Merge branch 'idr-4.11' of git://git.infradead.org/users/willy/linux-dax

Pull IDR rewrite from Matthew Wilcox:
 "The most significant part of the following is the patch to rewrite the
  IDR & IDA to be clients of the radix tree. But there's much more,
  including an enhancement of the IDA to be significantly more space
  efficient, an IDR & IDA test suite, some improvements to the IDR API
  (and driver changes to take advantage of those improvements), several
  improvements to the radix tree test suite and RCU annotations.

  The IDR & IDA rewrite had a good spin in linux-next and Andrew's tree
  for most of the last cycle. Coupled with the IDR test suite, I feel
  pretty confident that any remaining bugs are quite hard to hit. 0-day
  did a great job of watching my git tree and pointing out problems; as
  it hit them, I added new test-cases to be sure not to be caught the
  same way twice"

Willy goes on to expand a bit on the IDR rewrite rationale:
 "The radix tree and the IDR use very similar data structures.

  Merging the two codebases lets us share the memory allocation pools,
  and results in a net deletion of 500 lines of code. It also opens up
  the possibility of exposing more of the features of the radix tree to
  users of the IDR (and I have some interesting patches along those
  lines waiting for 4.12)

  It also shrinks the size of the 'struct idr' from 40 bytes to 24 which
  will shrink a fair few data structures that embed an IDR"

* 'idr-4.11' of git://git.infradead.org/users/willy/linux-dax: (32 commits)
  radix tree test suite: Add config option for map shift
  idr: Add missing __rcu annotations
  radix-tree: Fix __rcu annotations
  radix-tree: Add rcu_dereference and rcu_assign_pointer calls
  radix tree test suite: Run iteration tests for longer
  radix tree test suite: Fix split/join memory leaks
  radix tree test suite: Fix leaks in regression2.c
  radix tree test suite: Fix leaky tests
  radix tree test suite: Enable address sanitizer
  radix_tree_iter_resume: Fix out of bounds error
  radix-tree: Store a pointer to the root in each node
  radix-tree: Chain preallocated nodes through ->parent
  radix tree test suite: Dial down verbosity with -v
  radix tree test suite: Introduce kmalloc_verbose
  idr: Return the deleted entry from idr_remove
  radix tree test suite: Build separate binaries for some tests
  ida: Use exceptional entries for small IDAs
  ida: Move ida_bitmap to a percpu variable
  Reimplement IDR and IDA using the radix tree
  radix-tree: Add radix_tree_iter_delete
  ...

56 files changed, 1703 insertions, 2077 deletions

diff --git a/drivers/atm/nicstar.c b/drivers/atm/nicstar.c
index cb28579e8a94..d879f3bca107 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 615e5b5178a0..116509852a34 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2915,11 +2915,9 @@ out_idr_remove_vol:
 	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 aee149bdf4c0..a301fcf46e88 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 c02db01f6583..0218cea6be4d 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 400c66ba4c6b..cf0500671353 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 abdd0cf710bf..fac28bd8fbee 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 5c1cb2df3a54..c3adefe95e50 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 3c01b89aed67..bf70b3ef0a07 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 52bda854593b..3e5735064b71 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