On Thu, Nov 17, 2016 at 3:17 AM, Matthew Wilcox
<mawilcox@xxxxxxxxxxxxxxxxx> wrote:
> From: Matthew Wilcox <willy@xxxxxxxxxxxxx>
>
> 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.
I'm still see no reason for this.
>
> Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxx>
> ---
> include/linux/idr.h | 128 ++--
> include/linux/radix-tree.h | 5 +-
> init/main.c | 3 +-
> lib/idr.c | 1075 -------------------------------
> lib/radix-tree.c | 536 +++++++++++++--
> tools/testing/radix-tree/Makefile | 5 +-
> tools/testing/radix-tree/idr.c | 148 +++++
> 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, 701 insertions(+), 1210 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 5fd3f6e..f54ceea 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
>
> /**
> * DOC: idr sync
> @@ -71,22 +46,30 @@ struct idr {
> * 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()
> @@ -113,17 +96,12 @@ 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
> *
> @@ -131,57 +109,58 @@ 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
> @@ -196,9 +175,6 @@ 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 ca4eea1..6483c73c 100644
> --- a/include/linux/radix-tree.h
> +++ b/include/linux/radix-tree.h
> @@ -98,7 +98,10 @@ 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 2858be7..2757b84 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -550,14 +550,13 @@ 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();
> rcu_init();
>
> /* trace_printk() and trace points may be used after this */
> 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 6098336..3c88abb7 100644
> --- a/lib/idr.c
> +++ b/lib/idr.c
> @@ -1,1068 +1,8 @@
> -/*
> - * 2002-10-18 written by Jim Houston jim.houston@xxxxxxxx
> - * 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@xxxxxxxxx>
> - */
> -
> -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.
> - *
> - * @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.
> @@ -1130,18 +70,3 @@ 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 1bd5df8..19a4a9a 100644
> --- a/lib/radix-tree.c
> +++ b/lib/radix-tree.c
> @@ -24,19 +24,20 @@
>
> #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/percpu.h>
> -#include <linux/slab.h>
> #include <linux/kmemleak.h>
> #include <linux/notifier.h>
> -#include <linux/cpu.h>
> -#include <linux/string.h>
> -#include <linux/rcupdate.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/string.h>
>
>
> /* Number of nodes in fully populated tree of given height */
> @@ -61,6 +62,15 @@ 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 {
> @@ -148,27 +158,38 @@ 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;
> }
>
> /*
> @@ -238,6 +259,13 @@ 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)
> {
> @@ -276,11 +304,47 @@ 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
>
> /*
> @@ -288,10 +352,9 @@ 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
> @@ -521,7 +584,7 @@ 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;
> @@ -538,15 +601,22 @@ 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);
> @@ -565,26 +635,9 @@ static int radix_tree_extend(struct radix_tree_root *root,
> return maxshift + RADIX_TREE_MAP_SHIFT;
> }
>
> -/**
> - * __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;
> @@ -598,7 +651,7 @@ 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;
> @@ -609,7 +662,7 @@ 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;
> @@ -635,7 +688,6 @@ 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
> @@ -670,6 +722,7 @@ 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 *ptr, unsigned order, bool replace)
> {
> @@ -741,6 +794,31 @@ 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
> @@ -891,6 +969,7 @@ 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;
> @@ -926,7 +1005,7 @@ 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;
> @@ -1569,6 +1648,8 @@ static inline bool 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
> @@ -1628,7 +1709,12 @@ bool __radix_tree_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;
> }
>
> @@ -1641,6 +1727,17 @@ bool __radix_tree_delete_node(struct radix_tree_root *root,
> return deleted;
> }
>
> +static void radix_tree_iter_delete(struct radix_tree_root *root,
> + struct radix_tree_iter *iter)
> +{
> + unsigned offset = (iter->index >> iter->shift) & RADIX_TREE_MAP_MASK;
> + struct radix_tree_node *node = iter->node;
> +
> + node->slots[offset] = NULL;
> + node->count--;
> + __radix_tree_delete_node(root, node);
> +}
> +
> static inline void delete_sibling_entries(struct radix_tree_node *node,
> void *ptr, unsigned offset)
> {
> @@ -1663,7 +1760,7 @@ static inline void delete_sibling_entries(struct radix_tree_node *node,
> *
> * 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,
> @@ -1683,16 +1780,21 @@ 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);
>
> delete_sibling_entries(node, node_to_entry(slot), offset);
> node->slots[offset] = NULL;
> @@ -1711,7 +1813,7 @@ 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)
> {
> @@ -1728,8 +1830,7 @@ 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);
> }
> }
>
> @@ -1744,6 +1845,333 @@ int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag)
> }
> EXPORT_SYMBOL(radix_tree_tagged);
>
> +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 an id larger than the last id allocated
> + * @idr: idr handle
> + * @ptr: pointer to be associated with the new id
> + * @end: the maximum id (exclusive)
> + * @gfp: memory allocation flags
> + *
> + * Allocates an ID the same way that idr_alloc_cyclic() does, but does
> + * not wrap around. This is useful for cases where we need to know
> + * whether wrapping has occurred.
> + */
> +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);
> +
> +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);
> +
> +void *idr_replace(struct idr *idr, void *ptr, int id)
> +{
> + 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, NULL, &slot);
> +
> + if (!entry)
> + return ERR_PTR(-ENOENT);
> +
> + radix_tree_replace_slot(slot, ptr);
> +
> + return entry;
> +}
> +EXPORT_SYMBOL(idr_replace);
> +
> +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);
> +
> +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);
> +
> +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);
> +
> +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);
> +
> +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..0f9e7b1
> --- /dev/null
> +++ b/tools/testing/radix-tree/idr.c
> @@ -0,0 +1,148 @@
> +/*
> + * idr.c: Test the IDR API
> + * Copyright (c) 2016 Matthew Wilcox <willy@xxxxxxxxxxxxx>
> + *
> + * 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);
> + else
> + item = item_create(i - 0x3fff);
> +
> + id = idr_alloc_cyclic(&idr, item, 1, 0x4000, GFP_KERNEL);
> + assert(id == item->index);
> + }
> +
> + idr_for_each(&idr, item_idr_free, &idr);
> +}
> +
> +void idr_checks(void)
> +{
> + unsigned long i;
> + DEFINE_IDR(idr);
> +
> + for (i = 0; i < 10000; i++) {
> + struct item *item = item_create(i);
> + 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);
> + 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);
> + assert(idr_alloc(&idr, item, 1, 20000, GFP_KERNEL) == i);
> + }
> +
> + idr_destroy(&idr);
> +
> + 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_callback(NULL, CPU_DEAD, NULL);
> +}
> 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 7d14812..e267d5f 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 1faf0a3..4baec38 100644
> --- a/tools/testing/radix-tree/test.h
> +++ b/tools/testing/radix-tree/test.h
> @@ -36,6 +36,8 @@ void tag_check(void);
> void multiorder_checks(void);
> void iteration_test(void);
> 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
>
> --
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