Add generic red-black tree code to rbtree.h.
Signed-off-by: Daniel Santos <daniel.santos@xxxxxxxxx>
---
include/linux/rbtree.h | 1125 +++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 1123 insertions(+), 2 deletions(-)
diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h
index 0022c1b..210ebeb 100644
--- a/include/linux/rbtree.h
+++ b/include/linux/rbtree.h
@@ -1,7 +1,8 @@
/*
Red Black Trees
(C) 1999 Andrea Arcangeli <andrea@xxxxxxx>
-
+ (C) 2012 Daniel Santos <daniel.santos@xxxxxxxxx>
+
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
@@ -31,6 +32,7 @@
#include <linux/kernel.h>
#include <linux/stddef.h>
+#include <linux/bug.h>
struct rb_node {
unsigned long __rb_parent_color;
@@ -61,6 +63,7 @@ struct rb_root {
extern void rb_insert_color(struct rb_node *, struct rb_root *);
extern void rb_erase(struct rb_node *, struct rb_root *);
+typedef long (*rb_compare_f)(const void *a, const void *b);
/* Find logical next and previous nodes in a tree */
extern struct rb_node *rb_next(const struct rb_node *);
@@ -69,7 +72,7 @@ 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,
@@ -81,4 +84,1122 @@ 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 parameter 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
+ * @member: (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 - values for strct rb_relationship's flags
+ * @RB_HAS_LEFTMOST: 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: Same as above (for right side of tree).
+ * @RB_HAS_COUNT: The container has an unsigned long field that will
+ * receive updates of the object count in the tree.
+ * @RB_UNIQUE_KEYS: The tree contains only unique values.
+ * @RB_INSERT_REPLACES: When set, the rb_insert() will replace a value if it
+ * matches the supplied one (valid only when
+ * RB_UNIQUE_KEYS is set).
+ * @RB_ALL_FLAGS: (internal use)
+ */
+
+enum rb_flags {
+ RB_HAS_LEFTMOST = 0x00000001,
+ RB_HAS_RIGHTMOST = 0x00000002,
+ RB_HAS_COUNT = 0x00000004,
+ RB_UNIQUE_KEYS = 0x00000008,
+ RB_INSERT_REPLACES = 0x00000010,
+ RB_ALL_FLAGS = RB_HAS_LEFTMOST | RB_HAS_RIGHTMOST
+ | RB_HAS_COUNT | RB_UNIQUE_KEYS
+ | RB_INSERT_REPLACES,
+};
+
+/**
+ * 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 RB_HAS_LEFTMOST is set) 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: Offset of container's unsigned long count member.
+ * @node_offset: Offset of object's struct rb_node member.
+ * @key_offset: Offset of object's key member.
+ * @flags: See enum rb_flags.
+ * @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 declare it as accepting
+ * pointers to your key members, or sanity checks will fail.
+ * Further, it is optimal if the function is declared inline.
+ *
+ * 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_compare_f ins_compare;
+ unsigned key_size;
+};
+
+#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);
+
+ /* Due to a bug in versions of gcc prior to 4.6, the following
+ * expressions are always evalulated at run-time:
+ *
+ * (!(rel->flags & RB_UNIQUE_KEYS) && (rel->flags & RB_INSERT_REPLACES))
+ *
+ * The work-around for this bug is separate each bitwise AND test using
+ * an if/else construct and evaluate only the last test with the
+ * BUILD_BUG_ON macro.
+ */
+
+ if (rel->flags & RB_INSERT_REPLACES)
+ BUILD_BUG_ON42(!(rel->flags & RB_UNIQUE_KEYS));
+}
+
+
+/**
+ * __rb_find() - Perform a (normal) search on a Red-Black Tree, starting at the
+ * specified node, traversing downward.
+ * @node: Node (subtree) to start the search from.
+ * @key: Pointer to a key to search for.
+ * @rel: Pointer to the relationship definition constant.
+ */
+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 on a Red-Black Tree.
+ * @root: Root of the tree.
