scsi: storvsc: 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/20210809230355.8186-1-bvanassche@acm.orgSigned-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/storvsc_drv.c

@@ -710,7 +710,7 @@ static u64 storvsc_next_request_id(struct vmbus_channel *channel, u64 rqst_addr)
 	 * Cannot return an ID of 0, which is reserved for an unsolicited
 	 * message from Hyper-V.
 	 */
-	return (u64)blk_mq_unique_tag(request->cmd->request) + 1;
+	return (u64)blk_mq_unique_tag(scsi_cmd_to_rq(request->cmd)) + 1;
 }
 
 static void handle_sc_creation(struct vmbus_channel *new_sc)
@@ -1202,7 +1202,7 @@ static void storvsc_on_io_completion(struct storvsc_device *stor_device,
 	    vstor_packet->vm_srb.srb_status != SRB_STATUS_SUCCESS)
 		storvsc_log(device, STORVSC_LOGGING_ERROR,
 			"tag#%d cmd 0x%x status: scsi 0x%x srb 0x%x hv 0x%x\n",
-			request->cmd->request->tag,
+			scsi_cmd_to_rq(request->cmd)->tag,
 			stor_pkt->vm_srb.cdb[0],
 			vstor_packet->vm_srb.scsi_status,
 			vstor_packet->vm_srb.srb_status,