On Fri, 2017-03-24 at 20:36 +0800, Ming Lei wrote:=20

+	/* block new I/O coming */
+	blk_freeze_queue_start(q);

As I have already mentioned two times, the comment above
blk_freeze_queue_start() should be made more clear. It should mention that
without that call blk_queue_enter() won't check the "dying" flag after it
has been set. If that is not mentioned in a comment the next person who
reads the blk_set_queue_dying() function will wonder why the
blk_freeze_queue_start() call is really needed and whether it can be remove=
d.

 		/*
 		 * read pair of barrier in blk_freeze_queue_start(),
 		 * we need to order reading DEAD flag of .q_usage_counter
-		 * and reading .mq_freeze_depth, otherwise the following
-		 * wait may never return if the two read are reordered.
+		 * and reading .mq_freeze_depth or dying flag, otherwise
+		 * the following wait may never return if the two read
+		 * are reordered.
 		 */
 		smp_rmb();

Please fix the spelling in the above comment ("two read").

Thanks,

Bart.