linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 * scsi_scan.c

 *

 * Copyright (C) 2000 Eric Youngdale,

 * Copyright (C) 2002 Patrick Mansfield

 *

 * The general scanning/probing algorithm is as follows, exceptions are

 * made to it depending on device specific flags, compilation options, and

 * global variable (boot or module load time) settings.

 *

 * A specific LUN is scanned via an INQUIRY command; if the LUN has a

 * device attached, a scsi_device is allocated and setup for it.

 *

 * For every id of every channel on the given host:

 *

 *  Scan LUN 0; if the target responds to LUN 0 (even if there is no

 *  device or storage attached to LUN 0):

 *

 *      If LUN 0 has a device attached, allocate and setup a

 *      scsi_device for it.

 *

 *      If target is SCSI-3 or up, issue a REPORT LUN, and scan

 *      all of the LUNs returned by the REPORT LUN; else,

 *      sequentially scan LUNs up until some maximum is reached,

 *      or a LUN is seen that cannot have a device attached to it.

 */

​

#include <linux/module.h>

#include <linux/moduleparam.h>

#include <linux/init.h>

#include <linux/blkdev.h>

#include <linux/delay.h>

#include <linux/kthread.h>

#include <linux/spinlock.h>

#include <linux/async.h>

#include <linux/slab.h>

#include <asm/unaligned.h>

​

#include <scsi/scsi.h>

#include <scsi/scsi_cmnd.h>

#include <scsi/scsi_device.h>

#include <scsi/scsi_driver.h>

#include <scsi/scsi_devinfo.h>

#include <scsi/scsi_host.h>

#include <scsi/scsi_transport.h>

#include <scsi/scsi_dh.h>

#include <scsi/scsi_eh.h>

​

#include "scsi_priv.h"

#include "scsi_logging.h"

​

#define ALLOC_FAILURE_MSG   KERN_ERR "%s: Allocation failure during" \

    " SCSI scanning, some SCSI devices might not be configured\n"

​

/*

 * Default timeout

 */

#define SCSI_TIMEOUT (2*HZ)

#define SCSI_REPORT_LUNS_TIMEOUT (30*HZ)

​

/*

 * Prefix values for the SCSI id's (stored in sysfs name field)

 */

#define SCSI_UID_SER_NUM 'S'

#define SCSI_UID_UNKNOWN 'Z'

​

/*

 * Return values of some of the scanning functions.

 *

 * SCSI_SCAN_NO_RESPONSE: no valid response received from the target, this

 * includes allocation or general failures preventing IO from being sent.

 *

 * SCSI_SCAN_TARGET_PRESENT: target responded, but no device is available

 * on the given LUN.

 *

 * SCSI_SCAN_LUN_PRESENT: target responded, and a device is available on a

 * given LUN.

 */

#define SCSI_SCAN_NO_RESPONSE       0

#define SCSI_SCAN_TARGET_PRESENT    1

#define SCSI_SCAN_LUN_PRESENT       2

​

static const char *scsi_null_device_strs = "nullnullnullnull";

​

#define MAX_SCSI_LUNS   512

​

static u64 max_scsi_luns = MAX_SCSI_LUNS;

​

module_param_named(max_luns, max_scsi_luns, ullong, S_IRUGO|S_IWUSR);

MODULE_PARM_DESC(max_luns,

         "last scsi LUN (should be between 1 and 2^64-1)");