/* 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) * * 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 inlineunsigned 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 inlinestruct 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 inlinestruct 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 inlinestruct assoc_array_ptr *__assoc_array_x_to_ptr(const void *p, unsigned long t){	return (struct assoc_array_ptr *)((unsigned long)p | t);}static inlinestruct assoc_array_ptr *assoc_array_leaf_to_ptr(const void *p){	return __assoc_array_x_to_ptr(p, ASSOC_ARRAY_PTR_LEAF_TYPE);}static inlinestruct 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 inlinestruct 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 */