scsi_ioctl.c

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/*
 * Copyright (C) 2001 Jens Axboe <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public Licens
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
 *
 */
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/capability.h>
#include <linux/completion.h>
#include <linux/cdrom.h>
#include <linux/ratelimit.h>
#include <linux/slab.h>
#include <linux/times.h>
#include <asm/uaccess.h>

#include <scsi/scsi.h>
#include <scsi/scsi_ioctl.h>
#include <scsi/scsi_cmnd.h>

struct blk_cmd_filter {
    unsigned long read_ok[BLK_SCSI_CMD_PER_LONG];
    unsigned long write_ok[BLK_SCSI_CMD_PER_LONG];
};

static struct blk_cmd_filter blk_default_cmd_filter;

/* Command group 3 is reserved and should never be used.  */
const unsigned char scsi_command_size_tbl[8] =
{
    6, 10, 10, 12,
    16, 12, 10, 10
};
EXPORT_SYMBOL(scsi_command_size_tbl);

#include <scsi/sg.h>

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

static int scsi_get_idlun(struct request_queue *q, int __user *p)
{
    return put_user(0, p);
}

static int scsi_get_bus(struct request_queue *q, int __user *p)
{
    return put_user(0, p);
}

static int sg_get_timeout(struct request_queue *q)
{
    return jiffies_to_clock_t(q->sg_timeout);
}

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

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

    return err;
}

static int sg_get_reserved_size(struct request_queue *q, int __user *p)
{
    unsigned val = min(q->sg_reserved_size, queue_max_sectors(q) << 9);

    return put_user(val, p);
}

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

    if (err)
        return err;

    if (size < 0)
        return -EINVAL;
    if (size > (queue_max_sectors(q) << 9))
        size = queue_max_sectors(q) << 9;

    q->sg_reserved_size = size;
    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 void blk_set_cmd_filter_defaults(struct blk_cmd_filter *filter)
{
    /* Basic read-only commands */
    __set_bit(TEST_UNIT_READY, filter->read_ok);
    __set_bit(REQUEST_SENSE, filter->read_ok);
    __set_bit(READ_6, filter->read_ok);
    __set_bit(READ_10, filter->read_ok);
    __set_bit(READ_12, filter->read_ok);
    __set_bit(READ_16, filter->read_ok);
    __set_bit(READ_BUFFER, filter->read_ok);
    __set_bit(READ_DEFECT_DATA, filter->read_ok);
    __set_bit(READ_CAPACITY, filter->read_ok);
    __set_bit(READ_LONG, filter->read_ok);
    __set_bit(INQUIRY, filter->read_ok);
    __set_bit(MODE_SENSE, filter->read_ok);
    __set_bit(MODE_SENSE_10, filter->read_ok);
    __set_bit(LOG_SENSE, filter->read_ok);
    __set_bit(START_STOP, filter->read_ok);
    __set_bit(GPCMD_VERIFY_10, filter->read_ok);
    __set_bit(VERIFY_16, filter->read_ok);
    __set_bit(REPORT_LUNS, filter->read_ok);
    __set_bit(SERVICE_ACTION_IN, filter->read_ok);
    __set_bit(RECEIVE_DIAGNOSTIC, filter->read_ok);
    __set_bit(MAINTENANCE_IN, filter->read_ok);
    __set_bit(GPCMD_READ_BUFFER_CAPACITY, filter->read_ok);

    /* Audio CD commands */
    __set_bit(GPCMD_PLAY_CD, filter->read_ok);
    __set_bit(GPCMD_PLAY_AUDIO_10, filter->read_ok);
    __set_bit(GPCMD_PLAY_AUDIO_MSF, filter->read_ok);
    __set_bit(GPCMD_PLAY_AUDIO_TI, filter->read_ok);
    __set_bit(GPCMD_PAUSE_RESUME, filter->read_ok);

