/*
   * scsi_sysfs.c
   *
   * SCSI sysfs interface routines.
   *
   * Created to pull SCSI mid layer sysfs routines into one file.
   */

  #include <linux/module.h>

  #include <linux/slab.h>

  #include <linux/init.h>
  #include <linux/blkdev.h>
  #include <linux/device.h>

  #include <linux/pm_runtime.h>

  
  #include <scsi/scsi.h>
  #include <scsi/scsi_device.h>
  #include <scsi/scsi_host.h>
  #include <scsi/scsi_tcq.h>
  #include <scsi/scsi_transport.h>

  #include <scsi/scsi_driver.h>

  
  #include "scsi_priv.h"
  #include "scsi_logging.h"

  static struct device_type scsi_dev_type;

  static const struct {

  	enum scsi_device_state	value;
  	char			*name;
  } sdev_states[] = {
  	{ SDEV_CREATED, "created" },
  	{ SDEV_RUNNING, "running" },
  	{ SDEV_CANCEL, "cancel" },
  	{ SDEV_DEL, "deleted" },
  	{ SDEV_QUIESCE, "quiesce" },
  	{ SDEV_OFFLINE,	"offline" },
  	{ SDEV_BLOCK,	"blocked" },

  	{ SDEV_CREATED_BLOCK, "created-blocked" },

  };
  
  const char *scsi_device_state_name(enum scsi_device_state state)
  {
  	int i;
  	char *name = NULL;

  	for (i = 0; i < ARRAY_SIZE(sdev_states); i++) {

  		if (sdev_states[i].value == state) {
  			name = sdev_states[i].name;
  			break;
  		}
  	}
  	return name;
  }

  static const struct {

  	enum scsi_host_state	value;
  	char			*name;
  } shost_states[] = {
  	{ SHOST_CREATED, "created" },
  	{ SHOST_RUNNING, "running" },
  	{ SHOST_CANCEL, "cancel" },
  	{ SHOST_DEL, "deleted" },
  	{ SHOST_RECOVERY, "recovery" },

  	{ SHOST_CANCEL_RECOVERY, "cancel/recovery" },
  	{ SHOST_DEL_RECOVERY, "deleted/recovery", },

  };
  const char *scsi_host_state_name(enum scsi_host_state state)
  {
  	int i;
  	char *name = NULL;

  	for (i = 0; i < ARRAY_SIZE(shost_states); i++) {

  		if (shost_states[i].value == state) {
  			name = shost_states[i].name;
  			break;
  		}
  	}
  	return name;
  }

  static int check_set(unsigned int *val, char *src)
  {
  	char *last;
  
  	if (strncmp(src, "-", 20) == 0) {
  		*val = SCAN_WILD_CARD;
  	} else {
  		/*
  		 * Doesn't check for int overflow
  		 */
  		*val = simple_strtoul(src, &last, 0);
  		if (*last != '\0')
  			return 1;
  	}
  	return 0;
  }
  
  static int scsi_scan(struct Scsi_Host *shost, const char *str)
  {
  	char s1[15], s2[15], s3[15], junk;
  	unsigned int channel, id, lun;
  	int res;
  
  	res = sscanf(str, "%10s %10s %10s %c", s1, s2, s3, &junk);
  	if (res != 3)
  		return -EINVAL;
  	if (check_set(&channel, s1))
  		return -EINVAL;
  	if (check_set(&id, s2))
  		return -EINVAL;
  	if (check_set(&lun, s3))
  		return -EINVAL;

  	if (shost->transportt->user_scan)
  		res = shost->transportt->user_scan(shost, channel, id, lun);
  	else
  		res = scsi_scan_host_selected(shost, channel, id, lun, 1);

  	return res;
  }
  
  /*
   * shost_show_function: macro to create an attr function that can be used to
   * show a non-bit field.
   */
  #define shost_show_function(name, field, format_string)			\
  static ssize_t								\

  show_##name (struct device *dev, struct device_attribute *attr, 	\
  	     char *buf)							\

  {									\

  	struct Scsi_Host *shost = class_to_shost(dev);			\

  	return snprintf (buf, 20, format_string, shost->field);		\
  }
  
  /*
   * shost_rd_attr: macro to create a function and attribute variable for a
   * read only field.
   */
  #define shost_rd_attr2(name, field, format_string)			\
  	shost_show_function(name, field, format_string)			\

  static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL);

  
  #define shost_rd_attr(field, format_string) \
  shost_rd_attr2(field, field, format_string)
  
  /*
   * Create the actual show/store functions and data structures.
   */

  static ssize_t
  store_scan(struct device *dev, struct device_attribute *attr,
  	   const char *buf, size_t count)

