;
-	return num;
-}
-
-#endif /* _ASM_GENERIC_BITOPS___FFS_H_ */
diff --git a/tools/testing/radix-tree/linux/bitops/ffs.h b/tools/testing/radix-tree/linux/bitops/ffs.h
deleted file mode 100644
index fbbb43af7dc08201e78fb51b56746e6f28b1d3de..0000000000000000000000000000000000000000
--- a/tools/testing/radix-tree/linux/bitops/ffs.h
+++ /dev/null
@@ -1,41 +0,0 @@
-#ifndef _ASM_GENERIC_BITOPS_FFS_H_
-#define _ASM_GENERIC_BITOPS_FFS_H_
-
-/**
- * ffs - find first bit set
- * @x: the word to search
- *
- * This is defined the same way as
- * the libc and compiler builtin ffs routines, therefore
- * differs in spirit from the above ffz (man ffs).
- */
-static inline int ffs(int x)
-{
-	int r = 1;
-
-	if (!x)
-		return 0;
-	if (!(x & 0xffff)) {
-		x >>= 16;
-		r += 16;
-	}
-	if (!(x & 0xff)) {
-		x >>= 8;
-		r += 8;
-	}
-	if (!(x & 0xf)) {
-		x >>= 4;
-		r += 4;
-	}
-	if (!(x & 3)) {
-		x >>= 2;
-		r += 2;
-	}
-	if (!(x & 1)) {
-		x >>= 1;
-		r += 1;
-	}
-	return r;
-}
-
-#endif /* _ASM_GENERIC_BITOPS_FFS_H_ */
diff --git a/tools/testing/radix-tree/linux/bitops/ffz.h b/tools/testing/radix-tree/linux/bitops/ffz.h
deleted file mode 100644
index 6744bd4cdf465733899110a54073e6398cdbc8cc..0000000000000000000000000000000000000000
--- a/tools/testing/radix-tree/linux/bitops/ffz.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _ASM_GENERIC_BITOPS_FFZ_H_
-#define _ASM_GENERIC_BITOPS_FFZ_H_
-
-/*
- * ffz - find first zero in word.
- * @word: The word to search
- *
- * Undefined if no zero exists, so code should check against ~0UL first.
- */
-#define ffz(x)  __ffs(~(x))
-
-#endif /* _ASM_GENERIC_BITOPS_FFZ_H_ */
diff --git a/tools/testing/radix-tree/linux/bitops/find.h b/tools/testing/radix-tree/linux/bitops/find.h
deleted file mode 100644
index 72a51e5a12ef1b3738f25249eeed3417745788c1..0000000000000000000000000000000000000000
--- a/tools/testing/radix-tree/linux/bitops/find.h
+++ /dev/null
@@ -1,13 +0,0 @@
-#ifndef _ASM_GENERIC_BITOPS_FIND_H_
-#define _ASM_GENERIC_BITOPS_FIND_H_
-
-extern unsigned long find_next_bit(const unsigned long *addr, unsigned long
-		size, unsigned long offset);
-
-extern unsigned long find_next_zero_bit(const unsigned long *addr, unsigned
-		long size, unsigned long offset);
-
-#define find_first_bit(addr, size) find_next_bit((addr), (size), 0)
-#define find_first_zero_bit(addr, size) find_next_zero_bit((addr), (size), 0)
-
-#endif /*_ASM_GENERIC_BITOPS_FIND_H_ */
diff --git a/tools/testing/radix-tree/linux/bitops/fls.h b/tools/testing/radix-tree/linux/bitops/fls.h
deleted file mode 100644
index 850859bc5069a0a772a8772ffbed1571976762b2..0000000000000000000000000000000000000000
--- a/tools/testing/radix-tree/linux/bitops/fls.h
+++ /dev/null
@@ -1,41 +0,0 @@
-#ifndef _ASM_GENERIC_BITOPS_FLS_H_
-#define _ASM_GENERIC_BITOPS_FLS_H_
-
-/**
- * fls - find last (most-significant) bit set
- * @x: the word to search
- *
- * This is defined the same way as ffs.
- * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
- */
-
-static inline int fls(int x)
-{
-	int r = 32;
-
-	if (!x)
-		return 0;
-	if (!(x & 0xffff0000u)) {
-		x <<= 16;
-		r -= 16;
-	}
-	if (!(x & 0xff000000u)) {
-		x <<= 8;
-		r -= 8;
-	}
-	if (!(x & 0xf0000000u)) {
-		x <<= 4;
-		r -= 4;
-	}
-	if (!(x & 0xc0000000u)) {
-		x <<= 2;
-		r -= 2;
-	}
-	if (!(x & 0x80000000u)) {
-		x <<= 1;
-		r -= 1;
-	}
-	return r;
-}
-
-#endif /* _ASM_GENERIC_BITOPS_FLS_H_ */
diff --git a/tools/testing/radix-tree/linux/bitops/fls64.h b/tools/testing/radix-tree/linux/bitops/fls64.h
deleted file mode 100644
index 1b6b17ce2428091e605c8cbda7103b1d42836780..0000000000000000000000000000000000000000
--- a/tools/testing/radix-tree/linux/bitops/fls64.h
+++ /dev/null
@@ -1,14 +0,0 @@
-#ifndef _ASM_GENERIC_BITOPS_FLS64_H_
-#define _ASM_GENERIC_BITOPS_FLS64_H_
-
-#include <asm/types.h>
-
-static inline int fls64(__u64 x)
-{
-	__u32 h = x >> 32;
-	if (h)
-		return fls(h) + 32;
-	return fls(x);
-}
-
-#endif /* _ASM_GENERIC_BITOPS_FLS64_H_ */
diff --git a/tools/testing/radix-tree/linux/bitops/hweight.h b/tools/testing/radix-tree/linux/bitops/hweight.h
deleted file mode 100644
index fbbc383771dae56660cf8ea6ba3c57f21b0a1b9e..0000000000000000000000000000000000000000
--- a/tools/testing/radix-tree/linux/bitops/hweight.h
+++ /dev/null
@@ -1,11 +0,0 @@
-#ifndef _ASM_GENERIC_BITOPS_HWEIGHT_H_
-#define _ASM_GENERIC_BITOPS_HWEIGHT_H_
-
-#include <asm/types.h>
-
-extern unsigned int hweight32(unsigned int w);
-extern unsigned int hweight16(unsigned int w);
-extern unsigned int hweight8(unsigned int w);
-extern unsigned long hweight64(__u64 w);
-
-#endif /* _ASM_GENERIC_BITOPS_HWEIGHT_H_ */
diff --git a/tools/testing/radix-tree/linux/bitops/le.h b/tools/testing/radix-tree/linux/bitops/le.h
deleted file mode 100644
index b9c7e5d2d2ad67631e4318665fe900ac36634097..0000000000000000000000000000000000000000
--- a/tools/testing/radix-tree/linux/bitops/le.h
+++ /dev/null
@@ -1,53 +0,0 @@
-#ifndef _ASM_GENERIC_BITOPS_LE_H_
-#define _ASM_GENERIC_BITOPS_LE_H_
-
-#include <asm/types.h>
-#include <asm/byteorder.h>
-
-#define BITOP_WORD(nr)		((nr) / BITS_PER_LONG)
-#define BITOP_LE_SWIZZLE	((BITS_PER_LONG-1) & ~0x7)
-
-#if defined(__LITTLE_ENDIAN)
-
-#define generic_test_le_bit(nr, addr) test_bit(nr, addr)
-#define generic___set_le_bit(nr, addr) __set_bit(nr, addr)
-#define generic___clear_le_bit(nr, addr) __clear_bit(nr, addr)
-
-#define generic_test_and_set_le_bit(nr, addr) test_and_set_bit(nr, addr)
-#define generic_test_and_clear_le_bit(nr, addr) test_and_clear_bit(nr, addr)
-
-#define generic___test_and_set_le_bit(nr, addr) __test_and_set_bit(nr, addr)
