btrfs-progs: kernel-lib: add rb_root_cached helpers
Copy inline helpers for the cached variant of the rbtree, not used yet. Rename 'new' for C++ compatibility. Signed-off-by: David Sterba <dsterba@suse.com>
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David Sterba
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2b603d9819
commit
68d04374f7
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@ -37,6 +37,8 @@
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#include <btrfs/rbtree_types.h>
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#endif /* BTRFS_FLAT_INCLUDES */
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#include <stdbool.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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@ -101,6 +103,234 @@ static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
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typeof(*pos), field); 1; }); \
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pos = n)
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/* Same as rb_first(), but O(1) */
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#define rb_first_cached(root) (root)->rb_leftmost
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static inline void rb_insert_color_cached(struct rb_node *node,
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struct rb_root_cached *root,
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bool leftmost)
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{
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if (leftmost)
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root->rb_leftmost = node;
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rb_insert_color(node, &root->rb_root);
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}
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static inline struct rb_node *
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rb_erase_cached(struct rb_node *node, struct rb_root_cached *root)
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{
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struct rb_node *leftmost = NULL;
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if (root->rb_leftmost == node)
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leftmost = root->rb_leftmost = rb_next(node);
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rb_erase(node, &root->rb_root);
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return leftmost;
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}
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static inline void rb_replace_node_cached(struct rb_node *victim,
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struct rb_node *new_node,
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struct rb_root_cached *root)
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{
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if (root->rb_leftmost == victim)
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root->rb_leftmost = new_node;
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rb_replace_node(victim, new_node, &root->rb_root);
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}
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/*
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* The below helper functions use 2 operators with 3 different
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* calling conventions. The operators are related like:
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*
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* comp(a->key,b) < 0 := less(a,b)
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* comp(a->key,b) > 0 := less(b,a)
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* comp(a->key,b) == 0 := !less(a,b) && !less(b,a)
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*
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* If these operators define a partial order on the elements we make no
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* guarantee on which of the elements matching the key is found. See
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* rb_find().
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*
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* The reason for this is to allow the find() interface without requiring an
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* on-stack dummy object, which might not be feasible due to object size.
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*/
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/**
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* rb_add_cached() - insert @node into the leftmost cached tree @tree
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* @node: node to insert
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* @tree: leftmost cached tree to insert @node into
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* @less: operator defining the (partial) node order
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*
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* Returns @node when it is the new leftmost, or NULL.
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*/
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static __always_inline struct rb_node *
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rb_add_cached(struct rb_node *node, struct rb_root_cached *tree,
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bool (*less)(struct rb_node *, const struct rb_node *))
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{
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struct rb_node **link = &tree->rb_root.rb_node;
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struct rb_node *parent = NULL;
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bool leftmost = true;
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while (*link) {
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parent = *link;
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if (less(node, parent)) {
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link = &parent->rb_left;
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} else {
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link = &parent->rb_right;
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leftmost = false;
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}
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}
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rb_link_node(node, parent, link);
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rb_insert_color_cached(node, tree, leftmost);
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return leftmost ? node : NULL;
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}
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/**
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* rb_add() - insert @node into @tree
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* @node: node to insert
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* @tree: tree to insert @node into
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* @less: operator defining the (partial) node order
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*/
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static __always_inline void
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rb_add(struct rb_node *node, struct rb_root *tree,
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bool (*less)(struct rb_node *, const struct rb_node *))
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{
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struct rb_node **link = &tree->rb_node;
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struct rb_node *parent = NULL;
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while (*link) {
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parent = *link;
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if (less(node, parent))
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link = &parent->rb_left;
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else
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link = &parent->rb_right;
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}
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rb_link_node(node, parent, link);
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rb_insert_color(node, tree);
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}
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/**
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* rb_find_add() - find equivalent @node in @tree, or add @node
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* @node: node to look-for / insert
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* @tree: tree to search / modify
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* @cmp: operator defining the node order
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*
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* Returns the rb_node matching @node, or NULL when no match is found and @node
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* is inserted.
