[PATCH v3 33/33] Reimplement IDR and IDA using the radix tree

Matthew Wilcox
2016-11-28T19:57:29Z

From: Matthew Wilcox <willy@linux.intel.com>

The IDR is very similar to the radix tree. It has some functionality
that the radix tree did not have (alloc next free, cyclic allocation,
a callback-based for_each, destroy tree), which is readily implementable
on top of the radix tree. A few small changes were needed in order to
use a tag to represent nodes with free space below them.

The IDA is reimplemented as a client of the newly enhanced radix tree.
As in the current implementation, it uses a bitmap at the last level of
the tree.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
---
include/linux/idr.h | 132 ++--
include/linux/radix-tree.h | 5 +-
init/main.c | 3 +-
lib/idr.c | 1078 -------------------------------
lib/radix-tree.c | 632 ++++++++++++++++--
tools/testing/radix-tree/Makefile | 5 +-
tools/testing/radix-tree/idr.c | 160 +++++
tools/testing/radix-tree/linux/idr.h | 1 +
tools/testing/radix-tree/linux/kernel.h | 2 +
tools/testing/radix-tree/main.c | 6 +
tools/testing/radix-tree/test.h | 2 +
11 files changed, 811 insertions(+), 1215 deletions(-)
create mode 100644 tools/testing/radix-tree/idr.c
create mode 100644 tools/testing/radix-tree/linux/idr.h

diff --git a/include/linux/idr.h b/include/linux/idr.h
index 3c01b89..0035799 100644
--- a/include/linux/idr.h
+++ b/include/linux/idr.h
@@ -12,47 +12,22 @@
#ifndef __IDR_H__
#define __IDR_H__

-#include <linux/types.h>
-#include <linux/bitops.h>
-#include <linux/init.h>
-#include <linux/rcupdate.h>
-
-/*
- * 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.
- */
-#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;
- };
-};
+#include <linux/radix-tree.h>
+#include <linux/gfp.h>

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;
+ struct radix_tree_root idr_rt;
+ unsigned int idr_next;
};

-#define IDR_INIT(name) \
+/* Set the IDR flag and the IDR_FREE tag */
+#define IDR_RT_MARKER ((__force gfp_t)(3 << __GFP_BITS_SHIFT))
+
+#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
@@ -64,7 +39,7 @@ struct idr {
*/
static inline unsigned int idr_get_cursor(struct idr *idr)
{
- return READ_ONCE(idr->cur);
+ return READ_ONCE(idr->idr_next);
}

/**
@@ -77,7 +52,7 @@ 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 +72,30 @@ 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 *, int start, int end, gfp_t gfp_mask);
+int idr_alloc_cyclic(struct idr *, void *, int start, int end, gfp_t gfp_mask);
+int idr_for_each(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 *idp, int id)
+{
+ radix_tree_delete(&idp->idr_rt, id);
+}
+
+static inline void idr_init(struct idr *idp)
+{
+ memset(idp, 0, sizeof(*idp));
+ idp->idr_rt.gfp_mask = IDR_RT_MARKER;
+}
+
+static inline bool idr_is_empty(struct idr *idp)
+{
+ return radix_tree_empty(&idp->idr_rt);
+}

/**
* idr_preload_end - end preload section started with idr_preload()
@@ -139,17 +122,12 @@ static inline void idr_preload_end(void)
*/
static inline void *idr_find(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 +135,58 @@ 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];
};

struct ida {
- struct idr idr;
+ struct radix_tree_root ida_rt;
struct ida_bitmap *free_bitmap;
};

-#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), }
+#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)
+{
+ memset(ida, 0, sizeof(*ida));
+ ida->ida_rt.gfp_mask = IDR_RT_MARKER;
+}
+
/**
* ida_get_new - allocate new ID
* @ida: idr handle
@@ -222,9 +201,6 @@ static inline int ida_get_new(struct ida *ida, int *p_id)