+ * @key: Pointer to a key to search for.
+ * @rel: Pointer to the relationship definition constant.
+ */
+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);
+
+ /* don't use this function on a tree with unique keys */
+ 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 a tree containing
+ * non-unique keys.
+ * @root: Root of the tree.
+ * @key: Pointer to a key.
+ * @rel: Pointer to the relationship definition constant.
+ *
+ * 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 a tree containing
+ * non-unique keys.
+ * @root: Root of the tree.
+ * @key: Pointer to a key.
+ * @rel: Pointer to the relationship definition constant.
+ *
+ * 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 tree containing non-unique keys,
+ * whos key matches the supplied node.
+ * @node: Node of the current object in the tree.
+ * @rel: Pointer to the relationship definition constant.
+ *
+ * Generally 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);
+
+ /* don't use this function on a tree with unique keys */
+ 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 tree containing non-unique
+ * keys, whos key matches the supplied node.
+ * @node: Node of the current object in the tree.
+ * @rel: Pointer to the relationship definition constant.
+ *
+ * Generally 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);
+
+ /* don't use this function on a tree with unique keys */
+ 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) traversing upwards.
+ * @root: Root of the tree
+ * @start: Node to start from
+ * @key: Key to search for
+ * @matched: Pointer for a result value to be returned to (see enum
+ * rb_find_subtree_match)
+ * @ret_link: Pointer for a link pointer to be returned
+ * @ret_parent: Pointer for a parent pointer to be returned
+ * @rel: A constant relationship definition
+ * @doing_insert: Rather or not we're doing an insert.
+ *
+ * Travels up a tree, starting from the specified node, until it locates the
+ * node (representing the subtree) under which the object (specified by key)
+ * can be located, or until that object its self is located.
+ *
+ * This function is used by find_near and insert_near, but behaves differently
+ * for each case (and perhaps could have been implemented as two separate
+ * functions). Specifically, when doing_insert is non-zero, it will set values
+ * in the location provided by populate ret_link & ret_parent. Unused
+ * functionality when doing_insert is zero should be "compiled-out" in an
+ * optimized build.
+ */
+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, triple 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 diverging 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;
+}
+
+/**
+ * rb_find_near() - Perform a search starting at the specified node instead of
+ * the top of the tree.
+ * @from: Node to start search from
+ * @key: Key to search for
+ * @rel: Pointer to the relationship definition constant.
+ *
+ * Travels up the tree starting from the specified node and then back down
+ * again, searching for the object specified by key. This function is larger
+ * than a normal search, but can yield better performance if the target object
+ * is near the supplied node. Performance is roughly O(log2(distance / 2) * 2
+ * + 1).
+ */
+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)
+ rb_replace_node(found, node, root);
+ 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);
+
+done:
+ return found;
+}
+
+
+/**
+ * rb_insert() - Insert a node into a tree.
+ * @root: Pointer to struct rb_root.
+ * @node: Pointer to the node of the new object to insert.
+ * @rel: Pointer to the relationship definition constant.
+ *
+ * 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 * const key = __rb_node_to_key(node, rel);
+ int leftmost = 1;
+ int rightmost = 1;
+
+ /* optimization/hack good on gcc 4.6.0+, when -findirect-inline is able
+ * to inline the compare function. This manages to force gcc to put
+ * the value of the key in a register, instead of retrieving it prior
+ * to each compare. The necessity of this hasn't been tested beyond
+ * gcc 4.7.1.
