drivers/scsi/scsi_ioctl.c - kernel/common - Git at Google

 /*
  * Changes:
  * Arnaldo Carvalho de Melo <[email protected]> 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 <asm/uaccess.h>

 #include <scsi/scsi.h>
 #include <scsi/scsi_device.h>
 #include <scsi/scsi_eh.h>
 #include <scsi/scsi_host.h>
 #include <scsi/scsi_ioctl.h>
 #include <scsi/scsi_request.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

 /*
  * If we are told to probe a host, we will return 0 if  the host is not
  * present, 1 if the host is present, and will return an identifying
  * string at *arg, if arg is non null, filling to the length stored at
  * (int *) arg
  */

 static int ioctl_probe(struct Scsi_Host *host, void __user *buffer)
 {
 	unsigned int len, slen;
 	const char *string;
 	int temp = host->hostt->present;

 	if (temp && 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 temp;
 }

 /*

  * The SCSI_IOCTL_SEND_COMMAND ioctl sends a command out to the SCSI host.
  * The IOCTL_NORMAL_TIMEOUT and NORMAL_RETRIES  variables are used.
  *
  * dev is the SCSI device struct ptr, *(int *) arg is the length of the
  * input data, if any, not including the command string & counts,
  * *((int *)arg + 1) is the output buffer size in bytes.
  *
  * *(char *) ((int *) arg)[2] the actual command byte.
  *
  * Note that if more than MAX_BUF bytes are requested to be transferred,
  * the ioctl will fail with error EINVAL.
  *
  * This size *does not* include the initial lengths that were passed.
  *
  * The SCSI command is read from the memory location immediately after the
  * length words, and the input data is right after the command.  The SCSI
  * routines know the command size based on the opcode decode.
  *
  * The output area is then filled in starting from the command byte.
  */

 static int ioctl_internal_command(struct scsi_device *sdev, char *cmd,
 				  int timeout, int retries)
 {
 	struct scsi_request *sreq;
 	int result;
 	struct scsi_sense_hdr sshdr;

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

 	sreq = scsi_allocate_request(sdev, GFP_KERNEL);
 	if (!sreq) {
 		printk(KERN_WARNING "SCSI internal ioctl failed, no memory\n");
 		return -ENOMEM;
 	}

 	sreq->sr_data_direction = DMA_NONE;
         scsi_wait_req(sreq, cmd, NULL, 0, timeout, retries);

 	SCSI_LOG_IOCTL(2, printk("Ioctl returned  0x%x\n", sreq->sr_result));

 	if ((driver_byte(sreq->sr_result) & DRIVER_SENSE) &&
 	    (scsi_request_normalize_sense(sreq, &sshdr))) {
 		switch (sshdr.sense_key) {
 		case ILLEGAL_REQUEST:
 			if (cmd[0] == ALLOW_MEDIUM_REMOVAL)
 				sdev->lockable = 0;
 			else
 				printk(KERN_INFO "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 && (cmd[0] != TEST_UNIT_READY)) {
 				printk(KERN_INFO "Device not ready. Make sure"
 				       " there is a disc in the drive.\n");
 				break;
 			}
 		case UNIT_ATTENTION:
 			if (sdev->removable) {
 				sdev->changed = 1;
 				sreq->sr_result = 0;	/* This is no longer considered an error */
 				break;
 			}
 		default:	/* Fall through for non-removable media */
 			printk(KERN_INFO "ioctl_internal_command: <%d %d %d "
 			       "%d> return code = %x\n",
 			       sdev->host->host_no,
 			       sdev->channel,
 			       sdev->id,
 			       sdev->lun,
 			       sreq->sr_result);
 			scsi_print_req_sense("   ", sreq);
 			break;
 		}
 	}

 	result = sreq->sr_result;
 	SCSI_LOG_IOCTL(2, printk("IOCTL Releasing command\n"));
 	scsi_release_request(sreq);
 	return result;
 }

 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);

