[RBTREE] Merge colour and parent fields of struct rb_node.
We only used a single bit for colour information, so having a whole
machine word of space allocated for it was a bit wasteful. Instead,
store it in the lowest bit of the 'parent' pointer, since that was
always going to be aligned anyway.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
diff --git a/lib/rbtree.c b/lib/rbtree.c
index 63473e0..4a7173c 100644
--- a/lib/rbtree.c
+++ b/lib/rbtree.c
@@ -26,60 +26,66 @@
static void __rb_rotate_left(struct rb_node *node, struct rb_root *root)
{
struct rb_node *right = node->rb_right;
+ struct rb_node *parent = rb_parent(node);
if ((node->rb_right = right->rb_left))
- right->rb_left->rb_parent = node;
+ rb_set_parent(right->rb_left, node);
right->rb_left = node;
- if ((right->rb_parent = node->rb_parent))
+ rb_set_parent(right, parent);
+
+ if (parent)
{
- if (node == node->rb_parent->rb_left)
- node->rb_parent->rb_left = right;
+ if (node == parent->rb_left)
+ parent->rb_left = right;
else
- node->rb_parent->rb_right = right;
+ parent->rb_right = right;
}
else
root->rb_node = right;
- node->rb_parent = right;
+ rb_set_parent(node, right);
}
static void __rb_rotate_right(struct rb_node *node, struct rb_root *root)
{
struct rb_node *left = node->rb_left;
+ struct rb_node *parent = rb_parent(node);
if ((node->rb_left = left->rb_right))
- left->rb_right->rb_parent = node;
+ rb_set_parent(left->rb_right, node);
left->rb_right = node;
- if ((left->rb_parent = node->rb_parent))
+ rb_set_parent(left, parent);
+
+ if (parent)
{
- if (node == node->rb_parent->rb_right)
- node->rb_parent->rb_right = left;
+ if (node == parent->rb_right)
+ parent->rb_right = left;
else
- node->rb_parent->rb_left = left;
+ parent->rb_left = left;
}
else
root->rb_node = left;
- node->rb_parent = left;
+ rb_set_parent(node, left);
}
void rb_insert_color(struct rb_node *node, struct rb_root *root)
{
struct rb_node *parent, *gparent;
- while ((parent = node->rb_parent) && parent->rb_color == RB_RED)
+ while ((parent = rb_parent(node)) && rb_is_red(parent))
{
- gparent = parent->rb_parent;
+ gparent = rb_parent(parent);
if (parent == gparent->rb_left)
{
{
register struct rb_node *uncle = gparent->rb_right;
- if (uncle && uncle->rb_color == RB_RED)
+ if (uncle && rb_is_red(uncle))
{
- uncle->rb_color = RB_BLACK;
- parent->rb_color = RB_BLACK;
- gparent->rb_color = RB_RED;
+ rb_set_black(uncle);
+ rb_set_black(parent);
+ rb_set_red(gparent);
node = gparent;
continue;
}
@@ -94,17 +100,17 @@
node = tmp;
}
- parent->rb_color = RB_BLACK;
- gparent->rb_color = RB_RED;
+ rb_set_black(parent);
+ rb_set_red(gparent);
__rb_rotate_right(gparent, root);
} else {
{
register struct rb_node *uncle = gparent->rb_left;
- if (uncle && uncle->rb_color == RB_RED)
+ if (uncle && rb_is_red(uncle))
{
- uncle->rb_color = RB_BLACK;
- parent->rb_color = RB_BLACK;
- gparent->rb_color = RB_RED;
+ rb_set_black(uncle);
+ rb_set_black(parent);
+ rb_set_red(gparent);
node = gparent;
continue;
}
@@ -119,13 +125,13 @@
node = tmp;
}
- parent->rb_color = RB_BLACK;
- gparent->rb_color = RB_RED;
+ rb_set_black(parent);
+ rb_set_red(gparent);
__rb_rotate_left(gparent, root);
}
}
- root->rb_node->rb_color = RB_BLACK;
+ rb_set_black(root->rb_node);
}
EXPORT_SYMBOL(rb_insert_color);
@@ -134,43 +140,40 @@
{
struct rb_node *other;
- while ((!node || node->rb_color == RB_BLACK) && node != root->rb_node)
+ while ((!node || rb_is_black(node)) && node != root->rb_node)
{
if (parent->rb_left == node)
{
other = parent->rb_right;
- if (other->rb_color == RB_RED)
+ if (rb_is_red(other))
{
- other->rb_color = RB_BLACK;
- parent->rb_color = RB_RED;
+ rb_set_black(other);
+ rb_set_red(parent);
__rb_rotate_left(parent, root);
other = parent->rb_right;
}
- if ((!other->rb_left ||
- other->rb_left->rb_color == RB_BLACK)
- && (!other->rb_right ||
- other->rb_right->rb_color == RB_BLACK))
+ if ((!other->rb_left || rb_is_black(other->rb_left)) &&
+ (!other->rb_right || rb_is_black(other->rb_right)))
{
- other->rb_color = RB_RED;
+ rb_set_red(other);
node = parent;
- parent = node->rb_parent;
+ parent = rb_parent(node);
}
else
{
- if (!other->rb_right ||
- other->rb_right->rb_color == RB_BLACK)
+ if (!other->rb_right || rb_is_black(other->rb_right))
{
- register struct rb_node *o_left;
+ struct rb_node *o_left;
if ((o_left = other->rb_left))
- o_left->rb_color = RB_BLACK;
- other->rb_color = RB_RED;
+ rb_set_black(o_left);
+ rb_set_red(other);
__rb_rotate_right(other, root);
other = parent->rb_right;
}
- other->rb_color = parent->rb_color;
- parent->rb_color = RB_BLACK;
+ rb_set_colour(other, rb_colour(parent));
