drbd: Add interval tree data structure

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/drivers/block/drbd/drbd_interval.h b/drivers/block/drbd/drbd_interval.h
new file mode 100644
index 000000000000..bf8dcf7bab09
--- /dev/null
+++ b/drivers/block/drbd/drbd_interval.h
@@ -0,0 +1,31 @@
+#ifndef __DRBD_INTERVAL_H
+#define __DRBD_INTERVAL_H
+
+#include <linux/types.h>
+#include <linux/rbtree.h>
+
+struct drbd_interval {
+        struct rb_node rb;
+        sector_t sector;        /* start sector of the interval */
+        unsigned int size;      /* size in bytes */
+        sector_t end;           /* highest interval end in subtree */
+};
+
+static inline void drbd_clear_interval(struct drbd_interval *i)
+{
+        RB_CLEAR_NODE(&i->rb);
+}
+
+static inline bool drbd_interval_empty(struct drbd_interval *i)
+{
+        return RB_EMPTY_NODE(&i->rb);
+}
+
+bool drbd_insert_interval(struct rb_root *, struct drbd_interval *);
+struct drbd_interval *drbd_find_interval(struct rb_root *, sector_t,
+                                         struct drbd_interval *);
+void drbd_remove_interval(struct rb_root *, struct drbd_interval *);
+struct drbd_interval *drbd_find_overlap(struct rb_root *, sector_t,
+                                        unsigned int);
+
+#endif  /* __DRBD_INTERVAL_H */