    /* CD/DVD data reading */
    __set_bit(GPCMD_READ_CD, filter->read_ok);
    __set_bit(GPCMD_READ_CD_MSF, filter->read_ok);
    __set_bit(GPCMD_READ_DISC_INFO, filter->read_ok);
    __set_bit(GPCMD_READ_CDVD_CAPACITY, filter->read_ok);
    __set_bit(GPCMD_READ_DVD_STRUCTURE, filter->read_ok);
    __set_bit(GPCMD_READ_HEADER, filter->read_ok);
    __set_bit(GPCMD_READ_TRACK_RZONE_INFO, filter->read_ok);
    __set_bit(GPCMD_READ_SUBCHANNEL, filter->read_ok);
    __set_bit(GPCMD_READ_TOC_PMA_ATIP, filter->read_ok);
    __set_bit(GPCMD_REPORT_KEY, filter->read_ok);
    __set_bit(GPCMD_SCAN, filter->read_ok);
    __set_bit(GPCMD_GET_CONFIGURATION, filter->read_ok);
    __set_bit(GPCMD_READ_FORMAT_CAPACITIES, filter->read_ok);
    __set_bit(GPCMD_GET_EVENT_STATUS_NOTIFICATION, filter->read_ok);
    __set_bit(GPCMD_GET_PERFORMANCE, filter->read_ok);
    __set_bit(GPCMD_SEEK, filter->read_ok);
    __set_bit(GPCMD_STOP_PLAY_SCAN, filter->read_ok);

    /* Basic writing commands */
    __set_bit(WRITE_6, filter->write_ok);
    __set_bit(WRITE_10, filter->write_ok);
    __set_bit(WRITE_VERIFY, filter->write_ok);
    __set_bit(WRITE_12, filter->write_ok);
    __set_bit(WRITE_VERIFY_12, filter->write_ok);
    __set_bit(WRITE_16, filter->write_ok);
    __set_bit(WRITE_LONG, filter->write_ok);
    __set_bit(WRITE_LONG_2, filter->write_ok);
    __set_bit(ERASE, filter->write_ok);
    __set_bit(GPCMD_MODE_SELECT_10, filter->write_ok);
    __set_bit(MODE_SELECT, filter->write_ok);
    __set_bit(LOG_SELECT, filter->write_ok);
    __set_bit(GPCMD_BLANK, filter->write_ok);
    __set_bit(GPCMD_CLOSE_TRACK, filter->write_ok);
    __set_bit(GPCMD_FLUSH_CACHE, filter->write_ok);
    __set_bit(GPCMD_FORMAT_UNIT, filter->write_ok);
    __set_bit(GPCMD_REPAIR_RZONE_TRACK, filter->write_ok);
    __set_bit(GPCMD_RESERVE_RZONE_TRACK, filter->write_ok);
    __set_bit(GPCMD_SEND_DVD_STRUCTURE, filter->write_ok);
    __set_bit(GPCMD_SEND_EVENT, filter->write_ok);
    __set_bit(GPCMD_SEND_KEY, filter->write_ok);
    __set_bit(GPCMD_SEND_OPC, filter->write_ok);
    __set_bit(GPCMD_SEND_CUE_SHEET, filter->write_ok);
    __set_bit(GPCMD_SET_SPEED, filter->write_ok);
    __set_bit(GPCMD_PREVENT_ALLOW_MEDIUM_REMOVAL, filter->write_ok);
    __set_bit(GPCMD_LOAD_UNLOAD, filter->write_ok);
    __set_bit(GPCMD_SET_STREAMING, filter->write_ok);
    __set_bit(GPCMD_SET_READ_AHEAD, filter->write_ok);
}

int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm)
{
    struct blk_cmd_filter *filter = &blk_default_cmd_filter;

    /* root can do any command. */
    if (capable(CAP_SYS_RAWIO))
        return 0;

    /* if there's no filter set, assume we're filtering everything out */
    if (!filter)
        return -EPERM;

    /* Anybody who can open the device can do a read-safe command */
    if (test_bit(cmd[0], filter->read_ok))
        return 0;