  {

  	struct Scsi_Host *shost = class_to_shost(dev);

  	int res;
  
  	res = scsi_scan(shost, buf);
  	if (res == 0)
  		res = count;
  	return res;
  };

  static DEVICE_ATTR(scan, S_IWUSR, NULL, store_scan);

  static ssize_t

  store_shost_state(struct device *dev, struct device_attribute *attr,
  		  const char *buf, size_t count)

  {
  	int i;

  	struct Scsi_Host *shost = class_to_shost(dev);

  	enum scsi_host_state state = 0;

  	for (i = 0; i < ARRAY_SIZE(shost_states); i++) {

  		const int len = strlen(shost_states[i].name);
  		if (strncmp(shost_states[i].name, buf, len) == 0 &&
  		   buf[len] == '
  ') {
  			state = shost_states[i].value;
  			break;
  		}
  	}
  	if (!state)
  		return -EINVAL;
  
  	if (scsi_host_set_state(shost, state))
  		return -EINVAL;
  	return count;
  }
  
  static ssize_t

  show_shost_state(struct device *dev, struct device_attribute *attr, char *buf)

  {

  	struct Scsi_Host *shost = class_to_shost(dev);

  	const char *name = scsi_host_state_name(shost->shost_state);
  
  	if (!name)
  		return -EINVAL;
  
  	return snprintf(buf, 20, "%s
  ", name);
  }

  /* DEVICE_ATTR(state) clashes with dev_attr_state for sdev */
  struct device_attribute dev_attr_hstate =
  	__ATTR(state, S_IRUGO | S_IWUSR, show_shost_state, store_shost_state);

  static ssize_t
  show_shost_mode(unsigned int mode, char *buf)
  {
  	ssize_t len = 0;
  
  	if (mode & MODE_INITIATOR)
  		len = sprintf(buf, "%s", "Initiator");
  
  	if (mode & MODE_TARGET)
  		len += sprintf(buf + len, "%s%s", len ? ", " : "", "Target");
  
  	len += sprintf(buf + len, "
  ");
  
  	return len;
  }

  static ssize_t
  show_shost_supported_mode(struct device *dev, struct device_attribute *attr,
  			  char *buf)

  {

  	struct Scsi_Host *shost = class_to_shost(dev);

  	unsigned int supported_mode = shost->hostt->supported_mode;

  	if (supported_mode == MODE_UNKNOWN)
  		/* by default this should be initiator */
  		supported_mode = MODE_INITIATOR;
  
  	return show_shost_mode(supported_mode, buf);

  }

  static DEVICE_ATTR(supported_mode, S_IRUGO | S_IWUSR, show_shost_supported_mode, NULL);

  static ssize_t
  show_shost_active_mode(struct device *dev,
  		       struct device_attribute *attr, char *buf)

  {

  	struct Scsi_Host *shost = class_to_shost(dev);

  
  	if (shost->active_mode == MODE_UNKNOWN)
  		return snprintf(buf, 20, "unknown
  ");
  	else
  		return show_shost_mode(shost->active_mode, buf);
  }

  static DEVICE_ATTR(active_mode, S_IRUGO | S_IWUSR, show_shost_active_mode, NULL);

  static int check_reset_type(char *str)
  {
  	if (strncmp(str, "adapter", 10) == 0)
  		return SCSI_ADAPTER_RESET;
  	else if (strncmp(str, "firmware", 10) == 0)
  		return SCSI_FIRMWARE_RESET;
  	else
  		return 0;
  }
  
  static ssize_t
  store_host_reset(struct device *dev, struct device_attribute *attr,
  		const char *buf, size_t count)
  {
  	struct Scsi_Host *shost = class_to_shost(dev);
  	struct scsi_host_template *sht = shost->hostt;
  	int ret = -EINVAL;
  	char str[10];
  	int type;
  
  	sscanf(buf, "%s", str);
  	type = check_reset_type(str);
  
  	if (!type)
  		goto exit_store_host_reset;
  
  	if (sht->host_reset)
  		ret = sht->host_reset(shost, type);
  
  exit_store_host_reset:
  	if (ret == 0)
  		ret = count;
  	return ret;
  }
  
  static DEVICE_ATTR(host_reset, S_IWUSR, NULL, store_host_reset);

  shost_rd_attr(unique_id, "%u
  ");
  shost_rd_attr(host_busy, "%hu
  ");
  shost_rd_attr(cmd_per_lun, "%hd
  ");

  shost_rd_attr(can_queue, "%hd
  ");

  shost_rd_attr(sg_tablesize, "%hu
  ");

  shost_rd_attr(sg_prot_tablesize, "%hu
  ");

  shost_rd_attr(unchecked_isa_dma, "%d
  ");

  shost_rd_attr(prot_capabilities, "%u
  ");
  shost_rd_attr(prot_guard_type, "%hd
  ");

  shost_rd_attr2(proc_name, hostt->proc_name, "%s
  ");

  static struct attribute *scsi_sysfs_shost_attrs[] = {
  	&dev_attr_unique_id.attr,
  	&dev_attr_host_busy.attr,
  	&dev_attr_cmd_per_lun.attr,
  	&dev_attr_can_queue.attr,
  	&dev_attr_sg_tablesize.attr,

