dm integrity: do not check integrity for failed read operations

Even though read operations fail, dm_integrity_map_continue() calls
integrity_metadata() to check integrity.  In this case, just complete
these.

This also makes it so read I/O errors do not generate integrity warnings
in the kernel log.

Cc: stable@vger.kernel.org
Signed-off-by: Hyunchul Lee <cheol.lee@lge.com>
Acked-by: Milan Broz <gmazyland@gmail.com>
Acked-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-integrity.c

@@ -1702,7 +1702,11 @@ static void dm_integrity_map_continue(struct dm_integrity_io *dio, bool from_map
 
 	if (need_sync_io) {
 		wait_for_completion_io(&read_comp);
+		if (likely(!bio->bi_status))
 			integrity_metadata(&dio->work);
+		else
+			dec_in_flight(dio);
+
 	} else {
 		INIT_WORK(&dio->work, integrity_metadata);
 		queue_work(ic->metadata_wq, &dio->work);