static inline bool ida_is_empty(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 5dea8f6..d069069 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -103,7 +103,10 @@ 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 (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;
diff --git a/init/main.c b/init/main.c
index cbed073..777a6b6 100644
--- a/init/main.c
+++ b/init/main.c
@@ -550,7 +550,7 @@ 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
@@ -565,7 +565,6 @@ 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/idr.c b/lib/idr.c
index 52d2979..918b595 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -1,1071 +1,8 @@
-/*
- * 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/export.h>
-#endif
-#include <linux/err.h>
-#include <linux/string.h>
#include <linux/idr.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);
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
- * @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
- *
- * 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.
- *
- * 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.
- */
-int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask)
-{
- int max = end > 0 ? end - 1 : INT_MAX; /* inclusive upper limit */
- struct idr_layer *pa[MAX_IDR_LEVEL + 1];
- int id;
-
- might_sleep_if(gfpflags_allow_blocking(gfp_mask));
-
- /* sanity checks */
- if (WARN_ON_ONCE(start < 0))
- return -EINVAL;
- if (unlikely(max < start))
- return -ENOSPC;
-
- /* 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;
-
- idr_fill_slot(idr, ptr, id, pa);
- return id;
-}
-EXPORT_SYMBOL_GPL(idr_alloc);
-
-/**
- * idr_alloc_cyclic - allocate new idr entry in a cyclical fashion
- * @idr: the (initialized) idr
- * @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().
- *
- * 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.
- */
-void idr_destroy(struct idr *idp)
-{
- __idr_remove_all(idp);
-
- 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);
-
-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;
-
- if (id > idr_max(p->layer + 1))
- return NULL;
- BUG_ON(n == 0);
-
- 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);
-}
-EXPORT_SYMBOL(idr_find_slowpath);
-
-/**
- * idr_for_each - iterate through all stored pointers
- * @idp: idr handle
- * @fn: function to be called for each pointer
- * @data: data passed back 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.
- *
- * We check the return of @fn each time. If it returns anything other
- * than %0, we break out and return that value.
- *
- * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove().
- */
-int idr_for_each(struct idr *idp,
- 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);
-
- 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;
- }
- }
-
- return error;
-}
-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.
- */
-void *idr_get_next(struct idr *idp, int *nextidp)
-{
- struct idr_layer *p, *pa[MAX_IDR_LEVEL + 1];
- struct idr_layer **paa = &pa[0];
- int id = *nextidp;
- int n, max;
-
- /* find first ent */
- p = *paa = rcu_dereference_raw(idp->top);
- if (!p)
- 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;
-}
-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
- *
- * 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.
- *
- * The caller must serialize with writers.
- */
-void *idr_replace(struct idr *idp, void *ptr, int id)
-{
- int n;
- struct idr_layer *p, *old_p;
-
- if (id < 0)
- 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)))
- return ERR_PTR(-ENOENT);
-
- old_p = p->ary[n];
- rcu_assign_pointer(p->ary[n], ptr);
-
- return old_p;
-}
-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>
- */
-
-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.
- */
-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);
-
-/**
- * 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
- *
- * Allocate new ID above or equal to @starting_id. It should be called
- * with any required locks.
- *
- * 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.
- *
- * @p_id returns a value in the range @starting_id ... %0x7fffffff.
- */
-int ida_get_new_above(struct ida *ida, int starting_id, int *p_id)
-{
- struct idr_layer *pa[MAX_IDR_LEVEL + 1];
- 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;
-
- __set_bit(t, bitmap->bitmap);
- if (++bitmap->nr_busy == IDA_BITMAP_BITS)
- idr_mark_full(pa, idr_id);
-
- *p_id = id;
-
- /* 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);
- }
-
- return 0;
-}
-EXPORT_SYMBOL(ida_get_new_above);
-
-/**
- * ida_remove - remove the given ID
- * @ida: ida handle
- * @id: ID to free
- */
-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;
- struct ida_bitmap *bitmap;
-
- if (idr_id > idr_max(ida->idr.layers))
- 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;
- }
-
- 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))
- 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);
- }
-
- 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
- */
-void ida_destroy(struct ida *ida)
-{
- idr_destroy(&ida->idr);
- kfree(ida->free_bitmap);
-}
-EXPORT_SYMBOL(ida_destroy);
-
/**
* ida_simple_get - get a new id.
* @ida: the (initialized) ida.
@@ -1141,18 +78,3 @@ 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 a227727..5e8fc32 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 */
@@ -60,6 +61,15 @@ 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 since it can only store a 31-bit integer
+ * at its maximum height
+ */
+#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)
+
+/*
* Per-cpu pool of preloaded nodes
*/
struct radix_tree_preload {
@@ -147,27 +157,38 @@ static inline int tag_get(struct radix_tree_node *node, unsigned int tag,