  	&dev_attr_sg_prot_tablesize.attr,

  	&dev_attr_unchecked_isa_dma.attr,
  	&dev_attr_proc_name.attr,
  	&dev_attr_scan.attr,
  	&dev_attr_hstate.attr,
  	&dev_attr_supported_mode.attr,
  	&dev_attr_active_mode.attr,

  	&dev_attr_prot_capabilities.attr,
  	&dev_attr_prot_guard_type.attr,

  	&dev_attr_host_reset.attr,

  	NULL
  };
  
  struct attribute_group scsi_shost_attr_group = {
  	.attrs =	scsi_sysfs_shost_attrs,
  };

  const struct attribute_group *scsi_sysfs_shost_attr_groups[] = {

  	&scsi_shost_attr_group,

  	NULL
  };

  static void scsi_device_cls_release(struct device *class_dev)

  {
  	struct scsi_device *sdev;
  
  	sdev = class_to_sdev(class_dev);
  	put_device(&sdev->sdev_gendev);
  }

  static void scsi_device_dev_release_usercontext(struct work_struct *work)

  {
  	struct scsi_device *sdev;
  	struct device *parent;
  	struct scsi_target *starget;

  	struct list_head *this, *tmp;

  	unsigned long flags;

  	sdev = container_of(work, struct scsi_device, ew.work);
  
  	parent = sdev->sdev_gendev.parent;

  	starget = to_scsi_target(parent);
  
  	spin_lock_irqsave(sdev->host->host_lock, flags);
  	starget->reap_ref++;
  	list_del(&sdev->siblings);
  	list_del(&sdev->same_target_siblings);
  	list_del(&sdev->starved_entry);
  	spin_unlock_irqrestore(sdev->host->host_lock, flags);

  	cancel_work_sync(&sdev->event_work);
  
  	list_for_each_safe(this, tmp, &sdev->event_list) {
  		struct scsi_event *evt;
  
  		evt = list_entry(this, struct scsi_event, node);
  		list_del(&evt->node);
  		kfree(evt);
  	}

  	blk_put_queue(sdev->request_queue);

  	/* NULL queue means the device can't be used */
  	sdev->request_queue = NULL;

  
  	scsi_target_reap(scsi_target(sdev));
  
  	kfree(sdev->inquiry);
  	kfree(sdev);
  
  	if (parent)
  		put_device(parent);
  }

  static void scsi_device_dev_release(struct device *dev)
  {

  	struct scsi_device *sdp = to_scsi_device(dev);

  	execute_in_process_context(scsi_device_dev_release_usercontext,

  				   &sdp->ew);

  }

  static struct class sdev_class = {

  	.name		= "scsi_device",

  	.dev_release	= scsi_device_cls_release,

  };
  
  /* all probing is done in the individual ->probe routines */
  static int scsi_bus_match(struct device *dev, struct device_driver *gendrv)
  {

  	struct scsi_device *sdp;
  
  	if (dev->type != &scsi_dev_type)
  		return 0;
  
  	sdp = to_scsi_device(dev);

  	if (sdp->no_uld_attach)
  		return 0;
  	return (sdp->inq_periph_qual == SCSI_INQ_PQ_CON)? 1: 0;
  }

  static int scsi_bus_uevent(struct device *dev, struct kobj_uevent_env *env)

  {

  	struct scsi_device *sdev;
  
  	if (dev->type != &scsi_dev_type)
  		return 0;
  
  	sdev = to_scsi_device(dev);

  	add_uevent_var(env, "MODALIAS=" SCSI_DEVICE_MODALIAS_FMT, sdev->type);

  	return 0;
  }

  struct bus_type scsi_bus_type = {
          .name		= "scsi",
          .match		= scsi_bus_match,

  	.uevent		= scsi_bus_uevent,

  #ifdef CONFIG_PM

  	.pm		= &scsi_bus_pm_ops,

  #endif

  };

  EXPORT_SYMBOL_GPL(scsi_bus_type);

  
  int scsi_sysfs_register(void)
  {
  	int error;
  
  	error = bus_register(&scsi_bus_type);
  	if (!error) {
  		error = class_register(&sdev_class);
  		if (error)
  			bus_unregister(&scsi_bus_type);
  	}
  
  	return error;
  }
  
  void scsi_sysfs_unregister(void)
  {
  	class_unregister(&sdev_class);
  	bus_unregister(&scsi_bus_type);
  }
  
  /*
   * sdev_show_function: macro to create an attr function that can be used to
   * show a non-bit field.
   */
  #define sdev_show_function(field, format_string)				\
  static ssize_t								\

  sdev_show_##field (struct device *dev, struct device_attribute *attr,	\
  		   char *buf)						\

