1 files changed, 120 insertions, 0 deletions

diff --git a/include/linux/prio_tree.h b/include/linux/prio_tree.h
new file mode 100644
index 000000000000..db04abb557e0
--- /dev/null
+++ b/include/linux/prio_tree.h
@@ -0,0 +1,120 @@
+#ifndef _LINUX_PRIO_TREE_H
+#define _LINUX_PRIO_TREE_H
+
+/*
+ * K&R 2nd ed. A8.3 somewhat obliquely hints that initial sequences of struct
+ * fields with identical types should end up at the same location. We'll use
+ * this until we can scrap struct raw_prio_tree_node.
+ *
+ * Note: all this could be done more elegantly by using unnamed union/struct
+ * fields. However, gcc 2.95.3 and apparently also gcc 3.0.4 don't support this
+ * language extension.
+ */
+
+struct raw_prio_tree_node {
+        struct prio_tree_node   *left;
+        struct prio_tree_node   *right;
+        struct prio_tree_node   *parent;
+};
+
+struct prio_tree_node {
+        struct prio_tree_node   *left;
+        struct prio_tree_node   *right;
+        struct prio_tree_node   *parent;
+        unsigned long           start;
+        unsigned long           last;   /* last location _in_ interval */
+};
+
+struct prio_tree_root {
+        struct prio_tree_node   *prio_tree_node;
+        unsigned short          index_bits;
+        unsigned short          raw;
+                /*
+                 * 0: nodes are of type struct prio_tree_node
+                 * 1: nodes are of type raw_prio_tree_node
+                 */
+};
+
+struct prio_tree_iter {
+        struct prio_tree_node   *cur;
+        unsigned long           mask;
+        unsigned long           value;
+        int                     size_level;
+
+        struct prio_tree_root   *root;
+        pgoff_t                 r_index;
+        pgoff_t                 h_index;
+};
+
+static inline void prio_tree_iter_init(struct prio_tree_iter *iter,
+                struct prio_tree_root *root, pgoff_t r_index, pgoff_t h_index)
+{
+        iter->root = root;
+        iter->r_index = r_index;
+        iter->h_index = h_index;
+        iter->cur = NULL;
+}
+
+#define __INIT_PRIO_TREE_ROOT(ptr, _raw)        \
+do {                                    \
+        (ptr)->prio_tree_node = NULL;   \
+        (ptr)->index_bits = 1;          \
+        (ptr)->raw = (_raw);            \
+} while (0)
+
+#define INIT_PRIO_TREE_ROOT(ptr)        __INIT_PRIO_TREE_ROOT(ptr, 0)
+#define INIT_RAW_PRIO_TREE_ROOT(ptr)    __INIT_PRIO_TREE_ROOT(ptr, 1)
+
+#define INIT_PRIO_TREE_NODE(ptr)                                \
+do {                                                            \
+        (ptr)->left = (ptr)->right = (ptr)->parent = (ptr);     \
+} while (0)
+
+#define INIT_PRIO_TREE_ITER(ptr)        \
+do {                                    \
+        (ptr)->cur = NULL;              \
+        (ptr)->mask = 0UL;              \
+        (ptr)->value = 0UL;             \
+        (ptr)->size_level = 0;          \
+} while (0)
+
+#define prio_tree_entry(ptr, type, member) \
+       ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
+
+static inline int prio_tree_empty(const struct prio_tree_root *root)
+{
+        return root->prio_tree_node == NULL;
+}
+
+static inline int prio_tree_root(const struct prio_tree_node *node)
+{
+        return node->parent == node;
+}
+
+static inline int prio_tree_left_empty(const struct prio_tree_node *node)
+{
+        return node->left == node;
+}
+
+static inline int prio_tree_right_empty(const struct prio_tree_node *node)
+{
+        return node->right == node;
+}
+
+
+struct prio_tree_node *prio_tree_replace(struct prio_tree_root *root,
+                struct prio_tree_node *old, struct prio_tree_node *node);
+struct prio_tree_node *prio_tree_insert(struct prio_tree_root *root,
+                struct prio_tree_node *node);
+void prio_tree_remove(struct prio_tree_root *root, struct prio_tree_node *node);
+struct prio_tree_node *prio_tree_next(struct prio_tree_iter *iter);
+
+#define raw_prio_tree_replace(root, old, node) \
+        prio_tree_replace(root, (struct prio_tree_node *) (old), \
+            (struct prio_tree_node *) (node))
+#define raw_prio_tree_insert(root, node) \
+        prio_tree_insert(root, (struct prio_tree_node *) (node))
+#define raw_prio_tree_remove(root, node) \
+        prio_tree_remove(root, (struct prio_tree_node *) (node))
+
+#endif /* _LINUX_PRIO_TREE_H */