scsi: scsi_debug: Reduce code duplication

All VPD pages have the page code in byte one. Reduce code duplication by
storing the VPD page code once.

Reviewed-by: Avri Altman <avri.altman@wdc.com>
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/20240130214911.1863909-13-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Author: bvanassche

drivers/scsi/scsi_debug.c

@@ -1903,7 +1903,8 @@ static int resp_inquiry(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)
 		u32 len;
 		char lu_id_str[6];
 		int host_no = devip->sdbg_host->shost->host_no;
-		
+
+		arr[1] = cmd[2];
 		port_group_id = (((host_no + 1) & 0x7f) << 8) +
 		    (devip->channel & 0x7f);
 		if (sdebug_vpd_use_hostno == 0)
@@ -1914,7 +1915,6 @@ static int resp_inquiry(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)
 				 (devip->target * 1000) - 3;
 		len = scnprintf(lu_id_str, 6, "%d", lu_id_num);
 		if (0 == cmd[2]) { /* supported vital product data pages */
-			arr[1] = cmd[2];	/*sanity */
 			n = 4;
 			arr[n++] = 0x0;   /* this page */
 			arr[n++] = 0x80;  /* unit serial number */
@@ -1935,23 +1935,18 @@ static int resp_inquiry(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)
 			}
 			arr[3] = n - 4;	  /* number of supported VPD pages */
 		} else if (0x80 == cmd[2]) { /* unit serial number */
-			arr[1] = cmd[2];	/*sanity */
 			arr[3] = len;
 			memcpy(&arr[4], lu_id_str, len);
 		} else if (0x83 == cmd[2]) { /* device identification */
-			arr[1] = cmd[2];	/*sanity */
 			arr[3] = inquiry_vpd_83(&arr[4], port_group_id,
 						target_dev_id, lu_id_num,
 						lu_id_str, len,
 						&devip->lu_name);
 		} else if (0x84 == cmd[2]) { /* Software interface ident. */
-			arr[1] = cmd[2];	/*sanity */
 			arr[3] = inquiry_vpd_84(&arr[4]);
 		} else if (0x85 == cmd[2]) { /* Management network addresses */
-			arr[1] = cmd[2];	/*sanity */
 			arr[3] = inquiry_vpd_85(&arr[4]);
 		} else if (0x86 == cmd[2]) { /* extended inquiry */
-			arr[1] = cmd[2];	/*sanity */
 			arr[3] = 0x3c;	/* number of following entries */
 			if (sdebug_dif == T10_PI_TYPE3_PROTECTION)
 				arr[4] = 0x4;	/* SPT: GRD_CHK:1 */
@@ -1961,30 +1956,23 @@ static int resp_inquiry(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)
 				arr[4] = 0x0;   /* no protection stuff */
 			arr[5] = 0x7;   /* head of q, ordered + simple q's */
 		} else if (0x87 == cmd[2]) { /* mode page policy */
-			arr[1] = cmd[2];	/*sanity */
 			arr[3] = 0x8;	/* number of following entries */
 			arr[4] = 0x2;	/* disconnect-reconnect mp */
 			arr[6] = 0x80;	/* mlus, shared */
 			arr[8] = 0x18;	 /* protocol specific lu */
 			arr[10] = 0x82;	 /* mlus, per initiator port */
 		} else if (0x88 == cmd[2]) { /* SCSI Ports */
-			arr[1] = cmd[2];	/*sanity */
 			arr[3] = inquiry_vpd_88(&arr[4], target_dev_id);
 		} else if (is_disk_zbc && 0x89 == cmd[2]) { /* ATA info */
-			arr[1] = cmd[2];        /*sanity */
 			n = inquiry_vpd_89(&arr[4]);
 			put_unaligned_be16(n, arr + 2);
 		} else if (is_disk_zbc && 0xb0 == cmd[2]) { /* Block limits */
-			arr[1] = cmd[2];        /*sanity */
 			arr[3] = inquiry_vpd_b0(&arr[4]);
 		} else if (is_disk_zbc && 0xb1 == cmd[2]) { /* Block char. */
-			arr[1] = cmd[2];        /*sanity */
 			arr[3] = inquiry_vpd_b1(devip, &arr[4]);
 		} else if (is_disk && 0xb2 == cmd[2]) { /* LB Prov. */
-			arr[1] = cmd[2];        /*sanity */
 			arr[3] = inquiry_vpd_b2(&arr[4]);
 		} else if (is_zbc && cmd[2] == 0xb6) { /* ZB dev. charact. */
-			arr[1] = cmd[2];        /*sanity */
 			arr[3] = inquiry_vpd_b6(devip, &arr[4]);
 		} else {
 			mk_sense_invalid_fld(scp, SDEB_IN_CDB, 2, -1);