-#define generic___test_and_clear_le_bit(nr, addr) __test_and_clear_bit(nr, addr)
-
-#define generic_find_next_zero_le_bit(addr, size, offset) find_next_zero_bit(addr, size, offset)
-
-#elif defined(__BIG_ENDIAN)
-
-#define generic_test_le_bit(nr, addr) \
-	test_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
-#define generic___set_le_bit(nr, addr) \
-	__set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
-#define generic___clear_le_bit(nr, addr) \
-	__clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
-
-#define generic_test_and_set_le_bit(nr, addr) \
-	test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
-#define generic_test_and_clear_le_bit(nr, addr) \
-	test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
-
-#define generic___test_and_set_le_bit(nr, addr) \
-	__test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
-#define generic___test_and_clear_le_bit(nr, addr) \
-	__test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
-
-extern unsigned long generic_find_next_zero_le_bit(const unsigned long *addr,
-		unsigned long size, unsigned long offset);
-
-#else
-#error "Please fix <asm/byteorder.h>"
-#endif
-
-#define generic_find_first_zero_le_bit(addr, size) \
-        generic_find_next_zero_le_bit((addr), (size), 0)
-
-#endif /* _ASM_GENERIC_BITOPS_LE_H_ */
diff --git a/tools/testing/radix-tree/linux/bitops/non-atomic.h b/tools/testing/radix-tree/linux/bitops/non-atomic.h
deleted file mode 100644
index 6a1bcb9d2c4a13c6007a1922c4623d0dfb6c6bf2..0000000000000000000000000000000000000000
--- a/tools/testing/radix-tree/linux/bitops/non-atomic.h
+++ /dev/null
@@ -1,110 +0,0 @@
-#ifndef _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
-#define _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
-
-#include <asm/types.h>
-
-#define BITOP_WORD(nr)		((nr) / BITS_PER_LONG)
-
-/**
- * __set_bit - Set a bit in memory
- * @nr: the bit to set
- * @addr: the address to start counting from
- *
- * Unlike set_bit(), this function is non-atomic and may be reordered.
- * If it's called on the same region of memory simultaneously, the effect
- * may be that only one operation succeeds.
- */
-static inline void __set_bit(int nr, volatile unsigned long *addr)
-{
-	unsigned long mask = BIT_MASK(nr);
-	unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
-
-	*p  |= mask;
-}
-
-static inline void __clear_bit(int nr, volatile unsigned long *addr)
-{
-	unsigned long mask = BIT_MASK(nr);
-	unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
-
-	*p &= ~mask;
-}
-
-/**
- * __change_bit - Toggle a bit in memory
- * @nr: the bit to change
- * @addr: the address to start counting from
- *
- * Unlike change_bit(), this function is non-atomic and may be reordered.
- * If it's called on the same region of memory simultaneously, the effect
- * may be that only one operation succeeds.
- */
-static inline void __change_bit(int nr, volatile unsigned long *addr)
-{
-	unsigned long mask = BIT_MASK(nr);
-	unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
-
-	*p ^= mask;
-}
-
-/**
- * __test_and_set_bit - Set a bit and return its old value
- * @nr: Bit to set
- * @addr: Address to count from
- *
- * This operation is non-atomic and can be reordered.
- * If two examples of this operation race, one can appear to succeed
- * but actually fail.  You must protect multiple accesses with a lock.
- */
-static inline int __test_and_set_bit(int nr, volatile unsigned long *addr)
-{
-	unsigned long mask = BIT_MASK(nr);
-	unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
-	unsigned long old = *p;
-
-	*p = old | mask;
-	return (old & mask) != 0;
-}
-
-/**
- * __test_and_clear_bit - Clear a bit and return its old value
- * @nr: Bit to clear
- * @addr: Address to count from
- *
- * This operation is non-atomic and can be reordered.
- * If two examples of this operation race, one can appear to succeed
- * but actually fail.  You must protect multiple accesses with a lock.
- */
-static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr)
-{
-	unsigned long mask = BIT_MASK(nr);
-	unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
-	unsigned long old = *p;
-
-	*p = old & ~mask;
-	return (old & mask) != 0;
-}
-
-/* WARNING: non atomic and it can be reordered! */
-static inline int __test_and_change_bit(int nr,
-					    volatile unsigned long *addr)
-{
-	unsigned long mask = BIT_MASK(nr);
-	unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
-	unsigned long old = *p;
-
-	*p = old ^ mask;
-	return (old & mask) != 0;
-}
-
-/**
- * test_bit - Determine whether a bit is set
- * @nr: bit number to test
- * @addr: Address to start counting from
- */
-static inline int test_bit(int nr, const volatile unsigned long *addr)
-{
-	return 1UL & (addr[BITOP_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
-}
-
-#endif /* _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ */
diff --git a/tools/testing/radix-tree/linux/export.h b/tools/testing/radix-tree/linux/export.h
deleted file mode 100644
index b6afd131998d45d7c05cfff4c612af3d56a82116..0000000000000000000000000000000000000000
--- a/tools/testing/radix-tree/linux/export.h
+++ /dev/null
@@ -1,2 +0,0 @@
-
-#define EXPORT_SYMBOL(sym)
diff --git a/tools/testing/radix-tree/linux/gfp.h b/tools/testing/radix-tree/linux/gfp.h
index 5b09b2ce6c33ad0e732a70e65347258e00f5a741..39a0dcb9475a3c4e261db2b195b7691d0b39c491 100644
--- a/tools/testing/radix-tree/linux/gfp.h
+++ b/tools/testing/radix-tree/linux/gfp.h
@@ -1,6 +1,8 @@
 #ifndef _GFP_H
 #define _GFP_H
 