static inline void root_tag_set(struct radix_tree_root *root, unsigned int 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(struct radix_tree_root *root, unsigned int tag)
{
- return (__force int)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT));
+ return (__force int)root->gfp_mask & (1 << (tag + ROOT_TAG_SHIFT));
}

static inline unsigned root_tags_get(struct radix_tree_root *root)
{
- return (__force unsigned)root->gfp_mask >> __GFP_BITS_SHIFT;
+ return (__force unsigned)root->gfp_mask >> ROOT_TAG_SHIFT;
+}
+
+/*
+ * IDRs do not expose the tagging functionality of the radix tree to their
+ * users. Reuse tag 0 to track whether a node has free space below it.
+ */
+#define IDR_FREE 0
+
+static inline bool is_idr(struct radix_tree_root *root)
+{
+ return (__force unsigned)root->gfp_mask & ROOT_IS_IDR;
}

/*
@@ -184,6 +205,11 @@ 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
*
@@ -237,6 +263,13 @@ static inline unsigned long node_maxindex(struct radix_tree_node *node)
return shift_maxindex(node->shift);
}

+static unsigned long next_index(unsigned long index,
+ 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 +308,47 @@ 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, index | node_maxindex(node),
+ 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 {
+ struct ida_bitmap *bitmap = entry;
+
+ pr_debug("ida btmp: %p index %lu data", bitmap, index);
+ 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 %p free %d bitmap %p\n", ida, root->rnode,
+ root->gfp_mask >> ROOT_TAG_SHIFT,
+ ida->free_bitmap);
+ dump_ida_node(root->rnode, 0);
+}
#endif

/*
@@ -287,10 +356,9 @@ 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)
+radix_tree_node_alloc(gfp_t gfp_mask)
{
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
@@ -520,7 +588,7 @@ 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_mask,
unsigned long index, unsigned int shift)
{
struct radix_tree_node *slot;
@@ -537,15 +605,22 @@ static int radix_tree_extend(struct radix_tree_root *root,
goto out;

do {
- struct radix_tree_node *node = radix_tree_node_alloc(root);
+ struct radix_tree_node *node = radix_tree_node_alloc(gfp_mask);

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);
@@ -609,6 +684,8 @@ static inline void radix_tree_shrink(struct radix_tree_root *root,
* one (root->rnode) as far as dependent read barriers go.
*/
root->rnode = 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
@@ -657,7 +734,12 @@ 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;
}

@@ -667,26 +749,9 @@ static void delete_node(struct radix_tree_root *root,
} while (node);
}

-/**
- * __radix_tree_create - create a slot in a radix tree
- * @root: radix tree root
- * @index: index key
- * @order: index occupies 2^order aligned slots
- * @nodep: returns node
- * @slotp: returns slot
- *
- * Create, if necessary, and return the node and slot for an item
- * at position @index in the radix tree @root.
- *
- * Until there is more than one item in the tree, no nodes are
- * allocated and @root->rnode is used as a direct slot instead of
- * pointing to a node, in which case *@nodep will be NULL.
- *
- * Returns -ENOMEM, or 0 for success.
- */
-int __radix_tree_create(struct radix_tree_root *root, unsigned long index,
- unsigned order, struct radix_tree_node **nodep,
- void ***slotp)
+static int _radix_tree_create(struct radix_tree_root *root, gfp_t gfp_mask,
+ unsigned long index, unsigned int order,
+ struct radix_tree_node **nodep, void ***slotp)
{
struct radix_tree_node *node = NULL, *child;
void **slot = (void **)&root->rnode;
@@ -700,7 +765,7 @@ 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_mask, max, shift);
if (error < 0)
return error;
shift = error;
@@ -711,7 +776,7 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index,
shift -= RADIX_TREE_MAP_SHIFT;
if (child == NULL) {
/* Have to add a child node. */
- child = radix_tree_node_alloc(root);
+ child = radix_tree_node_alloc(gfp_mask);
if (!child)
return -ENOMEM;
child->shift = shift;
@@ -738,7 +803,6 @@ 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
@@ -773,6 +837,7 @@ static void radix_tree_free_nodes(struct radix_tree_node *node)
}
}

+#ifdef CONFIG_RADIX_TREE_MULTIORDER
static inline int insert_entries(struct radix_tree_node *node, void **slot,
void *item, unsigned order, bool replace)
{
@@ -852,6 +917,31 @@ static inline int insert_entries(struct radix_tree_node *node, void **slot,
#endif