 /*
  * This interface is deprecated - users should use the scsi generic (sg)
  * interface instead, as this is a more flexible approach to performing
  * generic SCSI commands on a device.
  *
  * The structure that we are passed should look like:
  *
  * struct sdata {
  *  unsigned int inlen;      [i] Length of data to be written to device
  *  unsigned int outlen;     [i] Length of data to be read from device
  *  unsigned char cmd[x];    [i] SCSI command (6 <= x <= 12).
  *                           [o] Data read from device starts here.
  *                           [o] On error, sense buffer starts here.
  *  unsigned char wdata[y];  [i] Data written to device starts here.
  * };
  * Notes:
  *   -  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 (4K on i386, 8K on alpha).
  *   -  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.
  *      See the drivers/scsi/scsi.h file for more information on this.
  *
  */
 #define OMAX_SB_LEN 16		/* Old sense buffer length */

 int scsi_ioctl_send_command(struct scsi_device *sdev,
 			    struct scsi_ioctl_command __user *sic)
 {
 	char *buf;
 	unsigned char cmd[MAX_COMMAND_SIZE];
 	char __user *cmd_in;
 	struct scsi_request *sreq;
 	unsigned char opcode;
 	unsigned int inlen, outlen, cmdlen;
 	unsigned int needed, buf_needed;
 	int timeout, retries, result;
 	int data_direction, gfp_mask = GFP_KERNEL;

 	if (!sic)
 		return -EINVAL;

 	if (sdev->host->unchecked_isa_dma)
 		gfp_mask |= GFP_DMA;

 	/*
 	 * Verify that we can read at least this much.
 	 */
 	if (!access_ok(VERIFY_READ, sic, sizeof(Scsi_Ioctl_Command)))
 		return -EFAULT;

 	if(__get_user(inlen, &sic->inlen))
 		return -EFAULT;

 	if(__get_user(outlen, &sic->outlen))
 		return -EFAULT;

 	/*
 	 * We do not transfer more than MAX_BUF with this interface.
 	 * If the user needs to transfer more data than this, they
 	 * should use scsi_generics (sg) instead.
 	 */
 	if (inlen > MAX_BUF)
 		return -EINVAL;
 	if (outlen > MAX_BUF)
 		return -EINVAL;

 	cmd_in = sic->data;
 	if(get_user(opcode, cmd_in))
 		return -EFAULT;

 	needed = buf_needed = (inlen > outlen ? inlen : outlen);
 	if (buf_needed) {
 		buf_needed = (buf_needed + 511) & ~511;
 		if (buf_needed > MAX_BUF)
 			buf_needed = MAX_BUF;
 		buf = kmalloc(buf_needed, gfp_mask);
 		if (!buf)
 			return -ENOMEM;
 		memset(buf, 0, buf_needed);
 		if (inlen == 0) {
 			data_direction = DMA_FROM_DEVICE;
 		} else if (outlen == 0 ) {
 			data_direction = DMA_TO_DEVICE;
 		} else {
 			/*
 			 * Can this ever happen?
 			 */
 			data_direction = DMA_BIDIRECTIONAL;
 		}

 	} else {
 		buf = NULL;
 		data_direction = DMA_NONE;
 	}

 	/*
 	 * Obtain the command from the user's address space.
 	 */
 	cmdlen = COMMAND_SIZE(opcode);

 	result = -EFAULT;

 	if (!access_ok(VERIFY_READ, cmd_in, cmdlen + inlen))
 		goto error;

 	if(__copy_from_user(cmd, cmd_in, cmdlen))
 		goto error;

