scsi: scsi_debug: Rework subpage code error handling

Move the subpage code checks into the switch statement to make it easier
to add support for new page code / subpage code combinations.

Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Tested-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240130214911.1863909-16-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Author: bvanassche

drivers/scsi/scsi_debug.c

@@ -2703,22 +2703,22 @@ static int resp_mode_sense(struct scsi_cmnd *scp,
 		ap = arr + offset;
 	}
 
-	if ((subpcode > 0x0) && (subpcode < 0xff) && (0x19 != pcode)) {
-		/* TODO: Control Extension page */
-		mk_sense_invalid_fld(scp, SDEB_IN_CDB, 3, -1);
-		return check_condition_result;
-	}
-
 	switch (pcode) {
 	case 0x1:	/* Read-Write error recovery page, direct access */
+		if (subpcode > 0x0 && subpcode < 0xff)
+			goto bad_subpcode;
 		len = resp_err_recov_pg(ap, pcontrol, target);
 		offset += len;
 		break;
 	case 0x2:	/* Disconnect-Reconnect page, all devices */
+		if (subpcode > 0x0 && subpcode < 0xff)
+			goto bad_subpcode;
 		len = resp_disconnect_pg(ap, pcontrol, target);
 		offset += len;
 		break;
 	case 0x3:       /* Format device page, direct access */
+		if (subpcode > 0x0 && subpcode < 0xff)
+			goto bad_subpcode;
 		if (is_disk) {
 			len = resp_format_pg(ap, pcontrol, target);
 			offset += len;
@@ -2727,6 +2727,8 @@ static int resp_mode_sense(struct scsi_cmnd *scp,
 		}
 		break;
 	case 0x8:	/* Caching page, direct access */
+		if (subpcode > 0x0 && subpcode < 0xff)
+			goto bad_subpcode;
 		if (is_disk || is_zbc) {
 			len = resp_caching_pg(ap, pcontrol, target);
 			offset += len;
@@ -2735,14 +2737,14 @@ static int resp_mode_sense(struct scsi_cmnd *scp,
 		}
 		break;
 	case 0xa:	/* Control Mode page, all devices */
+		if (subpcode > 0x0 && subpcode < 0xff)
+			goto bad_subpcode;
 		len = resp_ctrl_m_pg(ap, pcontrol, target);
 		offset += len;
 		break;
 	case 0x19:	/* if spc==1 then sas phy, control+discover */
-		if ((subpcode > 0x2) && (subpcode < 0xff)) {
-			mk_sense_invalid_fld(scp, SDEB_IN_CDB, 3, -1);
-			return check_condition_result;
-		}
+		if (subpcode > 0x2 && subpcode < 0xff)
+			goto bad_subpcode;
 		len = 0;
 		if ((0x0 == subpcode) || (0xff == subpcode))
 			len += resp_sas_sf_m_pg(ap + len, pcontrol, target);
@@ -2754,35 +2756,31 @@ static int resp_mode_sense(struct scsi_cmnd *scp,
 		offset += len;
 		break;
 	case 0x1c:	/* Informational Exceptions Mode page, all devices */
+		if (subpcode > 0x0 && subpcode < 0xff)
+			goto bad_subpcode;
 		len = resp_iec_m_pg(ap, pcontrol, target);
 		offset += len;
 		break;
 	case 0x3f:	/* Read all Mode pages */
-		if ((0 == subpcode) || (0xff == subpcode)) {
-			len = resp_err_recov_pg(ap, pcontrol, target);
-			len += resp_disconnect_pg(ap + len, pcontrol, target);
-			if (is_disk) {
-				len += resp_format_pg(ap + len, pcontrol,
-						      target);
-				len += resp_caching_pg(ap + len, pcontrol,
-						       target);
-			} else if (is_zbc) {
-				len += resp_caching_pg(ap + len, pcontrol,
-						       target);
-			}
-			len += resp_ctrl_m_pg(ap + len, pcontrol, target);
-			len += resp_sas_sf_m_pg(ap + len, pcontrol, target);
-			if (0xff == subpcode) {
-				len += resp_sas_pcd_m_spg(ap + len, pcontrol,
-						  target, target_dev_id);
-				len += resp_sas_sha_m_spg(ap + len, pcontrol);
-			}
-			len += resp_iec_m_pg(ap + len, pcontrol, target);
-			offset += len;
-		} else {
-			mk_sense_invalid_fld(scp, SDEB_IN_CDB, 3, -1);
-			return check_condition_result;
+		if (subpcode > 0x0 && subpcode < 0xff)
+			goto bad_subpcode;
+		len = resp_err_recov_pg(ap, pcontrol, target);
+		len += resp_disconnect_pg(ap + len, pcontrol, target);
+		if (is_disk) {
+			len += resp_format_pg(ap + len, pcontrol, target);
+			len += resp_caching_pg(ap + len, pcontrol, target);
+		} else if (is_zbc) {
+			len += resp_caching_pg(ap + len, pcontrol, target);
+		}
+		len += resp_ctrl_m_pg(ap + len, pcontrol, target);
+		len += resp_sas_sf_m_pg(ap + len, pcontrol, target);
+		if (0xff == subpcode) {
+			len += resp_sas_pcd_m_spg(ap + len, pcontrol, target,
+						  target_dev_id);
+			len += resp_sas_sha_m_spg(ap + len, pcontrol);
 		}
+		len += resp_iec_m_pg(ap + len, pcontrol, target);
+		offset += len;
 		break;
 	default:
 		goto bad_pcode;
@@ -2796,6 +2794,10 @@ static int resp_mode_sense(struct scsi_cmnd *scp,
 bad_pcode:
 	mk_sense_invalid_fld(scp, SDEB_IN_CDB, 2, 5);
 	return check_condition_result;
+
+bad_subpcode:
+	mk_sense_invalid_fld(scp, SDEB_IN_CDB, 3, -1);
+	return check_condition_result;
 }
 
 #define SDEBUG_MAX_MSELECT_SZ 512