+#include <linux/types.h>
+
 #define __GFP_BITS_SHIFT 26
 #define __GFP_BITS_MASK ((gfp_t)((1 << __GFP_BITS_SHIFT) - 1))
 
@@ -13,10 +15,12 @@
 #define __GFP_DIRECT_RECLAIM	0x400000u
 #define __GFP_KSWAPD_RECLAIM	0x2000000u
 
-#define __GFP_RECLAIM		(__GFP_DIRECT_RECLAIM|__GFP_KSWAPD_RECLAIM)
+#define __GFP_RECLAIM	(__GFP_DIRECT_RECLAIM|__GFP_KSWAPD_RECLAIM)
+
+#define GFP_ATOMIC	(__GFP_HIGH|__GFP_ATOMIC|__GFP_KSWAPD_RECLAIM)
+#define GFP_KERNEL	(__GFP_RECLAIM | __GFP_IO | __GFP_FS)
+#define GFP_NOWAIT	(__GFP_KSWAPD_RECLAIM)
 
-#define GFP_ATOMIC		(__GFP_HIGH|__GFP_ATOMIC|__GFP_KSWAPD_RECLAIM)
-#define GFP_KERNEL		(__GFP_RECLAIM | __GFP_IO | __GFP_FS)
 
 static inline bool gfpflags_allow_blocking(const gfp_t gfp_flags)
 {
diff --git a/tools/testing/radix-tree/linux/idr.h b/tools/testing/radix-tree/linux/idr.h
new file mode 100644
index 0000000000000000000000000000000000000000..4e342f2e37cfb838a0a30c16b143364c57d828a2
--- /dev/null
+++ b/tools/testing/radix-tree/linux/idr.h
@@ -0,0 +1 @@
+#include "../../../../include/linux/idr.h"
diff --git a/tools/testing/radix-tree/linux/init.h b/tools/testing/radix-tree/linux/init.h
index 360cabb3c4e7631e5c4f4cdd14747e776e132fd9..1bb0afc213099feb547052670d820eb9842e649b 100644
--- a/tools/testing/radix-tree/linux/init.h
+++ b/tools/testing/radix-tree/linux/init.h
@@ -1 +1 @@
-/* An empty file stub that allows radix-tree.c to compile. */
+#define __init
diff --git a/tools/testing/radix-tree/linux/kernel.h b/tools/testing/radix-tree/linux/kernel.h
index 9b43b4975d832b8c1b682fd5ef0ac0f4d5b5cf6d..b21a77fddcf7357cf4b9cffc7f1746e0e2053d05 100644
--- a/tools/testing/radix-tree/linux/kernel.h
+++ b/tools/testing/radix-tree/linux/kernel.h
@@ -1,64 +1,21 @@
 #ifndef _KERNEL_H
 #define _KERNEL_H
 
-#include <assert.h>
+#include "../../include/linux/kernel.h"
 #include <string.h>
 #include <stdio.h>
-#include <stddef.h>
 #include <limits.h>
 
-#include "../../include/linux/compiler.h"
-#include "../../include/linux/err.h"
+#include <linux/compiler.h>
+#include <linux/err.h>
+#include <linux/bitops.h>
+#include <linux/log2.h>
 #include "../../../include/linux/kconfig.h"
 
-#ifdef BENCHMARK
-#define RADIX_TREE_MAP_SHIFT	6
-#else
-#define RADIX_TREE_MAP_SHIFT	3
-#endif
-
-#ifndef NULL
-#define NULL	0
-#endif
-
-#define BUG_ON(expr)	assert(!(expr))
-#define WARN_ON(expr)	assert(!(expr))
-#define __init
-#define __must_check
-#define panic(expr)
 #define printk printf
-#define __force
-#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
 #define pr_debug printk
-
-#define smp_rmb()	barrier()
-#define smp_wmb()	barrier()
-#define cpu_relax()	barrier()
+#define pr_cont printk
 