 	/*
 	 * Obtain the data to be sent to the device (if any).
 	 */

 	if(copy_from_user(buf, cmd_in + cmdlen, inlen))
 		goto error;

 	switch (opcode) {
 	case SEND_DIAGNOSTIC:
 	case FORMAT_UNIT:
 		timeout = FORMAT_UNIT_TIMEOUT;
 		retries = 1;
 		break;
 	case START_STOP:
 		timeout = START_STOP_TIMEOUT;
 		retries = NORMAL_RETRIES;
 		break;
 	case MOVE_MEDIUM:
 		timeout = MOVE_MEDIUM_TIMEOUT;
 		retries = NORMAL_RETRIES;
 		break;
 	case READ_ELEMENT_STATUS:
 		timeout = READ_ELEMENT_STATUS_TIMEOUT;
 		retries = NORMAL_RETRIES;
 		break;
 	case READ_DEFECT_DATA:
 		timeout = READ_DEFECT_DATA_TIMEOUT;
 		retries = 1;
 		break;
 	default:
 		timeout = IOCTL_NORMAL_TIMEOUT;
 		retries = NORMAL_RETRIES;
 		break;
 	}

 	sreq = scsi_allocate_request(sdev, GFP_KERNEL);
         if (!sreq) {
                 result = -EINTR;
                 goto error;
         }

 	sreq->sr_data_direction = data_direction;
         scsi_wait_req(sreq, cmd, buf, needed, timeout, retries);

 	/*
 	 * If there was an error condition, pass the info back to the user.
 	 */
 	result = sreq->sr_result;
 	if (result) {
 		int sb_len = sizeof(sreq->sr_sense_buffer);

 		sb_len = (sb_len > OMAX_SB_LEN) ? OMAX_SB_LEN : sb_len;
 		if (copy_to_user(cmd_in, sreq->sr_sense_buffer, sb_len))
 			result = -EFAULT;
 	} else {
 		if (copy_to_user(cmd_in, buf, outlen))
 			result = -EFAULT;
 	}

 	scsi_release_request(sreq);
 error:
 	kfree(buf);
 	return result;
 }
 EXPORT_SYMBOL(scsi_ioctl_send_command);

 /*
  * 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);

         if (!dev)
 		return -ENXIO;
         return copy_to_user(arg, dev->bus_id, sizeof(dev->bus_id))? -EFAULT: 0;
 }


 /*
  * 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 scsi_devices[] element, a structure.
  */
 int scsi_ioctl(struct scsi_device *sdev, int cmd, void __user *arg)
 {
 	char scsi_cmd[MAX_COMMAND_SIZE];

 	/* No idea how this happens.... */
 	if (!sdev)
 		return -ENXIO;

 	/*
 	 * If we are in the middle of error recovery, don't let anyone
 	 * else try and use this device.  Also, if error recovery fails, it
 	 * may try and take the device offline, in which case all further
 	 * access to the device is prohibited.
 	 */
 	if (!scsi_block_when_processing_errors(sdev))
 		return -ENODEV;

 	/* 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 SCSI_IOCTL_GET_IDLUN:
 		if (!access_ok(VERIFY_WRITE, arg, sizeof(struct scsi_idlun)))
 			return -EFAULT;

 		__put_user((sdev->id & 0xff)
 			 + ((sdev->lun & 0xff) << 8)
 			 + ((sdev->channel & 0xff) << 16)
 			 + ((sdev->host->host_no & 0xff) << 24),
 			 &((struct scsi_idlun __user *)arg)->dev_id);
 		__put_user(sdev->host->unique_id,
 			 &((struct scsi_idlun __user *)arg)->host_unique_id);
 		return 0;
 	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_SEND_COMMAND:
 		if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
 			return -EACCES;
 		return scsi_ioctl_send_command(sdev, 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);
 	case SCSI_IOCTL_START_UNIT:
 		scsi_cmd[0] = START_STOP;
 		scsi_cmd[1] = 0;
 		scsi_cmd[2] = scsi_cmd[3] = scsi_cmd[5] = 0;
 		scsi_cmd[4] = 1;
 		return ioctl_internal_command(sdev, scsi_cmd,
 				     START_STOP_TIMEOUT, NORMAL_RETRIES);
 	case SCSI_IOCTL_STOP_UNIT:
 		scsi_cmd[0] = START_STOP;
 		scsi_cmd[1] = 0;
 		scsi_cmd[2] = scsi_cmd[3] = scsi_cmd[5] = 0;
 		scsi_cmd[4] = 0;
 		return ioctl_internal_command(sdev, scsi_cmd,
 				     START_STOP_TIMEOUT, NORMAL_RETRIES);
         case SCSI_IOCTL_GET_PCI:
                 return scsi_ioctl_get_pci(sdev, arg);
 	default:
 		if (sdev->host->hostt->ioctl)
 			return sdev->host->hostt->ioctl(sdev, cmd, arg);
 	}
 	return -EINVAL;
 }
 EXPORT_SYMBOL(scsi_ioctl);

