linux-master/lib/rbtree.c

18  *  1) A node is either red or black
21  *  4) Both children of every red node are black
26  *  consecutive red nodes in a path and every red node is therefore followed by
85 __rb_insert(struct rb_node *node, struct rb_root *root,
88 	struct rb_node *parent = rb_red_parent(node), *gparent, *tmp;
92 		 * Loop invariant: node is red.
96 			 * The inserted node is root. Either this is the
97 			 * first node, or we recursed at Case 1 below and
100 			rb_set_parent_color(node, NULL, RB_BLACK);
119 				 * Case 1 - node's uncle is red (color flips).
133 				node = gparent;
134 				parent = rb_parent(node);
135 				rb_set_parent_color(node, parent, RB_RED);
140 			if (node == tmp) {
142 				 * Case 2 - node's uncle is black and node is
154 				tmp = node->rb_left;
156 				WRITE_ONCE(node->rb_left, parent);
160 				rb_set_parent_color(parent, node, RB_RED);
161 				augment_rotate(parent, node);
162 				parent = node;
163 				tmp = node->rb_right;
167 			 * Case 3 - node's uncle is black and node is
189 				node = gparent;
190 				parent = rb_parent(node);
191 				rb_set_parent_color(node, parent, RB_RED);
196 			if (node == tmp) {
198 				tmp = node->rb_right;
200 				WRITE_ONCE(node->rb_right, parent);
204 				rb_set_parent_color(parent, node, RB_RED);
205 				augment_rotate(parent, node);
206 				parent = node;
207 				tmp = node->rb_left;
230 	struct rb_node *node = NULL, *sibling, *tmp1, *tmp2;
235 		 * - node is black (or NULL on first iteration)
236 		 * - node is not the root (parent is not NULL)
237 		 * - All leaf paths going through parent and node have a
238 		 *   black node count that is 1 lower than other leaf paths.
241 		if (node != sibling) {	/* node == parent->rb_left */
285 						node = parent;
286 						parent = rb_parent(node);
375 						node = parent;
376 						parent = rb_parent(node);
424 static inline void dummy_propagate(struct rb_node *node, struct rb_node *stop) {}
434 void rb_insert_color(struct rb_node *node, struct rb_root *root)
436 	__rb_insert(node, root, dummy_rotate);
440 void rb_erase(struct rb_node *node, struct rb_root *root)
443 	rebalance = __rb_erase_augmented(node, root, &dummy_callbacks);
456 void __rb_insert_augmented(struct rb_node *node, struct rb_root *root,
459 	__rb_insert(node, root, augment_rotate);
464  * This function returns the first node (in sort order) of the tree.
492 struct rb_node *rb_next(const struct rb_node *node)
496 	if (RB_EMPTY_NODE(node))
503 	if (node->rb_right) {
504 		node = node->rb_right;
505 		while (node->rb_left)
506 			node = node->rb_left;
507 		return (struct rb_node *)node;
512 	 * so any 'next' node must be in the general direction of our parent.
515 	 * parent, said parent is our 'next' node.
517 	while ((parent = rb_parent(node)) && node == parent->rb_right)
518 		node = parent;
524 struct rb_node *rb_prev(const struct rb_node *node)
528 	if (RB_EMPTY_NODE(node))
535 	if (node->rb_left) {
536 		node = node->rb_left;
537 		while (node->rb_right)
538 			node = node->rb_right;
539 		return (struct rb_node *)node;
546 	while ((parent = rb_parent(node)) && node == parent->rb_left)
547 		node = parent;
584 	/* Set the parent's pointer to the new node last after an RCU barrier
592 static struct rb_node *rb_left_deepest_node(const struct rb_node *node)
595 		if (node->rb_left)
596 			node = node->rb_left;
597 		else if (node->rb_right)
598 			node = node->rb_right;
600 			return (struct rb_node *)node;
604 struct rb_node *rb_next_postorder(const struct rb_node *node)
607 	if (!node)
609 	parent = rb_parent(node);
611 	/* If we're sitting on node, we've already seen our children */
612 	if (parent && node == parent->rb_left && parent->rb_right) {
613 		/* If we are the parent's left node, go to the parent's right
614 		 * node then all the way down to the left */
617 		/* Otherwise we are the parent's right node, and the parent