[PATCH v4 11/13] rbtree.h: Generic Red-Black Trees

Daniel Santos
2012-06-23T04:02:25Z

Add generic red-black tree code to rbtree.h

Signed-off-by: Daniel Santos <daniel.santos@pobox.com>
---
include/linux/rbtree.h | 1044 +++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 1042 insertions(+), 2 deletions(-)

diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h
index 033b507..959bd27 100644
--- a/include/linux/rbtree.h
+++ b/include/linux/rbtree.h
@@ -1,7 +1,8 @@
/*
Red Black Trees
(C) 1999 Andrea Arcangeli <andrea@suse.de>
-
+ (C) 2012 Daniel Santos <daniel.santos@pobox.com>
+
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
@@ -96,6 +97,8 @@ static inline struct page * rb_insert_page_cache(struct inode * inode,

#include <linux/kernel.h>
#include <linux/stddef.h>
+#include <linux/typecheck.h>
+#include <linux/bug.h>

struct rb_node
{
@@ -148,6 +151,7 @@ extern void rb_insert_color(struct rb_node *, struct rb_root *);
extern void rb_erase(struct rb_node *, struct rb_root *);

typedef void (*rb_augment_f)(struct rb_node *node, void *data);
+typedef long (*rb_compare_f)(const void *a, const void *b);

extern void rb_augment_insert(struct rb_node *node,
rb_augment_f func, void *data);
@@ -162,7 +166,7 @@ extern struct rb_node *rb_first(const struct rb_root *);
extern struct rb_node *rb_last(const 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,
+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,
@@ -174,4 +178,1040 @@ static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
*rb_link = node;
}

+
+#define __JUNK junk,
+#define _iff_empty(test_or_junk, t, f) __iff_empty(test_or_junk, t, f)
+#define __iff_empty(__ignored1, __ignored2, result, ...) result
+
+/**
+ * IFF_EMPTY() - Expands to the second argument when the first is empty, the
+ * third if non-empty.
+ * @test: An argument to test for emptiness.
+ * @t: A value to expand to if test is empty.
+ * @f: A value to expand to if test is non-empty.
+ *
+ * Caveats:
+ * IFF_EMPTY isn't perfect. The test parmater must either be empty or a valid
+ * pre-processor token as well as result in a valid token when pasted to the
+ * end of a word.
+ *
+ * Valid Examples:
+ * IFF_EMPTY(a, b, c) = c
+ * IFF_EMPTY( , b, c) = b
+ * IFF_EMPTY( , , c) = (nothing)
+ *
+ * Invalid Examples:
+ * IFF_EMPTY(., b, c)
+ * IFF_EMPTY(+, b, c)
+ */
+#define IFF_EMPTY(test, t, f) _iff_empty(__JUNK##test, t, f)
+
+/**
+ * IS_EMPTY() - test if a pre-processor argument is empty.
+ * @arg: An argument (empty or non-empty)
+ *
+ * If empty, expands to 1, 0 otherwise. See IFF_EMPTY() for caveats &
+ * limitations.
+ */
+#define IS_EMPTY(arg) IFF_EMPTY(arg, 1, 0)
+
+/**
+ * OPT_OFFSETOF() - return the offsetof for the supplied expression, or zero
+ * if m is an empty argument.
+ * @type: struct/union type
+ * @m: (optional) struct member name
+ *
+ * Since any offsetof can return zero if the specified member is the first in
+ * the struct/union, you should also check if the argument is empty separately
+ * with IS_EMPTY(m).
+ */
+#define OPT_OFFSETOF(type, member) IFF_EMPTY(member, 0, offsetof(type, member))
+
+enum rb_flags {
+RB_HAS_LEFTMOST = 0x00000001, /* The container has a struct rb_node *leftmost
+ member that will receive a pointer to the
+ leftmost (smallest) object in the tree that
+ is updated during inserts & deletions */
+RB_HAS_RIGHTMOST = 0x00000002, /* same as above (for right side of tree) */
+RB_HAS_COUNT = 0x00000004, /* The container has an unsigned long integer
+ field that will receive updates of the
+ object count in the tree. */
+RB_UNIQUE_KEYS = 0x00000008, /* the tree contains only unique values. */
+RB_INSERT_REPLACES = 0x00000010, /* when set, the rb_insert() will replace a
+ value if it matches the supplied one (valid
+ only when RB_UNIQUE_KEYS is set). */
+RB_IS_AUGMENTED = 0x00000020, /* is an augmented tree */
+RB_CRITICAL_PATH = 0x00000040, /* generate larger code for {find,insert}_near
+ functions that can be faster on some CPUs
+ with large L1 caches (but slower on a
+ Phenom 9850). This may be a complete flop
+ and just need to be removed. */
+RB_ALL_FLAGS = RB_HAS_LEFTMOST | RB_HAS_RIGHTMOST
+ | RB_HAS_COUNT | RB_UNIQUE_KEYS
+ | RB_INSERT_REPLACES | RB_IS_AUGMENTED
+ | RB_CRITICAL_PATH,
+};
+
+/**
+ * struct rb_relationship - Defines relationship between a container and
+ * the objects it contains.