 /*
  * the scsi_nonblock_ioctl() function is designed for ioctls which may
  * be executed even if the device is in recovery.
  */
 int scsi_nonblockable_ioctl(struct scsi_device *sdev, int cmd,
 			    void __user *arg, struct file *filp)
 {
 	int val, result;

 	/* The first set of iocts may be executed even if we're doing
 	 * error processing, as long as the device was opened
 	 * non-blocking */
 	if (filp && filp->f_flags & O_NONBLOCK) {
 		if (test_bit(SHOST_RECOVERY,
 			     &sdev->host->shost_state))
 			return -ENODEV;
 	} else if (!scsi_block_when_processing_errors(sdev))
 		return -ENODEV;

 	switch (cmd) {
 	case SG_SCSI_RESET:
 		result = get_user(val, (int __user *)arg);
 		if (result)
 			return result;
 		if (val == SG_SCSI_RESET_NOTHING)
 			return 0;
 		switch (val) {
 		case SG_SCSI_RESET_DEVICE:
 			val = SCSI_TRY_RESET_DEVICE;
 			break;
 		case SG_SCSI_RESET_BUS:
 			val = SCSI_TRY_RESET_BUS;
 			break;
 		case SG_SCSI_RESET_HOST:
 			val = SCSI_TRY_RESET_HOST;
 			break;
 		default:
 			return -EINVAL;
 		}
 		if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
 			return -EACCES;
 		return (scsi_reset_provider(sdev, val) ==
 			SUCCESS) ? 0 : -EIO;
 	}
 	return -ENODEV;
 }
 EXPORT_SYMBOL(scsi_nonblockable_ioctl);
	/*
	* Changes:
	* Arnaldo Carvalho de Melo <[email protected]> 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 <asm/uaccess.h>

	#include <scsi/scsi.h>
	#include <scsi/scsi_device.h>
	#include <scsi/scsi_eh.h>
	#include <scsi/scsi_host.h>
	#include <scsi/scsi_ioctl.h>
	#include <scsi/scsi_request.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

	/*
	* If we are told to probe a host, we will return 0 if the host is not
	* present, 1 if the host is present, and will return an identifying
	* string at *arg, if arg is non null, filling to the length stored at
	* (int *) arg
	*/

	static int ioctl_probe(struct Scsi_Host host, void __user buffer)
	{
	unsigned int len, slen;
	const char *string;
	int temp = host->hostt->present;

	if (temp && 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 temp;
	}

	/*

	* The SCSI_IOCTL_SEND_COMMAND ioctl sends a command out to the SCSI host.
	* The IOCTL_NORMAL_TIMEOUT and NORMAL_RETRIES variables are used.
	*
	* dev is the SCSI device struct ptr, (int ) arg is the length of the
	* input data, if any, not including the command string & counts,
	* ((int )arg + 1) is the output buffer size in bytes.
	*
	* (char ) ((int *) arg)[2] the actual command byte.
	*
	* Note that if more than MAX_BUF bytes are requested to be transferred,
	* the ioctl will fail with error EINVAL.
	*
	* This size does not include the initial lengths that were passed.
	*
	* The SCSI command is read from the memory location immediately after the
	* length words, and the input data is right after the command. The SCSI
	* routines know the command size based on the opcode decode.
	*
	* The output area is then filled in starting from the command byte.
	*/

	static int ioctl_internal_command(struct scsi_device sdev, char cmd,
	int timeout, int retries)
	{
	struct scsi_request *sreq;
	int result;
	struct scsi_sense_hdr sshdr;

