| /* 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 */ |