+ * @root_offset: Offset of container's struct rb_root member.
+ * @left_offset: (Used only if has_left.) Offset of the container's struct
+ * rb_node *leftmost member for storing a pointer to the
+ * leftmost node in the tree, which is kept updated as inserts
+ * and deletions are made.
+ * @right_offset: Same as left_offset, except for right side of tree.
+ * @count_offset:
+ * @node_offset: Offset of object's struct rb_node member.
+ * @key_offset: Offset of object's key member.
+ * @flags: TODO
+ * @compare: Pointer to key rb_compare_f function to compare keys.
+ * Although it will be cast to and called as type long (*)(const
+ * void *a, const void *b), you should delcare it as accepting
+ * pointers to your key members, or sanity checks will fail.
+ * Further, it is optimial if the function is declared inline.
+ * @augment: Pointer to the rb_augment_f or zero if tree is not augmented.
+ *
+ * Instances of struct rb_relationship should be compile-time constants (or
+ * rather, the value of its members).
+ */
+struct rb_relationship {
+ ssize_t root_offset;
+ ssize_t left_offset;
+ ssize_t right_offset;
+ ssize_t count_offset;
+ ssize_t node_offset;
+ ssize_t key_offset;
+ int flags;
+ const rb_compare_f compare;
+ const rb_augment_f augment;
+};
+
+#define __RB_PTR(type, ptr, offset) ((type *)((char *)(ptr) + (offset)))
+
+/* public conversion functions for use with run-time values */
+static __always_inline
+struct rb_root *rb_to_root(const void *ptr,
+ const struct rb_relationship *rel)
+{
+ return __RB_PTR(struct rb_root, ptr, rel->root_offset);
+}
+
+static __always_inline
+struct rb_node **rb_root_to_left(struct rb_root *root,
+ const struct rb_relationship *rel)
+{
+ return __RB_PTR(struct rb_node *, root,
+ rel->left_offset - rel->root_offset);
+}
+
+static __always_inline
+struct rb_node **rb_root_to_right(struct rb_root *root,
+ const struct rb_relationship *rel)
+{
+ return __RB_PTR(struct rb_node *, root,
+ rel->right_offset - rel->root_offset);
+}
+
+static __always_inline
+unsigned long *rb_root_to_count(struct rb_root *root,
+ const struct rb_relationship *rel)
+{
+ return __RB_PTR(unsigned long, root,
+ rel->count_offset - rel->root_offset);
+}
+
+static __always_inline
+const void *rb_node_to_key(const struct rb_node *node,
+ const struct rb_relationship *rel)
+{
+ return __RB_PTR(const void, node,
+ rel->key_offset - rel->node_offset);
+}
+
+static __always_inline
+void *rb_node_to_obj(const struct rb_node *node,
+ const struct rb_relationship *rel)
+{
+ return __RB_PTR(void, node, -rel->node_offset);
+}
+
+static __always_inline
+struct rb_node *rb_to_node(const void *ptr, const struct rb_relationship *rel)
+{
+ return __RB_PTR(struct rb_node, ptr, rel->node_offset);
+}
+
+static __always_inline
+const void *rb_to_key(const void *ptr, const struct rb_relationship *rel)
+{
+ return __RB_PTR(const void, ptr, rel->key_offset);
+}
+
+
+/* checked conversion functions that will error on run-time values */
+static __always_inline
+struct rb_root *__rb_to_root(const void *ptr,
+ const struct rb_relationship *rel)
+{
+ BUILD_BUG_ON_NON_CONST42(rel->root_offset);
+ return rb_to_root(ptr, rel);
+}
+
+static __always_inline
+struct rb_node **__rb_root_to_left(struct rb_root *root,
+ const struct rb_relationship *rel)
+{
+ BUILD_BUG_ON42(!(rel->flags & RB_HAS_LEFTMOST));
+ BUILD_BUG_ON_NON_CONST42(rel->root_offset);
+ BUILD_BUG_ON_NON_CONST42(rel->left_offset);
+ return rb_root_to_left(root, rel);
+}
+
+static __always_inline
+struct rb_node **__rb_root_to_right(struct rb_root *root,
+ const struct rb_relationship *rel)
+{
+ BUILD_BUG_ON42(!(rel->flags & RB_HAS_RIGHTMOST));
+ BUILD_BUG_ON_NON_CONST42(rel->root_offset);
+ BUILD_BUG_ON_NON_CONST42(rel->right_offset);
+ return rb_root_to_right(root, rel);
+}
+
+static __always_inline
+unsigned long *__rb_root_to_count(struct rb_root *root,
+ const struct rb_relationship *rel)
+{
+ BUILD_BUG_ON42(!(rel->flags & RB_HAS_COUNT));
+ BUILD_BUG_ON_NON_CONST42(rel->root_offset);
