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1408 serge 1
/*
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 * include/linux/idr.h
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 *
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 * 2002-10-18  written by Jim Houston jim.houston@ccur.com
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 *	Copyright (C) 2002 by Concurrent Computer Corporation
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 *	Distributed under the GNU GPL license version 2.
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 *
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 * Small id to pointer translation service avoiding fixed sized
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 * tables.
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 */
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#ifndef __IDR_H__
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#define __IDR_H__
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1964 serge 15
#include 
1967 serge 16
#include 
1964 serge 17
#include 
1408 serge 18
//#include 
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//#include 
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struct rcu_head {
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    struct rcu_head *next;
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    void (*func)(struct rcu_head *head);
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};
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1964 serge 27
#if BITS_PER_LONG == 32
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# define IDR_BITS 5
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# define IDR_FULL 0xfffffffful
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/* We can only use two of the bits in the top level because there is
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   only one possible bit in the top level (5 bits * 7 levels = 35
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   bits, but you only use 31 bits in the id). */
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# define TOP_LEVEL_FULL (IDR_FULL >> 30)
1964 serge 34
#elif BITS_PER_LONG == 64
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# define IDR_BITS 6
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# define IDR_FULL 0xfffffffffffffffful
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/* We can only use two of the bits in the top level because there is
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   only one possible bit in the top level (6 bits * 6 levels = 36
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   bits, but you only use 31 bits in the id). */
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# define TOP_LEVEL_FULL (IDR_FULL >> 62)
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#else
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# error "BITS_PER_LONG is not 32 or 64"
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#endif
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#define IDR_SIZE (1 << IDR_BITS)
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#define IDR_MASK ((1 << IDR_BITS)-1)
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#define MAX_ID_SHIFT (sizeof(int)*8 - 1)
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#define MAX_ID_BIT (1U << MAX_ID_SHIFT)
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#define MAX_ID_MASK (MAX_ID_BIT - 1)
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/* Leave the possibility of an incomplete final layer */
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#define MAX_LEVEL (MAX_ID_SHIFT + IDR_BITS - 1) / IDR_BITS
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/* Number of id_layer structs to leave in free list */
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#define IDR_FREE_MAX MAX_LEVEL + MAX_LEVEL
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struct idr_layer {
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	unsigned long		 bitmap; /* A zero bit means "space here" */
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	struct idr_layer __rcu	*ary[1<
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	int			 count;	 /* When zero, we can release it */
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	int			 layer;	 /* distance from leaf */
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    struct rcu_head      rcu_head;
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};
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struct idr {
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	struct idr_layer __rcu *top;
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	struct idr_layer *id_free;
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	int		  layers; /* only valid without concurrent changes */
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	int		  id_free_cnt;
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//   spinlock_t    lock;
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};
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#define IDR_INIT(name)						\
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{								\
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	.top		= NULL,					\
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	.id_free	= NULL,					\
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	.layers 	= 0,					\
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	.id_free_cnt	= 0,					\
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//   .lock       = __SPIN_LOCK_UNLOCKED(name.lock),  \
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}
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#define DEFINE_IDR(name)	struct idr name = IDR_INIT(name)
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/* Actions to be taken after a call to _idr_sub_alloc */
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#define IDR_NEED_TO_GROW -2
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#define IDR_NOMORE_SPACE -3
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#define _idr_rc_to_errno(rc) ((rc) == -1 ? -EAGAIN : -ENOSPC)
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/**
1964 serge 91
 * DOC: idr sync
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 * idr synchronization (stolen from radix-tree.h)
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 *
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 * idr_find() is able to be called locklessly, using RCU. The caller must
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 * ensure calls to this function are made within rcu_read_lock() regions.
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 * Other readers (lock-free or otherwise) and modifications may be running
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 * concurrently.
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 *
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 * It is still required that the caller manage the synchronization and
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 * lifetimes of the items. So if RCU lock-free lookups are used, typically
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 * this would mean that the items have their own locks, or are amenable to
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 * lock-free access; and that the items are freed by RCU (or only freed after
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 * having been deleted from the idr tree *and* a synchronize_rcu() grace
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 * period).
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 */
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/*
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 * This is what we export.
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 */
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void *idr_find(struct idr *idp, int id);
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int idr_pre_get(struct idr *idp, gfp_t gfp_mask);
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int idr_get_new(struct idr *idp, void *ptr, int *id);
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int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id);
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int idr_for_each(struct idr *idp,
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		 int (*fn)(int id, void *p, void *data), void *data);
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void *idr_get_next(struct idr *idp, int *nextid);
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void *idr_replace(struct idr *idp, void *ptr, int id);
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void idr_remove(struct idr *idp, int id);
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void idr_remove_all(struct idr *idp);
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void idr_destroy(struct idr *idp);
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void idr_init(struct idr *idp);
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/*
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 * IDA - IDR based id allocator, use when translation from id to
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 * pointer isn't necessary.
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 *
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 * IDA_BITMAP_LONGS is calculated to be one less to accommodate
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 * ida_bitmap->nr_busy so that the whole struct fits in 128 bytes.
1408 serge 131
 */
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#define IDA_CHUNK_SIZE		128	/* 128 bytes per chunk */
1964 serge 133
#define IDA_BITMAP_LONGS	(IDA_CHUNK_SIZE / sizeof(long) - 1)
1408 serge 134
#define IDA_BITMAP_BITS		(IDA_BITMAP_LONGS * sizeof(long) * 8)
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struct ida_bitmap {
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	long			nr_busy;
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	unsigned long		bitmap[IDA_BITMAP_LONGS];
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};
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struct ida {
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	struct idr		idr;
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	struct ida_bitmap	*free_bitmap;
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};
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#define IDA_INIT(name)		{ .idr = IDR_INIT(name), .free_bitmap = NULL, }
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#define DEFINE_IDA(name)	struct ida name = IDA_INIT(name)
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1964 serge 149
int ida_pre_get(struct ida *ida, gfp_t gfp_mask);
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int ida_get_new_above(struct ida *ida, int starting_id, int *p_id);
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int ida_get_new(struct ida *ida, int *p_id);
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void ida_remove(struct ida *ida, int id);
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void ida_destroy(struct ida *ida);
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void ida_init(struct ida *ida);
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void idr_init_cache(void);
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#endif /* __IDR_H__ */