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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>
This commit is contained in:
Xiao Guangrong 2012-03-23 15:02:15 -07:00 committed by Linus Torvalds
parent 742245d5c2
commit 97e834c504
1 changed files with 22 additions and 25 deletions
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47
lib/prio_tree.c
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@ -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;