+ BUILD_BUG_ON_NON_CONST42(rel->count_offset);
+ return rb_root_to_count(root, rel);
+}
+
+static __always_inline
+const void *__rb_node_to_key(const struct rb_node *node,
+ const struct rb_relationship *rel)
+{
+ BUILD_BUG_ON_NON_CONST42(rel->node_offset);
+ BUILD_BUG_ON_NON_CONST42(rel->key_offset);
+ return rb_node_to_key(node, rel);
+}
+
+static __always_inline
+void *__rb_node_to_obj(const struct rb_node *node,
+ const struct rb_relationship *rel)
+{
+ BUILD_BUG_ON_NON_CONST42(rel->node_offset);
+ return rb_node_to_obj(node, rel);
+}
+
+static __always_inline
+struct rb_node *__rb_to_node(const void *ptr, const struct rb_relationship *rel)
+{
+ BUILD_BUG_ON_NON_CONST42(rel->node_offset);
+ return rb_to_node(ptr, rel);
+}
+
+static __always_inline
+const void *__rb_to_key(const void *ptr, const struct rb_relationship *rel)
+{
+ BUILD_BUG_ON_NON_CONST42(rel->key_offset);
+ return rb_to_key(ptr, rel);
+}
+
+/** __rb_assert_good_rel -- perform compile-time sanity checks on a struct
+ * rb_relationship
+ * rel: Pointer to a const struct rb_relationship to check
+ */
+static __always_inline
+void __rb_assert_good_rel(const struct rb_relationship *rel)
+{
+ BUILD_BUG_ON_NON_CONST42(rel->flags);
+ BUILD_BUG_ON42(rel->flags & ~RB_ALL_FLAGS);
+
+ BUILD_BUG_ON_NON_CONST42(rel->root_offset);
+ BUILD_BUG_ON_NON_CONST42(rel->node_offset);
+ BUILD_BUG_ON_NON_CONST42(rel->key_offset);
+
+ if (rel->flags & RB_HAS_LEFTMOST)
+ BUILD_BUG_ON_NON_CONST42(rel->count_offset);
+
+ if (rel->flags & RB_HAS_RIGHTMOST)
+ BUILD_BUG_ON_NON_CONST42(rel->right_offset);
+
+ if (rel->flags & RB_HAS_COUNT)
+ BUILD_BUG_ON_NON_CONST42(rel->left_offset);
+
+ /* need if () construct to avoid false-positive prior to gcc 4.6 */
+ if (rel->flags & RB_INSERT_REPLACES)
+ BUILD_BUG_ON42(!(rel->flags & RB_UNIQUE_KEYS));
+}
+
+
+/** __rb_find - Perform a (normal) search of rbtree starting at the specified
+ * node, traversing downward.
+ * node: Node (root or subtree) to start the search from
+ * key: Pointer to a key to search for
+ * rel: Pointer to a const struct rb_relationship
+ */
+static __always_inline __flatten
+struct rb_node *__rb_find(
+ struct rb_node *node,
+ const void *key,
+ const struct rb_relationship *rel)
+{
+ __rb_assert_good_rel(rel);
+ while (node) {
+ long diff = rel->compare(key, __rb_node_to_key(node, rel));
+
+ if (diff > 0)
+ node = node->rb_right;
+ else if (diff < 0)
+ node = node->rb_left;
+ else
+ return node;
+ }
+
+ return 0;
+}
+
+/** rb_find - Perform a (normal) search of a Red-Black Tree.
+ * root: Root of the tree
+ * key: Pointer to a key to search for
+ * rel: Pointer to a const struct rb_relationship
+ */
+static __always_inline __flatten
+struct rb_node *rb_find(
+ struct rb_root *root,
+ const void *key,
+ const struct rb_relationship *rel)
+{
+ return __rb_find(root->rb_node, key, rel);
+}
+
+static __always_inline __flatten
+struct rb_node *__rb_find_first_last(
+ struct rb_node *node,
+ const void *key,
+ const struct rb_relationship *rel,
+ const int find_first)
+{
+ __rb_assert_good_rel(rel);
+
+ /* calling this function with a unique key tree maps to normal find */
+ if (rel->flags & RB_UNIQUE_KEYS)
+ return __rb_find(node, key, rel);
+
+ /* if this section is compiled, we should non-unqiue only */
+ BUILD_BUG_ON42(rel->flags & RB_UNIQUE_KEYS);
+ BUILD_BUG_ON_NON_CONST(find_first);
+
+ while (node) {
+ long diff = rel->compare(key, __rb_node_to_key(node, rel));
+
+ if (diff > 0)
+ node = node->rb_right;
+ else if (diff < 0)
+ node = node->rb_left;
+ else {
+ if (find_first && node->rb_left)
+ node = node->rb_left;
+ else if (!find_first && node->rb_right)
+ node = node->rb_right;
+ else
+ return node;
+ }
+ }
+
+ return 0;
+}
+
+/** rb_find_first - Search for first occurrence of key in the tree.
+ * root: Root of the tree
+ * key: Pointer to a key
+ * rel: Pointer to a const struct rb_relationship
+ *
+ * This function is intended for use with trees containing non-unique keys.
+ * When called for trees with unique keys, it maps to __rb_find (a normal
+ * search).
