// SPDX-License-Identifier: GPL-2.0-only
/*
 * Changes:
 * Arnaldo Carvalho de Melo <acme@conectiva.com.br> 08/23/2000
 * - get rid of some verify_areas and use __copy*user and __get/put_user
 *   for the ones that remain
 */
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/uaccess.h>
#include <linux/cdrom.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_ioctl.h>
#include <scsi/sg.h>
#include <scsi/scsi_dbg.h>

#include "scsi_logging.h"

#define NORMAL_RETRIES                  5
#define IOCTL_NORMAL_TIMEOUT                    (10 * HZ)

#define MAX_BUF PAGE_SIZE

/**
 * ioctl_probe  --  return host identification
 * @host:       host to identify
 * @buffer:     userspace buffer for identification
 *
 * Return:
 * * if successful, %1 and an identifying string at @buffer, if @buffer
 * is non-NULL, filling to the length stored at * (int *) @buffer.
 * * <0 error code on failure.
 */
static int ioctl_probe(struct Scsi_Host *host, void __user *buffer)
{
        unsigned int len, slen;
        const char *string;

        if (buffer) {
                if (get_user(len, (unsigned int __user *) buffer))
                        return -EFAULT;

                if (host->hostt->info)
                        string = host->hostt->info(host);
                else
                        string = host->hostt->name;
                if (string) {
                        slen = strlen(string);
                        if (len > slen)
                                len = slen + 1;
                        if (copy_to_user(buffer, string, len))
                                return -EFAULT;
                }
        }
        return 1;
}

static int ioctl_internal_command(struct scsi_device *sdev, char *cmd,
                                  int timeout, int retries)
{
        int result;
        struct scsi_sense_hdr sshdr;
        const struct scsi_exec_args exec_args = {
                .sshdr = &sshdr,
        };

        SCSI_LOG_IOCTL(1, sdev_printk(KERN_INFO, sdev,
                                      "Trying ioctl with scsi command %d\n", *cmd));

        result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, NULL, 0, timeout,
                                  retries, &exec_args);

        SCSI_LOG_IOCTL(2, sdev_printk(KERN_INFO, sdev,
                                      "Ioctl returned  0x%x\n", result));

        if (result < 0)
                goto out;
        if (scsi_sense_valid(&sshdr)) {
                switch (sshdr.sense_key) {
                case ILLEGAL_REQUEST:
                        if (cmd[0] == ALLOW_MEDIUM_REMOVAL)
                                sdev->lockable = 0;
                        else
                                sdev_printk(KERN_INFO, sdev,
                                            "ioctl_internal_command: "
                                            "ILLEGAL REQUEST "
                                            "asc=0x%x ascq=0x%x\n",
                                            sshdr.asc, sshdr.ascq);
                        break;
                case NOT_READY: /* This happens if there is no disc in drive */
                        if (sdev->removable)
                                break;
                        fallthrough;
                case UNIT_ATTENTION:
                        if (sdev->removable) {
                                sdev->changed = 1;
                                result = 0;     /* This is no longer considered an error */
                                break;
                        }
                        fallthrough;    /* for non-removable media */
                default:
                        sdev_printk(KERN_INFO, sdev,
                                    "ioctl_internal_command return code = %x\n",
                                    result);
                        scsi_print_sense_hdr(sdev, NULL, &sshdr);
                        break;
                }
        }
out:
        SCSI_LOG_IOCTL(2, sdev_printk(KERN_INFO, sdev,
                                      "IOCTL Releasing command\n"));
        return result;
}

/**
 * scsi_set_medium_removal() - send command to allow or prevent medium removal
 * @sdev: target scsi device
 * @state: removal state to set (prevent or allow)
 *
 * Returns:
 * * %0 if @sdev is not removable or not lockable or successful.
 * * non-%0 is a SCSI result code if > 0 or kernel error code if < 0.
 * * Sets @sdev->locked to the new state on success.
 */
int scsi_set_medium_removal(struct scsi_device *sdev, char state)
{
        char scsi_cmd[MAX_COMMAND_SIZE];
        int ret;

        if (!sdev->removable || !sdev->lockable)
               return 0;

        scsi_cmd[0] = ALLOW_MEDIUM_REMOVAL;
        scsi_cmd[1] = 0;
        scsi_cmd[2] = 0;
        scsi_cmd[3] = 0;
        scsi_cmd[4] = state;
        scsi_cmd[5] = 0;

        ret = ioctl_internal_command(sdev, scsi_cmd,
                        IOCTL_NORMAL_TIMEOUT, NORMAL_RETRIES);
        if (ret == 0)
                sdev->locked = (state == SCSI_REMOVAL_PREVENT);
        return ret;
}
EXPORT_SYMBOL(scsi_set_medium_removal);