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

	sreq = scsi_allocate_request(sdev, GFP_KERNEL);
	if (!sreq) {
	printk(KERN_WARNING "SCSI internal ioctl failed, no memory\n");
	return -ENOMEM;
	}

	sreq->sr_data_direction = DMA_NONE;
	scsi_wait_req(sreq, cmd, NULL, 0, timeout, retries);

	SCSI_LOG_IOCTL(2, printk("Ioctl returned 0x%x\n", sreq->sr_result));

	if ((driver_byte(sreq->sr_result) & DRIVER_SENSE) &&
	(scsi_request_normalize_sense(sreq, &sshdr))) {
	switch (sshdr.sense_key) {
	case ILLEGAL_REQUEST:
	if (cmd[0] == ALLOW_MEDIUM_REMOVAL)
	sdev->lockable = 0;
	else
	printk(KERN_INFO "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 && (cmd[0] != TEST_UNIT_READY)) {
	printk(KERN_INFO "Device not ready. Make sure"
	" there is a disc in the drive.\n");
	break;
	}
	case UNIT_ATTENTION:
	if (sdev->removable) {
	sdev->changed = 1;
	sreq->sr_result = 0; /* This is no longer considered an error */
	break;
	}
	default: /* Fall through for non-removable media */
	printk(KERN_INFO "ioctl_internal_command: <%d %d %d "
	"%d> return code = %x\n",
	sdev->host->host_no,
	sdev->channel,
	sdev->id,
	sdev->lun,
	sreq->sr_result);
	scsi_print_req_sense(" ", sreq);
	break;
	}
	}

	result = sreq->sr_result;
	SCSI_LOG_IOCTL(2, printk("IOCTL Releasing command\n"));
	scsi_release_request(sreq);
	return result;
	}

	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);

	/*
	* This interface is deprecated - users should use the scsi generic (sg)
	* interface instead, as this is a more flexible approach to performing
	* generic SCSI commands on a device.
	*
	* The structure that we are passed should look like:
	*
	* struct sdata {
	* unsigned int inlen; [i] Length of data to be written to device
	* unsigned int outlen; [i] Length of data to be read from device
	* unsigned char cmd[x]; [i] SCSI command (6 <= x <= 12).
	* [o] Data read from device starts here.
	* [o] On error, sense buffer starts here.
	* unsigned char wdata[y]; [i] Data written to device starts here.
	* };
	* Notes:
	* - 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 (4K on i386, 8K on alpha).
	* - 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.
	* See the drivers/scsi/scsi.h file for more information on this.
	*
	*/
	#define OMAX_SB_LEN 16 /* Old sense buffer length */

	int scsi_ioctl_send_command(struct scsi_device *sdev,
	struct scsi_ioctl_command __user *sic)
	{
	char *buf;
	unsigned char cmd[MAX_COMMAND_SIZE];
	char __user *cmd_in;
	struct scsi_request *sreq;
	unsigned char opcode;
	unsigned int inlen, outlen, cmdlen;
	unsigned int needed, buf_needed;
	int timeout, retries, result;
	int data_direction, gfp_mask = GFP_KERNEL;

	if (!sic)
	return -EINVAL;

	if (sdev->host->unchecked_isa_dma)
	gfp_mask \|= GFP_DMA;

	/*
	* Verify that we can read at least this much.
	*/
	if (!access_ok(VERIFY_READ, sic, sizeof(Scsi_Ioctl_Command)))
	return -EFAULT;

	if(__get_user(inlen, &sic->inlen))
	return -EFAULT;

	if(__get_user(outlen, &sic->outlen))
	return -EFAULT;

