dm zoned: use dmz_zone_to_dev() when handling metadata I/O

Use accessors to retrieve the device pointer in preparation
for adding an additional block device.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-zoned-metadata.c

@@ -1310,6 +1310,7 @@ static int dmz_update_zone_cb(struct blk_zone *blkz, unsigned int idx,
  */
 static int dmz_update_zone(struct dmz_metadata *zmd, struct dm_zone *zone)
 {
+	struct dmz_dev *dev = dmz_zone_to_dev(zmd, zone);
 	unsigned int noio_flag;
 	int ret;
 
@@ -1320,16 +1321,16 @@ static int dmz_update_zone(struct dmz_metadata *zmd, struct dm_zone *zone)
 	 * GFP_NOIO was specified.
 	 */
 	noio_flag = memalloc_noio_save();
-	ret = blkdev_report_zones(zmd->dev->bdev, dmz_start_sect(zmd, zone), 1,
+	ret = blkdev_report_zones(dev->bdev, dmz_start_sect(zmd, zone), 1,
 				  dmz_update_zone_cb, zone);
 	memalloc_noio_restore(noio_flag);
 
 	if (ret == 0)
 		ret = -EIO;
 	if (ret < 0) {
-		dmz_dev_err(zmd->dev, "Get zone %u report failed",
+		dmz_dev_err(dev, "Get zone %u report failed",
 			    zone->id);
-		dmz_check_bdev(zmd->dev);
+		dmz_check_bdev(dev);
 		return ret;
 	}
 
@@ -1343,6 +1344,7 @@ static int dmz_update_zone(struct dmz_metadata *zmd, struct dm_zone *zone)
 static int dmz_handle_seq_write_err(struct dmz_metadata *zmd,
 				    struct dm_zone *zone)
 {
+	struct dmz_dev *dev = dmz_zone_to_dev(zmd, zone);
 	unsigned int wp = 0;
 	int ret;
 
@@ -1351,7 +1353,7 @@ static int dmz_handle_seq_write_err(struct dmz_metadata *zmd,
 	if (ret)
 		return ret;
 
-	dmz_dev_warn(zmd->dev, "Processing zone %u write error (zone wp %u/%u)",
+	dmz_dev_warn(dev, "Processing zone %u write error (zone wp %u/%u)",
 		     zone->id, zone->wp_block, wp);
 
 	if (zone->wp_block < wp) {
@@ -1384,7 +1386,7 @@ static int dmz_reset_zone(struct dmz_metadata *zmd, struct dm_zone *zone)
 		return 0;
 
 	if (!dmz_is_empty(zone) || dmz_seq_write_err(zone)) {
-		struct dmz_dev *dev = zmd->dev;
+		struct dmz_dev *dev = dmz_zone_to_dev(zmd, zone);
 
 		ret = blkdev_zone_mgmt(dev->bdev, REQ_OP_ZONE_RESET,
 				       dmz_start_sect(zmd, zone),