/*
 * The scsi_ioctl_get_pci() function places into arg the value
 * pci_dev::slot_name (8 characters) for the PCI device (if any).
 * Returns: 0 on success
 *          -ENXIO if there isn't a PCI device pointer
 *                 (could be because the SCSI driver hasn't been
 *                  updated yet, or because it isn't a SCSI
 *                  device)
 *          any copy_to_user() error on failure there
 */
static int scsi_ioctl_get_pci(struct scsi_device *sdev, void __user *arg)
{
        struct device *dev = scsi_get_device(sdev->host);
        const char *name;

        if (!dev)
                return -ENXIO;

        name = dev_name(dev);

        /* compatibility with old ioctl which only returned
         * 20 characters */
        return copy_to_user(arg, name, min(strlen(name), (size_t)20))
                ? -EFAULT: 0;
}

static int sg_get_version(int __user *p)
{
        static const int sg_version_num = 30527;
        return put_user(sg_version_num, p);
}

static int sg_set_timeout(struct scsi_device *sdev, int __user *p)
{
        int timeout, err = get_user(timeout, p);

        if (!err)
                sdev->sg_timeout = clock_t_to_jiffies(timeout);

        return err;
}

static int sg_get_reserved_size(struct scsi_device *sdev, int __user *p)
{
        int val = min(sdev->sg_reserved_size,
                      queue_max_bytes(sdev->request_queue));

        return put_user(val, p);
}

static int sg_set_reserved_size(struct scsi_device *sdev, int __user *p)
{
        int size, err = get_user(size, p);

        if (err)
                return err;

        if (size < 0)
                return -EINVAL;

        sdev->sg_reserved_size = min_t(unsigned int, size,
                                       queue_max_bytes(sdev->request_queue));
        return 0;
}

/*
 * will always return that we are ATAPI even for a real SCSI drive, I'm not
 * so sure this is worth doing anything about (why would you care??)
 */
static int sg_emulated_host(struct request_queue *q, int __user *p)
{
        return put_user(1, p);
}

static int scsi_get_idlun(struct scsi_device *sdev, void __user *argp)
{
        struct scsi_idlun v = {
                .dev_id = (sdev->id & 0xff) +
                        ((sdev->lun & 0xff) << 8) +
                        ((sdev->channel & 0xff) << 16) +
                        ((sdev->host->host_no & 0xff) << 24),
                .host_unique_id = sdev->host->unique_id
        };
        if (copy_to_user(argp, &v, sizeof(struct scsi_idlun)))
                return -EFAULT;
        return 0;
}

static int scsi_send_start_stop(struct scsi_device *sdev, int data)
{
        u8 cdb[MAX_COMMAND_SIZE] = { };

        cdb[0] = START_STOP;
        cdb[4] = data;
        return ioctl_internal_command(sdev, cdb, START_STOP_TIMEOUT,
                                      NORMAL_RETRIES);
}

/**
 * scsi_cmd_allowed() - Check if the given command is allowed.
 * @cmd:            SCSI command to check
 * @open_for_write: is the file / block device opened for writing?
 *
 * Only a subset of commands are allowed for unprivileged users. Commands used
 * to format the media, update the firmware, etc. are not permitted.
 *
 * Return: %true if the cmd is allowed, otherwise @false.
 */
bool scsi_cmd_allowed(unsigned char *cmd, bool open_for_write)
{
        /* root can do any command. */
        if (capable(CAP_SYS_RAWIO))
                return true;

