scsi: core: Drop message byte helper

The message byte is now unused, so we can drop the helper to set the
message byte and the check for message bytes during error recovery.

Link: https://lore.kernel.org/r/[e-mail]
Reviewed-by: Bart Van Assche <[e-mail]>
Signed-off-by: Hannes Reinecke <[e-mail]>
Signed-off-by: Martin K. Petersen <[e-mail]>

block/scsi_ioctl.c

···
 	 */
 	hdr->status = req->result & 0xff;
 	hdr->masked_status = status_byte(req->result);
-	hdr->msg_status = msg_byte(req->result);
+	hdr->msg_status = COMMAND_COMPLETE;
 	hdr->host_status = host_byte(req->result);
 	hdr->driver_status = 0;
 	if (scsi_status_is_check_condition(hdr->status))

drivers/scsi/scsi_error.c

···
 		return FAILED;
 
 	/*
-	 * next, check the message byte.
-	 */
-	if (msg_byte(scmd->result) != COMMAND_COMPLETE)
-		return FAILED;
-
-	/*
 	 * now, check the status byte to see if this indicates
 	 * anything special.
 	 */
···
 	case DID_PARITY:
 		return (scmd->request->cmd_flags & REQ_FAILFAST_DEV);
 	case DID_ERROR:
-		if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
-		    status_byte(scmd->result) == RESERVATION_CONFLICT)
+		if (status_byte(scmd->result) == RESERVATION_CONFLICT)
 			return 0;
 		fallthrough;
 	case DID_SOFT_ERROR:
···
 		 */
 		return SUCCESS;
 	case DID_ERROR:
-		if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
-		    status_byte(scmd->result) == RESERVATION_CONFLICT)
+		if (status_byte(scmd->result) == RESERVATION_CONFLICT)
 			/*
 			 * execute reservation conflict processing code
 			 * lower down
···
 	default:
 		return FAILED;
 	}
-
-	/*
-	 * next, check the message byte.
-	 */
-	if (msg_byte(scmd->result) != COMMAND_COMPLETE)
-		return FAILED;
 
 	/*
 	 * check the status byte to see if this indicates anything special.

drivers/scsi/sg.c

···
 
 		srp->header.status = 0xff & result;
 		srp->header.masked_status = status_byte(result);
-		srp->header.msg_status = msg_byte(result);
+		srp->header.msg_status = COMMAND_COMPLETE;
 		srp->header.host_status = host_byte(result);
 		srp->header.driver_status = driver_byte(result);
 		if ((sdp->sgdebug > 0) &&

drivers/xen/xen-scsiback.c

···
 
 	pr_err("[%s:%d] cmnd[0]=%02x -> st=%02x msg=%02x host=%02x\n",
 	       tpg->tport->tport_name, pending_req->v2p->lun,
-	       pending_req->cmnd[0], status_byte(errors), msg_byte(errors),
+	       pending_req->cmnd[0], status_byte(errors), COMMAND_COMPLETE,
 	       host_byte(errors));
 }
 

include/scsi/scsi.h

···
  *  These are set by:
  *
  *      status byte = set from target device
- *      msg_byte    = return status from host adapter itself.
+ *      msg_byte    (unused)
  *      host_byte   = set by low-level driver to indicate status.
  */
 #define status_byte(result) (((result) >> 1) & 0x7f)
-#define msg_byte(result)    (((result) >> 8) & 0xff)
 #define host_byte(result)   (((result) >> 16) & 0xff)
 
 #define sense_class(sense)  (((sense) >> 4) & 0x7)

include/scsi/scsi_cmnd.h

···
 	return cmd->result & 0xff;
 }
 
-static inline void set_msg_byte(struct scsi_cmnd *cmd, char status)
-{
-	cmd->result = (cmd->result & 0xffff00ff) | (status << 8);
-}
-
 static inline void set_host_byte(struct scsi_cmnd *cmd, char status)
 {
 	cmd->result = (cmd->result & 0xff00ffff) | (status << 16);