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![Thomas Gleixner](/assets/img/avatar_default.png)
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1334 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
139 lines
4.7 KiB
C
139 lines
4.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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Red Black Trees
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(C) 1999 Andrea Arcangeli <andrea@suse.de>
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linux/include/linux/rbtree.h
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To use rbtrees you'll have to implement your own insert and search cores.
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This will avoid us to use callbacks and to drop drammatically performances.
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I know it's not the cleaner way, but in C (not in C++) to get
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performances and genericity...
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See Documentation/rbtree.txt for documentation and samples.
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*/
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#ifndef _LINUX_RBTREE_H
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#define _LINUX_RBTREE_H
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#include <linux/kernel.h>
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#include <linux/stddef.h>
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#include <linux/rcupdate.h>
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struct rb_node {
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unsigned long __rb_parent_color;
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struct rb_node *rb_right;
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struct rb_node *rb_left;
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} __attribute__((aligned(sizeof(long))));
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/* The alignment might seem pointless, but allegedly CRIS needs it */
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struct rb_root {
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struct rb_node *rb_node;
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};
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/*
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* Leftmost-cached rbtrees.
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*
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* We do not cache the rightmost node based on footprint
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* size vs number of potential users that could benefit
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* from O(1) rb_last(). Just not worth it, users that want
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* this feature can always implement the logic explicitly.
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* Furthermore, users that want to cache both pointers may
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* find it a bit asymmetric, but that's ok.
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*/
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struct rb_root_cached {
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struct rb_root rb_root;
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struct rb_node *rb_leftmost;
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};
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#define rb_parent(r) ((struct rb_node *)((r)->__rb_parent_color & ~3))
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#define RB_ROOT (struct rb_root) { NULL, }
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#define RB_ROOT_CACHED (struct rb_root_cached) { {NULL, }, NULL }
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#define rb_entry(ptr, type, member) container_of(ptr, type, member)
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#define RB_EMPTY_ROOT(root) (READ_ONCE((root)->rb_node) == NULL)
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/* 'empty' nodes are nodes that are known not to be inserted in an rbtree */
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#define RB_EMPTY_NODE(node) \
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((node)->__rb_parent_color == (unsigned long)(node))
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#define RB_CLEAR_NODE(node) \
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((node)->__rb_parent_color = (unsigned long)(node))
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extern void rb_insert_color(struct rb_node *, struct rb_root *);
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extern void rb_erase(struct rb_node *, struct rb_root *);
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/* Find logical next and previous nodes in a tree */
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extern struct rb_node *rb_next(const struct rb_node *);
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extern struct rb_node *rb_prev(const struct rb_node *);
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extern struct rb_node *rb_first(const struct rb_root *);
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extern struct rb_node *rb_last(const struct rb_root *);
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extern void rb_insert_color_cached(struct rb_node *,
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struct rb_root_cached *, bool);
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extern void rb_erase_cached(struct rb_node *node, struct rb_root_cached *);
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/* Same as rb_first(), but O(1) */
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#define rb_first_cached(root) (root)->rb_leftmost
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/* Postorder iteration - always visit the parent after its children */
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extern struct rb_node *rb_first_postorder(const struct rb_root *);
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extern struct rb_node *rb_next_postorder(const struct rb_node *);
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/* Fast replacement of a single node without remove/rebalance/add/rebalance */
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extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
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struct rb_root *root);
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extern void rb_replace_node_rcu(struct rb_node *victim, struct rb_node *new,
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struct rb_root *root);
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extern void rb_replace_node_cached(struct rb_node *victim, struct rb_node *new,
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struct rb_root_cached *root);
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static inline void rb_link_node(struct rb_node *node, struct rb_node *parent,
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struct rb_node **rb_link)
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{
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node->__rb_parent_color = (unsigned long)parent;
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node->rb_left = node->rb_right = NULL;
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*rb_link = node;
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}
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static inline void rb_link_node_rcu(struct rb_node *node, struct rb_node *parent,
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struct rb_node **rb_link)
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{
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node->__rb_parent_color = (unsigned long)parent;
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node->rb_left = node->rb_right = NULL;
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rcu_assign_pointer(*rb_link, node);
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}
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#define rb_entry_safe(ptr, type, member) \
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({ typeof(ptr) ____ptr = (ptr); \
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____ptr ? rb_entry(____ptr, type, member) : NULL; \
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})
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/**
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* rbtree_postorder_for_each_entry_safe - iterate in post-order over rb_root of
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* given type allowing the backing memory of @pos to be invalidated
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*
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* @pos: the 'type *' to use as a loop cursor.
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* @n: another 'type *' to use as temporary storage
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* @root: 'rb_root *' of the rbtree.
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* @field: the name of the rb_node field within 'type'.
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*
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* rbtree_postorder_for_each_entry_safe() provides a similar guarantee as
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* list_for_each_entry_safe() and allows the iteration to continue independent
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* of changes to @pos by the body of the loop.
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*
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* Note, however, that it cannot handle other modifications that re-order the
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* rbtree it is iterating over. This includes calling rb_erase() on @pos, as
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* rb_erase() may rebalance the tree, causing us to miss some nodes.
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*/
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#define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \
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for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \
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pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \
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typeof(*pos), field); 1; }); \
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pos = n)
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#endif /* _LINUX_RBTREE_H */
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