        /* Anybody who can open the device can do a read-safe command */
        switch (cmd[0]) {
        /* Basic read-only commands */
        case TEST_UNIT_READY:
        case REQUEST_SENSE:
        case READ_6:
        case READ_10:
        case READ_12:
        case READ_16:
        case READ_BUFFER:
        case READ_DEFECT_DATA:
        case READ_CAPACITY: /* also GPCMD_READ_CDVD_CAPACITY */
        case READ_LONG:
        case INQUIRY:
        case MODE_SENSE:
        case MODE_SENSE_10:
        case LOG_SENSE:
        case START_STOP:
        case GPCMD_VERIFY_10:
        case VERIFY_16:
        case REPORT_LUNS:
        case SERVICE_ACTION_IN_16:
        case RECEIVE_DIAGNOSTIC:
        case MAINTENANCE_IN: /* also GPCMD_SEND_KEY, which is a write command */
        case GPCMD_READ_BUFFER_CAPACITY:
        /* Audio CD commands */
        case GPCMD_PLAY_CD:
        case GPCMD_PLAY_AUDIO_10:
        case GPCMD_PLAY_AUDIO_MSF:
        case GPCMD_PLAY_AUDIO_TI:
        case GPCMD_PAUSE_RESUME:
        /* CD/DVD data reading */
        case GPCMD_READ_CD:
        case GPCMD_READ_CD_MSF:
        case GPCMD_READ_DISC_INFO:
        case GPCMD_READ_DVD_STRUCTURE:
        case GPCMD_READ_HEADER:
        case GPCMD_READ_TRACK_RZONE_INFO:
        case GPCMD_READ_SUBCHANNEL:
        case GPCMD_READ_TOC_PMA_ATIP:
        case GPCMD_REPORT_KEY:
        case GPCMD_SCAN:
        case GPCMD_GET_CONFIGURATION:
        case GPCMD_READ_FORMAT_CAPACITIES:
        case GPCMD_GET_EVENT_STATUS_NOTIFICATION:
        case GPCMD_GET_PERFORMANCE:
        case GPCMD_SEEK:
        case GPCMD_STOP_PLAY_SCAN:
        /* ZBC */
        case ZBC_IN:
                return true;
        /* Basic writing commands */
        case WRITE_6:
        case WRITE_10:
        case WRITE_VERIFY:
        case WRITE_12:
        case WRITE_VERIFY_12:
        case WRITE_16:
        case WRITE_LONG:
        case WRITE_LONG_2:
        case WRITE_SAME:
        case WRITE_SAME_16:
        case WRITE_SAME_32:
        case ERASE:
        case GPCMD_MODE_SELECT_10:
        case MODE_SELECT:
        case LOG_SELECT:
        case GPCMD_BLANK:
        case GPCMD_CLOSE_TRACK:
        case GPCMD_FLUSH_CACHE:
        case GPCMD_FORMAT_UNIT:
        case GPCMD_REPAIR_RZONE_TRACK:
        case GPCMD_RESERVE_RZONE_TRACK:
        case GPCMD_SEND_DVD_STRUCTURE:
        case GPCMD_SEND_EVENT:
        case GPCMD_SEND_OPC:
        case GPCMD_SEND_CUE_SHEET:
        case GPCMD_SET_SPEED:
        case GPCMD_PREVENT_ALLOW_MEDIUM_REMOVAL:
        case GPCMD_LOAD_UNLOAD:
        case GPCMD_SET_STREAMING:
        case GPCMD_SET_READ_AHEAD:
        /* ZBC */
        case ZBC_OUT:
                return open_for_write;
        default:
                return false;
        }
}
EXPORT_SYMBOL(scsi_cmd_allowed);

static int scsi_fill_sghdr_rq(struct scsi_device *sdev, struct request *rq,
                struct sg_io_hdr *hdr, bool open_for_write)
{
        struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(rq);

        if (hdr->cmd_len < 6)
                return -EMSGSIZE;
        if (copy_from_user(scmd->cmnd, hdr->cmdp, hdr->cmd_len))
                return -EFAULT;
        if (!scsi_cmd_allowed(scmd->cmnd, open_for_write))
                return -EPERM;
        scmd->cmd_len = hdr->cmd_len;

        rq->timeout = msecs_to_jiffies(hdr->timeout);
        if (!rq->timeout)
                rq->timeout = sdev->sg_timeout;
        if (!rq->timeout)
                rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
        if (rq->timeout < BLK_MIN_SG_TIMEOUT)
                rq->timeout = BLK_MIN_SG_TIMEOUT;

        return 0;
}

static int scsi_complete_sghdr_rq(struct request *rq, struct sg_io_hdr *hdr,
                struct bio *bio)
{
        struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(rq);
        int r, ret = 0;