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
 
-#define container_of(ptr, type, member) ({                      \
-	const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
-	(type *)( (char *)__mptr - offsetof(type, member) );})
-#define min(a, b) ((a) < (b) ? (a) : (b))
-
-#define cond_resched()	sched_yield()
-
-static inline int in_interrupt(void)
-{
-	return 0;
-}
-
-/*
- * This looks more complex than it should be. But we need to
- * get the type for the ~ right in round_down (it needs to be
- * as wide as the result!), and we want to evaluate the macro
- * arguments just once each.
- */
-#define __round_mask(x, y) ((__typeof__(x))((y)-1))
-#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
-#define round_down(x, y) ((x) & ~__round_mask(x, y))
-
-#define xchg(ptr, x)	uatomic_xchg(ptr, x)
-
 #endif /* _KERNEL_H */
diff --git a/tools/testing/radix-tree/linux/mempool.h b/tools/testing/radix-tree/linux/mempool.h
deleted file mode 100644
index 6a2dc55b41d636ca08aacdf9546fe9e757dd787b..0000000000000000000000000000000000000000
--- a/tools/testing/radix-tree/linux/mempool.h
+++ /dev/null
@@ -1,16 +0,0 @@
-
-#include <linux/slab.h>
-
-typedef void *(mempool_alloc_t)(int gfp_mask, void *pool_data);
-typedef void (mempool_free_t)(void *element, void *pool_data);
-
-typedef struct {
-	mempool_alloc_t *alloc;
-	mempool_free_t *free;
-	void *data;
-} mempool_t;
-
-void *mempool_alloc(mempool_t *pool, int gfp_mask);
-void mempool_free(void *element, mempool_t *pool);
-mempool_t *mempool_create(int min_nr, mempool_alloc_t *alloc_fn,
-			mempool_free_t *free_fn, void *pool_data);
diff --git a/tools/testing/radix-tree/linux/percpu.h b/tools/testing/radix-tree/linux/percpu.h
index 5837f1d56f1788c7b113d9ffc89fe32a545c3317..3ea01a1a88c2b2adcbb475ca3f609586c2758831 100644
--- a/tools/testing/radix-tree/linux/percpu.h
+++ b/tools/testing/radix-tree/linux/percpu.h
@@ -1,7 +1,10 @@
-
+#define DECLARE_PER_CPU(type, val) extern type val
 #define DEFINE_PER_CPU(type, val) type val
 
 #define __get_cpu_var(var)	var
 #define this_cpu_ptr(var)	var
+#define this_cpu_read(var)	var
+#define this_cpu_xchg(var, val)		uatomic_xchg(&var, val)
+#define this_cpu_cmpxchg(var, old, new)	uatomic_cmpxchg(&var, old, new)
 #define per_cpu_ptr(ptr, cpu)   ({ (void)(cpu); (ptr); })
 #define per_cpu(var, cpu)	(*per_cpu_ptr(&(var), cpu))
diff --git a/tools/testing/radix-tree/linux/preempt.h b/tools/testing/radix-tree/linux/preempt.h
index 65c04c226965d9a0816f889103f42a24957f3fc8..35c5ac81529fa9d9f6c0ab526db47d793dd209f3 100644
--- a/tools/testing/radix-tree/linux/preempt.h
+++ b/tools/testing/radix-tree/linux/preempt.h
@@ -1,4 +1,14 @@
+#ifndef __LINUX_PREEMPT_H
+#define __LINUX_PREEMPT_H
+
 extern int preempt_count;
 
 #define preempt_disable()	uatomic_inc(&preempt_count)
 #define preempt_enable()	uatomic_dec(&preempt_count)
+
+static inline int in_interrupt(void)
+{
+	return 0;
+}
+
+#endif /* __LINUX_PREEMPT_H */
diff --git a/tools/testing/radix-tree/linux/radix-tree.h b/tools/testing/radix-tree/linux/radix-tree.h
index ce694ddd4aea7d42b0d0c88d6807a244678c150b..bf1bb231f9b5cd98a4c0451eaf1eb8744ee89cf5 100644
--- a/tools/testing/radix-tree/linux/radix-tree.h
+++ b/tools/testing/radix-tree/linux/radix-tree.h
@@ -1 +1,26 @@
+#ifndef _TEST_RADIX_TREE_H
+#define _TEST_RADIX_TREE_H
+
+#include "generated/map-shift.h"
 #include "../../../../include/linux/radix-tree.h"
+
+extern int kmalloc_verbose;
+extern int test_verbose;
+
+static inline void trace_call_rcu(struct rcu_head *head,
+		void (*func)(struct rcu_head *head))
+{
+	if (kmalloc_verbose)
+		printf("Delaying free of %p to slab\n", (char *)head -
+				offsetof(struct radix_tree_node, rcu_head));
+	call_rcu(head, func);
+}
+
+#define printv(verbosity_level, fmt, ...) \
+	if(test_verbose >= verbosity_level) \
+		printf(fmt, ##__VA_ARGS__)
+
+#undef call_rcu
+#define call_rcu(x, y) trace_call_rcu(x, y)
+
+#endif /* _TEST_RADIX_TREE_H */
diff --git a/tools/testing/radix-tree/linux/types.h b/tools/testing/radix-tree/linux/types.h
deleted file mode 100644
index 8491d89873bb03005a0a4dde1a8cf531b9a63c25..0000000000000000000000000000000000000000
--- a/tools/testing/radix-tree/linux/types.h
+++ /dev/null
@@ -1,23 +0,0 @@
-#ifndef _TYPES_H
-#define _TYPES_H
-
-#include "../../include/linux/types.h"
-
-#define __rcu
-#define __read_mostly
-
-static inline void INIT_LIST_HEAD(struct list_head *list)
-{
-	list->next = list;
-	list->prev = list;
-}
-
-typedef struct {
-	unsigned int x;
-} spinlock_t;
-
-#define uninitialized_var(x) x = x
-
-#include <linux/gfp.h>
-
-#endif
diff --git a/tools/testing/radix-tree/main.c b/tools/testing/radix-tree/main.c
index f7e9801a6754f884fe86ff932e9a38ab29b18747..b829127d56705747a0a74c73e8b11b8cae8ecc27 100644
--- a/tools/testing/radix-tree/main.c
+++ b/tools/testing/radix-tree/main.c
@@ -3,6 +3,7 @@
 #include <unistd.h>
 #include <time.h>
 #include <assert.h>
+#include <limits.h>
 
