1 files changed, 29 insertions, 0 deletions

diff --git a/include/linux/idr.h b/include/linux/idr.h
index 826803449db7..915572fa030b 100644
--- a/include/linux/idr.h
+++ b/include/linux/idr.h
@@ -83,4 +83,33 @@ void idr_remove(struct idr *idp, int id);
 void idr_destroy(struct idr *idp);
 void idr_init(struct idr *idp);
 
+
+/*
+ * IDA - IDR based id allocator, use when translation from id to
+ * pointer isn't necessary.
+ */
+#define IDA_CHUNK_SIZE          128     /* 128 bytes per chunk */
+#define IDA_BITMAP_LONGS        (128 / sizeof(long) - 1)
+#define IDA_BITMAP_BITS         (IDA_BITMAP_LONGS * sizeof(long) * 8)
+
+struct ida_bitmap {
+        long                    nr_busy;
+        unsigned long           bitmap[IDA_BITMAP_LONGS];
+};
+
+struct ida {
+        struct idr              idr;
+        struct ida_bitmap       *free_bitmap;
+};
+
+#define IDA_INIT(name)          { .idr = IDR_INIT(name), .free_bitmap = NULL, }
+#define DEFINE_IDA(name)        struct ida name = IDA_INIT(name)
+
+int ida_pre_get(struct ida *ida, gfp_t gfp_mask);
+int ida_get_new_above(struct ida *ida, int starting_id, int *p_id);
+int ida_get_new(struct ida *ida, int *p_id);
+void ida_remove(struct ida *ida, int id);
+void ida_destroy(struct ida *ida);
+void ida_init(struct ida *ida);
+
 #endif /* __IDR_H__ */