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/*

 * include/linux/idr.h

 *

 * 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.

 *

 * Small id to pointer translation service avoiding fixed sized

 * tables.

 */

#ifndef __IDR_H__

#define __IDR_H__

#include 

#include 

//#include 

//#include 

struct rcu_head {

    struct rcu_head *next;

    void (*func)(struct rcu_head *head);

};

#if BITS_PER_LONG == 32

# define IDR_BITS 5

# define IDR_FULL 0xfffffffful

/* We can only use two of the bits in the top level because there is

   only one possible bit in the top level (5 bits * 7 levels = 35

   bits, but you only use 31 bits in the id). */

# define TOP_LEVEL_FULL (IDR_FULL >> 30)

#elif BITS_PER_LONG == 64

# define IDR_BITS 6

# define IDR_FULL 0xfffffffffffffffful

/* We can only use two of the bits in the top level because there is

   only one possible bit in the top level (6 bits * 6 levels = 36

   bits, but you only use 31 bits in the id). */

# define TOP_LEVEL_FULL (IDR_FULL >> 62)

#else

# error "BITS_PER_LONG is not 32 or 64"

#endif

#define IDR_SIZE (1 << IDR_BITS)

#define IDR_MASK ((1 << IDR_BITS)-1)

#define MAX_ID_SHIFT (sizeof(int)*8 - 1)

#define MAX_ID_BIT (1U << MAX_ID_SHIFT)

#define MAX_ID_MASK (MAX_ID_BIT - 1)

/* Leave the possibility of an incomplete final layer */

#define MAX_LEVEL (MAX_ID_SHIFT + IDR_BITS - 1) / IDR_BITS

/* Number of id_layer structs to leave in free list */

#define IDR_FREE_MAX MAX_LEVEL + MAX_LEVEL

struct idr_layer {

	unsigned long		 bitmap; /* A zero bit means "space here" */

	struct idr_layer __rcu	*ary[1<

	int			 count;	 /* When zero, we can release it */

	int			 layer;	 /* distance from leaf */

    struct rcu_head      rcu_head;

};

struct idr {

	struct idr_layer __rcu *top;

	struct idr_layer *id_free;

	int		  layers; /* only valid without concurrent changes */

	int		  id_free_cnt;

//   spinlock_t    lock;

};

#define IDR_INIT(name)						\

{								\

	.top		= NULL,					\

	.id_free	= NULL,					\

	.layers 	= 0,					\

	.id_free_cnt	= 0,					\

//   .lock       = __SPIN_LOCK_UNLOCKED(name.lock),  \

}

#define DEFINE_IDR(name)	struct idr name = IDR_INIT(name)

/* Actions to be taken after a call to _idr_sub_alloc */

#define IDR_NEED_TO_GROW -2

#define IDR_NOMORE_SPACE -3

#define _idr_rc_to_errno(rc) ((rc) == -1 ? -EAGAIN : -ENOSPC)

/**

 * DOC: idr sync

 * idr synchronization (stolen from radix-tree.h)

 *

 * idr_find() is able to be called locklessly, using RCU. The caller must

 * ensure calls to this function are made within rcu_read_lock() regions.

 * Other readers (lock-free or otherwise) and modifications may be running

 * concurrently.

 *

 * It is still required that the caller manage the synchronization and

 * lifetimes of the items. So if RCU lock-free lookups are used, typically

 * this would mean that the items have their own locks, or are amenable to

 * lock-free access; and that the items are freed by RCU (or only freed after

 * having been deleted from the idr tree *and* a synchronize_rcu() grace

 * period).

 */

/*

 * This is what we export.

 */

void *idr_find(struct idr *idp, int id);

int idr_pre_get(struct idr *idp, gfp_t gfp_mask);

int idr_get_new(struct idr *idp, void *ptr, int *id);

int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id);

int idr_for_each(struct idr *idp,

		 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_remove_all(struct idr *idp);

void idr_destroy(struct idr *idp);

void idr_init(struct idr *idp);

/*

 * 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_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 ida_bitmap	*free_bitmap;

};

#define IDA_INIT(name)		{ .idr = IDR_INIT(name), .free_bitmap = NULL, }

#define DEFINE_IDA(name)	struct ida name = IDA_INIT(name)

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);

int ida_get_new(struct ida *ida, int *p_id);

void ida_remove(struct ida *ida, int id);

void ida_destroy(struct ida *ida);

void ida_init(struct ida *ida);

void idr_init_cache(void);

#endif /* __IDR_H__ */