/*
   * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
   *
   * 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;

  }

  /**
   * sg_scsi_ioctl  --  handle deprecated SCSI_IOCTL_SEND_COMMAND ioctl
   * @file:	file this ioctl operates on (optional)
   * @q:		request queue to send scsi commands down
   * @disk:	gendisk to operate on (option)
   * @sic:	userspace structure describing the command to perform
   *
   * Send down the scsi command described by @sic to the device below
   * the request queue @q.  If @file is non-NULL it's used to perform
   * fine-grained permission checks that allow users to send down
   * non-destructive SCSI commands.  If the caller has a struct gendisk
   * available it should be passed in as @disk to allow the low level
   * driver to use the information contained in it.  A non-NULL @disk
   * is only allowed if the caller knows that the low level driver doesn't
   * need it (e.g. in the scsi subsystem).
   *
   * 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.
   */

  #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
  ", 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;
  	}
  
  	/* In particular, rule out all resets and host-specific ioctls.  */
  	printk_ratelimited(KERN_WARNING
  			   "%s: sending ioctl %x to a partition!
  ", current->comm, cmd);
  
  	return capable(CAP_SYS_RAWIO) ? 0 : -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);