+ */
+#if GCC_VERSION >= 40600
+ u16 __maybe_unused key16;
+ u32 __maybe_unused key32;
+ u64 __maybe_unused key64;
+
+ if (rel->key_size == 2)
+ key16 = *(u16*)key;
+ else if (rel->key_size == 4)
+ key32 = *(u32*)key;
+ else if (rel->key_size == 8)
+ key64 = *(u64*)key;
+#endif
+
+ __rb_assert_good_rel(rel);
+
+
+ while (*p) {
+ long diff;
+ const void *cur_key = __rb_node_to_key(*p, rel);
+
+#if GCC_VERSION >= 40600
+ if (rel->key_size == 2)
+ diff = rel->ins_compare(&key16, cur_key);
+ else if (rel->key_size == 4)
+ diff = rel->ins_compare(&key32, cur_key);
+ else if (rel->key_size == 8)
+ diff = rel->ins_compare(&key64, cur_key);
+ else
+#endif
+ /* On gcc 4.5.x & prior, or for other key sizes, we
+ * pass key ptr as a const void*, which tends to
+ * optimize more poorly
+ */
+ diff = rel->ins_compare(key, cur_key);
+
+ 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);
+}
+
+/**
+ * rb_insert_near() - Perform an insert, but use the supplied start node to
+ * find the location for the new node.
+ * @root: Pointer to struct rb_root.
+ * @start: Node to start search for insert location from.
+ * @node: Pointer to the node of the new object to insert.
+ * @rel: Pointer to the relationship definition constant.
+ *
+ * This function is larger than rb_insert, but can yield better performance
+ * when the position where the new node is being is close to start. Performance
+ * is roughly O(log2(distance / 2) * 2 + 1).
+ */
+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);
+}
+
+/**
+ * rb_remove() - Remove a node from an rbtree.
+ * @root: Pointer to struct rb_root.
+ * @node: Pointer to the node of the object to be removed.
+ * @rel: Pointer to the relationship definition constant.
+ */
+static __always_inline __flatten
+void rb_remove(
+ struct rb_root *root,
+ struct rb_node *node,
+ const struct rb_relationship *rel)
+{
+ BUILD_BUG_ON_NON_CONST42(rel->flags);
+
+ 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);
+}
+
+
+/**
+ * RB_RELATIONSHIP - Define the relationship between 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 long member that will be
+ * updated with the number of objects in the tree. 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 member 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 or RB_HAS_COUNT 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 declare it as accepting
+ * pointers to your key members, or sanity checks will fail.
+ * Further, it is optimal if the function is declared inline.
+ * @_ins_compare:
+ *
+ * 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 *a - *b;
+ * }
+ *
+ * static inline long greater_int(const int *a, const int *b)
+ * {
+ * return *a > *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, greater_int);
+ */
+#define RB_RELATIONSHIP( \
+ cont_type, root, left, right, count, \
+ obj_type, node, key, \
+ _flags, _compare, _ins_compare) { \
+ .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), \
+ .compare = (const rb_compare_f) (_compare), \
+ .ins_compare = (const rb_compare_f) (_ins_compare), \
+ .key_size = sizeof(((obj_type *)0)->key) \
+}
+
+/* compile-time 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) {}
+static inline void __rb_verify_ins_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_RELATIONSHIP
+ * @root: see RB_RELATIONSHIP
+ * @left: see RB_RELATIONSHIP
+ * @right: see RB_RELATIONSHIP
+ * @count: see RB_RELATIONSHIP
+ * @obj_type: see RB_RELATIONSHIP
+ * @node: see RB_RELATIONSHIP
+ * @key: see RB_RELATIONSHIP
+ * @flags: see RB_RELATIONSHIP
+ * @compare: see RB_RELATIONSHIP
+ * @ing_compare: see RB_RELATIONSHIP
+ * @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 declared 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, ins_compare, \
+ find_mod, insert_mod, find_near_mod, insert_near_mod) \
+ \
+/* Compile-time sanity checks. 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) \
+{ \
+ /* {,ins_}compare functions should take ptr to key member */ \
+ typeof((compare)(&obj->key, &obj->key)) _diff = \
+ (compare)(&obj->key, &obj->key); \
+ typeof((ins_compare)(&obj->key, &obj->key)) _ins_diff = \
+ (ins_compare)(&obj->key, &obj->key); \
+ __rb_verify_compare_fn_ret(&_diff); \
+ __rb_verify_ins_compare_fn_ret(&_ins_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, ins_compare); \
+ \
+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
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