/**
+ * __radix_tree_create - create a slot in a radix tree
+ * @root: radix tree root
+ * @index: index key
+ * @order: index occupies 2^order aligned slots
+ * @nodep: returns node
+ * @slotp: returns slot
+ *
+ * Create, if necessary, and return the node and slot for an item
+ * at position @index in the radix tree @root.
+ *
+ * Until there is more than one item in the tree, no nodes are
+ * allocated and @root->rnode is used as a direct slot instead of
+ * pointing to a node, in which case *@nodep will be NULL.
+ *
+ * Returns -ENOMEM, or 0 for success.
+ */
+int __radix_tree_create(struct radix_tree_root *root, unsigned long index,
+ unsigned order, struct radix_tree_node **nodep,
+ void ***slotp)
+{
+ return _radix_tree_create(root, root_gfp_mask(root), index, order,
+ nodep, slotp);
+}
+
+/**
* __radix_tree_insert - insert into a radix tree
* @root: radix tree root
* @index: index key
@@ -1171,6 +1261,7 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index,
void **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;
@@ -1208,7 +1299,7 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index,

for (;;) {
if (node->shift > order) {
- child = radix_tree_node_alloc(root);
+ child = radix_tree_node_alloc(gfp);
if (!child)
goto nomem;
child->shift = node->shift - RADIX_TREE_MAP_SHIFT;
@@ -1836,6 +1927,16 @@ void __radix_tree_delete_node(struct radix_tree_root *root,
delete_node(root, node, NULL, NULL);
}

+static void radix_tree_iter_delete(struct radix_tree_root *root,
+ const struct radix_tree_iter *iter)
+{
+ struct radix_tree_node *node = iter->node;
+
+ node->slots[iter_offset(iter)] = NULL;
+ node->count--;
+ __radix_tree_delete_node(root, node);
+}
+
/**
* radix_tree_delete_item - delete an item from a radix tree
* @root: radix tree root
@@ -1844,7 +1945,7 @@ void __radix_tree_delete_node(struct radix_tree_root *root,
*
* Remove @item at @index from the radix tree rooted at @root.
*
- * Returns the address of the deleted item, or NULL if it was not present
+ * Returns the value of the deleted item, 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,
@@ -1864,16 +1965,21 @@ void *radix_tree_delete_item(struct radix_tree_root *root,
return NULL;

if (!node) {
- root_tag_clear_all(root);
+ if (is_idr(root))
+ root_tag_set(root, IDR_FREE);
+ else
+ 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);
+ 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);

__radix_tree_replace(root, node, slot, NULL, NULL, NULL);

@@ -1888,7 +1994,7 @@ EXPORT_SYMBOL(radix_tree_delete_item);
*
* Remove the item at @index from the radix tree rooted at @root.
*
- * Returns the address of the deleted item, or NULL if it was not present.
+ * Returns the value of the deleted item, or NULL if it was not present.
*/
void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
{
@@ -1905,8 +2011,7 @@ void radix_tree_clear_tags(struct radix_tree_root *root,
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);
}
}