        /*
         * fill in all the output members
         */
        hdr->status = scmd->result & 0xff;
        hdr->masked_status = sg_status_byte(scmd->result);
        hdr->msg_status = COMMAND_COMPLETE;
        hdr->host_status = host_byte(scmd->result);
        hdr->driver_status = 0;
        if (scsi_status_is_check_condition(hdr->status))
                hdr->driver_status = DRIVER_SENSE;
        hdr->info = 0;
        if (hdr->masked_status || hdr->host_status || hdr->driver_status)
                hdr->info |= SG_INFO_CHECK;
        hdr->resid = scmd->resid_len;
        hdr->sb_len_wr = 0;

        if (scmd->sense_len && hdr->sbp) {
                int len = min((unsigned int) hdr->mx_sb_len, scmd->sense_len);

                if (!copy_to_user(hdr->sbp, scmd->sense_buffer, len))
                        hdr->sb_len_wr = len;
                else
                        ret = -EFAULT;
        }

        r = blk_rq_unmap_user(bio);
        if (!ret)
                ret = r;

        return ret;
}

static int sg_io(struct scsi_device *sdev, struct sg_io_hdr *hdr,
                bool open_for_write)
{
        unsigned long start_time;
        ssize_t ret = 0;
        int writing = 0;
        int at_head = 0;
        struct request *rq;
        struct scsi_cmnd *scmd;
        struct bio *bio;

        if (hdr->interface_id != 'S')
                return -EINVAL;

        if (hdr->dxfer_len > (queue_max_hw_sectors(sdev->request_queue) << 9))
                return -EIO;

        if (hdr->dxfer_len)
                switch (hdr->dxfer_direction) {
                default:
                        return -EINVAL;
                case SG_DXFER_TO_DEV:
                        writing = 1;
                        break;
                case SG_DXFER_TO_FROM_DEV:
                case SG_DXFER_FROM_DEV:
                        break;
                }
        if (hdr->flags & SG_FLAG_Q_AT_HEAD)
                at_head = 1;

        rq = scsi_alloc_request(sdev->request_queue, writing ?
                             REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
        if (IS_ERR(rq))
                return PTR_ERR(rq);
        scmd = blk_mq_rq_to_pdu(rq);

        if (hdr->cmd_len > sizeof(scmd->cmnd)) {
                ret = -EINVAL;
                goto out_put_request;
        }

        ret = scsi_fill_sghdr_rq(sdev, rq, hdr, open_for_write);
        if (ret < 0)
                goto out_put_request;

        ret = blk_rq_map_user_io(rq, NULL, hdr->dxferp, hdr->dxfer_len,
                        GFP_KERNEL, hdr->iovec_count && hdr->dxfer_len,
                        hdr->iovec_count, 0, rq_data_dir(rq));
        if (ret)
                goto out_put_request;

        bio = rq->bio;
        scmd->allowed = 0;

        start_time = jiffies;

        blk_execute_rq(rq, at_head);

        hdr->duration = jiffies_to_msecs(jiffies - start_time);

        ret = scsi_complete_sghdr_rq(rq, hdr, bio);

out_put_request:
        blk_mq_free_request(rq);
        return ret;
}

/**
 * sg_scsi_ioctl  --  handle deprecated SCSI_IOCTL_SEND_COMMAND ioctl
 * @q:          request queue to send scsi commands down
 * @open_for_write: is the file / block device opened for writing?
 * @sic:        userspace structure describing the command to perform
 *
 * Send down the scsi command described by @sic to the device below
 * the request queue @q.
 *
 * Notes:
 *   -  This interface is deprecated - users should use the SG_IO
 *      interface instead, as this is a more flexible approach to
 *      performing SCSI commands on a device.
 *   -  The SCSI command length is determined by examining the 1st byte
 *      of the given command. There is no way to override this.
 *   -  Data transfers are limited to PAGE_SIZE
 *   -  The length (x + y) must be at least OMAX_SB_LEN bytes long to
 *      accommodate the sense buffer when an error occurs.
 *      The sense buffer is truncated to OMAX_SB_LEN (16) bytes so that
 *      old code will not be surprised.
 *   -  If a Unix error occurs (e.g. ENOMEM) then the user will receive
 *      a negative return and the Unix error code in 'errno'.
 *      If the SCSI command succeeds then 0 is returned.
 *      Positive numbers returned are the compacted SCSI error codes (4
 *      bytes in one int) where the lowest byte is the SCSI status.
 */
static int sg_scsi_ioctl(struct request_queue *q, bool open_for_write,
                struct scsi_ioctl_command __user *sic)
{
        struct request *rq;
        int err;
        unsigned int in_len, out_len, bytes, opcode, cmdlen;
        struct scsi_cmnd *scmd;
        char *buffer = NULL;