  {									\
  	struct scsi_device *sdev;					\
  	sdev = to_scsi_device(dev);					\
  	return snprintf (buf, 20, format_string, sdev->field);		\
  }									\
  
  /*
   * sdev_rd_attr: macro to create a function and attribute variable for a
   * read only field.
   */
  #define sdev_rd_attr(field, format_string)				\
  	sdev_show_function(field, format_string)			\
  static DEVICE_ATTR(field, S_IRUGO, sdev_show_##field, NULL);
  
  
  /*

   * sdev_rw_attr: create a function and attribute variable for a

   * read/write field.
   */
  #define sdev_rw_attr(field, format_string)				\
  	sdev_show_function(field, format_string)				\
  									\
  static ssize_t								\

  sdev_store_##field (struct device *dev, struct device_attribute *attr,	\
  		    const char *buf, size_t count)			\

  {									\
  	struct scsi_device *sdev;					\
  	sdev = to_scsi_device(dev);					\

  	sscanf (buf, format_string, &sdev->field);			\

  	return count;							\
  }									\
  static DEVICE_ATTR(field, S_IRUGO | S_IWUSR, sdev_show_##field, sdev_store_##field);
  
  /* Currently we don't export bit fields, but we might in future,
   * so leave this code in */
  #if 0
  /*
   * sdev_rd_attr: create a function and attribute variable for a
   * read/write bit field.
   */
  #define sdev_rw_attr_bit(field)						\
  	sdev_show_function(field, "%d
  ")					\
  									\
  static ssize_t								\

  sdev_store_##field (struct device *dev, struct device_attribute *attr,	\
  		    const char *buf, size_t count)			\

  {									\
  	int ret;							\
  	struct scsi_device *sdev;					\
  	ret = scsi_sdev_check_buf_bit(buf);				\
  	if (ret >= 0)	{						\
  		sdev = to_scsi_device(dev);				\
  		sdev->field = ret;					\
  		ret = count;						\
  	}								\
  	return ret;							\
  }									\
  static DEVICE_ATTR(field, S_IRUGO | S_IWUSR, sdev_show_##field, sdev_store_##field);
  
  /*
   * scsi_sdev_check_buf_bit: return 0 if buf is "0", return 1 if buf is "1",
   * else return -EINVAL.
   */
  static int scsi_sdev_check_buf_bit(const char *buf)
  {
  	if ((buf[1] == '\0') || ((buf[1] == '
  ') && (buf[2] == '\0'))) {
  		if (buf[0] == '1')
  			return 1;
  		else if (buf[0] == '0')
  			return 0;
  		else 
  			return -EINVAL;
  	} else
  		return -EINVAL;
  }
  #endif
  /*
   * Create the actual show/store functions and data structures.
   */
  sdev_rd_attr (device_blocked, "%d
  ");
  sdev_rd_attr (queue_depth, "%d
  ");
  sdev_rd_attr (type, "%d
  ");
  sdev_rd_attr (scsi_level, "%d
  ");
  sdev_rd_attr (vendor, "%.8s
  ");
  sdev_rd_attr (model, "%.16s
  ");
  sdev_rd_attr (rev, "%.4s
  ");

  /*
   * TODO: can we make these symlinks to the block layer ones?
   */

  static ssize_t

  sdev_show_timeout (struct device *dev, struct device_attribute *attr, char *buf)

  {
  	struct scsi_device *sdev;
  	sdev = to_scsi_device(dev);

  	return snprintf(buf, 20, "%d
  ", sdev->request_queue->rq_timeout / HZ);

  }
  
  static ssize_t

  sdev_store_timeout (struct device *dev, struct device_attribute *attr,
  		    const char *buf, size_t count)

  {
  	struct scsi_device *sdev;
  	int timeout;
  	sdev = to_scsi_device(dev);
  	sscanf (buf, "%d
  ", &timeout);

  	blk_queue_rq_timeout(sdev->request_queue, timeout * HZ);

  	return count;
  }
  static DEVICE_ATTR(timeout, S_IRUGO | S_IWUSR, sdev_show_timeout, sdev_store_timeout);
  
  static ssize_t

  store_rescan_field (struct device *dev, struct device_attribute *attr,
  		    const char *buf, size_t count)

  {
  	scsi_rescan_device(dev);
  	return count;
  }
  static DEVICE_ATTR(rescan, S_IWUSR, NULL, store_rescan_field);

  static void sdev_store_delete_callback(struct device *dev)
  {
  	scsi_remove_device(to_scsi_device(dev));
  }

  static ssize_t
  sdev_store_delete(struct device *dev, struct device_attribute *attr,
  		  const char *buf, size_t count)

  {

  	int rc;
  