@@ -1921,6 +2026,425 @@ int radix_tree_tagged(struct radix_tree_root *root, unsigned int 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);
+
+static int __idr_get_empty(struct radix_tree_root *root, gfp_t gfp,
+ unsigned long start, int end,
+ struct radix_tree_node **nodep, void ***slotp)
+{
+ struct radix_tree_node *node = NULL, *child;
+ void **slot = (void **)&root->rnode;
+ unsigned long maxindex;
+ 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 -ENOSPC;
+
+ if (start > maxindex) {
+ int error = radix_tree_extend(root, gfp, start, shift);
+ if (error < 0)
+ return error;
+ shift = error;
+ child = root->rnode;
+ }
+
+ while (shift) {
+ shift -= RADIX_TREE_MAP_SHIFT;
+ if (child == NULL) {
+ /* Have to add a child node. */
+ child = radix_tree_node_alloc(gfp);
+ if (!child)
+ return -ENOMEM;
+ child->shift = shift;
+ child->offset = offset;
+ child->parent = node;
+ 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 -ENOSPC;
+ while (offset == RADIX_TREE_MAP_SIZE) {
+ offset = node->offset + 1;
+ node = node->parent;
+ if (!node)
+ goto grow;
+ shift = node->shift;
+ }
+ child = node->slots[offset];
+ }
+ slot = &node->slots[offset];
+ }
+
+ *nodep = node;
+ *slotp = slot;
+ return start;
+}
+
+/**
+ * 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)
+ * @gfp: memory allocation flags
+ *
+ * Allocates an unused ID in the range [start, end). Returns -ENOSPC
+ * if there are no unused IDs in that range.
+ */
+int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp)
+{
+ struct radix_tree_node *node;
+ void **slot;
+ int id;
+
+ if (WARN_ON_ONCE(start < 0))
+ return -EINVAL;
+
+ id = __idr_get_empty(&idr->idr_rt, gfp, start, end, &node, &slot);
+ if (id < 0)
+ return id;
+
+ BUG_ON(radix_tree_is_internal_node(ptr));
+
+ rcu_assign_pointer(*slot, ptr);
+ if (node)
+ node->count++;
+ node_tag_clear(&idr->idr_rt, node, IDR_FREE,
+ get_slot_offset(node, slot));
+ return id;
+}
+EXPORT_SYMBOL(idr_alloc);
+
+/**
+ * idr_alloc_cyclic - allocate new idr entry in a cyclical fashion
+ * @idr: idr handle
+ * @ptr: pointer to be associated with the new id
+ * @start: the minimum id (inclusive)
+ * @end: the maximum id (exclusive)
+ * @gfp: memory allocation flags
+ *
+ * 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.
+ */
+int idr_alloc_cyclic(struct idr *idr, void *ptr, int start, int end, gfp_t gfp)
+{
+ int id, curr = idr->idr_next;
+
+ if (curr < start)
+ curr = start;
+
+ id = idr_alloc(idr, ptr, curr, end, gfp);
+ if ((id == -ENOSPC) && (curr > start))
+ id = idr_alloc(idr, ptr, start, curr, gfp);
+
+ if (id >= 0)
+ idr->idr_next = id + 1U;
+
+ return id;
+}
+EXPORT_SYMBOL(idr_alloc_cyclic);
+
+/**
+ * idr_for_each - iterate through all stored pointers
+ * @idr: idr handle
+ * @fn: function to be called for each pointer
+ * @data: data passed to callback function
+ *
+ * The callback function will be called for each entry in @idr, passing
+ * the id, the pointer and the data pointer passed to this function.
+ *
+ * If @fn returns anything other than %0, the iteration stops and that
+ * value is returned from this function.
+ *
+ * idr_for_each() can be called concurrently with idr_get_new() 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 *idr,
+ int (*fn)(int id, void *p, void *data), void *data)
+{
+ struct radix_tree_iter iter;
+ void **slot;
+
+ radix_tree_for_each_slot(slot, &idr->idr_rt, &iter, 0) {
+ int ret = fn(iter.index, *slot, data);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(idr_for_each);
+
+/**
+ * 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 *idr, int *nextid)
+{
+ struct radix_tree_iter iter;
+ void **slot;
+
+ radix_tree_for_each_slot(slot, &idr->idr_rt, &iter, *nextid) {
+ *nextid = iter.index;
+ return *slot;
+ }
+
+ return NULL;
+}
+EXPORT_SYMBOL(idr_get_next);
+
+/**
+ * idr_replace - replace pointer for given id
+ * @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.
+ *
+ * This function can be called under the RCU read lock concurrently with
+ * idr_remove().
+ */
+void *idr_replace(struct idr *idr, void *ptr, int id)
+{
+ struct radix_tree_node *node;
+ void **slot;
+ void *entry;
+
+ if (id < 0)
