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    scsi_ioctl.c 19.96 KiB
    /*
     * 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 <linux/uio.h>
    #include <linux/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 max_sectors_bytes(struct request_queue *q)
    {
    	unsigned int max_sectors = queue_max_sectors(q);
    
    	max_sectors = min_t(unsigned int, max_sectors, INT_MAX >> 9);
    
    	return max_sectors << 9;
    }
    
    static int sg_get_reserved_size(struct request_queue *q, int __user *p)
    {
    	int val = min_t(int, q->sg_reserved_size, max_sectors_bytes(q));
    
    	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;
    
    	q->sg_reserved_size = min(size, max_sectors_bytes(q));
    	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_16, 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(WRITE_SAME, filter->write_ok);
    	__set_bit(WRITE_SAME_16, filter->write_ok);
    	__set_bit(WRITE_SAME_32, 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;
    
    	/* 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)
    {
    	struct scsi_request *req = scsi_req(rq);
    
    	if (copy_from_user(req->cmd, hdr->cmdp, hdr->cmd_len))
    		return -EFAULT;
    	if (blk_verify_command(req->cmd, mode & FMODE_WRITE))
    		return -EPERM;
    
    	/*
    	 * fill in request structure
    	 */
    	req->cmd_len = hdr->cmd_len;
    
    	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)
    {
    	struct scsi_request *req = scsi_req(rq);
    	int r, ret = 0;
    
    	/*
    	 * fill in all the output members
    	 */
    	hdr->status = req->result & 0xff;
    	hdr->masked_status = status_byte(req->result);
    	hdr->msg_status = msg_byte(req->result);
    	hdr->host_status = host_byte(req->result);
    	hdr->driver_status = driver_byte(req->result);
    	hdr->info = 0;
    	if (hdr->masked_status || hdr->host_status || hdr->driver_status)
    		hdr->info |= SG_INFO_CHECK;
    	hdr->resid = req->resid_len;
    	hdr->sb_len_wr = 0;
    
    	if (req->sense_len && hdr->sbp) {
    		int len = min((unsigned int) hdr->mx_sb_len, req->sense_len);
    
    		if (!copy_to_user(hdr->sbp, req->sense, 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 request_queue *q, struct gendisk *bd_disk,
    		struct sg_io_hdr *hdr, fmode_t mode)
    {
    	unsigned long start_time;
    	ssize_t ret = 0;
    	int writing = 0;
    	int at_head = 0;
    	struct request *rq;
    	struct scsi_request *req;
    	struct bio *bio;
    
    	if (hdr->interface_id != 'S')
    		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;
    		}
    	if (hdr->flags & SG_FLAG_Q_AT_HEAD)
    		at_head = 1;
    
    	ret = -ENOMEM;
    	rq = blk_get_request(q, writing ? REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN,
    			GFP_KERNEL);
    	if (IS_ERR(rq))
    		return PTR_ERR(rq);
    	req = scsi_req(rq);
    
    	if (hdr->cmd_len > BLK_MAX_CDB) {
    		req->cmd = kzalloc(hdr->cmd_len, GFP_KERNEL);
    		if (!req->cmd)
    			goto out_put_request;
    	}
    
    	ret = blk_fill_sghdr_rq(q, rq, hdr, mode);
    	if (ret < 0)
    		goto out_free_cdb;
    
    	ret = 0;
    	if (hdr->iovec_count) {
    		struct iov_iter i;
    		struct iovec *iov = NULL;
    
    		ret = import_iovec(rq_data_dir(rq),
    				   hdr->dxferp, hdr->iovec_count,
    				   0, &iov, &i);
    		if (ret < 0)
    			goto out_free_cdb;
    
    		/* SG_IO howto says that the shorter of the two wins */
    		iov_iter_truncate(&i, hdr->dxfer_len);
    
    		ret = blk_rq_map_user_iov(q, rq, NULL, &i, GFP_KERNEL);
    		kfree(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_free_cdb;
    
    	bio = rq->bio;
    	req->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, at_head);
    
    	hdr->duration = jiffies_to_msecs(jiffies - start_time);
    
    	ret = blk_complete_sghdr_rq(rq, hdr, bio);
    
    out_free_cdb:
    	scsi_req_free_cmd(req);
    out_put_request:
    	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;
    	struct scsi_request *req;
    	int err;
    	unsigned int in_len, out_len, bytes, opcode, cmdlen;
    	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))
    		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 ? REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN,
    			__GFP_RECLAIM);
    	if (IS_ERR(rq)) {
    		err = PTR_ERR(rq);
    		goto error_free_buffer;
    	}
    	req = scsi_req(rq);
    
    	cmdlen = COMMAND_SIZE(opcode);
    
    	/*
    	 * get command and data to send to device, if any
    	 */
    	err = -EFAULT;
    	req->cmd_len = cmdlen;
    	if (copy_from_user(req->cmd, sic->data, cmdlen))
    		goto error;
    
    	if (in_len && copy_from_user(buffer, sic->data + cmdlen, in_len))
    		goto error;
    
    	err = blk_verify_command(req->cmd, mode & FMODE_WRITE);
    	if (err)
    		goto error;
    
    	/* default.  possible overriden later */
    	req->retries = 5;
    
    	switch (opcode) {
    	case SEND_DIAGNOSTIC:
    	case FORMAT_UNIT:
    		rq->timeout = FORMAT_UNIT_TIMEOUT;
    		req->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;
    		req->retries = 1;
    		break;
    	default:
    		rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
    		break;
    	}
    
    	if (bytes && blk_rq_map_kern(q, rq, buffer, bytes, __GFP_RECLAIM)) {
    		err = DRIVER_ERROR << 24;
    		goto error;
    	}
    
    	blk_execute_rq(q, disk, rq, 0);
    
    	err = req->result & 0xff;	/* only 8 bit SCSI status */
    	if (err) {
    		if (req->sense_len && req->sense) {
    			bytes = (OMAX_SB_LEN > req->sense_len) ?
    				req->sense_len : OMAX_SB_LEN;
    			if (copy_to_user(sic->data, req->sense, bytes))
    				err = -EFAULT;
    		}
    	} else {
    		if (copy_to_user(sic->data, buffer, out_len))
    			err = -EFAULT;
    	}
    	
    error:
    	blk_put_request(rq);
    
    error_free_buffer:
    	kfree(buffer);
    
    	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, REQ_OP_SCSI_OUT, __GFP_RECLAIM);
    	if (IS_ERR(rq))
    		return PTR_ERR(rq);
    	rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
    	scsi_req(rq)->cmd[0] = cmd;
    	scsi_req(rq)->cmd[4] = data;
    	scsi_req(rq)->cmd_len = 6;
    	blk_execute_rq(q, bd_disk, rq, 0);
    	err = scsi_req(rq)->result ? -EIO : 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);
    
    /**
     * scsi_req_init - initialize certain fields of a scsi_request structure
     * @req: Pointer to a scsi_request structure.
     * Initializes .__cmd[], .cmd, .cmd_len and .sense_len but no other members
     * of struct scsi_request.
     */
    void scsi_req_init(struct scsi_request *req)
    {
    	memset(req->__cmd, 0, sizeof(req->__cmd));
    	req->cmd = req->__cmd;
    	req->cmd_len = BLK_MAX_CDB;
    	req->sense_len = 0;
    }
    EXPORT_SYMBOL(scsi_req_init);
    
    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);