md: raid10: add prerequisite to run underneath dm-raid

In case md runs underneath the dm-raid target, the mddev does not have
a request queue or gendisk, thus avoid accesses to it.

This patch adds two missing conditionals to the raid10 personality.
Signed-of-by: NHeinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: NShaohua Li <shli@fb.com>

drivers/md/raid10.c

@@ -3782,8 +3782,10 @@ static int raid10_resize(struct mddev *mddev, sector_t sectors)
 			return ret;
 	}
 	md_set_array_sectors(mddev, size);
-	set_capacity(mddev->gendisk, mddev->array_sectors);
-	revalidate_disk(mddev->gendisk);
+	if (mddev->queue) {
+		set_capacity(mddev->gendisk, mddev->array_sectors);
+		revalidate_disk(mddev->gendisk);
+	}
 	if (sectors > mddev->dev_sectors &&
 	    mddev->recovery_cp > oldsize) {
 		mddev->recovery_cp = oldsize;
@@ -4593,8 +4595,10 @@ static void raid10_finish_reshape(struct mddev *mddev)
 			set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 		}
 		mddev->resync_max_sectors = size;
-		set_capacity(mddev->gendisk, mddev->array_sectors);
-		revalidate_disk(mddev->gendisk);
+		if (mddev->queue) {
+			set_capacity(mddev->gendisk, mddev->array_sectors);
+			revalidate_disk(mddev->gendisk);
+		}
 	} else {
 		int d;
 		for (d = conf->geo.raid_disks ;