 #include <linux/slab.h>
 #include <linux/radix-tree.h>
@@ -67,7 +68,7 @@ void big_gang_check(bool long_run)
 
 	for (i = 0; i < (long_run ? 1000 : 3); i++) {
 		__big_gang_check();
-		printf("%d ", i);
+		printv(2, "%d ", i);
 		fflush(stdout);
 	}
 }
@@ -128,14 +129,19 @@ void check_copied_tags(struct radix_tree_root *tree, unsigned long start, unsign
 			putchar('.'); */
 		if (idx[i] < start || idx[i] > end) {
 			if (item_tag_get(tree, idx[i], totag)) {
-				printf("%lu-%lu: %lu, tags %d-%d\n", start, end, idx[i], item_tag_get(tree, idx[i], fromtag), item_tag_get(tree, idx[i], totag));
+				printv(2, "%lu-%lu: %lu, tags %d-%d\n", start,
+				       end, idx[i], item_tag_get(tree, idx[i],
+								 fromtag),
+				       item_tag_get(tree, idx[i], totag));
 			}
 			assert(!item_tag_get(tree, idx[i], totag));
 			continue;
 		}
 		if (item_tag_get(tree, idx[i], fromtag) ^
 			item_tag_get(tree, idx[i], totag)) {
-			printf("%lu-%lu: %lu, tags %d-%d\n", start, end, idx[i], item_tag_get(tree, idx[i], fromtag), item_tag_get(tree, idx[i], totag));
+			printv(2, "%lu-%lu: %lu, tags %d-%d\n", start, end,
+			       idx[i], item_tag_get(tree, idx[i], fromtag),
+			       item_tag_get(tree, idx[i], totag));
 		}
 		assert(!(item_tag_get(tree, idx[i], fromtag) ^
 			 item_tag_get(tree, idx[i], totag)));
@@ -237,7 +243,7 @@ static void __locate_check(struct radix_tree_root *tree, unsigned long index,
 	item = item_lookup(tree, index);
 	index2 = find_item(tree, item);
 	if (index != index2) {
-		printf("index %ld order %d inserted; found %ld\n",
+		printv(2, "index %ld order %d inserted; found %ld\n",
 			index, order, index2);
 		abort();
 	}
@@ -288,43 +294,48 @@ static void single_thread_tests(bool long_run)
 {
 	int i;
 
-	printf("starting single_thread_tests: %d allocated, preempt %d\n",
+	printv(1, "starting single_thread_tests: %d allocated, preempt %d\n",
 		nr_allocated, preempt_count);
 	multiorder_checks();
 	rcu_barrier();
-	printf("after multiorder_check: %d allocated, preempt %d\n",
+	printv(2, "after multiorder_check: %d allocated, preempt %d\n",
 		nr_allocated, preempt_count);
 	locate_check();
 	rcu_barrier();
-	printf("after locate_check: %d allocated, preempt %d\n",
+	printv(2, "after locate_check: %d allocated, preempt %d\n",
 		nr_allocated, preempt_count);
 	tag_check();
 	rcu_barrier();
-	printf("after tag_check: %d allocated, preempt %d\n",
+	printv(2, "after tag_check: %d allocated, preempt %d\n",
 		nr_allocated, preempt_count);
 	gang_check();
 	rcu_barrier();
-	printf("after gang_check: %d allocated, preempt %d\n",
+	printv(2, "after gang_check: %d allocated, preempt %d\n",
 		nr_allocated, preempt_count);
 	add_and_check();
 	rcu_barrier();
-	printf("after add_and_check: %d allocated, preempt %d\n",
+	printv(2, "after add_and_check: %d allocated, preempt %d\n",
 		nr_allocated, preempt_count);
 	dynamic_height_check();
 	rcu_barrier();
-	printf("after dynamic_height_check: %d allocated, preempt %d\n",
+	printv(2, "after dynamic_height_check: %d allocated, preempt %d\n",
+		nr_allocated, preempt_count);
+	idr_checks();
+	ida_checks();
+	rcu_barrier();
+	printv(2, "after idr_checks: %d allocated, preempt %d\n",
 		nr_allocated, preempt_count);
 	big_gang_check(long_run);
 	rcu_barrier();
-	printf("after big_gang_check: %d allocated, preempt %d\n",
+	printv(2, "after big_gang_check: %d allocated, preempt %d\n",
 		nr_allocated, preempt_count);
 	for (i = 0; i < (long_run ? 2000 : 3); i++) {
 		copy_tag_check();
-		printf("%d ", i);
+		printv(2, "%d ", i);
 		fflush(stdout);
 	}
 	rcu_barrier();
-	printf("after copy_tag_check: %d allocated, preempt %d\n",
+	printv(2, "after copy_tag_check: %d allocated, preempt %d\n",
 		nr_allocated, preempt_count);
 }
 
@@ -334,24 +345,28 @@ int main(int argc, char **argv)
 	int opt;
 	unsigned int seed = time(NULL);
 
-	while ((opt = getopt(argc, argv, "ls:")) != -1) {
+	while ((opt = getopt(argc, argv, "ls:v")) != -1) {
 		if (opt == 'l')
 			long_run = true;
 		else if (opt == 's')
 			seed = strtoul(optarg, NULL, 0);
+		else if (opt == 'v')
+			test_verbose++;
 	}
 
 	printf("random seed %u\n", seed);
 	srand(seed);
 
+	printf("running tests\n");
+
 	rcu_register_thread();
 	radix_tree_init();
 
 	regression1_test();
 	regression2_test();
 	regression3_test();
-	iteration_test(0, 10);
-	iteration_test(7, 20);
+	iteration_test(0, 10 + 90 * long_run);
+	iteration_test(7, 10 + 90 * long_run);
 	single_thread_tests(long_run);
 
 	/* Free any remaining preallocated nodes */
@@ -360,9 +375,11 @@ int main(int argc, char **argv)
 	benchmark();
 
 	rcu_barrier();
-	printf("after rcu_barrier: %d allocated, preempt %d\n",
+	printv(2, "after rcu_barrier: %d allocated, preempt %d\n",
 		nr_allocated, preempt_count);
 	rcu_unregister_thread();
 
+	printf("tests completed\n");
+
 	exit(0);
 }
diff --git a/tools/testing/radix-tree/multiorder.c b/tools/testing/radix-tree/multiorder.c
index f79812a5e0708b9146c2dcb479d804637262b1b8..06c71178d07d98ab03bbf1575a3d98fa5299f7b1 100644
--- a/tools/testing/radix-tree/multiorder.c
+++ b/tools/testing/radix-tree/multiorder.c
@@ -30,7 +30,7 @@ static void __multiorder_tag_test(int index, int order)
 	/* our canonical entry */
 	base = index & ~((1 << order) - 1);
 