        if (!sic)
                return -EINVAL;

        /*
         * get in an out lengths, verify they don't exceed a page worth of data
         */
        if (get_user(in_len, &sic->inlen))
                return -EFAULT;
        if (get_user(out_len, &sic->outlen))
                return -EFAULT;
        if (in_len > PAGE_SIZE || out_len > PAGE_SIZE)
                return -EINVAL;
        if (get_user(opcode, &sic->data[0]))
                return -EFAULT;

        bytes = max(in_len, out_len);
        if (bytes) {
                buffer = kzalloc(bytes, GFP_NOIO | GFP_USER | __GFP_NOWARN);
                if (!buffer)
                        return -ENOMEM;

        }

        rq = scsi_alloc_request(q, in_len ? REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
        if (IS_ERR(rq)) {
                err = PTR_ERR(rq);
                goto error_free_buffer;
        }
        scmd = blk_mq_rq_to_pdu(rq);

        cmdlen = COMMAND_SIZE(opcode);

        /*
         * get command and data to send to device, if any
         */
        err = -EFAULT;
        scmd->cmd_len = cmdlen;
        if (copy_from_user(scmd->cmnd, sic->data, cmdlen))
                goto error;

        if (in_len && copy_from_user(buffer, sic->data + cmdlen, in_len))
                goto error;

        err = -EPERM;
        if (!scsi_cmd_allowed(scmd->cmnd, open_for_write))
                goto error;

        /* default.  possible overridden later */
        scmd->allowed = 5;

        switch (opcode) {
        case SEND_DIAGNOSTIC:
        case FORMAT_UNIT:
                rq->timeout = FORMAT_UNIT_TIMEOUT;
                scmd->allowed = 1;
                break;
        case START_STOP:
                rq->timeout = START_STOP_TIMEOUT;
                break;
        case MOVE_MEDIUM:
                rq->timeout = MOVE_MEDIUM_TIMEOUT;
                break;
        case READ_ELEMENT_STATUS:
                rq->timeout = READ_ELEMENT_STATUS_TIMEOUT;
                break;
        case READ_DEFECT_DATA:
                rq->timeout = READ_DEFECT_DATA_TIMEOUT;
                scmd->allowed = 1;
                break;
        default:
                rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
                break;
        }

        if (bytes) {
                err = blk_rq_map_kern(rq, buffer, bytes, GFP_NOIO);
                if (err)
                        goto error;
        }

        blk_execute_rq(rq, false);

        err = scmd->result & 0xff;      /* only 8 bit SCSI status */
        if (err) {
                if (scmd->sense_len && scmd->sense_buffer) {
                        /* limit sense len for backward compatibility */
                        if (copy_to_user(sic->data, scmd->sense_buffer,
                                         min(scmd->sense_len, 16U)))
                                err = -EFAULT;
                }
        } else {
                if (copy_to_user(sic->data, buffer, out_len))
                        err = -EFAULT;
        }

error:
        blk_mq_free_request(rq);

error_free_buffer:
        kfree(buffer);

