diff --git a/sys/kern/subr_devstat.c b/sys/kern/subr_devstat.c
index eab9a4f63ef..01322e020c8 100644
--- a/sys/kern/subr_devstat.c
+++ b/sys/kern/subr_devstat.c
@@ -201,6 +201,13 @@ devstat_start_transaction(struct devstat *ds)
 	ds->busy_count++;
 }
 
+void
+devstat_start_transaction_bio(struct devstat *ds, struct bio *bp)
+{
+
+	devstat_start_transaction(ds);
+}
+
 /*
  * Record the ending of a transaction, and incrment the various counters.
  */
diff --git a/sys/sys/devicestat.h b/sys/sys/devicestat.h
index 3655db44cd6..872f3f89add 100644
--- a/sys/sys/devicestat.h
+++ b/sys/sys/devicestat.h
@@ -225,6 +225,7 @@ struct devstat *devstat_new_entry(const char *dev_name,
 
 void devstat_remove_entry(struct devstat *ds);
 void devstat_start_transaction(struct devstat *ds);
+void devstat_start_transaction_bio(struct devstat *ds, struct bio *bp);
 void devstat_end_transaction(struct devstat *ds, u_int32_t bytes, 
 			     devstat_tag_type tag_type,
 			     devstat_trans_flags flags);