-	printf("Multiorder tag test with index %d, canonical entry %d\n",
+	printv(2, "Multiorder tag test with index %d, canonical entry %d\n",
 			index, base);
 
 	err = item_insert_order(&tree, index, order);
@@ -150,7 +150,7 @@ static void multiorder_check(unsigned long index, int order)
 	struct item *item2 = item_create(min, order);
 	RADIX_TREE(tree, GFP_KERNEL);
 
-	printf("Multiorder index %ld, order %d\n", index, order);
+	printv(2, "Multiorder index %ld, order %d\n", index, order);
 
 	assert(item_insert_order(&tree, index, order) == 0);
 
@@ -188,7 +188,7 @@ static void multiorder_shrink(unsigned long index, int order)
 	RADIX_TREE(tree, GFP_KERNEL);
 	struct radix_tree_node *node;
 
-	printf("Multiorder shrink index %ld, order %d\n", index, order);
+	printv(2, "Multiorder shrink index %ld, order %d\n", index, order);
 
 	assert(item_insert_order(&tree, 0, order) == 0);
 
@@ -209,7 +209,8 @@ static void multiorder_shrink(unsigned long index, int order)
 		item_check_absent(&tree, i);
 
 	if (!item_delete(&tree, 0)) {
-		printf("failed to delete index %ld (order %d)\n", index, order);		abort();
+		printv(2, "failed to delete index %ld (order %d)\n", index, order);
+		abort();
 	}
 
 	for (i = 0; i < 2*max; i++)
@@ -234,7 +235,7 @@ void multiorder_iteration(void)
 	void **slot;
 	int i, j, err;
 
-	printf("Multiorder iteration test\n");
+	printv(1, "Multiorder iteration test\n");
 
 #define NUM_ENTRIES 11
 	int index[NUM_ENTRIES] = {0, 2, 4, 8, 16, 32, 34, 36, 64, 72, 128};
@@ -275,7 +276,7 @@ void multiorder_tagged_iteration(void)
 	void **slot;
 	int i, j;
 
-	printf("Multiorder tagged iteration test\n");
+	printv(1, "Multiorder tagged iteration test\n");
 
 #define MT_NUM_ENTRIES 9
 	int index[MT_NUM_ENTRIES] = {0, 2, 4, 16, 32, 40, 64, 72, 128};
@@ -355,6 +356,10 @@ void multiorder_tagged_iteration(void)
 	item_kill_tree(&tree);
 }
 
+/*
+ * Basic join checks: make sure we can't find an entry in the tree after
+ * a larger entry has replaced it
+ */
 static void multiorder_join1(unsigned long index,
 				unsigned order1, unsigned order2)
 {
@@ -373,6 +378,10 @@ static void multiorder_join1(unsigned long index,
 	item_kill_tree(&tree);
 }
 
+/*
+ * Check that the accounting of exceptional entries is handled correctly
+ * by joining an exceptional entry to a normal pointer.
+ */
 static void multiorder_join2(unsigned order1, unsigned order2)
 {
 	RADIX_TREE(tree, GFP_KERNEL);
@@ -386,6 +395,9 @@ static void multiorder_join2(unsigned order1, unsigned order2)
 	assert(item2 == (void *)0x12UL);
 	assert(node->exceptional == 1);
 
+	item2 = radix_tree_lookup(&tree, 0);
+	free(item2);
+
 	radix_tree_join(&tree, 0, order1, item1);
 	item2 = __radix_tree_lookup(&tree, 1 << order2, &node, NULL);
 	assert(item2 == item1);
@@ -453,7 +465,7 @@ static void check_mem(unsigned old_order, unsigned new_order, unsigned alloc)
 {
 	struct radix_tree_preload *rtp = &radix_tree_preloads;
 	if (rtp->nr != 0)
-		printf("split(%u %u) remaining %u\n", old_order, new_order,
+		printv(2, "split(%u %u) remaining %u\n", old_order, new_order,
 							rtp->nr);
 	/*
 	 * Can't check for equality here as some nodes may have been
@@ -461,7 +473,7 @@ static void check_mem(unsigned old_order, unsigned new_order, unsigned alloc)
 	 * nodes allocated since they should have all been preloaded.
 	 */
 	if (nr_allocated > alloc)
-		printf("split(%u %u) allocated %u %u\n", old_order, new_order,
+		printv(2, "split(%u %u) allocated %u %u\n", old_order, new_order,
 							alloc, nr_allocated);
 }
 
@@ -471,6 +483,7 @@ static void __multiorder_split(int old_order, int new_order)
 	void **slot;
 	struct radix_tree_iter iter;
 	unsigned alloc;
+	struct item *item;
 
 	radix_tree_preload(GFP_KERNEL);
 	assert(item_insert_order(&tree, 0, old_order) == 0);
@@ -479,7 +492,7 @@ static void __multiorder_split(int old_order, int new_order)
 	/* Wipe out the preloaded cache or it'll confuse check_mem() */
 	radix_tree_cpu_dead(0);
 
-	radix_tree_tag_set(&tree, 0, 2);
+	item = radix_tree_tag_set(&tree, 0, 2);
 
 	radix_tree_split_preload(old_order, new_order, GFP_KERNEL);
 	alloc = nr_allocated;
@@ -492,6 +505,7 @@ static void __multiorder_split(int old_order, int new_order)
 	radix_tree_preload_end();
 
 	item_kill_tree(&tree);
+	free(item);
 }
 
 static void __multiorder_split2(int old_order, int new_order)
@@ -633,3 +647,10 @@ void multiorder_checks(void)
 
 	radix_tree_cpu_dead(0);
 }
+
+int __weak main(void)
+{
+	radix_tree_init();
+	multiorder_checks();
+	return 0;
+}
diff --git a/tools/testing/radix-tree/regression1.c b/tools/testing/radix-tree/regression1.c
index 0d6813a61b37f904b436e74448c910a350c10bb3..bf97742fc18c1cc62e923acc448a5db64b5578fb 100644
--- a/tools/testing/radix-tree/regression1.c
+++ b/tools/testing/radix-tree/regression1.c
@@ -193,7 +193,7 @@ void regression1_test(void)
 	long arg;
 