  	/* An attribute cannot be unregistered by one of its own methods,
  	 * so we have to use this roundabout approach.
  	 */
  	rc = device_schedule_callback(dev, sdev_store_delete_callback);
  	if (rc)
  		count = rc;

  	return count;
  };
  static DEVICE_ATTR(delete, S_IWUSR, NULL, sdev_store_delete);
  
  static ssize_t

  store_state_field(struct device *dev, struct device_attribute *attr,
  		  const char *buf, size_t count)

  {
  	int i;
  	struct scsi_device *sdev = to_scsi_device(dev);
  	enum scsi_device_state state = 0;

  	for (i = 0; i < ARRAY_SIZE(sdev_states); i++) {

  		const int len = strlen(sdev_states[i].name);
  		if (strncmp(sdev_states[i].name, buf, len) == 0 &&
  		   buf[len] == '
  ') {
  			state = sdev_states[i].value;
  			break;
  		}
  	}
  	if (!state)
  		return -EINVAL;
  
  	if (scsi_device_set_state(sdev, state))
  		return -EINVAL;
  	return count;
  }
  
  static ssize_t

  show_state_field(struct device *dev, struct device_attribute *attr, char *buf)

  {
  	struct scsi_device *sdev = to_scsi_device(dev);
  	const char *name = scsi_device_state_name(sdev->sdev_state);
  
  	if (!name)
  		return -EINVAL;
  
  	return snprintf(buf, 20, "%s
  ", name);
  }
  
  static DEVICE_ATTR(state, S_IRUGO | S_IWUSR, show_state_field, store_state_field);
  
  static ssize_t

  show_queue_type_field(struct device *dev, struct device_attribute *attr,
  		      char *buf)

  {
  	struct scsi_device *sdev = to_scsi_device(dev);
  	const char *name = "none";
  
  	if (sdev->ordered_tags)
  		name = "ordered";
  	else if (sdev->simple_tags)
  		name = "simple";
  
  	return snprintf(buf, 20, "%s
  ", name);
  }
  
  static DEVICE_ATTR(queue_type, S_IRUGO, show_queue_type_field, NULL);
  
  static ssize_t

  show_iostat_counterbits(struct device *dev, struct device_attribute *attr, 				char *buf)

  {
  	return snprintf(buf, 20, "%d
  ", (int)sizeof(atomic_t) * 8);
  }
  
  static DEVICE_ATTR(iocounterbits, S_IRUGO, show_iostat_counterbits, NULL);
  
  #define show_sdev_iostat(field)						\
  static ssize_t								\

  show_iostat_##field(struct device *dev, struct device_attribute *attr,	\
  		    char *buf)						\

  {									\
  	struct scsi_device *sdev = to_scsi_device(dev);			\
  	unsigned long long count = atomic_read(&sdev->field);		\
  	return snprintf(buf, 20, "0x%llx
  ", count);			\
  }									\
  static DEVICE_ATTR(field, S_IRUGO, show_iostat_##field, NULL)
  
  show_sdev_iostat(iorequest_cnt);
  show_sdev_iostat(iodone_cnt);
  show_sdev_iostat(ioerr_cnt);

  static ssize_t
  sdev_show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
  {
  	struct scsi_device *sdev;
  	sdev = to_scsi_device(dev);
  	return snprintf (buf, 20, SCSI_DEVICE_MODALIAS_FMT "
  ", sdev->type);
  }
  static DEVICE_ATTR(modalias, S_IRUGO, sdev_show_modalias, NULL);

  #define DECLARE_EVT_SHOW(name, Cap_name)				\
  static ssize_t								\
  sdev_show_evt_##name(struct device *dev, struct device_attribute *attr,	\

  		     char *buf)						\

  {									\
  	struct scsi_device *sdev = to_scsi_device(dev);			\
  	int val = test_bit(SDEV_EVT_##Cap_name, sdev->supported_events);\
  	return snprintf(buf, 20, "%d
  ", val);				\
  }
  
  #define DECLARE_EVT_STORE(name, Cap_name)				\
  static ssize_t								\

  sdev_store_evt_##name(struct device *dev, struct device_attribute *attr,\

  		      const char *buf, size_t count)			\
  {									\
  	struct scsi_device *sdev = to_scsi_device(dev);			\
  	int val = simple_strtoul(buf, NULL, 0);				\
  	if (val == 0)							\
  		clear_bit(SDEV_EVT_##Cap_name, sdev->supported_events);	\
  	else if (val == 1)						\
  		set_bit(SDEV_EVT_##Cap_name, sdev->supported_events);	\
  	else								\
  		return -EINVAL;						\
  	return count;							\
  }
  
  #define DECLARE_EVT(name, Cap_name)					\
  	DECLARE_EVT_SHOW(name, Cap_name)				\
  	DECLARE_EVT_STORE(name, Cap_name)				\
  	static DEVICE_ATTR(evt_##name, S_IRUGO, sdev_show_evt_##name,	\
  			   sdev_store_evt_##name);
  #define REF_EVT(name) &dev_attr_evt_##name.attr
  
