1 /* SPDX-License-Identifier: GPL-2.0-or-later */
11   I know it's not the cleaner way,  but in C (not in C++) to get
14   See Documentation/core-api/rbtree.rst for documentation and samples.
26 #define rb_parent(r)   ((struct rb_node *)((r)->__rb_parent_color & ~3))
30 #define RB_EMPTY_ROOT(root)  (READ_ONCE((root)->rb_node) == NULL)
32 /* 'empty' nodes are nodes that are known not to be inserted in an rbtree */
34 	((node)->__rb_parent_color == (unsigned long)(node))
36 	((node)->__rb_parent_color = (unsigned long)(node))
43 /* Find logical next and previous nodes in a tree */
49 /* Postorder iteration - always visit the parent after its children */
62 	node->__rb_parent_color = (unsigned long)parent;  in rb_link_node()
63 	node->rb_left = node->rb_right = NULL;  in rb_link_node()
71 	node->__rb_parent_color = (unsigned long)parent;  in rb_link_node_rcu()
72 	node->rb_left = node->rb_right = NULL;  in rb_link_node_rcu()
83  * rbtree_postorder_for_each_entry_safe - iterate in post-order over rb_root of
95  * Note, however, that it cannot handle other modifications that re-order the
97  * rb_erase() may rebalance the tree, causing us to miss some nodes.
101 	     pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \
106 #define rb_first_cached(root) (root)->rb_leftmost
113 		root->rb_leftmost = node;  in rb_insert_color_cached()
114 	rb_insert_color(node, &root->rb_root);  in rb_insert_color_cached()
123 	if (root->rb_leftmost == node)  in rb_erase_cached()
124 		leftmost = root->rb_leftmost = rb_next(node);  in rb_erase_cached()
126 	rb_erase(node, &root->rb_root);  in rb_erase_cached()
135 	if (root->rb_leftmost == victim)  in rb_replace_node_cached()
136 		root->rb_leftmost = new;  in rb_replace_node_cached()
137 	rb_replace_node(victim, new, &root->rb_root);  in rb_replace_node_cached()
144  *	comp(a->key,b) < 0  := less(a,b)
145  *	comp(a->key,b) > 0  := less(b,a)
146  *	comp(a->key,b) == 0 := !less(a,b) && !less(b,a)
153  * on-stack dummy object, which might not be feasible due to object size.
157  * rb_add_cached() - insert @node into the leftmost cached tree @tree
159  * @tree: leftmost cached tree to insert @node into
165 rb_add_cached(struct rb_node *node, struct rb_root_cached *tree,  in rb_add_cached()  argument
168 	struct rb_node **link = &tree->rb_root.rb_node;  in rb_add_cached()
175 			link = &parent->rb_left;  in rb_add_cached()
177 			link = &parent->rb_right;  in rb_add_cached()
183 	rb_insert_color_cached(node, tree, leftmost);  in rb_add_cached()
189  * rb_add() - insert @node into @tree
191  * @tree: tree to insert @node into
195 rb_add(struct rb_node *node, struct rb_root *tree,  in rb_add()  argument
198 	struct rb_node **link = &tree->rb_node;  in rb_add()
204 			link = &parent->rb_left;  in rb_add()
206 			link = &parent->rb_right;  in rb_add()
210 	rb_insert_color(node, tree);  in rb_add()
214  * rb_find_add() - find equivalent @node in @tree, or add @node
215  * @node: node to look-for / insert
216  * @tree: tree to search / modify
223 rb_find_add(struct rb_node *node, struct rb_root *tree,  in rb_find_add()  argument
226 	struct rb_node **link = &tree->rb_node;  in rb_find_add()
235 			link = &parent->rb_left;  in rb_find_add()
237 			link = &parent->rb_right;  in rb_find_add()
243 	rb_insert_color(node, tree);  in rb_find_add()
248  * rb_find_add_rcu() - find equivalent @node in @tree, or add @node
249  * @node: node to look-for / insert
250  * @tree: tree to search / modify
253  * Adds a Store-Release for link_node.
259 rb_find_add_rcu(struct rb_node *node, struct rb_root *tree,  in rb_find_add_rcu()  argument
262 	struct rb_node **link = &tree->rb_node;  in rb_find_add_rcu()
271 			link = &parent->rb_left;  in rb_find_add_rcu()
273 			link = &parent->rb_right;  in rb_find_add_rcu()
279 	rb_insert_color(node, tree);  in rb_find_add_rcu()
284  * rb_find() - find @key in tree @tree
286  * @tree: tree to search
292 rb_find(const void *key, const struct rb_root *tree,  in rb_find()  argument
295 	struct rb_node *node = tree->rb_node;  in rb_find()
301 			node = node->rb_left;  in rb_find()
303 			node = node->rb_right;  in rb_find()
312  * rb_find_rcu() - find @key in tree @tree
314  * @tree: tree to search
317  * Notably, tree descent vs concurrent tree rotations is unsound and can result
318  * in false-negatives.
323 rb_find_rcu(const void *key, const struct rb_root *tree,  in rb_find_rcu()  argument
326 	struct rb_node *node = tree->rb_node;  in rb_find_rcu()
332 			node = rcu_dereference_raw(node->rb_left);  in rb_find_rcu()
334 			node = rcu_dereference_raw(node->rb_right);  in rb_find_rcu()
343  * rb_find_first() - find the first @key in @tree
345  * @tree: tree to search
351 rb_find_first(const void *key, const struct rb_root *tree,  in rb_find_first()  argument
354 	struct rb_node *node = tree->rb_node;  in rb_find_first()
363 			node = node->rb_left;  in rb_find_first()
365 			node = node->rb_right;  in rb_find_first()
373  * rb_next_match() - find the next @key in @tree
375  * @tree: tree to search
391  * rb_for_each() - iterates a subtree matching @key
394  * @tree: tree to search
397 #define rb_for_each(node, key, tree, cmp) \  argument
398 	for ((node) = rb_find_first((key), (tree), (cmp)); \