 	/* Regression #1 */
-	printf("running regression test 1, should finish in under a minute\n");
+	printv(1, "running regression test 1, should finish in under a minute\n");
 	nr_threads = 2;
 	pthread_barrier_init(&worker_barrier, NULL, nr_threads);
 
@@ -216,5 +216,5 @@ void regression1_test(void)
 
 	free(threads);
 
-	printf("regression test 1, done\n");
+	printv(1, "regression test 1, done\n");
 }
diff --git a/tools/testing/radix-tree/regression2.c b/tools/testing/radix-tree/regression2.c
index a41325d7a170eff26cca5f789f718492209eb1d5..42dd2a33ed249080560d18ad99585553da843a29 100644
--- a/tools/testing/radix-tree/regression2.c
+++ b/tools/testing/radix-tree/regression2.c
@@ -80,7 +80,7 @@ void regression2_test(void)
 	unsigned long int start, end;
 	struct page *pages[1];
 
-	printf("running regression test 2 (should take milliseconds)\n");
+	printv(1, "running regression test 2 (should take milliseconds)\n");
 	/* 0. */
 	for (i = 0; i <= max_slots - 1; i++) {
 		p = page_alloc();
@@ -103,7 +103,7 @@ void regression2_test(void)
 
 	/* 4. */
 	for (i = max_slots - 1; i >= 0; i--)
-		radix_tree_delete(&mt_tree, i);
+		free(radix_tree_delete(&mt_tree, i));
 
 	/* 5. */
 	// NOTE: start should not be 0 because radix_tree_gang_lookup_tag_slot
@@ -114,7 +114,9 @@ void regression2_test(void)
 		PAGECACHE_TAG_TOWRITE);
 
 	/* We remove all the remained nodes */
-	radix_tree_delete(&mt_tree, max_slots);
+	free(radix_tree_delete(&mt_tree, max_slots));
 
-	printf("regression test 2, done\n");
+	BUG_ON(!radix_tree_empty(&mt_tree));
+
+	printv(1, "regression test 2, done\n");
 }
diff --git a/tools/testing/radix-tree/regression3.c b/tools/testing/radix-tree/regression3.c
index b594841fae8594c52a530b39cca7c2bdc772fb20..670c3d2ae7b189f9405d1ac536013a32ba9db188 100644
--- a/tools/testing/radix-tree/regression3.c
+++ b/tools/testing/radix-tree/regression3.c
@@ -34,21 +34,21 @@ void regression3_test(void)
 	void **slot;
 	bool first;
 
-	printf("running regression test 3 (should take milliseconds)\n");
+	printv(1, "running regression test 3 (should take milliseconds)\n");
 
 	radix_tree_insert(&root, 0, ptr0);
 	radix_tree_tag_set(&root, 0, 0);
 
 	first = true;
 	radix_tree_for_each_tagged(slot, &root, &iter, 0, 0) {
-		printf("tagged %ld %p\n", iter.index, *slot);
+		printv(2, "tagged %ld %p\n", iter.index, *slot);
 		if (first) {
 			radix_tree_insert(&root, 1, ptr);
 			radix_tree_tag_set(&root, 1, 0);
 			first = false;
 		}
 		if (radix_tree_deref_retry(*slot)) {
-			printf("retry at %ld\n", iter.index);
+			printv(2, "retry at %ld\n", iter.index);
 			slot = radix_tree_iter_retry(&iter);
 			continue;
 		}
@@ -57,13 +57,13 @@ void regression3_test(void)
 
 	first = true;
 	radix_tree_for_each_slot(slot, &root, &iter, 0) {
-		printf("slot %ld %p\n", iter.index, *slot);
+		printv(2, "slot %ld %p\n", iter.index, *slot);
 		if (first) {
 			radix_tree_insert(&root, 1, ptr);
 			first = false;
 		}
 		if (radix_tree_deref_retry(*slot)) {
-			printk("retry at %ld\n", iter.index);
+			printv(2, "retry at %ld\n", iter.index);
 			slot = radix_tree_iter_retry(&iter);
 			continue;
 		}
@@ -72,30 +72,30 @@ void regression3_test(void)
 
 	first = true;
 	radix_tree_for_each_contig(slot, &root, &iter, 0) {
-		printk("contig %ld %p\n", iter.index, *slot);
+		printv(2, "contig %ld %p\n", iter.index, *slot);
 		if (first) {
 			radix_tree_insert(&root, 1, ptr);
 			first = false;
 		}
 		if (radix_tree_deref_retry(*slot)) {
-			printk("retry at %ld\n", iter.index);
+			printv(2, "retry at %ld\n", iter.index);
 			slot = radix_tree_iter_retry(&iter);
 			continue;
 		}
 	}
 
 	radix_tree_for_each_slot(slot, &root, &iter, 0) {
-		printf("slot %ld %p\n", iter.index, *slot);
+		printv(2, "slot %ld %p\n", iter.index, *slot);
 		if (!iter.index) {
-			printf("next at %ld\n", iter.index);
+			printv(2, "next at %ld\n", iter.index);
 			slot = radix_tree_iter_resume(slot, &iter);
 		}
 	}
 
 	radix_tree_for_each_contig(slot, &root, &iter, 0) {
-		printf("contig %ld %p\n", iter.index, *slot);
+		printv(2, "contig %ld %p\n", iter.index, *slot);
 		if (!iter.index) {
-			printf("next at %ld\n", iter.index);
+			printv(2, "next at %ld\n", iter.index);
 			slot = radix_tree_iter_resume(slot, &iter);
 		}
 	}
@@ -103,9 +103,9 @@ void regression3_test(void)
 	radix_tree_tag_set(&root, 0, 0);
 	radix_tree_tag_set(&root, 1, 0);
 	radix_tree_for_each_tagged(slot, &root, &iter, 0, 0) {
-		printf("tagged %ld %p\n", iter.index, *slot);
+		printv(2, "tagged %ld %p\n", iter.index, *slot);
 		if (!iter.index) {
-			printf("next at %ld\n", iter.index);
+			printv(2, "next at %ld\n", iter.index);
 			slot = radix_tree_iter_resume(slot, &iter);
 		}
 	}
@@ -113,5 +113,5 @@ void regression3_test(void)
 	radix_tree_delete(&root, 0);
 	radix_tree_delete(&root, 1);
 