+ return ERR_PTR(-EINVAL);
+ if (!ptr || radix_tree_is_internal_node(ptr))
+ return ERR_PTR(-EINVAL);
+
+ entry = __radix_tree_lookup(&idr->idr_rt, id, &node, &slot);
+
+ if (!entry)
+ return ERR_PTR(-ENOENT);
+
+ __radix_tree_replace(&idr->idr_rt, node, slot, ptr, NULL, NULL);
+
+ return entry;
+}
+EXPORT_SYMBOL(idr_replace);
+
+/**
+ * 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 **slot = &idr->idr_rt.rnode;
+ if (radix_tree_is_internal_node(*slot))
+ radix_tree_free_nodes(*slot);
+ *slot = NULL;
+ root_tag_set(&idr->idr_rt, IDR_FREE);
+}
+EXPORT_SYMBOL(idr_destroy);
+
+/**
+ * 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)
+{
+ struct ida_bitmap *bitmap;
+
+ idr_preload(gfp);
+ idr_preload_end();
+
+ if (!ida->free_bitmap) {
+ bitmap = kmalloc(sizeof(struct ida_bitmap), gfp);
+ if (!bitmap)
+ return 0;
+ bitmap = xchg(&ida->free_bitmap, bitmap);
+ kfree(bitmap);
+ }
+
+ return 1;
+}
+EXPORT_SYMBOL(ida_pre_get);
+
+/**
+ * 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
+ *
+ * Allocate new ID above or equal to @starting_id. 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.
+ *
+ * @p_id returns a value in the range @starting_id ... %0x7fffffff.
+ */
+int ida_get_new_above(struct ida *ida, int start, int *id)
+{
+ struct radix_tree_root *root = &ida->ida_rt;
+ void **slot = (void **)&root->rnode;
+ struct radix_tree_node *node;
+ struct ida_bitmap *bitmap = NULL;
+ unsigned long index;
+ unsigned bit, offset = 0;
+
+ index = start / IDA_BITMAP_BITS;
+ bit = start % IDA_BITMAP_BITS;
+
+ restart:
+ index = __idr_get_empty(root, GFP_ATOMIC, index, INT_MAX, &node, &slot);
+ if (index > INT_MAX)
+ return index;
+
+ index *= IDA_BITMAP_BITS;
+ if (index > INT_MAX)
+ return -ENOSPC;
+
+ if (index > start)
+ bit = 0;
+ offset = get_slot_offset(node, slot);
+
+ bitmap = *slot;
+ if (bitmap) {
+ bit = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, bit);
+ index += bit;
+ if (index > INT_MAX)
+ return -ENOSPC;
+ if (bit == IDA_BITMAP_BITS) {
+ index /= IDA_BITMAP_BITS;
+ goto restart;
+ }
+ __set_bit(bit, bitmap->bitmap);
+ if (bitmap_full(bitmap->bitmap, IDA_BITMAP_BITS))
+ node_tag_clear(root, node, IDR_FREE, offset);
+ bitmap = xchg(&ida->free_bitmap, NULL);
+ kfree(bitmap);
+ } else {
+ index += bit;
+ bitmap = xchg(&ida->free_bitmap, NULL);
+ if (!bitmap)
+ return -EAGAIN;
+ memset(bitmap, 0, sizeof(*bitmap));
+ __set_bit(bit, bitmap->bitmap);
+ rcu_assign_pointer(*slot, bitmap);
+ if (node)
+ node->count++;
+ }
+
+ *id = index;
+ return 0;
+}
+EXPORT_SYMBOL(ida_get_new_above);
+
+/**
+ * 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)
+{
+ unsigned long index = id / IDA_BITMAP_BITS;
+ unsigned offset = id % IDA_BITMAP_BITS;
+ struct ida_bitmap *bitmap;
+ struct radix_tree_node *node;
+ void **slot;
+
+ bitmap = __radix_tree_lookup(&ida->ida_rt, index, &node, &slot);
+ if (!bitmap || !test_bit(offset, bitmap->bitmap))
+ goto err;
+
+ __clear_bit(offset, bitmap->bitmap);
+ node_tag_set(&ida->ida_rt, node, IDR_FREE, get_slot_offset(node, slot));
+ if (bitmap_empty(bitmap->bitmap, IDA_BITMAP_BITS)) {
+ *slot = NULL;
+ kfree(bitmap);
+ if (node) {
+ node->count--;
+ __radix_tree_delete_node(&ida->ida_rt, node);
+ }
+ }
+ return;
+ err:
+ WARN(1, "ida_remove called for id=%d which is not allocated.\n", id);
+}
+EXPORT_SYMBOL(ida_remove);
+
+/**
+ * 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)
+{
+ struct radix_tree_iter iter;
+ void **slot;
+
+ radix_tree_for_each_slot(slot, &ida->ida_rt, &iter, 0) {
+ struct ida_bitmap *bitmap = *slot;
+ kfree(bitmap);
+ radix_tree_iter_delete(&ida->ida_rt, &iter);
+ }
+
+ kfree(ida->free_bitmap);
+}
+EXPORT_SYMBOL(ida_destroy);
+
static void
radix_tree_node_ctor(void *arg)
{
diff --git a/tools/testing/radix-tree/Makefile b/tools/testing/radix-tree/Makefile
index 3635e4d..5a616a3 100644
--- a/tools/testing/radix-tree/Makefile
+++ b/tools/testing/radix-tree/Makefile
@@ -3,7 +3,7 @@ CFLAGS += -I. -I../../include -g -O2 -Wall -D_LGPL_SOURCE
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 \
+ regression1.o regression2.o regression3.o multiorder.o idr.o \
iteration_check.o benchmark.o