    /* Write-safe commands require a writable open */
    if (test_bit(cmd[0], filter->write_ok) && has_write_perm)
        return 0;

    return -EPERM;
}
EXPORT_SYMBOL(blk_verify_command);

static int blk_fill_sghdr_rq(struct request_queue *q, struct request *rq,
                 struct sg_io_hdr *hdr, fmode_t mode)
{
    if (copy_from_user(rq->cmd, hdr->cmdp, hdr->cmd_len))
        return -EFAULT;
    if (blk_verify_command(rq->cmd, mode & FMODE_WRITE))
        return -EPERM;

    /*
     * fill in request structure
     */
    rq->cmd_len = hdr->cmd_len;
    rq->cmd_type = REQ_TYPE_BLOCK_PC;

    rq->timeout = msecs_to_jiffies(hdr->timeout);
    if (!rq->timeout)
        rq->timeout = q->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 blk_complete_sghdr_rq(struct request *rq, struct sg_io_hdr *hdr,
                 struct bio *bio)
{
    int r, ret = 0;

    /*
     * fill in all the output members
     */
    hdr->status = rq->errors & 0xff;
    hdr->masked_status = status_byte(rq->errors);
    hdr->msg_status = msg_byte(rq->errors);
    hdr->host_status = host_byte(rq->errors);
    hdr->driver_status = driver_byte(rq->errors);
    hdr->info = 0;
    if (hdr->masked_status || hdr->host_status || hdr->driver_status)
        hdr->info |= SG_INFO_CHECK;
    hdr->resid = rq->resid_len;
    hdr->sb_len_wr = 0;

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

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

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

    return ret;
}

static int sg_io(struct request_queue *q, struct gendisk *bd_disk,
        struct sg_io_hdr *hdr, fmode_t mode)
{
    unsigned long start_time;
    int writing = 0, ret = 0;
    struct request *rq;
    char sense[SCSI_SENSE_BUFFERSIZE];
    struct bio *bio;

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

    if (hdr->dxfer_len > (queue_max_hw_sectors(q) << 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;
        }

    rq = blk_get_request(q, writing ? WRITE : READ, GFP_KERNEL);
    if (!rq)
        return -ENOMEM;

    if (blk_fill_sghdr_rq(q, rq, hdr, mode)) {
        blk_put_request(rq);
        return -EFAULT;
    }

    if (hdr->iovec_count) {
        const int size = sizeof(struct sg_iovec) * hdr->iovec_count;
        size_t iov_data_len;
        struct sg_iovec *sg_iov;
        struct iovec *iov;
        int i;

        sg_iov = kmalloc(size, GFP_KERNEL);
        if (!sg_iov) {
            ret = -ENOMEM;
            goto out;
        }

        if (copy_from_user(sg_iov, hdr->dxferp, size)) {
            kfree(sg_iov);
            ret = -EFAULT;
            goto out;
        }

        /*
         * Sum up the vecs, making sure they don't overflow
         */
        iov = (struct iovec *) sg_iov;
        iov_data_len = 0;
        for (i = 0; i < hdr->iovec_count; i++) {
            if (iov_data_len + iov[i].iov_len < iov_data_len) {
                kfree(sg_iov);
                ret = -EINVAL;
                goto out;
            }
            iov_data_len += iov[i].iov_len;
        }

        /* SG_IO howto says that the shorter of the two wins */
        if (hdr->dxfer_len < iov_data_len) {
            hdr->iovec_count = iov_shorten(iov,
                               hdr->iovec_count,
                               hdr->dxfer_len);
            iov_data_len = hdr->dxfer_len;
        }

        ret = blk_rq_map_user_iov(q, rq, NULL, sg_iov, hdr->iovec_count,
                      iov_data_len, GFP_KERNEL);
        kfree(sg_iov);
    } else if (hdr->dxfer_len)
        ret = blk_rq_map_user(q, rq, NULL, hdr->dxferp, hdr->dxfer_len,
                      GFP_KERNEL);

    if (ret)
        goto out;

    bio = rq->bio;
    memset(sense, 0, sizeof(sense));
    rq->sense = sense;
    rq->sense_len = 0;
    rq->retries = 0;

    start_time = jiffies;