+ */
+static __always_inline __flatten
+struct rb_node *rb_find_first(
+ struct rb_root *root,
+ const void *key,
+ const struct rb_relationship *rel)
+{
+ return __rb_find_first_last(root->rb_node, key, rel, 1);
+}
+
+/** rb_find_last - Search for last occurrence of key in the tree.
+ * root: Root of the tree
+ * key: Pointer to a key
+ * rel: Pointer to a const struct rb_relationship
+ *
+ * This function is intended for use with trees containing non-unique keys.
+ * When called for trees with unique keys, it maps to __rb_find (a normal
+ * search).
+ */
+static __always_inline __flatten
+struct rb_node *rb_find_last(
+ struct rb_root *root,
+ const void *key,
+ const struct rb_relationship *rel)
+{
+ return __rb_find_first_last(root->rb_node, key, rel, 0);
+}
+
+/** rb_find_next - Locate the next node (in a non-unique tree) whos key matches
+ * the supplied node.
+ * node: Node of the current object in the tree.
+ * rel: Pointer to a const struct rb_relationship
+ *
+ * Gernerally for use after calling rb_find_first(). Only valid for use with a
+ * tree with non-unique keys.
+ */
+static __always_inline __flatten
+struct rb_node *rb_find_next(
+ const struct rb_node *node,
+ const struct rb_relationship *rel)
+{
+ const void *key = __rb_node_to_key(node, rel);
+ struct rb_node *next = rb_next(node);
+
+ BUILD_BUG_ON42(rel->flags & RB_UNIQUE_KEYS);
+ return (next && !rel->compare(key, __rb_node_to_key(next, rel)))
+ ? next : NULL;
+}
+
+/** rb_find_prev - Locate the previous node (in a non-unique tree) whos key
+ * matches the supplied node.
+ * node: Node of the current object in the tree.
+ * rel: Pointer to a const struct rb_relationship
+ *
+ * Gernerally for use after calling rb_find_last(). Only valid for use with a
+ * tree with non-unique keys.
+ */
+static __always_inline __flatten
+struct rb_node *rb_find_prev(
+ const struct rb_node *node,
+ const struct rb_relationship *rel)
+{
+ const void *key = __rb_node_to_key(node, rel);
+ struct rb_node *prev = rb_prev(node);
+
+ BUILD_BUG_ON42(rel->flags & RB_UNIQUE_KEYS);
+ return (prev && !rel->compare(key, __rb_node_to_key(prev, rel)))
+ ? prev : NULL;
+}
+
+
+enum rb_find_subtree_match {
+ RB_MATCH_NONE = 0,
+ RB_MATCH_IMMEDIATE = 2,
+ RB_MATCH_LEFT = -1,
+ RB_MATCH_RIGHT = 1,
+};
+
+/**
+ * __rb_find_subtree - Locate the subtree that contains the specified key (if
+ * it exists) starting from a specific node traversing
+ * upwards.
+ *
+ * This function is used by find_near and insert_near, but behaves differently
+ * for each case (maybe it could have been made separate functions).
+ * Specifically, when doing_insert is non-zero, it will set values in the
+ * location provided by populate ret_link & ret_parent.
+ *
+ */
+static __always_inline __flatten
+struct rb_node *__rb_find_subtree(
+ struct rb_root *root,
+ struct rb_node *start,
+ const void *key,
+ int *matched,
+ struct rb_node ***ret_link, /* wow, tripple indirection.
+ Am I smart or just nuts? */
+ struct rb_node **ret_parent,
+ const struct rb_relationship *rel,
+ const int doing_insert)
+{
+ struct rb_node *prev = start;
+ struct rb_node *node = rb_parent(start);
+ long diff;
+
+ __rb_assert_good_rel(rel);
+ BUILD_BUG_ON_NON_CONST(doing_insert);
+ BUG_ON(doing_insert && (!root || !ret_link || !ret_parent));
+
+ /* already at top of tree, so return start value */
+ if (!node) {
+ *matched = RB_MATCH_NONE;
+ if (doing_insert) {
+ *ret_link = &root->rb_node;
+ *ret_parent = **ret_link;
+ }
+ return start;
+ }
+
+ /* The first compare is just to figure out which direction up the tree
+ * we're traveling. When compare returns a value with a different
+ * sign, we'll have found our subtree, or an exact match if zero.
+ */
+ diff = rel->compare(key, __rb_node_to_key(node, rel));
+
+ if (diff) {
+ int go_left = diff < 0;
+ while (1) {
+ prev = node;
+ node = rb_parent(prev);
+ if (!node)
+ /* Reached top of tree. In this case. rather
+ * than having the top down search start from
+ * the root, we'll start on the prev sibling
+ * since we've already tested the root node, we
+ * know that we don't need to go back the way
+ * we came.
