183 lines
5.5 KiB
C
183 lines
5.5 KiB
C
/* Private definitions for the generic associative array implementation.
|
|
*
|
|
* See Documentation/assoc_array.txt for information.
|
|
*
|
|
* Copyright (C) 2013 Red Hat, Inc. All Rights Reserved.
|
|
* Written by David Howells (dhowells@redhat.com)
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public Licence
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the Licence, or (at your option) any later version.
|
|
*/
|
|
|
|
#ifndef _LINUX_ASSOC_ARRAY_PRIV_H
|
|
#define _LINUX_ASSOC_ARRAY_PRIV_H
|
|
|
|
#ifdef CONFIG_ASSOCIATIVE_ARRAY
|
|
|
|
#include <linux/assoc_array.h>
|
|
|
|
#define ASSOC_ARRAY_FAN_OUT 16 /* Number of slots per node */
|
|
#define ASSOC_ARRAY_FAN_MASK (ASSOC_ARRAY_FAN_OUT - 1)
|
|
#define ASSOC_ARRAY_LEVEL_STEP (ilog2(ASSOC_ARRAY_FAN_OUT))
|
|
#define ASSOC_ARRAY_LEVEL_STEP_MASK (ASSOC_ARRAY_LEVEL_STEP - 1)
|
|
#define ASSOC_ARRAY_KEY_CHUNK_MASK (ASSOC_ARRAY_KEY_CHUNK_SIZE - 1)
|
|
#define ASSOC_ARRAY_KEY_CHUNK_SHIFT (ilog2(BITS_PER_LONG))
|
|
|
|
/*
|
|
* Undefined type representing a pointer with type information in the bottom
|
|
* two bits.
|
|
*/
|
|
struct assoc_array_ptr;
|
|
|
|
/*
|
|
* An N-way node in the tree.
|
|
*
|
|
* Each slot contains one of four things:
|
|
*
|
|
* (1) Nothing (NULL).
|
|
*
|
|
* (2) A leaf object (pointer types 0).
|
|
*
|
|
* (3) A next-level node (pointer type 1, subtype 0).
|
|
*
|
|
* (4) A shortcut (pointer type 1, subtype 1).
|
|
*
|
|
* The tree is optimised for search-by-ID, but permits reasonable iteration
|
|
* also.
|
|
*
|
|
* The tree is navigated by constructing an index key consisting of an array of
|
|
* segments, where each segment is ilog2(ASSOC_ARRAY_FAN_OUT) bits in size.
|
|
*
|
|
* The segments correspond to levels of the tree (the first segment is used at
|
|
* level 0, the second at level 1, etc.).
|
|
*/
|
|
struct assoc_array_node {
|
|
struct assoc_array_ptr *back_pointer;
|
|
u8 parent_slot;
|
|
struct assoc_array_ptr *slots[ASSOC_ARRAY_FAN_OUT];
|
|
unsigned long nr_leaves_on_branch;
|
|
};
|
|
|
|
/*
|
|
* A shortcut through the index space out to where a collection of nodes/leaves
|
|
* with the same IDs live.
|
|
*/
|
|
struct assoc_array_shortcut {
|
|
struct assoc_array_ptr *back_pointer;
|
|
int parent_slot;
|
|
int skip_to_level;
|
|
struct assoc_array_ptr *next_node;
|
|
unsigned long index_key[];
|
|
};
|
|
|
|
/*
|
|
* Preallocation cache.
|
|
*/
|
|
struct assoc_array_edit {
|
|
struct rcu_head rcu;
|
|
struct assoc_array *array;
|
|
const struct assoc_array_ops *ops;
|
|
const struct assoc_array_ops *ops_for_excised_subtree;
|
|
struct assoc_array_ptr *leaf;
|
|
struct assoc_array_ptr **leaf_p;
|
|
struct assoc_array_ptr *dead_leaf;
|
|
struct assoc_array_ptr *new_meta[3];
|
|
struct assoc_array_ptr *excised_meta[1];
|
|
struct assoc_array_ptr *excised_subtree;
|
|
struct assoc_array_ptr **set_backpointers[ASSOC_ARRAY_FAN_OUT];
|
|
struct assoc_array_ptr *set_backpointers_to;
|
|
struct assoc_array_node *adjust_count_on;
|
|
long adjust_count_by;
|
|
struct {
|
|
struct assoc_array_ptr **ptr;
|
|
struct assoc_array_ptr *to;
|
|
} set[2];
|
|
struct {
|
|
u8 *p;
|
|
u8 to;
|
|
} set_parent_slot[1];
|
|
u8 segment_cache[ASSOC_ARRAY_FAN_OUT + 1];
|
|
};
|
|
|
|
/*
|
|
* Internal tree member pointers are marked in the bottom one or two bits to
|
|
* indicate what type they are so that we don't have to look behind every
|
|
* pointer to see what it points to.