  DECLARE_EVT(media_change, MEDIA_CHANGE)

  /* Default template for device attributes.  May NOT be modified */

  static struct attribute *scsi_sdev_attrs[] = {
  	&dev_attr_device_blocked.attr,
  	&dev_attr_type.attr,
  	&dev_attr_scsi_level.attr,
  	&dev_attr_vendor.attr,
  	&dev_attr_model.attr,
  	&dev_attr_rev.attr,
  	&dev_attr_rescan.attr,
  	&dev_attr_delete.attr,
  	&dev_attr_state.attr,
  	&dev_attr_timeout.attr,
  	&dev_attr_iocounterbits.attr,
  	&dev_attr_iorequest_cnt.attr,
  	&dev_attr_iodone_cnt.attr,
  	&dev_attr_ioerr_cnt.attr,
  	&dev_attr_modalias.attr,

  	REF_EVT(media_change),

  	NULL
  };
  
  static struct attribute_group scsi_sdev_attr_group = {
  	.attrs =	scsi_sdev_attrs,
  };

  static const struct attribute_group *scsi_sdev_attr_groups[] = {

  	&scsi_sdev_attr_group,

  	NULL
  };

  static ssize_t
  sdev_store_queue_depth_rw(struct device *dev, struct device_attribute *attr,
  			  const char *buf, size_t count)

  {
  	int depth, retval;
  	struct scsi_device *sdev = to_scsi_device(dev);
  	struct scsi_host_template *sht = sdev->host->hostt;
  
  	if (!sht->change_queue_depth)
  		return -EINVAL;
  
  	depth = simple_strtoul(buf, NULL, 0);
  
  	if (depth < 1)
  		return -EINVAL;

  	retval = sht->change_queue_depth(sdev, depth,
  					 SCSI_QDEPTH_DEFAULT);

  	if (retval < 0)
  		return retval;

  	sdev->max_queue_depth = sdev->queue_depth;

  	return count;
  }
  
  static struct device_attribute sdev_attr_queue_depth_rw =
  	__ATTR(queue_depth, S_IRUGO | S_IWUSR, sdev_show_queue_depth,
  	       sdev_store_queue_depth_rw);

  static ssize_t

  sdev_show_queue_ramp_up_period(struct device *dev,
  			       struct device_attribute *attr,
  			       char *buf)
  {
  	struct scsi_device *sdev;
  	sdev = to_scsi_device(dev);
  	return snprintf(buf, 20, "%u
  ",
  			jiffies_to_msecs(sdev->queue_ramp_up_period));
  }
  
  static ssize_t
  sdev_store_queue_ramp_up_period(struct device *dev,
  				struct device_attribute *attr,
  				const char *buf, size_t count)
  {
  	struct scsi_device *sdev = to_scsi_device(dev);
  	unsigned long period;
  
  	if (strict_strtoul(buf, 10, &period))
  		return -EINVAL;
  
  	sdev->queue_ramp_up_period = msecs_to_jiffies(period);
  	return period;
  }
  
  static struct device_attribute sdev_attr_queue_ramp_up_period =
  	__ATTR(queue_ramp_up_period, S_IRUGO | S_IWUSR,
  	       sdev_show_queue_ramp_up_period,
  	       sdev_store_queue_ramp_up_period);
  
  static ssize_t

  sdev_store_queue_type_rw(struct device *dev, struct device_attribute *attr,
  			 const char *buf, size_t count)

  {
  	struct scsi_device *sdev = to_scsi_device(dev);
  	struct scsi_host_template *sht = sdev->host->hostt;
  	int tag_type = 0, retval;
  	int prev_tag_type = scsi_get_tag_type(sdev);
  
  	if (!sdev->tagged_supported || !sht->change_queue_type)
  		return -EINVAL;
  
  	if (strncmp(buf, "ordered", 7) == 0)
  		tag_type = MSG_ORDERED_TAG;
  	else if (strncmp(buf, "simple", 6) == 0)
  		tag_type = MSG_SIMPLE_TAG;
  	else if (strncmp(buf, "none", 4) != 0)
  		return -EINVAL;
  
  	if (tag_type == prev_tag_type)
  		return count;
  
  	retval = sht->change_queue_type(sdev, tag_type);
  	if (retval < 0)
  		return retval;
  
  	return count;
  }

  static int scsi_target_add(struct scsi_target *starget)
  {
  	int error;
  
  	if (starget->state != STARGET_CREATED)
  		return 0;
  
  	error = device_add(&starget->dev);
  	if (error) {
  		dev_err(&starget->dev, "target device_add failed, error %d
  ", error);

  		return error;
  	}
  	transport_add_device(&starget->dev);
  	starget->state = STARGET_RUNNING;

  	pm_runtime_set_active(&starget->dev);
  	pm_runtime_enable(&starget->dev);
  	device_enable_async_suspend(&starget->dev);

  	return 0;
  }

  static struct device_attribute sdev_attr_queue_type_rw =
  	__ATTR(queue_type, S_IRUGO | S_IWUSR, show_queue_type_field,
  	       sdev_store_queue_type_rw);