        return err;
}

int put_sg_io_hdr(const struct sg_io_hdr *hdr, void __user *argp)
{
#ifdef CONFIG_COMPAT
        if (in_compat_syscall()) {
                struct compat_sg_io_hdr hdr32 =  {
                        .interface_id    = hdr->interface_id,
                        .dxfer_direction = hdr->dxfer_direction,
                        .cmd_len         = hdr->cmd_len,
                        .mx_sb_len       = hdr->mx_sb_len,
                        .iovec_count     = hdr->iovec_count,
                        .dxfer_len       = hdr->dxfer_len,
                        .dxferp          = (uintptr_t)hdr->dxferp,
                        .cmdp            = (uintptr_t)hdr->cmdp,
                        .sbp             = (uintptr_t)hdr->sbp,
                        .timeout         = hdr->timeout,
                        .flags           = hdr->flags,
                        .pack_id         = hdr->pack_id,
                        .usr_ptr         = (uintptr_t)hdr->usr_ptr,
                        .status          = hdr->status,
                        .masked_status   = hdr->masked_status,
                        .msg_status      = hdr->msg_status,
                        .sb_len_wr       = hdr->sb_len_wr,
                        .host_status     = hdr->host_status,
                        .driver_status   = hdr->driver_status,
                        .resid           = hdr->resid,
                        .duration        = hdr->duration,
                        .info            = hdr->info,
                };

                if (copy_to_user(argp, &hdr32, sizeof(hdr32)))
                        return -EFAULT;

                return 0;
        }
#endif

        if (copy_to_user(argp, hdr, sizeof(*hdr)))
                return -EFAULT;

        return 0;
}
EXPORT_SYMBOL(put_sg_io_hdr);

int get_sg_io_hdr(struct sg_io_hdr *hdr, const void __user *argp)
{
#ifdef CONFIG_COMPAT
        struct compat_sg_io_hdr hdr32;

        if (in_compat_syscall()) {
                if (copy_from_user(&hdr32, argp, sizeof(hdr32)))
                        return -EFAULT;

                *hdr = (struct sg_io_hdr) {
                        .interface_id    = hdr32.interface_id,
                        .dxfer_direction = hdr32.dxfer_direction,
                        .cmd_len         = hdr32.cmd_len,
                        .mx_sb_len       = hdr32.mx_sb_len,
                        .iovec_count     = hdr32.iovec_count,
                        .dxfer_len       = hdr32.dxfer_len,
                        .dxferp          = compat_ptr(hdr32.dxferp),
                        .cmdp            = compat_ptr(hdr32.cmdp),
                        .sbp             = compat_ptr(hdr32.sbp),
                        .timeout         = hdr32.timeout,
                        .flags           = hdr32.flags,
                        .pack_id         = hdr32.pack_id,
                        .usr_ptr         = compat_ptr(hdr32.usr_ptr),
                        .status          = hdr32.status,
                        .masked_status   = hdr32.masked_status,
                        .msg_status      = hdr32.msg_status,
                        .sb_len_wr       = hdr32.sb_len_wr,
                        .host_status     = hdr32.host_status,
                        .driver_status   = hdr32.driver_status,
                        .resid           = hdr32.resid,
                        .duration        = hdr32.duration,
                        .info            = hdr32.info,
                };

                return 0;
        }
#endif

        if (copy_from_user(hdr, argp, sizeof(*hdr)))
                return -EFAULT;

        return 0;
}
EXPORT_SYMBOL(get_sg_io_hdr);

#ifdef CONFIG_COMPAT
struct compat_cdrom_generic_command {
        unsigned char   cmd[CDROM_PACKET_SIZE];
        compat_caddr_t  buffer;
        compat_uint_t   buflen;
        compat_int_t    stat;
        compat_caddr_t  sense;
        unsigned char   data_direction;
        unsigned char   pad[3];
        compat_int_t    quiet;
        compat_int_t    timeout;
        compat_caddr_t  unused;
};
#endif

static int scsi_get_cdrom_generic_arg(struct cdrom_generic_command *cgc,
                                      const void __user *arg)
{
#ifdef CONFIG_COMPAT
        if (in_compat_syscall()) {
                struct compat_cdrom_generic_command cgc32;

                if (copy_from_user(&cgc32, arg, sizeof(cgc32)))
                        return -EFAULT;