+ */
+ break;
+
+ diff = rel->compare(key, __rb_node_to_key(node, rel));
+ if (go_left ? diff > 0 : diff < 0)
+ /* found the divering node, so the child on the
+ * opposite side (of prev) is the subtree that
+ * will contain the key
+ */
+ break;
+ else if (!diff) {
+ /* exact match */
+ *matched = go_left
+ ? RB_MATCH_LEFT
+ : RB_MATCH_RIGHT;
+
+ goto find_parent_link;
+ }
+ }
+
+ *matched = RB_MATCH_NONE;
+ if (doing_insert) {
+ *ret_parent = prev;
+ *ret_link = go_left ? &prev->rb_left : &prev->rb_right;
+ return **ret_link;
+ } else {
+ return go_left ? prev->rb_left : prev->rb_right;
+ }
+ }
+
+ /* start node's parent was an exact match */
+ *matched = RB_MATCH_IMMEDIATE;
+
+find_parent_link:
+ if (doing_insert) {
+ struct rb_node *parent = rb_parent(node);
+
+ if (!parent) {
+ *ret_link = &root->rb_node;
+ *ret_parent = **ret_link;
+ } else if (parent->rb_left == node) {
+ *ret_link = &parent->rb_left;
+ *ret_parent = parent;
+ } else if (parent->rb_right == node) {
+ *ret_link = &parent->rb_left;
+ *ret_parent = parent;
+ } else {
+ BUG();
+ }
+ }
+
+ return node;
+}
+
+static __always_inline __flatten
+struct rb_node *rb_find_near(
+ struct rb_node *from,
+ const void *key,
+ const struct rb_relationship *rel)
+{
+ int matched;
+ struct rb_node *subtree;
+
+ subtree = __rb_find_subtree(NULL, from, key, &matched, NULL, NULL,
+ rel, 0);
+
+ if (matched)
+ return subtree;
+
+ return __rb_find(subtree, key, rel);
+}
+
+/* common insert epilogue used by rb_insert() and rb_insert_near() */
+static __always_inline __flatten
+struct rb_node *__rb_insert_epilogue(
+ struct rb_root *root,
+ struct rb_node *parent,
+ struct rb_node *node,
+ struct rb_node *found,
+ struct rb_node **rb_link,
+ const struct rb_relationship *rel)
+{
+ if ((rel->flags & RB_UNIQUE_KEYS) && found) {
+ if (rel->flags & RB_INSERT_REPLACES) {
+ /* if we're replacing the entry, we don't incrment
+ * count, but we do still need to do augment
+ */
+ rb_replace_node(found, node, root);
+ goto do_augment;
+ } else {
+ /* otherwise, we don't do either */
+ goto done;
+ }
+ } else {
+ rb_link_node(node, parent, rb_link);
+ rb_insert_color(node, root);
+ }
+
+ if ((rel->flags & RB_HAS_COUNT))
+ ++*__rb_root_to_count(root, rel);
+
+do_augment:
+ if (rel->augment)
+ rb_augment_insert(node, rel->augment, NULL);
+
+done:
+ return found;
+}
+
+
+/**
+ * rb_insert() - Inserts an object into a container.
+ * @root: Pointer to struct rb_root.
+ * @node: Pointer to the node of the new object to insert.
+ * @rel: Pointer to the compile-time constant relationship definition.
+ * @compare: Compare function
+ * @augmented: Augmented function (if using an augmented rbtree)
+ *
+ * If an object with the same key already exists and RB_INSERT_REPLACES is set
+ * then it is replaced with new object node; if RB_INSERT_REPLACES is not set,
+ * then no change is made. In either case, a pointer to the existing object
+ * node is returned.
+ *
+ * If no object with the same key exists, then the new object node is inserted
+ * and NULL is returned.
+ */
+static __always_inline __flatten
+struct rb_node *rb_insert(
+ struct rb_root *root,
+ struct rb_node *node,
+ const struct rb_relationship *rel)
+{
+ struct rb_node **p = &root->rb_node;
+ struct rb_node *parent = NULL;
+ const void *key = __rb_node_to_key(node, rel);
+ int leftmost = 1;
+ int rightmost = 1;
+
+ __rb_assert_good_rel(rel);
+
+ while (*p) {
+ long diff = rel->compare(key, __rb_node_to_key(*p, rel));
+ parent = *p;
+
+ if (diff > 0) {
+ p = &(*p)->rb_right;
+ if (rel->flags & RB_HAS_LEFTMOST)
+ leftmost = 0;
+ } else if (!(rel->flags & RB_UNIQUE_KEYS) || diff < 0) {
+ p = &(*p)->rb_left;
+ if (rel->flags & RB_HAS_RIGHTMOST)
+ rightmost = 0;
+ } else
+ break;
+ }
+
+ if ((rel->flags & RB_HAS_LEFTMOST) && leftmost) {
+ struct rb_node **left = __rb_root_to_left(root, rel);
+
+ if (!(rel->flags & RB_INSERT_REPLACES) || !(*p) || *left == *p)
+ *left = node;
+ }
+ if ((rel->flags & RB_HAS_RIGHTMOST) && rightmost) {
+ struct rb_node **right = __rb_root_to_right(root, rel);
+
+ if (!(rel->flags & RB_INSERT_REPLACES) || !(*p) || *right == *p)
+ *right = node;
+ }
+
+ return __rb_insert_epilogue(root, parent, node, *p, p, rel);
+}
+
+static __always_inline __flatten
+struct rb_node *rb_insert_near(
+ struct rb_root *root,
+ struct rb_node *start,
+ struct rb_node *node,
+ const struct rb_relationship *rel)
+{
+ const void *key = __rb_node_to_key(node, rel);
+ struct rb_node **p;
+ struct rb_node *parent;
+ struct rb_node *ret;
+ int matched;
+ long diff;
+
+ BUILD_BUG_ON_NON_CONST42(rel->flags);
+
+ ret = __rb_find_subtree(root, start, key, &matched, &p, &parent, rel,
+ 1);
+
+ if (!matched) {
+ while (*p) {
+ diff = rel->compare(__rb_node_to_key(*p, rel), key);
+ parent = *p;
+
+ if (diff > 0)
+ p = &(*p)->rb_right;
+ else if (!(rel->flags & RB_UNIQUE_KEYS) || diff < 0)
+ p = &(*p)->rb_left;
+ else
+ break;
+ }
+ ret = *p;
+ }
+
+ /* the longer way to see if we're left- or right-most (since we aren't
+ * starting from the top, we can't use the mechanism rb_insert()
+ * does.)