-	printf("regression test 3 passed\n");
+	printv(1, "regression test 3 passed\n");
 }
diff --git a/tools/testing/radix-tree/tag_check.c b/tools/testing/radix-tree/tag_check.c
index fd98c132207aa353f4acce5413b4bf7c23c1cfda..d4ff009892456a3b588df788488027da45209ecf 100644
--- a/tools/testing/radix-tree/tag_check.c
+++ b/tools/testing/radix-tree/tag_check.c
@@ -49,10 +49,10 @@ void simple_checks(void)
 	}
 	verify_tag_consistency(&tree, 0);
 	verify_tag_consistency(&tree, 1);
-	printf("before item_kill_tree: %d allocated\n", nr_allocated);
+	printv(2, "before item_kill_tree: %d allocated\n", nr_allocated);
 	item_kill_tree(&tree);
 	rcu_barrier();
-	printf("after item_kill_tree: %d allocated\n", nr_allocated);
+	printv(2, "after item_kill_tree: %d allocated\n", nr_allocated);
 }
 
 /*
@@ -257,7 +257,7 @@ static void do_thrash(struct radix_tree_root *tree, char *thrash_state, int tag)
 
 		gang_check(tree, thrash_state, tag);
 
-		printf("%d(%d) %d(%d) %d(%d) %d(%d) / "
+		printv(2, "%d(%d) %d(%d) %d(%d) %d(%d) / "
 				"%d(%d) present, %d(%d) tagged\n",
 			insert_chunk, nr_inserted,
 			delete_chunk, nr_deleted,
@@ -296,13 +296,13 @@ static void __leak_check(void)
 {
 	RADIX_TREE(tree, GFP_KERNEL);
 
-	printf("%d: nr_allocated=%d\n", __LINE__, nr_allocated);
+	printv(2, "%d: nr_allocated=%d\n", __LINE__, nr_allocated);
 	item_insert(&tree, 1000000);
-	printf("%d: nr_allocated=%d\n", __LINE__, nr_allocated);
+	printv(2, "%d: nr_allocated=%d\n", __LINE__, nr_allocated);
 	item_delete(&tree, 1000000);
-	printf("%d: nr_allocated=%d\n", __LINE__, nr_allocated);
+	printv(2, "%d: nr_allocated=%d\n", __LINE__, nr_allocated);
 	item_kill_tree(&tree);
-	printf("%d: nr_allocated=%d\n", __LINE__, nr_allocated);
+	printv(2, "%d: nr_allocated=%d\n", __LINE__, nr_allocated);
 }
 
 static void single_check(void)
@@ -336,15 +336,15 @@ void tag_check(void)
 	extend_checks();
 	contract_checks();
 	rcu_barrier();
-	printf("after extend_checks: %d allocated\n", nr_allocated);
+	printv(2, "after extend_checks: %d allocated\n", nr_allocated);
 	__leak_check();
 	leak_check();
 	rcu_barrier();
-	printf("after leak_check: %d allocated\n", nr_allocated);
+	printv(2, "after leak_check: %d allocated\n", nr_allocated);
 	simple_checks();
 	rcu_barrier();
-	printf("after simple_checks: %d allocated\n", nr_allocated);
+	printv(2, "after simple_checks: %d allocated\n", nr_allocated);
 	thrash_tags();
 	rcu_barrier();
-	printf("after thrash_tags: %d allocated\n", nr_allocated);
+	printv(2, "after thrash_tags: %d allocated\n", nr_allocated);
 }
diff --git a/tools/testing/radix-tree/test.c b/tools/testing/radix-tree/test.c
index e5726e3736468a7003f2b9529a36d84c659ace58..1a257d738a1e4e618563de835d55fc847c5daac1 100644
--- a/tools/testing/radix-tree/test.c
+++ b/tools/testing/radix-tree/test.c
@@ -29,15 +29,28 @@ int __item_insert(struct radix_tree_root *root, struct item *item)
 	return __radix_tree_insert(root, item->index, item->order, item);
 }
 
-int item_insert(struct radix_tree_root *root, unsigned long index)
+struct item *item_create(unsigned long index, unsigned int order)
 {
-	return __item_insert(root, item_create(index, 0));
+	struct item *ret = malloc(sizeof(*ret));
+
+	ret->index = index;
+	ret->order = order;
+	return ret;
 }
 
 int item_insert_order(struct radix_tree_root *root, unsigned long index,
 			unsigned order)
 {
-	return __item_insert(root, item_create(index, order));
+	struct item *item = item_create(index, order);
+	int err = __item_insert(root, item);
+	if (err)
+		free(item);
+	return err;
+}
+
+int item_insert(struct radix_tree_root *root, unsigned long index)
+{
+	return item_insert_order(root, index, 0);
 }
 
 void item_sanity(struct item *item, unsigned long index)
@@ -61,15 +74,6 @@ int item_delete(struct radix_tree_root *root, unsigned long index)
 	return 0;
 }
 
-struct item *item_create(unsigned long index, unsigned int order)
-{
-	struct item *ret = malloc(sizeof(*ret));
-
-	ret->index = index;
-	ret->order = order;
-	return ret;
-}
-
 void item_check_present(struct radix_tree_root *root, unsigned long index)
 {
 	struct item *item;
diff --git a/tools/testing/radix-tree/test.h b/tools/testing/radix-tree/test.h
index 056a23b56467ca54b07b5104da54eb4c5083e984..b30e11d9d271c39ccb284019938876ae2785f7ca 100644
--- a/tools/testing/radix-tree/test.h
+++ b/tools/testing/radix-tree/test.h
@@ -34,6 +34,8 @@ void tag_check(void);
 void multiorder_checks(void);
 void iteration_test(unsigned order, unsigned duration);
 void benchmark(void);
+void idr_checks(void);
+void ida_checks(void);
 
 struct item *
 item_tag_set(struct radix_tree_root *root, unsigned long index, int tag);