Update rbtree code
authorJens Axboe <jens.axboe@oracle.com>
Tue, 27 Mar 2007 08:16:21 +0000 (10:16 +0200)
committerJens Axboe <jens.axboe@oracle.com>
Tue, 27 Mar 2007 08:16:21 +0000 (10:16 +0200)
Grab from the later kernels, they embed the color in the pointer
to save some space.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
rbtree.c
rbtree.h

index cc4093aa4725c10f3c4788a4c2c273734b686941..6ad800fdffedd4e5d458aba719625ab83ecb5ffd 100644 (file)
--- a/rbtree.c
+++ b/rbtree.c
 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;
                                }
@@ -93,17 +99,17 @@ void rb_insert_color(struct rb_node *node, struct rb_root *root)
                                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;
                                }
@@ -118,13 +124,13 @@ void rb_insert_color(struct rb_node *node, struct rb_root *root)
                                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);
 }
 
 static void __rb_erase_color(struct rb_node *node, struct rb_node *parent,
@@ -132,43 +138,40 @@ static void __rb_erase_color(struct rb_node *node, struct rb_node *parent,
 {
        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_color(other, rb_color(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;
@@ -177,38 +180,35 @@ static void __rb_erase_color(struct rb_node *node, struct rb_node *parent,
                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_color(other, rb_color(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;
@@ -216,7 +216,7 @@ static void __rb_erase_color(struct rb_node *node, struct rb_node *parent,
                }
        }
        if (node)
-               node->rb_color = RB_BLACK;
+               rb_set_black(node);
 }
 
 void rb_erase(struct rb_node *node, struct rb_root *root)
@@ -236,48 +236,41 @@ void rb_erase(struct rb_node *node, struct rb_root *root)
                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_color(node);
 
                if (child)
-                       child->rb_parent = parent;
-               if (parent)
-               {
-                       if (parent->rb_left == node)
-                               parent->rb_left = child;
-                       else
-                               parent->rb_right = child;
-               }
-               else
-                       root->rb_node = child;
-
-               if (node->rb_parent == old)
+                       rb_set_parent(child, parent);
+               if (parent == old) {
+                       parent->rb_right = child;
                        parent = node;
-               node->rb_parent = old->rb_parent;
-               node->rb_color = old->rb_color;
+               } else
+                       parent->rb_left = child;
+
+               node->rb_parent_color = old->rb_parent_color;
                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_color(node);
 
        if (child)
-               child->rb_parent = parent;
+               rb_set_parent(child, parent);
        if (parent)
        {
                if (parent->rb_left == node)
@@ -322,6 +315,11 @@ struct rb_node *rb_last(struct rb_root *root)
 
 struct rb_node *rb_next(struct rb_node *node)
 {
+       struct rb_node *parent;
+
+       if (rb_parent(node) == node)
+               return NULL;
+
        /* If we have a right-hand child, go down and then left as far
           as we can. */
        if (node->rb_right) {
@@ -337,14 +335,19 @@ struct rb_node *rb_next(struct rb_node *node)
           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;
 }
 
 struct rb_node *rb_prev(struct rb_node *node)
 {
+       struct rb_node *parent;
+
+       if (rb_parent(node) == node)
+               return NULL;
+
        /* If we have a left-hand child, go down and then right as far
           as we can. */
        if (node->rb_left) {
@@ -356,8 +359,31 @@ struct rb_node *rb_prev(struct rb_node *node)
 
        /* 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 parent;
+}
+
+void rb_replace_node(struct rb_node *victim, struct rb_node *new,
+                    struct rb_root *root)
+{
+       struct rb_node *parent = rb_parent(victim);
+
+       /* Set the surrounding nodes to point to the replacement */
+       if (parent) {
+               if (victim == parent->rb_left)
+                       parent->rb_left = new;
+               else
+                       parent->rb_right = new;
+       } else {
+               root->rb_node = new;
+       }
+       if (victim->rb_left)
+               rb_set_parent(victim->rb_left, new);
+       if (victim->rb_right)
+               rb_set_parent(victim->rb_right, new);
 
-       return node->rb_parent;
+       /* Copy the pointers/colour from the victim to the replacement */
+       *new = *victim;
 }
index 2cb9e37c4e9929854e9b7e2dd274364f490e0031..344bc3495ddbd12548c32ebaf57cd3c6ee7e8be9 100644 (file)
--- a/rbtree.h
+++ b/rbtree.h
@@ -94,37 +94,48 @@ static inline struct page * rb_insert_page_cache(struct inode * inode,
 #ifndef        _LINUX_RBTREE_H
 #define        _LINUX_RBTREE_H
 
-#include <stdlib.h>
+#include <linux/kernel.h>
+#include <linux/stddef.h>
 
 struct rb_node
 {
-       struct rb_node *rb_parent;
-       int rb_color;
+       unsigned long  rb_parent_color;
 #define        RB_RED          0
 #define        RB_BLACK        1
        struct rb_node *rb_right;
        struct rb_node *rb_left;
-};
+} __attribute__((aligned(sizeof(long))));
+    /* The alignment might seem pointless, but allegedly CRIS needs it */
 
 struct rb_root
 {
        struct rb_node *rb_node;
 };
 
-#undef offsetof
-#ifdef __compiler_offsetof
-#define offsetof(TYPE,MEMBER) __compiler_offsetof(TYPE,MEMBER)
-#else
-#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
-#endif
 
-#define container_of(ptr, type, member) ({                      \
-       const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
-       (type *)( (char *)__mptr - offsetof(type,member) );})
+#define rb_parent(r)   ((struct rb_node *)((r)->rb_parent_color & ~3))
+#define rb_color(r)   ((r)->rb_parent_color & 1)
+#define rb_is_red(r)   (!rb_color(r))
+#define rb_is_black(r) rb_color(r)
+#define rb_set_red(r)  do { (r)->rb_parent_color &= ~1; } while (0)
+#define rb_set_black(r)  do { (r)->rb_parent_color |= 1; } while (0)
+
+static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p)
+{
+       rb->rb_parent_color = (rb->rb_parent_color & 3) | (unsigned long)p;
+}
+static inline void rb_set_color(struct rb_node *rb, int color)
+{
+       rb->rb_parent_color = (rb->rb_parent_color & ~1) | color;
+}
 
 #define RB_ROOT        (struct rb_root) { NULL, }
 #define        rb_entry(ptr, type, member) container_of(ptr, type, member)
 
+#define RB_EMPTY_ROOT(root)    ((root)->rb_node == NULL)
+#define RB_EMPTY_NODE(node)    (rb_parent(node) == node)
+#define RB_CLEAR_NODE(node)    (rb_set_parent(node, node))
+
 extern void rb_insert_color(struct rb_node *, struct rb_root *);
 extern void rb_erase(struct rb_node *, struct rb_root *);
 
@@ -134,11 +145,14 @@ extern struct rb_node *rb_prev(struct rb_node *);
 extern struct rb_node *rb_first(struct rb_root *);
 extern struct rb_node *rb_last(struct rb_root *);
 
+/* Fast replacement of a single node without remove/rebalance/add/rebalance */
+extern void rb_replace_node(struct rb_node *victim, struct rb_node *new, 
+                           struct rb_root *root);
+
 static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
                                struct rb_node ** rb_link)
 {
-       node->rb_parent = parent;
-       node->rb_color = RB_RED;
+       node->rb_parent_color = (unsigned long )parent;
        node->rb_left = node->rb_right = NULL;
 
        *rb_link = node;