	/*
	* We do not transfer more than MAX_BUF with this interface.
	* If the user needs to transfer more data than this, they
	* should use scsi_generics (sg) instead.
	*/
	if (inlen > MAX_BUF)
	return -EINVAL;
	if (outlen > MAX_BUF)
	return -EINVAL;

	cmd_in = sic->data;
	if(get_user(opcode, cmd_in))
	return -EFAULT;

	needed = buf_needed = (inlen > outlen ? inlen : outlen);
	if (buf_needed) {
	buf_needed = (buf_needed + 511) & ~511;
	if (buf_needed > MAX_BUF)
	buf_needed = MAX_BUF;
	buf = kmalloc(buf_needed, gfp_mask);
	if (!buf)
	return -ENOMEM;
	memset(buf, 0, buf_needed);
	if (inlen == 0) {
	data_direction = DMA_FROM_DEVICE;
	} else if (outlen == 0 ) {
	data_direction = DMA_TO_DEVICE;
	} else {
	/*
	* Can this ever happen?
	*/
	data_direction = DMA_BIDIRECTIONAL;
	}

	} else {
	buf = NULL;
	data_direction = DMA_NONE;
	}

	/*
	* Obtain the command from the user's address space.
	*/
	cmdlen = COMMAND_SIZE(opcode);

	result = -EFAULT;

	if (!access_ok(VERIFY_READ, cmd_in, cmdlen + inlen))
	goto error;

	if(__copy_from_user(cmd, cmd_in, cmdlen))
	goto error;

	/*
	* Obtain the data to be sent to the device (if any).
	*/

	if(copy_from_user(buf, cmd_in + cmdlen, inlen))
	goto error;

	switch (opcode) {
	case SEND_DIAGNOSTIC:
	case FORMAT_UNIT:
	timeout = FORMAT_UNIT_TIMEOUT;
	retries = 1;
	break;
	case START_STOP:
	timeout = START_STOP_TIMEOUT;
	retries = NORMAL_RETRIES;
	break;
	case MOVE_MEDIUM:
	timeout = MOVE_MEDIUM_TIMEOUT;
	retries = NORMAL_RETRIES;
	break;
	case READ_ELEMENT_STATUS:
	timeout = READ_ELEMENT_STATUS_TIMEOUT;
	retries = NORMAL_RETRIES;
	break;
	case READ_DEFECT_DATA:
	timeout = READ_DEFECT_DATA_TIMEOUT;
	retries = 1;
	break;
	default:
	timeout = IOCTL_NORMAL_TIMEOUT;
	retries = NORMAL_RETRIES;
	break;
	}

	sreq = scsi_allocate_request(sdev, GFP_KERNEL);
	if (!sreq) {
	result = -EINTR;
	goto error;
	}

	sreq->sr_data_direction = data_direction;
	scsi_wait_req(sreq, cmd, buf, needed, timeout, retries);

	/*
	* If there was an error condition, pass the info back to the user.
	*/
	result = sreq->sr_result;
	if (result) {
	int sb_len = sizeof(sreq->sr_sense_buffer);

	sb_len = (sb_len > OMAX_SB_LEN) ? OMAX_SB_LEN : sb_len;
	if (copy_to_user(cmd_in, sreq->sr_sense_buffer, sb_len))
	result = -EFAULT;
	} else {
	if (copy_to_user(cmd_in, buf, outlen))
	result = -EFAULT;
	}

	scsi_release_request(sreq);
	error:
	kfree(buf);
	return result;
	}
	EXPORT_SYMBOL(scsi_ioctl_send_command);

	/*
	* 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);

	if (!dev)
	return -ENXIO;
	return copy_to_user(arg, dev->bus_id, sizeof(dev->bus_id))? -EFAULT: 0;
	}


	/*
	* 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 scsi_devices[] element, a structure.
	*/
	int scsi_ioctl(struct scsi_device sdev, int cmd, void __user arg)
	{
	char scsi_cmd[MAX_COMMAND_SIZE];

	/* No idea how this happens.... */
	if (!sdev)
	return -ENXIO;