+ */
+ if (rel->flags & RB_HAS_LEFTMOST) {
+ struct rb_node **left = __rb_root_to_left(root, rel);
+ if (!*left || *left == ret ||
+ (*left == parent && &parent->rb_left == p))
+ *left = node;
+ }
+
+ if (rel->flags & RB_HAS_RIGHTMOST) {
+ struct rb_node **right = __rb_root_to_right(root, rel);
+ if (!*right || *right == ret ||
+ (*right == parent && &parent->rb_right == p))
+ *right = node;
+ }
+
+ return __rb_insert_epilogue(root, parent, node, ret, p, rel);
+}
+
+static __always_inline __flatten
+void rb_remove(
+ struct rb_root *root,
+ struct rb_node *node,
+ const struct rb_relationship *rel)
+{
+ struct rb_node *uninitialized_var(deepest);
+
+ BUILD_BUG_ON_NON_CONST42(rel->flags);
+
+ if (rel->augment)
+ deepest = rb_augment_erase_begin(node);
+
+ if (rel->flags & RB_HAS_LEFTMOST) {
+ struct rb_node **left = __rb_root_to_left(root, rel);
+
+ if (*left == node)
+ *left = rb_next(node);
+ }
+
+ if (rel->flags & RB_HAS_RIGHTMOST) {
+ struct rb_node **right = __rb_root_to_right(root, rel);
+
+ if (*right == node)
+ *right = rb_prev(node);
+ }
+
+ rb_erase(node, root);
+
+ if ((rel->flags & RB_HAS_COUNT))
+ --*__rb_root_to_count(root, rel);
+
+ if (rel->augment)
+ rb_augment_erase_end(deepest, rel->augment, NULL);
+}
+
+
+/**
+ * RB_RELATIONHIP - Define the relationship bewteen a container with a
+ * struct rb_root member, and the objects it contains.
+ * @cont_type: container type
+ * @root: Container's struct rb_root member name
+ * @left: (Optional) If the container needs a pointer to the tree's
+ * leftmost (smallest) object, then specify the container's struct
+ * rb_node *leftmost member. Otherwise, leave this parameter
+ * empty.
+ * @right: (Optional) Same as left, but for the rightmost (largest)
+ * @count (Optional) Name of container's unsigned int member that will be
+ * updated with the number of objects in the tree. It is assumed
+ * that there will never be more than 2^32 objects in a kernel
+ * rbtree, so overlfow is not handled or checked for. Note that if
+ * you add or remove objects from the tree without using the
+ * generic functions, you must update this value yourself.
+ * @obj_type: Type of object stored in container
+ * @node: The struct rb_node memeber of the object
+ * @key: The key member of the object
+ * @flags see enum rb_flags. Note: you do not have to specify
+ * RB_HAS_LEFTMOST, RB_HAS_RIGHTMOST, RB_HAS_COUNT or
+ * RB_IS_AUGMENTED as these will be added automatically if their
+ * respective field is non-empty.
+ * @compare: Pointer to key rb_compare_f function to compare keys.
+ * Although it will be cast to and called as type long (*)(const
+ * void *a, const void *b), you should delcare it as accepting
+ * pointers to your key members, or sanity checks will fail.
+ * Further, it is optimial if the function is declared inline.
+ * @_augment: (optional) pointer to the rb_augment_f or empty if tree is not
+ * augmented.
