diff --git a/include/pbl.h b/include/pbl.h
index f84ed3b..83a0580 100644
--- a/include/pbl.h
+++ b/include/pbl.h
@@ -6,6 +6,8 @@
 #ifndef __PBL_H__
 #define __PBL_H__
 
+#include <linux/types.h>
+
 extern unsigned long free_mem_ptr;
 extern unsigned long free_mem_end_ptr;
 
@@ -13,6 +15,18 @@
 
 #ifdef __PBL__
 #define IN_PBL	1
+
+struct pbl_bio {
+	void *priv;
+	int (*read)(struct pbl_bio *bio, off_t block_off, void *buf, unsigned nblocks);
+};
+
+static inline int pbl_bio_read(struct pbl_bio *bio, off_t block_off,
+			       void *buf, unsigned nblocks)
+{
+	return bio->read(bio, block_off, buf, nblocks);
+}
+
 #else
 #define IN_PBL	0
 #endif