scsi: virtio_scsi: Use scsi_cmd_to_rq() instead of scsi_cmnd.request

Prepare for removal of the request pointer by using scsi_cmd_to_rq()
instead. This patch does not change any functionality.

Link: https://lore.kernel.org/r/20210809230355.8186-49-bvanassche@acm.orgAcked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/virtio_scsi.c

@@ -519,7 +519,7 @@ static void virtio_scsi_init_hdr_pi(struct virtio_device *vdev,
 				    struct virtio_scsi_cmd_req_pi *cmd_pi,
 				    struct scsi_cmnd *sc)
 {
-	struct request *rq = sc->request;
+	struct request *rq = scsi_cmd_to_rq(sc);
 	struct blk_integrity *bi;
 
 	virtio_scsi_init_hdr(vdev, (struct virtio_scsi_cmd_req *)cmd_pi, sc);
@@ -543,7 +543,7 @@ static void virtio_scsi_init_hdr_pi(struct virtio_device *vdev,
 static struct virtio_scsi_vq *virtscsi_pick_vq_mq(struct virtio_scsi *vscsi,
 						  struct scsi_cmnd *sc)
 {
-	u32 tag = blk_mq_unique_tag(sc->request);
+	u32 tag = blk_mq_unique_tag(scsi_cmd_to_rq(sc));
 	u16 hwq = blk_mq_unique_tag_to_hwq(tag);
 
 	return &vscsi->req_vqs[hwq];