scsi: scsi_transport_sas: check reply payload length instead of bidi request

As a user of bsg-lib the SAS transport should not poke into request
internals but use the bsg_job fields instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/scsi_transport_sas.c

@@ -177,7 +177,7 @@ static int sas_smp_dispatch(struct bsg_job *job)
 	if (!scsi_is_host_device(job->dev))
 		rphy = dev_to_rphy(job->dev);
 
-	if (!job->req->next_rq) {
+	if (!job->reply_payload.payload_len) {
 		dev_warn(job->dev, "space for a smp response is missing\n");
 		bsg_job_done(job, -EINVAL, 0);
 		return 0;