+ *
+ * Example:
+ * struct my_container {
+ * struct rb_root root;
+ * unsigned int count;
+ * struct rb_node *left;
+ * };
+ *
+ * struct my_object {
+ * struct rb_node node;
+ * int key;
+ * };
+ *
+ * static inline long compare_int(const int *a, const int *b)
+ * {
+ * return (long)*a - (long)*b);
+ * }
+ *
+ * static const struct rb_relationship my_rel = RB_RELATIONSHIP(
+ * struct my_container, root, left, , count, // no rightmost
+ * struct my_object, node, key,
+ * 0, compare_int, ); // no augment
+ */
+#define RB_RELATIONSHIP( \
+ cont_type, root, left, right, count, \
+ obj_type, node, key, \
+ _flags, _compare, _augment) { \
+ .root_offset = offsetof(cont_type, root), \
+ .left_offset = OPT_OFFSETOF(cont_type, left), \
+ .right_offset = OPT_OFFSETOF(cont_type, right), \
+ .count_offset = OPT_OFFSETOF(cont_type, count), \
+ .node_offset = offsetof(obj_type, node), \
+ .key_offset = offsetof(obj_type, key), \
+ .flags = (_flags) \
+ | IFF_EMPTY(left , 0, RB_HAS_LEFTMOST) \
+ | IFF_EMPTY(right, 0, RB_HAS_RIGHTMOST) \
+ | IFF_EMPTY(count, 0, RB_HAS_COUNT) \
+ | IFF_EMPTY(_augment, 0, RB_IS_AUGMENTED), \
+ .compare = (const rb_compare_f) (_compare), \
+ .augment = IFF_EMPTY(_augment, 0, _augment) \
+}
+
+/* type-validation functions used by __rb_sanity_check_##prefix */
+static inline void __rb_verify_root(struct rb_root *root) {}
+static inline void __rb_verify_left(struct rb_node * const *left) {}
+static inline void __rb_verify_right(struct rb_node * const *right) {}
+static inline void __rb_verify_count(const unsigned int *count) {}
+static inline void __rb_verify_node(struct rb_node *node) {}
+static inline void __rb_verify_compare_fn_ret(long *diff) {}
+
+/**
+ * RB_DEFINE_INTERFACE - Defines a complete interface for a relationship
+ * between container and object including a struct
+ * rb_relationship and an interface of type-safe wrapper
+ * functions.
+ * @prefix: name for the relationship (see explanation below)
+ * @cont_type: see RB_RELATIONHIP
+ * @root: see RB_RELATIONHIP
+ * @left: see RB_RELATIONHIP
+ * @right: see RB_RELATIONHIP
+ * @count see RB_RELATIONHIP
+ * @obj_type: see RB_RELATIONHIP
+ * @node: see RB_RELATIONHIP
+ * @key: see RB_RELATIONHIP
+ * @flags see RB_RELATIONHIP
+ * @compare: see RB_RELATIONHIP
+ * @augment: see RB_RELATIONHIP
+ * @insert_mod: (Optional) Function modifiers for insert function,
+ * defaults to "static __always_inline" if left empty.
+ * @insert_near_mod: (Optional) Same as above, for insert_near.
+ * @find_mod: (Optional) Same as above, for find.
+ * @find_near_mod: (Optional) Same as above, for find_near.
+ *
+ * This macro can be delcared in the global scope of either a source or header
+ * file and will generate a static const struct rb_relationship variable named
+ * prefix##_rel as well as similarly named (i.e., prefix##_##func_name)
+ * type-safe wrapper functions for find, find_near, insert, insert_near and
+ * remove. If these function names are not sufficient, you can use the
+ * __RB_DEFINE_INTERFACE macro to specify them explicitly.
+ *
+ * The compare function will be passed pointers to the key members of two
+ * objects. If your compare function needs access to other members of your
+ * struct (e.g., compound keys, etc.) , you can use the rb_entry macro to
+ * access other members. However, if you use this mechanism, your find
+ * function must always pass it's key parameter as a pointer to the key member
+ * of an object of type obj_type, since the compare function is used for both
+ * inserts and lookups (else, you'll be screwed).
+ *
+ * Example:
+ * struct my_container {
+ * struct rb_root root;
+ * unsigned int count;
+ * struct rb_node *left;
+ * };
+ *
+ * struct my_object {
+ * struct rb_node node;
+ * int key;
+ * };
+ *
+ * static inline long compare_int(const int *a, const int *b)
+ * {
+ * return (long)*a - (long)*b);
+ * }
+ *
+ * RB_DEFINE_INTERFACE(
+ * my_tree,
+ * struct my_container, root, left, , count, // no rightmost
+ * struct my_object, node, key,
+ * 0, compare_int,
+ * , // defaults for find
+ * static __flatten, // let gcc decide rather or not to inline insert()
+ * , // defaults on find_near
+ * static __flatten noinline) // don't let gcc inline insert_near()
+ */
+#define RB_DEFINE_INTERFACE( \
+ prefix, \
+ cont_type, root, left, right, count, \
+ obj_type, node, key, \
+ flags, compare, augment, \
