Remove divide by zero possibility from calc_latency().
--- diff/drivers/md/dm-iostats.c	2002-12-16 16:06:12.000000000 +0000
+++ source/drivers/md/dm-iostats.c	2002-12-17 09:42:41.000000000 +0000
@@ -171,9 +171,9 @@
 {
 	unsigned long start_total = to_milli(&ic->start[rw]);
 	unsigned long end_total = to_milli(&ic->end[rw]);
+	unsigned long count = atomic_read(&ic->ios[rw]);
 
-	return (end_total - start_total) /
-		(unsigned long) atomic_read(&ic->ios[rw]);
+	return count ? ((end_total - start_total) / count) : 0;
 }
 
 static int iostats_status(struct dm_target *ti, status_type_t type,