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Commit 97e834c5 authored by Xiao Guangrong's avatar Xiao Guangrong Committed by Linus Torvalds
Browse files

prio_tree: introduce prio_set_parent() 



Introduce prio_set_parent() to abstract the operation which is used to
attach the node to its parent.

Signed-off-by: default avatarXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 742245d5

lib/prio_tree.c

+22 −25
Original line number Diff line number Diff line
@@ -85,6 +85,17 @@ static inline unsigned long prio_tree_maxindex(unsigned int bits) 
	return index_bits_to_maxindex[bits - 1];

}



static void prio_set_parent(struct prio_tree_node *parent,

			    struct prio_tree_node *child, bool left)

{

	if (left)

		parent->left = child;

	else

		parent->right = child;



	child->parent = parent;

}



/*

 * Extend a priority search tree so that it can store a node with heap_index

 * max_heap_index. In the worst case, this algorithm takes O((log n)^2).
@@ -113,15 +124,12 @@ static struct prio_tree_node *prio_tree_expand(struct prio_tree_root *root, 
		prio_tree_remove(root, root->prio_tree_node);

		INIT_PRIO_TREE_NODE(tmp);



		prev->left = tmp;

		tmp->parent = prev;

		prio_set_parent(prev, tmp, true);

		prev = tmp;

	}



	if (!prio_tree_empty(root)) {

		prev->left = root->prio_tree_node;

		prev->left->parent = prev;

	}

	if (!prio_tree_empty(root))

		prio_set_parent(prev, root->prio_tree_node, true);



	root->prio_tree_node = node;

	return node;
@@ -142,23 +150,14 @@ struct prio_tree_node *prio_tree_replace(struct prio_tree_root *root, 
		 * and does not help much to improve performance (IMO).

		 */

		root->prio_tree_node = node;

	} else {

		node->parent = old->parent;

		if (old->parent->left == old)

			old->parent->left = node;

		else

			old->parent->right = node;

	}

	} else

		prio_set_parent(old->parent, node, old->parent->left == old);



	if (!prio_tree_left_empty(old)) {

		node->left = old->left;

		old->left->parent = node;

	}

	if (!prio_tree_left_empty(old))

		prio_set_parent(node, old->left, true);



	if (!prio_tree_right_empty(old)) {

		node->right = old->right;

		old->right->parent = node;

	}

	if (!prio_tree_right_empty(old))

		prio_set_parent(node, old->right, false);



	return old;

}
@@ -218,16 +217,14 @@ struct prio_tree_node *prio_tree_insert(struct prio_tree_root *root, 
		if (index & mask) {

			if (prio_tree_right_empty(cur)) {

				INIT_PRIO_TREE_NODE(node);

				cur->right = node;

				node->parent = cur;

				prio_set_parent(cur, node, false);

				return res;

			} else

				cur = cur->right;

		} else {

			if (prio_tree_left_empty(cur)) {

				INIT_PRIO_TREE_NODE(node);

				cur->left = node;

				node->parent = cur;

				prio_set_parent(cur, node, true);

				return res;

			} else

				cur = cur->left;