  /**
   * scsi_sysfs_add_sdev - add scsi device to sysfs
   * @sdev:	scsi_device to add
   *
   * Return value:
   * 	0 on Success / non-zero on Failure
   **/
  int scsi_sysfs_add_sdev(struct scsi_device *sdev)
  {
  	int error, i;

  	struct request_queue *rq = sdev->request_queue;

  	struct scsi_target *starget = sdev->sdev_target;

  	error = scsi_device_set_state(sdev, SDEV_RUNNING);
  	if (error)

  		return error;

  	error = scsi_target_add(starget);
  	if (error)
  		return error;
  
  	transport_configure_device(&starget->dev);

  	device_enable_async_suspend(&sdev->sdev_gendev);

  	scsi_autopm_get_target(starget);
  	pm_runtime_set_active(&sdev->sdev_gendev);
  	pm_runtime_forbid(&sdev->sdev_gendev);
  	pm_runtime_enable(&sdev->sdev_gendev);
  	scsi_autopm_put_target(starget);
  
  	/* The following call will keep sdev active indefinitely, until
  	 * its driver does a corresponding scsi_autopm_pm_device().  Only
  	 * drivers supporting autosuspend will do this.
  	 */
  	scsi_autopm_get_device(sdev);

  	error = device_add(&sdev->sdev_gendev);
  	if (error) {

  		sdev_printk(KERN_INFO, sdev,
  				"failed to add device: %d
  ", error);

  		return error;

  	}

  	device_enable_async_suspend(&sdev->sdev_dev);

  	error = device_add(&sdev->sdev_dev);

  	if (error) {

  		sdev_printk(KERN_INFO, sdev,
  				"failed to add class device: %d
  ", error);

  		device_del(&sdev->sdev_gendev);

  		return error;

  	}

  	transport_add_device(&sdev->sdev_gendev);
  	sdev->is_visible = 1;

  	/* create queue files, which may be writable, depending on the host */

  	if (sdev->host->hostt->change_queue_depth) {
  		error = device_create_file(&sdev->sdev_gendev,
  					   &sdev_attr_queue_depth_rw);
  		error = device_create_file(&sdev->sdev_gendev,
  					   &sdev_attr_queue_ramp_up_period);
  	}

  	else
  		error = device_create_file(&sdev->sdev_gendev, &dev_attr_queue_depth);

  	if (error)

  		return error;

  	if (sdev->host->hostt->change_queue_type)
  		error = device_create_file(&sdev->sdev_gendev, &sdev_attr_queue_type_rw);
  	else
  		error = device_create_file(&sdev->sdev_gendev, &dev_attr_queue_type);

  	if (error)

  		return error;

  	error = bsg_register_queue(rq, &sdev->sdev_gendev, NULL, NULL);

  
  	if (error)

  		/* we're treating error on bsg register as non-fatal,
  		 * so pretend nothing went wrong */

  		sdev_printk(KERN_INFO, sdev,
  			    "Failed to register bsg queue, errno=%d
  ", error);

  	/* add additional host specific attributes */

  	if (sdev->host->hostt->sdev_attrs) {
  		for (i = 0; sdev->host->hostt->sdev_attrs[i]; i++) {

  			error = device_create_file(&sdev->sdev_gendev,

  					sdev->host->hostt->sdev_attrs[i]);

  			if (error)

  				return error;

  		}
  	}

  	return error;
  }

  void __scsi_remove_device(struct scsi_device *sdev)

  {

  	struct device *dev = &sdev->sdev_gendev;

  	if (sdev->is_visible) {
  		if (scsi_device_set_state(sdev, SDEV_CANCEL) != 0)
  			return;

  		bsg_unregister_queue(sdev->request_queue);
  		device_unregister(&sdev->sdev_dev);
  		transport_remove_device(dev);
  		device_del(dev);
  	} else
  		put_device(&sdev->sdev_dev);

  	scsi_device_set_state(sdev, SDEV_DEL);
  	if (sdev->host->hostt->slave_destroy)
  		sdev->host->hostt->slave_destroy(sdev);

  	transport_destroy_device(dev);

  
  	/* cause the request function to reject all I/O requests */
  	sdev->request_queue->queuedata = NULL;
  
  	/* Freeing the queue signals to block that we're done */
  	scsi_free_queue(sdev->request_queue);

  	put_device(dev);

  }
  
  /**
   * scsi_remove_device - unregister a device from the scsi bus
   * @sdev:	scsi_device to unregister
   **/
  void scsi_remove_device(struct scsi_device *sdev)
  {

  	struct Scsi_Host *shost = sdev->host;

  	mutex_lock(&shost->scan_mutex);