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*/
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static __always_inline struct rb_node *
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rb_find_add(struct rb_node *node, struct rb_root *tree,
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int (*cmp)(struct rb_node *, const struct rb_node *))
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{
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struct rb_node **link = &tree->rb_node;
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struct rb_node *parent = NULL;
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int c;
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while (*link) {
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parent = *link;
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c = cmp(node, parent);
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if (c < 0)
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link = &parent->rb_left;
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else if (c > 0)
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link = &parent->rb_right;
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else
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return parent;
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}
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rb_link_node(node, parent, link);
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rb_insert_color(node, tree);
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return NULL;
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}
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/**
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* rb_find() - find @key in tree @tree
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* @key: key to match
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* @tree: tree to search
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* @cmp: operator defining the node order
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*
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* Returns the rb_node matching @key or NULL.
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*/
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static __always_inline struct rb_node *
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rb_find(const void *key, const struct rb_root *tree,
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int (*cmp)(const void *key, const struct rb_node *))
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{
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struct rb_node *node = tree->rb_node;
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while (node) {
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int c = cmp(key, node);
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if (c < 0)
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node = node->rb_left;
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else if (c > 0)
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node = node->rb_right;
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else
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return node;
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}
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return NULL;
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}
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/**
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* rb_find_first() - find the first @key in @tree
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* @key: key to match
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* @tree: tree to search
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* @cmp: operator defining node order
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*
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* Returns the leftmost node matching @key, or NULL.
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*/
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static __always_inline struct rb_node *
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rb_find_first(const void *key, const struct rb_root *tree,
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int (*cmp)(const void *key, const struct rb_node *))
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{
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struct rb_node *node = tree->rb_node;
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struct rb_node *match = NULL;
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while (node) {
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int c = cmp(key, node);
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if (c <= 0) {
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if (!c)
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match = node;
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node = node->rb_left;
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} else if (c > 0) {
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node = node->rb_right;
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}
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}
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return match;
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}
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/**
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* rb_next_match() - find the next @key in @tree
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* @key: key to match
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* @tree: tree to search
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* @cmp: operator defining node order
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*
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* Returns the next node matching @key, or NULL.
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*/
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static __always_inline struct rb_node *
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rb_next_match(const void *key, struct rb_node *node,
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int (*cmp)(const void *key, const struct rb_node *))
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{
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node = rb_next(node);
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if (node && cmp(key, node))
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node = NULL;
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return node;
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}
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/**
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* rb_for_each() - iterates a subtree matching @key
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* @node: iterator
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* @key: key to match
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* @tree: tree to search
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* @cmp: operator defining node order
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*/
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#define rb_for_each(node, key, tree, cmp) \
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for ((node) = rb_find_first((key), (tree), (cmp)); \
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(node); (node) = rb_next_match((key), (node), (cmp)))
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#ifdef __cplusplus
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}
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#endif
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@ -59,6 +59,17 @@ rb_insert_augmented(struct rb_node *node, struct rb_root *root,
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__rb_insert_augmented(node, root, augment->rotate);
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}
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static inline void
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rb_insert_augmented_cached(struct rb_node *node,
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struct rb_root_cached *root, bool newleft,
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const struct rb_augment_callbacks *augment)
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{
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if (newleft)
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root->rb_leftmost = node;
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rb_insert_augmented(node, &root->rb_root, augment);
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}
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#define RB_DECLARE_CALLBACKS(rbstatic, rbname, rbstruct, rbfield, \
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rbtype, rbaugmented, rbcompute) \
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static inline void \
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@ -238,4 +249,13 @@ rb_erase_augmented(struct rb_node *node, struct rb_root *root,
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__rb_erase_color(rebalance, root, augment->rotate);
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}
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static __always_inline void
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rb_erase_augmented_cached(struct rb_node *node, struct rb_root_cached *root,
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const struct rb_augment_callbacks *augment)
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{
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if (root->rb_leftmost == node)
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root->rb_leftmost = rb_next(node);
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rb_erase_augmented(node, &root->rb_root, augment);
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}
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#endif /* _LINUX_RBTREE_AUGMENTED_H */
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