+ rb_set_black(parent);
if (other->rb_right)
- other->rb_right->rb_color = RB_BLACK;
+ rb_set_black(other->rb_right);
__rb_rotate_left(parent, root);
node = root->rb_node;
break;
@@ -179,38 +182,35 @@
else
{
other = parent->rb_left;
- if (other->rb_color == RB_RED)
+ if (rb_is_red(other))
{
- other->rb_color = RB_BLACK;
- parent->rb_color = RB_RED;
+ rb_set_black(other);
+ rb_set_red(parent);
__rb_rotate_right(parent, root);
other = parent->rb_left;
}
- if ((!other->rb_left ||
- other->rb_left->rb_color == RB_BLACK)
- && (!other->rb_right ||
- other->rb_right->rb_color == RB_BLACK))
+ if ((!other->rb_left || rb_is_black(other->rb_left)) &&
+ (!other->rb_right || rb_is_black(other->rb_right)))
{
- other->rb_color = RB_RED;
+ rb_set_red(other);
node = parent;
- parent = node->rb_parent;
+ parent = rb_parent(node);
}
else
{
- if (!other->rb_left ||
- other->rb_left->rb_color == RB_BLACK)
+ if (!other->rb_left || rb_is_black(other->rb_left))
{
register struct rb_node *o_right;
if ((o_right = other->rb_right))
- o_right->rb_color = RB_BLACK;
- other->rb_color = RB_RED;
+ rb_set_black(o_right);
+ rb_set_red(other);
__rb_rotate_left(other, root);
other = parent->rb_left;
}
- other->rb_color = parent->rb_color;
- parent->rb_color = RB_BLACK;
+ rb_set_colour(other, rb_colour(parent));
+ rb_set_black(parent);
if (other->rb_left)
- other->rb_left->rb_color = RB_BLACK;
+ rb_set_black(other->rb_left);
__rb_rotate_right(parent, root);
node = root->rb_node;
break;
@@ -218,7 +218,7 @@
}
}
if (node)
- node->rb_color = RB_BLACK;
+ rb_set_black(node);
}
void rb_erase(struct rb_node *node, struct rb_root *root)
@@ -238,43 +238,41 @@
while ((left = node->rb_left) != NULL)
node = left;
child = node->rb_right;
- parent = node->rb_parent;
- color = node->rb_color;
+ parent = rb_parent(node);
+ color = rb_colour(node);
if (child)
- child->rb_parent = parent;
-
- if (node->rb_parent == old) {
+ rb_set_parent(child, parent);
+ if (parent == old) {
parent->rb_right = child;
parent = node;
- } else
+ } else
parent->rb_left = child;
- node->rb_parent = old->rb_parent;
- node->rb_color = old->rb_color;
+ node->rb_parent_colour = old->rb_parent_colour;
node->rb_right = old->rb_right;
node->rb_left = old->rb_left;
- if (old->rb_parent)
+ if (rb_parent(old))
{
- if (old->rb_parent->rb_left == old)
- old->rb_parent->rb_left = node;
+ if (rb_parent(old)->rb_left == old)
+ rb_parent(old)->rb_left = node;
else
- old->rb_parent->rb_right = node;
+ rb_parent(old)->rb_right = node;
} else
root->rb_node = node;
- old->rb_left->rb_parent = node;
+ rb_set_parent(old->rb_left, node);
if (old->rb_right)
- old->rb_right->rb_parent = node;
+ rb_set_parent(old->rb_right, node);
goto color;
}
- parent = node->rb_parent;
- color = node->rb_color;
+ parent = rb_parent(node);
+ color = rb_colour(node);
if (child)
- child->rb_parent = parent;
+ rb_set_parent(child, parent);
if (parent)
{
if (parent->rb_left == node)
@@ -322,6 +320,8 @@
struct rb_node *rb_next(struct rb_node *node)
{
+ struct rb_node *parent;
+
/* If we have a right-hand child, go down and then left as far
as we can. */
if (node->rb_right) {
@@ -337,15 +337,17 @@
ancestor is a right-hand child of its parent, keep going
up. First time it's a left-hand child of its parent, said
parent is our 'next' node. */
- while (node->rb_parent && node == node->rb_parent->rb_right)
- node = node->rb_parent;
+ while ((parent = rb_parent(node)) && node == parent->rb_right)
+ node = parent;
- return node->rb_parent;
+ return parent;
}
EXPORT_SYMBOL(rb_next);
struct rb_node *rb_prev(struct rb_node *node)
{
+ struct rb_node *parent;
+
/* If we have a left-hand child, go down and then right as far
as we can. */
if (node->rb_left) {
@@ -357,17 +359,17 @@
/* No left-hand children. Go up till we find an ancestor which
is a right-hand child of its parent */
- while (node->rb_parent && node == node->rb_parent->rb_left)
- node = node->rb_parent;
+ while ((parent = rb_parent(node)) && node == parent->rb_left)
+ node = parent;
- return node->rb_parent;
+ return parent;
}
EXPORT_SYMBOL(rb_prev);
void rb_replace_node(struct rb_node *victim, struct rb_node *new,
struct rb_root *root)
{
- struct rb_node *parent = victim->rb_parent;
+ struct rb_node *parent = rb_parent(victim);
/* Set the surrounding nodes to point to the replacement */
if (parent) {
@@ -379,9 +381,9 @@
root->rb_node = new;
}
if (victim->rb_left)
- victim->rb_left->rb_parent = new;
+ rb_set_parent(victim->rb_left, new);
if (victim->rb_right)
- victim->rb_right->rb_parent = new;
+ rb_set_parent(victim->rb_right, new);
/* Copy the pointers/colour from the victim to the replacement */
*new = *victim;