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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 <linux/types.h>

#include <linux/bitops.h>

#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        *ary[1<<IDR_BITS];

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

};

struct idr {

        struct idr_layer *top;

        struct idr_layer *id_free;

        int               layers;

        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)

/*

 * 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_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.

 */

#define IDA_CHUNK_SIZE          128     /* 128 bytes per chunk */

#define IDA_BITMAP_LONGS        (128 / 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);

#endif /* __IDR_H__ */