rbtree: Add support for augmented rbtrees
Add support for augmented rbtrees in core rbtree code.
This will be used in subsequent patches, in x86 PAT code, which needs
interval trees to efficiently keep track of PAT ranges.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
LKML-Reference: <20100210232343.GA11465@linux-os.sc.intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/lib/rbtree.c b/lib/rbtree.c
index e2aa3be..15e10b1 100644
--- a/lib/rbtree.c
+++ b/lib/rbtree.c
@@ -44,6 +44,11 @@
else
root->rb_node = right;
rb_set_parent(node, right);
+
+ if (root->augment_cb) {
+ root->augment_cb(node);
+ root->augment_cb(right);
+ }
}
static void __rb_rotate_right(struct rb_node *node, struct rb_root *root)
@@ -67,12 +72,20 @@
else
root->rb_node = left;
rb_set_parent(node, left);
+
+ if (root->augment_cb) {
+ root->augment_cb(node);
+ root->augment_cb(left);
+ }
}
void rb_insert_color(struct rb_node *node, struct rb_root *root)
{
struct rb_node *parent, *gparent;
+ if (root->augment_cb)
+ root->augment_cb(node);
+
while ((parent = rb_parent(node)) && rb_is_red(parent))
{
gparent = rb_parent(parent);
@@ -227,12 +240,15 @@
else
{
struct rb_node *old = node, *left;
+ int old_parent_cb = 0;
+ int successor_parent_cb = 0;
node = node->rb_right;
while ((left = node->rb_left) != NULL)
node = left;
if (rb_parent(old)) {
+ old_parent_cb = 1;
if (rb_parent(old)->rb_left == old)
rb_parent(old)->rb_left = node;
else
@@ -247,8 +263,10 @@
if (parent == old) {
parent = node;
} else {
+ successor_parent_cb = 1;
if (child)
rb_set_parent(child, parent);
+
parent->rb_left = child;
node->rb_right = old->rb_right;
@@ -259,6 +277,24 @@
node->rb_left = old->rb_left;
rb_set_parent(old->rb_left, node);
+ if (root->augment_cb) {
+ /*
+ * Here, three different nodes can have new children.
+ * The parent of the successor node that was selected
+ * to replace the node to be erased.
+ * The node that is getting erased and is now replaced
+ * by its successor.
+ * The parent of the node getting erased-replaced.
+ */
+ if (successor_parent_cb)
+ root->augment_cb(parent);
+
+ root->augment_cb(node);
+
+ if (old_parent_cb)
+ root->augment_cb(rb_parent(old));
+ }
+
goto color;
}
@@ -267,15 +303,19 @@
if (child)
rb_set_parent(child, parent);
- if (parent)
- {
+
+ if (parent) {
if (parent->rb_left == node)
parent->rb_left = child;
else
parent->rb_right = child;
- }
- else
+
+ if (root->augment_cb)
+ root->augment_cb(parent);
+
+ } else {
root->rb_node = child;
+ }
color:
if (color == RB_BLACK)