	/*
	* If we are in the middle of error recovery, don't let anyone
	* else try and use this device. Also, if error recovery fails, it
	* may try and take the device offline, in which case all further
	* access to the device is prohibited.
	*/
	if (!scsi_block_when_processing_errors(sdev))
	return -ENODEV;

	/* 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 SCSI_IOCTL_GET_IDLUN:
	if (!access_ok(VERIFY_WRITE, arg, sizeof(struct scsi_idlun)))
	return -EFAULT;

	__put_user((sdev->id & 0xff)
	+ ((sdev->lun & 0xff) << 8)
	+ ((sdev->channel & 0xff) << 16)
	+ ((sdev->host->host_no & 0xff) << 24),
	&((struct scsi_idlun __user *)arg)->dev_id);
	__put_user(sdev->host->unique_id,
	&((struct scsi_idlun __user *)arg)->host_unique_id);
	return 0;
	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_SEND_COMMAND:
	if (!capable(CAP_SYS_ADMIN) \|\| !capable(CAP_SYS_RAWIO))
	return -EACCES;
	return scsi_ioctl_send_command(sdev, 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);
	case SCSI_IOCTL_START_UNIT:
	scsi_cmd[0] = START_STOP;
	scsi_cmd[1] = 0;
	scsi_cmd[2] = scsi_cmd[3] = scsi_cmd[5] = 0;
	scsi_cmd[4] = 1;
	return ioctl_internal_command(sdev, scsi_cmd,
	START_STOP_TIMEOUT, NORMAL_RETRIES);
	case SCSI_IOCTL_STOP_UNIT:
	scsi_cmd[0] = START_STOP;
	scsi_cmd[1] = 0;
	scsi_cmd[2] = scsi_cmd[3] = scsi_cmd[5] = 0;
	scsi_cmd[4] = 0;
	return ioctl_internal_command(sdev, scsi_cmd,
	START_STOP_TIMEOUT, NORMAL_RETRIES);
	case SCSI_IOCTL_GET_PCI:
	return scsi_ioctl_get_pci(sdev, arg);
	default:
	if (sdev->host->hostt->ioctl)
	return sdev->host->hostt->ioctl(sdev, cmd, arg);
	}
	return -EINVAL;
	}
	EXPORT_SYMBOL(scsi_ioctl);

	/*
	* the scsi_nonblock_ioctl() function is designed for ioctls which may
	* be executed even if the device is in recovery.
	*/
	int scsi_nonblockable_ioctl(struct scsi_device *sdev, int cmd,
	void __user arg, struct file filp)
	{
	int val, result;

	/* The first set of iocts may be executed even if we're doing
	* error processing, as long as the device was opened
	* non-blocking */
	if (filp && filp->f_flags & O_NONBLOCK) {
	if (test_bit(SHOST_RECOVERY,
	&sdev->host->shost_state))
	return -ENODEV;
	} else if (!scsi_block_when_processing_errors(sdev))
	return -ENODEV;

	switch (cmd) {
	case SG_SCSI_RESET:
	result = get_user(val, (int __user *)arg);
	if (result)
	return result;
	if (val == SG_SCSI_RESET_NOTHING)
	return 0;
	switch (val) {
	case SG_SCSI_RESET_DEVICE:
	val = SCSI_TRY_RESET_DEVICE;
	break;
	case SG_SCSI_RESET_BUS:
	val = SCSI_TRY_RESET_BUS;
	break;
	case SG_SCSI_RESET_HOST:
	val = SCSI_TRY_RESET_HOST;
	break;
	default:
	return -EINVAL;
	}
	if (!capable(CAP_SYS_ADMIN) \|\| !capable(CAP_SYS_RAWIO))
	return -EACCES;
	return (scsi_reset_provider(sdev, val) ==
	SUCCESS) ? 0 : -EIO;
	}
	return -ENODEV;
	}
	EXPORT_SYMBOL(scsi_nonblockable_ioctl);