dm-delay: fix max_delay calculations

delay_ctr() pointlessly compared max_delay in cases where multiple delay
classes were initialized identically. Also, when write delays were
configured different than read delays, delay_ctr() never compared their
value against max_delay. Fix these issues.

Fixes: 70bbeb2 ("dm delay: for short delays, use kthread instead of timers and wq")
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Author: bmarzins

drivers/md/dm-delay.c

@@ -242,19 +242,18 @@ static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		ret = delay_class_ctr(ti, &dc->flush, argv);
 		if (ret)
 			goto bad;
-		max_delay = max(max_delay, dc->write.delay);
-		max_delay = max(max_delay, dc->flush.delay);
 		goto out;
 	}
 
 	ret = delay_class_ctr(ti, &dc->write, argv + 3);
 	if (ret)
 		goto bad;
+	max_delay = max(max_delay, dc->write.delay);
+
 	if (argc == 6) {
 		ret = delay_class_ctr(ti, &dc->flush, argv + 3);
 		if (ret)
 			goto bad;
-		max_delay = max(max_delay, dc->flush.delay);
 		goto out;
 	}