+ find_mod, insert_mod, find_near_mod, insert_near_mod) \
+ \
+/* You need not call this function for validation to occur. We define \
+ * __rb_sanity_check function first, so errors will (hopefully) get \
+ * caught here and produce a more helpful error message than a failure \
+ * in the RB_RELATIONSHIP macro expansion. \
+ */ \
+static inline __maybe_unused \
+void __rb_sanity_check_ ## prefix(cont_type *cont, obj_type *obj) \
+{ \
+ /* compare function should accept pointer to key member */ \
+ typeof((compare)(&obj->key, &obj->key)) diff = \
+ (compare)(&obj->key, &obj->key); \
+ __rb_verify_compare_fn_ret(&diff); \
+ \
+ /* validate types of container members */ \
+ __rb_verify_root(&cont->root); \
+ __rb_verify_left (IFF_EMPTY(left , 0, &cont->left)); \
+ __rb_verify_right(IFF_EMPTY(right , 0, &cont->right)); \
+ __rb_verify_count(IFF_EMPTY(count , 0, &cont->count)); \
+ \
+ /* validate types of object node */ \
+ __rb_verify_node(&obj->node); \
+} \
+ \
+static const struct rb_relationship prefix ## _rel = \
+RB_RELATIONSHIP( \
+ cont_type, root, left, right, count, \
+ obj_type, node, key, \
+ flags, compare, augment); \
+ \
+IFF_EMPTY(find_mod, static __always_inline, find_mod) \
+obj_type *prefix ## _find(cont_type *cont, \
+ const typeof(((obj_type *)0)->key) *_key) \
+{ \
+ struct rb_node *ret = rb_find( \
+ &cont->root, _key, &prefix ## _rel); \
+ return ret ? rb_entry(ret, obj_type, node) : 0; \
+} \
+ \
+IFF_EMPTY(insert_mod, static __always_inline, insert_mod) \
+obj_type *prefix ## _insert(cont_type *cont, obj_type *obj) \
+{ \
+ struct rb_node *ret = rb_insert( \
+ &cont->root, &obj->node, &prefix ## _rel); \
+ return ret ? rb_entry(ret, obj_type, node) : 0; \
+} \
+ \
+IFF_EMPTY(find_near_mod, static __always_inline, find_near_mod) \
+obj_type *prefix ## _find_near(obj_type *near, \
+ const typeof(((obj_type *)0)->key) *_key) \
+{ \
+ struct rb_node *ret = rb_find_near( \
+ &near->node, _key, &prefix ## _rel); \
+ return ret ? rb_entry(ret, obj_type, node) : 0; \
+} \
+ \
+IFF_EMPTY(insert_near_mod, static __always_inline, insert_near_mod) \
+obj_type *prefix ## _insert_near(cont_type *cont, obj_type *near, \
+ obj_type *obj) \
+{ \
+ struct rb_node *ret = rb_insert_near( \
+ &cont->root, &near->node, &obj->node, \
+ &prefix ## _rel); \
+ return ret ? rb_entry(ret, obj_type, node) : 0; \
+} \
+ \
+static __always_inline \
+void prefix ## _remove(cont_type *cont, obj_type *obj) \
+{ \
+ rb_remove(&cont->root, &obj->node, &prefix ## _rel); \
+} \
+ \
+IFF_EMPTY(find_mod, static __always_inline, find_mod) __maybe_unused \
+obj_type *prefix ## _find_first(cont_type *cont, \
+ const typeof(((obj_type *)0)->key) *_key) \
+{ \
+ struct rb_node *ret = rb_find_first( \
+ &cont->root, _key, &prefix ## _rel); \
+ return ret ? rb_entry(ret, obj_type, node) : 0; \
+} \
+ \
+IFF_EMPTY(find_mod, static __always_inline, find_mod) __maybe_unused \
+obj_type *prefix ## _find_last(cont_type *cont, \
+ const typeof(((obj_type *)0)->key) *_key) \
+{ \
+ struct rb_node *ret = rb_find_last( \
+ &cont->root, _key, &prefix ## _rel); \
+ return ret ? rb_entry(ret, obj_type, node) : 0; \
+} \
+ \
+static __always_inline \
+obj_type *prefix ## _find_next(const obj_type *obj) \
+{ \
+ struct rb_node *ret = rb_find_next(&obj->node, &prefix ## _rel);\
+ return ret ? rb_entry(ret, obj_type, node) : 0; \
+} \
+ \
+static __always_inline \
+obj_type *prefix ## _find_prev(const obj_type *obj) \
+{ \
+ struct rb_node *ret = rb_find_prev(&obj->node, &prefix ## _rel);\
+ return ret ? rb_entry(ret, obj_type, node) : 0; \
+} \
+ \
+static __always_inline obj_type *prefix ## _next(const obj_type *obj) \
+{ \
+ struct rb_node *ret = rb_next(&obj->node); \
+ return ret ? rb_entry(ret, obj_type, node) : 0; \
+} \
+ \
+static __always_inline obj_type *prefix ## _prev(const obj_type *obj) \
+{ \
+ struct rb_node *ret = rb_prev(&obj->node); \
+ return ret ? rb_entry(ret, obj_type, node) : 0; \
+} \
+ \
+static __always_inline obj_type *prefix ## _first(cont_type *cont) \
+{ \
+ struct rb_node *ret = rb_first(&cont->root); \
+ return ret ? rb_entry(ret, obj_type, node) : 0; \
+} \
+ \
+static __always_inline obj_type *prefix ## _last(cont_type *cont) \
+{ \
+ struct rb_node *ret = rb_last(&cont->root); \
+ return ret ? rb_entry(ret, obj_type, node) : 0; \
+}
+
#endif /* _LINUX_RBTREE_H */
--
1.7.3.4