name : assoc_array_priv.h /* SPDX-License-Identifier: GPL-2.0-or-later */ /* Private definitions for the generic associative array implementation. * * See Documentation/core-api/assoc_array.rst for information. * * Copyright (C) 2013 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) */ #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 */