122 строки
3.4 KiB
C
122 строки
3.4 KiB
C
/*
|
|
* 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>
|
|
#include <linux/init.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);
|
|
|
|
void __init idr_init_cache(void);
|
|
|
|
#endif /* __IDR_H__ */
|