                *cgc = (struct cdrom_generic_command) {
                        .buffer         = compat_ptr(cgc32.buffer),
                        .buflen         = cgc32.buflen,
                        .stat           = cgc32.stat,
                        .sense          = compat_ptr(cgc32.sense),
                        .data_direction = cgc32.data_direction,
                        .quiet          = cgc32.quiet,
                        .timeout        = cgc32.timeout,
                        .unused         = compat_ptr(cgc32.unused),
                };
                memcpy(&cgc->cmd, &cgc32.cmd, CDROM_PACKET_SIZE);
                return 0;
        }
#endif
        if (copy_from_user(cgc, arg, sizeof(*cgc)))
                return -EFAULT;

        return 0;
}

static int scsi_put_cdrom_generic_arg(const struct cdrom_generic_command *cgc,
                                      void __user *arg)
{
#ifdef CONFIG_COMPAT
        if (in_compat_syscall()) {
                struct compat_cdrom_generic_command cgc32 = {
                        .buffer         = (uintptr_t)(cgc->buffer),
                        .buflen         = cgc->buflen,
                        .stat           = cgc->stat,
                        .sense          = (uintptr_t)(cgc->sense),
                        .data_direction = cgc->data_direction,
                        .quiet          = cgc->quiet,
                        .timeout        = cgc->timeout,
                        .unused         = (uintptr_t)(cgc->unused),
                };
                memcpy(&cgc32.cmd, &cgc->cmd, CDROM_PACKET_SIZE);

                if (copy_to_user(arg, &cgc32, sizeof(cgc32)))
                        return -EFAULT;

                return 0;
        }
#endif
        if (copy_to_user(arg, cgc, sizeof(*cgc)))
                return -EFAULT;

        return 0;
}

static int scsi_cdrom_send_packet(struct scsi_device *sdev, bool open_for_write,
                void __user *arg)
{
        struct cdrom_generic_command cgc;
        struct sg_io_hdr hdr;
        int err;

        err = scsi_get_cdrom_generic_arg(&cgc, arg);
        if (err)
                return err;

        cgc.timeout = clock_t_to_jiffies(cgc.timeout);
        memset(&hdr, 0, sizeof(hdr));
        hdr.interface_id = 'S';
        hdr.cmd_len = sizeof(cgc.cmd);
        hdr.dxfer_len = cgc.buflen;
        switch (cgc.data_direction) {
        case CGC_DATA_UNKNOWN:
                hdr.dxfer_direction = SG_DXFER_UNKNOWN;
                break;
        case CGC_DATA_WRITE:
                hdr.dxfer_direction = SG_DXFER_TO_DEV;
                break;
        case CGC_DATA_READ:
                hdr.dxfer_direction = SG_DXFER_FROM_DEV;
                break;
        case CGC_DATA_NONE:
                hdr.dxfer_direction = SG_DXFER_NONE;
                break;
        default:
                return -EINVAL;
        }

        hdr.dxferp = cgc.buffer;
        hdr.sbp = cgc.sense;
        if (hdr.sbp)
                hdr.mx_sb_len = sizeof(struct request_sense);
        hdr.timeout = jiffies_to_msecs(cgc.timeout);
        hdr.cmdp = ((struct cdrom_generic_command __user *) arg)->cmd;
        hdr.cmd_len = sizeof(cgc.cmd);

        err = sg_io(sdev, &hdr, open_for_write);
        if (err == -EFAULT)
                return -EFAULT;

        if (hdr.status)
                return -EIO;

        cgc.stat = err;
        cgc.buflen = hdr.resid;
        if (scsi_put_cdrom_generic_arg(&cgc, arg))
                return -EFAULT;

        return err;
}

static int scsi_ioctl_sg_io(struct scsi_device *sdev, bool open_for_write,
                void __user *argp)
{
        struct sg_io_hdr hdr;
        int error;

        error = get_sg_io_hdr(&hdr, argp);
        if (error)
                return error;
        error = sg_io(sdev, &hdr, open_for_write);
        if (error == -EFAULT)
                return error;
        if (put_sg_io_hdr(&hdr, argp))
                return -EFAULT;
        return error;
}

/**
 * scsi_ioctl - Dispatch ioctl to scsi device
 * @sdev: scsi device receiving ioctl
 * @open_for_write: is the file / block device opened for writing?
 * @cmd: which ioctl is it
 * @arg: data associated with ioctl
 *
 * Description: The scsi_ioctl() function differs from most ioctls in that it
 * does not take a major/minor number as the dev field.  Rather, it takes
 * a pointer to a &struct scsi_device.
 *
 * Return: varies depending on the @cmd
 */
int scsi_ioctl(struct scsi_device *sdev, bool open_for_write, int cmd,
                void __user *arg)
{
        struct request_queue *q = sdev->request_queue;
        struct scsi_sense_hdr sense_hdr;

