diff -ur a/drivers/xen/blkback/blkback.c b/drivers/xen/blkback/blkback.c
--- a/drivers/xen/blkback/blkback.c	2009-08-15 16:53:47.000000000 +0800
+++ b/drivers/xen/blkback/blkback.c	2009-08-16 06:15:19.000000000 +0800
@@ -203,11 +203,11 @@
 static void refill_credit(blkif_t *blkif)
 {
 	blkif->credit_time = jiffies + msecs_to_jiffies(blkif->credit_msec);
-	blkif->available_credit += blkif->credit_req;
+	blkif->remaining_credit += blkif->credit_req;
 
 	/* this allows for bursting. */
-	if (blkif->available_credit > (blkif->credit_req * blkif->credit_msec))
-		blkif->available_credit = blkif->credit_req;
+	if (blkif->remaining_credit > (blkif->credit_req * blkif->credit_msec))
+		blkif->remaining_credit = blkif->credit_req;
 }
 
 int blkif_schedule(void *arg)
diff -ur a/drivers/xen/blkback/xenbus.c b/drivers/xen/blkback/xenbus.c
--- a/drivers/xen/blkback/xenbus.c	2009-08-15 16:53:47.000000000 +0800
+++ b/drivers/xen/blkback/xenbus.c	2009-08-16 11:35:34.000000000 +0800
@@ -265,7 +265,7 @@
 
 	/* Default to unlimited I/O operations. */
 	*credit = ~0UL;
-	*usec = 0;
+	*msec = 0;
 
 	ratestr = xenbus_read(xbt, dev->nodename, "credit", NULL);
 	if (IS_ERR(ratestr))
@@ -288,6 +288,7 @@
 	return;
 
  fail:
+#define WPRINTK(fmt, args...) \
 	WPRINTK("Failed to parse I/O credit limit. I/O operations are unlimited.\n");
 	kfree(ratestr);
 }