s390/dasd: Fix gendisk parent after copy pair swap

commit c943bfc upstream.

After a copy pair swap the block device's "device" symlink points to
the secondary CCW device, but the gendisk's parent remained the
primary, leaving /sys/block/<dasdx> under the wrong parent.

Move the gendisk to the secondary's device with device_move(), keeping
the sysfs topology consistent after the swap.

Fixes: 413862c ("s390/dasd: add copy pair swap capability")
Cc: stable@vger.kernel.org #6.1
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Stefan Haberland

drivers/s390/block/dasd_eckd.c

@@ -6150,6 +6150,7 @@ static int dasd_eckd_copy_pair_swap(struct dasd_device *device, char *prim_busid
 	struct dasd_copy_relation *copy;
 	struct dasd_block *block;
 	struct gendisk *gdp;
+	int rc;
 
 	copy = device->copy;
 	if (!copy)
@@ -6184,6 +6185,13 @@ static int dasd_eckd_copy_pair_swap(struct dasd_device *device, char *prim_busid
 	/* swap blocklayer device link */
 	gdp = block->gdp;
 	dasd_add_link_to_gendisk(gdp, secondary);
+	rc = device_move(disk_to_dev(gdp), &secondary->cdev->dev, DPM_ORDER_NONE);
+	if (rc) {
+		dev_err(&primary->cdev->dev,
+			"copy_pair_swap: moving blockdevice parent %s->%s failed (%d)\n",
+			dev_name(&primary->cdev->dev),
+			dev_name(&secondary->cdev->dev), rc);
+	}
 
 	/* re-enable device */
 	dasd_device_remove_stop_bits(primary, DASD_STOPPED_PPRC);