        /* Check for deprecated ioctls ... all the ioctls which don't
         * follow the new unique numbering scheme are deprecated */
        switch (cmd) {
        case SCSI_IOCTL_SEND_COMMAND:
        case SCSI_IOCTL_TEST_UNIT_READY:
        case SCSI_IOCTL_BENCHMARK_COMMAND:
        case SCSI_IOCTL_SYNC:
        case SCSI_IOCTL_START_UNIT:
        case SCSI_IOCTL_STOP_UNIT:
                printk(KERN_WARNING "program %s is using a deprecated SCSI "
                       "ioctl, please convert it to SG_IO\n", current->comm);
                break;
        default:
                break;
        }

        switch (cmd) {
        case SG_GET_VERSION_NUM:
                return sg_get_version(arg);
        case SG_SET_TIMEOUT:
                return sg_set_timeout(sdev, arg);
        case SG_GET_TIMEOUT:
                return jiffies_to_clock_t(sdev->sg_timeout);
        case SG_GET_RESERVED_SIZE:
                return sg_get_reserved_size(sdev, arg);
        case SG_SET_RESERVED_SIZE:
                return sg_set_reserved_size(sdev, arg);
        case SG_EMULATED_HOST:
                return sg_emulated_host(q, arg);
        case SG_IO:
                return scsi_ioctl_sg_io(sdev, open_for_write, arg);
        case SCSI_IOCTL_SEND_COMMAND:
                return sg_scsi_ioctl(q, open_for_write, arg);
        case CDROM_SEND_PACKET:
                return scsi_cdrom_send_packet(sdev, open_for_write, arg);
        case CDROMCLOSETRAY:
                return scsi_send_start_stop(sdev, 3);
        case CDROMEJECT:
                return scsi_send_start_stop(sdev, 2);
        case SCSI_IOCTL_GET_IDLUN:
                return scsi_get_idlun(sdev, arg);
        case SCSI_IOCTL_GET_BUS_NUMBER:
                return put_user(sdev->host->host_no, (int __user *)arg);
        case SCSI_IOCTL_PROBE_HOST:
                return ioctl_probe(sdev->host, arg);
        case SCSI_IOCTL_DOORLOCK:
                return scsi_set_medium_removal(sdev, SCSI_REMOVAL_PREVENT);
        case SCSI_IOCTL_DOORUNLOCK:
                return scsi_set_medium_removal(sdev, SCSI_REMOVAL_ALLOW);
        case SCSI_IOCTL_TEST_UNIT_READY:
                return scsi_test_unit_ready(sdev, IOCTL_NORMAL_TIMEOUT,
                                            NORMAL_RETRIES, &sense_hdr);
        case SCSI_IOCTL_START_UNIT:
                return scsi_send_start_stop(sdev, 1);
        case SCSI_IOCTL_STOP_UNIT:
                return scsi_send_start_stop(sdev, 0);
        case SCSI_IOCTL_GET_PCI:
                return scsi_ioctl_get_pci(sdev, arg);
        case SG_SCSI_RESET:
                return scsi_ioctl_reset(sdev, arg);
        }

#ifdef CONFIG_COMPAT
        if (in_compat_syscall()) {
                if (!sdev->host->hostt->compat_ioctl)
                        return -EINVAL;
                return sdev->host->hostt->compat_ioctl(sdev, cmd, arg);
        }
#endif
        if (!sdev->host->hostt->ioctl)
                return -EINVAL;
        return sdev->host->hostt->ioctl(sdev, cmd, arg);
}
EXPORT_SYMBOL(scsi_ioctl);

/**
 * scsi_ioctl_block_when_processing_errors - prevent commands from being queued
 * @sdev: target scsi device
 * @cmd: which ioctl is it
 * @ndelay: no delay (non-blocking)
 *
 * We can process a reset even when a device isn't fully operable.
 *
 * Return: %0 on success, <0 error code.
 */
int scsi_ioctl_block_when_processing_errors(struct scsi_device *sdev, int cmd,
                bool ndelay)
{
        if (cmd == SG_SCSI_RESET && ndelay) {
                if (scsi_host_in_recovery(sdev->host))
                        return -EAGAIN;
        } else {
                if (!scsi_block_when_processing_errors(sdev))
                        return -ENODEV;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(scsi_ioctl_block_when_processing_errors);