    /* ignore return value. All information is passed back to caller
     * (if he doesn't check that is his problem).
     * N.B. a non-zero SCSI status is _not_ necessarily an error.
     */
    blk_execute_rq(q, bd_disk, rq, 0);

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

    return blk_complete_sghdr_rq(rq, hdr, bio);
out:
    blk_put_request(rq);
    return ret;
}

#define OMAX_SB_LEN 16          /* For backward compatibility */
int sg_scsi_ioctl(struct request_queue *q, struct gendisk *disk, fmode_t mode,
        struct scsi_ioctl_command __user *sic)
{
    struct request *rq;
    int err;
    unsigned int in_len, out_len, bytes, opcode, cmdlen;
    char *buffer = NULL, sense[SCSI_SENSE_BUFFERSIZE];

    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))
        return -EFAULT;

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

    }

    rq = blk_get_request(q, in_len ? WRITE : READ, __GFP_WAIT);

    cmdlen = COMMAND_SIZE(opcode);

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

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

    err = blk_verify_command(rq->cmd, mode & FMODE_WRITE);
    if (err)
        goto error;

    /* default.  possible overriden later */
    rq->retries = 5;

    switch (opcode) {
    case SEND_DIAGNOSTIC:
    case FORMAT_UNIT:
        rq->timeout = FORMAT_UNIT_TIMEOUT;
        rq->retries = 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;
        rq->retries = 1;
        break;
    default:
        rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
        break;
    }

    if (bytes && blk_rq_map_kern(q, rq, buffer, bytes, __GFP_WAIT)) {
        err = DRIVER_ERROR << 24;
        goto out;
    }

    memset(sense, 0, sizeof(sense));
    rq->sense = sense;
    rq->sense_len = 0;
    rq->cmd_type = REQ_TYPE_BLOCK_PC;

    blk_execute_rq(q, disk, rq, 0);

out:
    err = rq->errors & 0xff;    /* only 8 bit SCSI status */
    if (err) {
        if (rq->sense_len && rq->sense) {
            bytes = (OMAX_SB_LEN > rq->sense_len) ?
                rq->sense_len : OMAX_SB_LEN;
            if (copy_to_user(sic->data, rq->sense, bytes))
                err = -EFAULT;
        }
    } else {
        if (copy_to_user(sic->data, buffer, out_len))
            err = -EFAULT;
    }
    
error:
    kfree(buffer);
    blk_put_request(rq);
    return err;
}
EXPORT_SYMBOL_GPL(sg_scsi_ioctl);

/* Send basic block requests */
static int __blk_send_generic(struct request_queue *q, struct gendisk *bd_disk,
                  int cmd, int data)
{
    struct request *rq;
    int err;

    rq = blk_get_request(q, WRITE, __GFP_WAIT);
    rq->cmd_type = REQ_TYPE_BLOCK_PC;
    rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
    rq->cmd[0] = cmd;
    rq->cmd[4] = data;
    rq->cmd_len = 6;
    err = blk_execute_rq(q, bd_disk, rq, 0);
    blk_put_request(rq);

    return err;
}

static inline int blk_send_start_stop(struct request_queue *q,
                      struct gendisk *bd_disk, int data)
{
    return __blk_send_generic(q, bd_disk, GPCMD_START_STOP_UNIT, data);
}

int scsi_cmd_ioctl(struct request_queue *q, struct gendisk *bd_disk, fmode_t mode,
           unsigned int cmd, void __user *arg)
{
    int err;

    if (!q)
        return -ENXIO;

    switch (cmd) {
        /*
         * new sgv3 interface
         */
        case SG_GET_VERSION_NUM:
            err = sg_get_version(arg);
            break;
        case SCSI_IOCTL_GET_IDLUN:
            err = scsi_get_idlun(q, arg);
            break;
        case SCSI_IOCTL_GET_BUS_NUMBER:
            err = scsi_get_bus(q, arg);
            break;
        case SG_SET_TIMEOUT:
            err = sg_set_timeout(q, arg);
            break;
        case SG_GET_TIMEOUT:
            err = sg_get_timeout(q);
            break;
        case SG_GET_RESERVED_SIZE:
            err = sg_get_reserved_size(q, arg);
            break;
        case SG_SET_RESERVED_SIZE:
            err = sg_set_reserved_size(q, arg);
            break;
        case SG_EMULATED_HOST:
            err = sg_emulated_host(q, arg);
            break;
        case SG_IO: {
            struct sg_io_hdr hdr;