ifdef BENCHMARK
@@ -23,7 +23,8 @@ find_next_bit.o: ../../lib/find_bit.c

$(OFILES): *.h */*.h \
../../include/linux/*.h \
- ../../../include/linux/radix-tree.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 //' < $< > $@
diff --git a/tools/testing/radix-tree/idr.c b/tools/testing/radix-tree/idr.c
new file mode 100644
index 0000000..4033dbc
--- /dev/null
+++ b/tools/testing/radix-tree/idr.c
@@ -0,0 +1,160 @@
+/*
+ * idr.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/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);
+ idr_remove(data, 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);
+}
+
+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);
+}
+
+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_for_each(&idr, item_idr_free, &idr);
+
+ assert(idr_is_empty(&idr));
+
+ 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_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_destroy(&idr);
+
+ idr_replace_test();
+
+ idr_alloc_test();
+}
+
+void ida_checks(void)
+{
+ DEFINE_IDA(ida);
+
+ unsigned long i;
+ int id;
+
+ for (i = 0; i < 10000; i++) {
+ ida_pre_get(&ida, GFP_KERNEL);
+ ida_get_new(&ida, &id);
+ assert(id == i);
+ }
+
+ ida_remove(&ida, 20);
+ ida_remove(&ida, 21);
+ for (i = 0; i < 3; i++) {
+ ida_pre_get(&ida, GFP_KERNEL);
+ ida_get_new(&ida, &id);
+ if (i == 2)
+ assert(id == 10000);
+ }
+
+ for (i = 0; i < 5000; i++)
+ ida_remove(&ida, i);
+
+ ida_pre_get(&ida, GFP_KERNEL);
+ ida_get_new_above(&ida, 5000, &id);
+ assert(id == 10001);
+
+ ida_destroy(&ida);
+
+ assert(ida_is_empty(&ida));
+
+ ida_pre_get(&ida, GFP_KERNEL);
+ ida_get_new_above(&ida, 1, &id);
+ assert(id == 1);
+
+ ida_remove(&ida, id);
+ ida_destroy(&ida);
+
+ radix_tree_cpu_dead(1);
+}
diff --git a/tools/testing/radix-tree/linux/idr.h b/tools/testing/radix-tree/linux/idr.h
new file mode 100644
index 0000000..4e342f2
--- /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/kernel.h b/tools/testing/radix-tree/linux/kernel.h
index 9b43b49..7d214e9 100644
--- a/tools/testing/radix-tree/linux/kernel.h
+++ b/tools/testing/radix-tree/linux/kernel.h
@@ -30,6 +30,7 @@
#define __force
#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
#define pr_debug printk
+#define pr_cont printk

#define smp_rmb() barrier()
#define smp_wmb() barrier()
@@ -41,6 +42,7 @@
const typeof( ((type *)0)->member ) *__mptr = (ptr); \
(type *)( (char *)__mptr - offsetof(type, member) );})
#define min(a, b) ((a) < (b) ? (a) : (b))
+#define max(a, b) ((a) < (b) ? (b) : (a))

#define cond_resched() sched_yield()

diff --git a/tools/testing/radix-tree/main.c b/tools/testing/radix-tree/main.c
index f7e9801..ddd90a1 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>
@@ -314,6 +315,11 @@ static void single_thread_tests(bool long_run)
rcu_barrier();
printf("after dynamic_height_check: %d allocated, preempt %d\n",
nr_allocated, preempt_count);
+ idr_checks();
+ ida_checks();
+ rcu_barrier();
+ printf("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",
diff --git a/tools/testing/radix-tree/test.h b/tools/testing/radix-tree/test.h
index 056a23b..b30e11d 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);
--
2.10.2