scsi: scsi_debug: Add zone_max_open module parameter

Add the zone_max_open module parameters to control the maximum number of
open zones of a ZBC device. This parameter is ignored for device types
other than 0x14 (zbc=2 case).

Link: https://lore.kernel.org/r/20200422104221.378203-5-damien.lemoal@wdc.comSigned-off-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/scsi_debug.c

@@ -822,7 +822,7 @@ static int dif_errors;
 /* ZBC global data */
 static bool sdeb_zbc_in_use;		/* true when ptype=TYPE_ZBC [0x14] */
 static const int zbc_zone_size_mb;
-static const int zbc_max_open_zones = DEF_ZBC_MAX_OPEN_ZONES;
+static int sdeb_zbc_max_open = DEF_ZBC_MAX_OPEN_ZONES;
 
 static int submit_queues = DEF_SUBMIT_QUEUES;  /* > 1 for multi-queue (mq) */
 static struct sdebug_queue *sdebug_q_arr;  /* ptr to array of submit queues */
@@ -4788,10 +4788,10 @@ static int sdebug_device_create_zones(struct sdebug_dev_info *devip)
 	devip->nr_zones = (capacity + devip->zsize - 1) >> devip->zsize_shift;
 
 	/* zbc_max_open_zones can be 0, meaning "not reported" (no limit) */
-	if (zbc_max_open_zones >= devip->nr_zones - 1)
+	if (sdeb_zbc_max_open >= devip->nr_zones - 1)
 		devip->max_open = (devip->nr_zones - 1) / 2;
 	else
-		devip->max_open = zbc_max_open_zones;
+		devip->max_open = sdeb_zbc_max_open;
 
 	devip->zstate = kcalloc(devip->nr_zones,
 				sizeof(struct sdeb_zone_state), GFP_KERNEL);
@@ -5540,6 +5540,7 @@ module_param_named(wp, sdebug_wp, bool, S_IRUGO | S_IWUSR);
 module_param_named(write_same_length, sdebug_write_same_length, int,
 		   S_IRUGO | S_IWUSR);
 module_param_named(zbc, sdeb_zbc_model_s, charp, S_IRUGO);
+module_param_named(zone_max_open, sdeb_zbc_max_open, int, S_IRUGO);
 
 MODULE_AUTHOR("Eric Youngdale + Douglas Gilbert");
 MODULE_DESCRIPTION("SCSI debug adapter driver");
@@ -5602,6 +5603,7 @@ MODULE_PARM_DESC(vpd_use_hostno, "0 -> dev ids ignore hostno (def=1 -> unique de
 MODULE_PARM_DESC(wp, "Write Protect (def=0)");
 MODULE_PARM_DESC(write_same_length, "Maximum blocks per WRITE SAME cmd (def=0xffff)");
 MODULE_PARM_DESC(zbc, "'none' [0]; 'aware' [1]; 'managed' [2] (def=0). Can have 'host-' prefix");
+MODULE_PARM_DESC(zone_max_open, "Maximum number of open zones; [0] for no limit (def=auto)");
 
 #define SDEBUG_INFO_LEN 256
 static char sdebug_info[SDEBUG_INFO_LEN];