            err = -EFAULT;
            if (copy_from_user(&hdr, arg, sizeof(hdr)))
                break;
            err = sg_io(q, bd_disk, &hdr, mode);
            if (err == -EFAULT)
                break;

            if (copy_to_user(arg, &hdr, sizeof(hdr)))
                err = -EFAULT;
            break;
        }
        case CDROM_SEND_PACKET: {
            struct cdrom_generic_command cgc;
            struct sg_io_hdr hdr;

            err = -EFAULT;
            if (copy_from_user(&cgc, arg, sizeof(cgc)))
                break;
            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;
            err = 0;
            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:
                    err = -EINVAL;
            }
            if (err)
                break;

            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(q, bd_disk, &hdr, mode);
            if (err == -EFAULT)
                break;

            if (hdr.status)
                err = -EIO;

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

            break;
        }

        /*
         * old junk scsi send command ioctl
         */
        case SCSI_IOCTL_SEND_COMMAND:
            printk(KERN_WARNING "program %s is using a deprecated SCSI ioctl, please convert it to SG_IO\n", current->comm);
            err = -EINVAL;
            if (!arg)
                break;

            err = sg_scsi_ioctl(q, bd_disk, mode, arg);
            break;
        case CDROMCLOSETRAY:
            err = blk_send_start_stop(q, bd_disk, 0x03);
            break;
        case CDROMEJECT:
            err = blk_send_start_stop(q, bd_disk, 0x02);
            break;
        default:
            err = -ENOTTY;
    }

    return err;
}
EXPORT_SYMBOL(scsi_cmd_ioctl);

int scsi_verify_blk_ioctl(struct block_device *bd, unsigned int cmd)
{
    if (bd && bd == bd->bd_contains)
        return 0;

    /* Actually none of these is particularly useful on a partition,
     * but they are safe.
     */
    switch (cmd) {
    case SCSI_IOCTL_GET_IDLUN:
    case SCSI_IOCTL_GET_BUS_NUMBER:
    case SCSI_IOCTL_GET_PCI:
    case SCSI_IOCTL_PROBE_HOST:
    case SG_GET_VERSION_NUM:
    case SG_SET_TIMEOUT:
    case SG_GET_TIMEOUT:
    case SG_GET_RESERVED_SIZE:
    case SG_SET_RESERVED_SIZE:
    case SG_EMULATED_HOST:
        return 0;
    case CDROM_GET_CAPABILITY:
        /* Keep this until we remove the printk below.  udev sends it
         * and we do not want to spam dmesg about it.   CD-ROMs do
         * not have partitions, so we get here only for disks.
         */
        return -ENOIOCTLCMD;
    default:
        break;
    }

    if (capable(CAP_SYS_RAWIO))
        return 0;

    /* In particular, rule out all resets and host-specific ioctls.  */
    printk_ratelimited(KERN_WARNING
               "%s: sending ioctl %x to a partition!\n", current->comm, cmd);

    return -ENOIOCTLCMD;
}
EXPORT_SYMBOL(scsi_verify_blk_ioctl);

int scsi_cmd_blk_ioctl(struct block_device *bd, fmode_t mode,
               unsigned int cmd, void __user *arg)
{
    int ret;

    ret = scsi_verify_blk_ioctl(bd, cmd);
    if (ret < 0)
        return ret;

    return scsi_cmd_ioctl(bd->bd_disk->queue, bd->bd_disk, mode, cmd, arg);
}
EXPORT_SYMBOL(scsi_cmd_blk_ioctl);

static int __init blk_scsi_ioctl_init(void)
{
    blk_set_cmd_filter_defaults(&blk_default_cmd_filter);
    return 0;
}
fs_initcall(blk_scsi_ioctl_init);