dm log: clean interface

Clean up the dm-log interface to prepare for publishing it in include/linux.

Signed-off-by: Heinz Mauelshagen <hjm@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index cb78457..4db2337 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -10,6 +10,8 @@
 
 #ifdef __KERNEL__
 
+#include <linux/bio.h>
+
 struct dm_target;
 struct dm_table;
 struct dm_dev;