|
|
*
|
|
* We provide functions to test type annotations and to create and translate
|
|
* the annotated pointers.
|
|
*/
|
|
#define ASSOC_ARRAY_PTR_TYPE_MASK 0x1UL
|
|
#define ASSOC_ARRAY_PTR_LEAF_TYPE 0x0UL /* Points to leaf (or nowhere) */
|
|
#define ASSOC_ARRAY_PTR_META_TYPE 0x1UL /* Points to node or shortcut */
|
|
#define ASSOC_ARRAY_PTR_SUBTYPE_MASK 0x2UL
|
|
#define ASSOC_ARRAY_PTR_NODE_SUBTYPE 0x0UL
|
|
#define ASSOC_ARRAY_PTR_SHORTCUT_SUBTYPE 0x2UL
|
|
|
|
static inline bool assoc_array_ptr_is_meta(const struct assoc_array_ptr *x)
|
|
{
|
|
return (unsigned long)x & ASSOC_ARRAY_PTR_TYPE_MASK;
|
|
}
|
|
static inline bool assoc_array_ptr_is_leaf(const struct assoc_array_ptr *x)
|
|
{
|
|
return !assoc_array_ptr_is_meta(x);
|
|
}
|
|
static inline bool assoc_array_ptr_is_shortcut(const struct assoc_array_ptr *x)
|
|
{
|
|
return (unsigned long)x & ASSOC_ARRAY_PTR_SUBTYPE_MASK;
|
|
}
|
|
static inline bool assoc_array_ptr_is_node(const struct assoc_array_ptr *x)
|
|
{
|
|
return !assoc_array_ptr_is_shortcut(x);
|
|
}
|
|
|
|
static inline void *assoc_array_ptr_to_leaf(const struct assoc_array_ptr *x)
|
|
{
|
|
return (void *)((unsigned long)x & ~ASSOC_ARRAY_PTR_TYPE_MASK);
|
|
}
|
|
|
|
static inline
|
|
unsigned long __assoc_array_ptr_to_meta(const struct assoc_array_ptr *x)
|
|
{
|
|
return (unsigned long)x &
|
|
~(ASSOC_ARRAY_PTR_SUBTYPE_MASK | ASSOC_ARRAY_PTR_TYPE_MASK);
|
|
}
|
|
static inline
|
|
struct assoc_array_node *assoc_array_ptr_to_node(const struct assoc_array_ptr *x)
|
|
{
|
|
return (struct assoc_array_node *)__assoc_array_ptr_to_meta(x);
|
|
}
|
|
static inline
|
|
struct assoc_array_shortcut *assoc_array_ptr_to_shortcut(const struct assoc_array_ptr *x)
|
|
{
|
|
return (struct assoc_array_shortcut *)__assoc_array_ptr_to_meta(x);
|
|
}
|
|
|
|
static inline
|
|
struct assoc_array_ptr *__assoc_array_x_to_ptr(const void *p, unsigned long t)
|
|
{
|
|
return (struct assoc_array_ptr *)((unsigned long)p | t);
|
|
}
|
|
static inline
|
|
struct assoc_array_ptr *assoc_array_leaf_to_ptr(const void *p)
|
|
{
|
|
return __assoc_array_x_to_ptr(p, ASSOC_ARRAY_PTR_LEAF_TYPE);
|
|
}
|
|
static inline
|
|
struct assoc_array_ptr *assoc_array_node_to_ptr(const struct assoc_array_node *p)
|
|
{
|
|
return __assoc_array_x_to_ptr(
|
|
p, ASSOC_ARRAY_PTR_META_TYPE | ASSOC_ARRAY_PTR_NODE_SUBTYPE);
|
|
}
|
|
static inline
|
|
struct assoc_array_ptr *assoc_array_shortcut_to_ptr(const struct assoc_array_shortcut *p)
|
|
{
|
|
return __assoc_array_x_to_ptr(
|
|
p, ASSOC_ARRAY_PTR_META_TYPE | ASSOC_ARRAY_PTR_SHORTCUT_SUBTYPE);
|
|
}
|
|
|
|
#endif /* CONFIG_ASSOCIATIVE_ARRAY */
|
|
#endif /* _LINUX_ASSOC_ARRAY_PRIV_H */
|