  	__scsi_remove_device(sdev);

  	mutex_unlock(&shost->scan_mutex);

  }
  EXPORT_SYMBOL(scsi_remove_device);

  static void __scsi_remove_target(struct scsi_target *starget)

  {
  	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
  	unsigned long flags;

  	struct scsi_device *sdev;

  
  	spin_lock_irqsave(shost->host_lock, flags);
  	starget->reap_ref++;

   restart:
  	list_for_each_entry(sdev, &shost->__devices, siblings) {

  		if (sdev->channel != starget->channel ||

  		    sdev->id != starget->id ||

  		    scsi_device_get(sdev))

  			continue;
  		spin_unlock_irqrestore(shost->host_lock, flags);
  		scsi_remove_device(sdev);

  		scsi_device_put(sdev);

  		spin_lock_irqsave(shost->host_lock, flags);

  		goto restart;

  	}
  	spin_unlock_irqrestore(shost->host_lock, flags);
  	scsi_target_reap(starget);
  }

  static int __remove_child (struct device * dev, void * data)
  {
  	if (scsi_is_target_device(dev))
  		__scsi_remove_target(to_scsi_target(dev));
  	return 0;
  }

  /**
   * scsi_remove_target - try to remove a target and all its devices
   * @dev: generic starget or parent of generic stargets to be removed
   *
   * Note: This is slightly racy.  It is possible that if the user
   * requests the addition of another device then the target won't be
   * removed.
   */
  void scsi_remove_target(struct device *dev)
  {

  	if (scsi_is_target_device(dev)) {
  		__scsi_remove_target(to_scsi_target(dev));
  		return;
  	}

  	get_device(dev);

  	device_for_each_child(dev, NULL, __remove_child);

  	put_device(dev);

  }
  EXPORT_SYMBOL(scsi_remove_target);
  
  int scsi_register_driver(struct device_driver *drv)
  {
  	drv->bus = &scsi_bus_type;
  
  	return driver_register(drv);
  }
  EXPORT_SYMBOL(scsi_register_driver);
  
  int scsi_register_interface(struct class_interface *intf)
  {
  	intf->class = &sdev_class;
  
  	return class_interface_register(intf);
  }
  EXPORT_SYMBOL(scsi_register_interface);

  /**
   * scsi_sysfs_add_host - add scsi host to subsystem
   * @shost:     scsi host struct to add to subsystem

   **/
  int scsi_sysfs_add_host(struct Scsi_Host *shost)
  {
  	int error, i;

  	/* add host specific attributes */

  	if (shost->hostt->shost_attrs) {
  		for (i = 0; shost->hostt->shost_attrs[i]; i++) {

  			error = device_create_file(&shost->shost_dev,

  					shost->hostt->shost_attrs[i]);

  			if (error)
  				return error;
  		}
  	}
  
  	transport_register_device(&shost->shost_gendev);

  	transport_configure_device(&shost->shost_gendev);

  	return 0;
  }

  static struct device_type scsi_dev_type = {
  	.name =		"scsi_device",
  	.release =	scsi_device_dev_release,
  	.groups =	scsi_sdev_attr_groups,
  };

  void scsi_sysfs_device_initialize(struct scsi_device *sdev)
  {
  	unsigned long flags;
  	struct Scsi_Host *shost = sdev->host;
  	struct scsi_target  *starget = sdev->sdev_target;
  
  	device_initialize(&sdev->sdev_gendev);
  	sdev->sdev_gendev.bus = &scsi_bus_type;

  	sdev->sdev_gendev.type = &scsi_dev_type;

  	dev_set_name(&sdev->sdev_gendev, "%d:%d:%d:%d",
  		     sdev->host->host_no, sdev->channel, sdev->id, sdev->lun);

  	device_initialize(&sdev->sdev_dev);

  	sdev->sdev_dev.parent = get_device(&sdev->sdev_gendev);

  	sdev->sdev_dev.class = &sdev_class;

  	dev_set_name(&sdev->sdev_dev, "%d:%d:%d:%d",
  		     sdev->host->host_no, sdev->channel, sdev->id, sdev->lun);

  	sdev->scsi_level = starget->scsi_level;

  	transport_setup_device(&sdev->sdev_gendev);
  	spin_lock_irqsave(shost->host_lock, flags);
  	list_add_tail(&sdev->same_target_siblings, &starget->devices);
  	list_add_tail(&sdev->siblings, &shost->__devices);
  	spin_unlock_irqrestore(shost->host_lock, flags);
  }
  
  int scsi_is_sdev_device(const struct device *dev)
  {

  	return dev->type == &scsi_dev_type;

  }
  EXPORT_SYMBOL(scsi_is_sdev_device);
  
  /* A blank transport template that is used in drivers that don't
   * yet implement Transport Attributes */
  struct scsi_transport_template blank_transport_template = { { { {NULL, }, }, }, };