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: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/lib/prio_tree.c b/lib/prio_tree.c
index 928482b..8d443af 100644
--- a/lib/prio_tree.c
+++ b/lib/prio_tree.c
@@ -85,6 +85,17 @@
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 @@
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 @@
* 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 @@
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;