[mirror_ubuntu-bionic-kernel.git] / drivers / scsi / scsi_sysfs.c

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

#include <linux/module.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/device.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" },
};

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] == '\n') {
                        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\n", 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, "\n");

        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\n");
        else
                return show_shost_mode(shost->active_mode, buf);
}

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

shost_rd_attr(unique_id, "%u\n");
shost_rd_attr(host_busy, "%hu\n");
shost_rd_attr(cmd_per_lun, "%hd\n");
shost_rd_attr(can_queue, "%hd\n");
shost_rd_attr(sg_tablesize, "%hu\n");
shost_rd_attr(unchecked_isa_dma, "%d\n");
shost_rd_attr2(proc_name, hostt->proc_name, "%s\n");

static struct device_attribute *scsi_sysfs_shost_attrs[] = {
        &dev_attr_unique_id,
        &dev_attr_host_busy,
        &dev_attr_cmd_per_lun,
        &dev_attr_can_queue,
        &dev_attr_sg_tablesize,
        &dev_attr_unchecked_isa_dma,
        &dev_attr_proc_name,
        &dev_attr_scan,
        &dev_attr_hstate,
        &dev_attr_supported_mode,
        &dev_attr_active_mode,
        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);
        }

        if (sdev->request_queue) {
                sdev->request_queue->queuedata = NULL;
                /* user context needed to free queue */
                scsi_free_queue(sdev->request_queue);
                /* temporary expedient, try to catch use of queue lock
                 * after free of sdev */
                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 = to_scsi_device(dev);

        add_uevent_var(env, "MODALIAS=" SCSI_DEVICE_MODALIAS_FMT, sdev->type);
        return 0;
}

static int scsi_bus_suspend(struct device * dev, pm_message_t state)
{
        struct device_driver *drv;
        struct scsi_device *sdev;
        int err;

        if (dev->type != &scsi_dev_type)
                return 0;

        drv = dev->driver;
        sdev = to_scsi_device(dev);

        err = scsi_device_quiesce(sdev);
        if (err)
                return err;

        if (drv && drv->suspend) {
                err = drv->suspend(dev, state);
                if (err)
                        return err;
        }

        return 0;
}

static int scsi_bus_resume(struct device * dev)
{
        struct device_driver *drv;
        struct scsi_device *sdev;
        int err = 0;

        if (dev->type != &scsi_dev_type)
                return 0;

        drv = dev->driver;
        sdev = to_scsi_device(dev);

        if (drv && drv->resume)
                err = drv->resume(dev);

        scsi_device_resume(sdev);

        return err;
}

static int scsi_bus_remove(struct device *dev)
{
        struct device_driver *drv = dev->driver;
        struct scsi_device *sdev = to_scsi_device(dev);
        int err = 0;

        /* reset the prep_fn back to the default since the
         * driver may have altered it and it's being removed */
        blk_queue_prep_rq(sdev->request_queue, scsi_prep_fn);

        if (drv && drv->remove)
                err = drv->remove(dev);

        return 0;
}

struct bus_type scsi_bus_type = {
        .name           = "scsi",
        .match          = scsi_bus_match,
        .uevent         = scsi_bus_uevent,
        .suspend        = scsi_bus_suspend,
        .resume         = scsi_bus_resume,
        .remove         = scsi_bus_remove,
};

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_rd_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);                                     \
        snscanf (buf, 20, 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\n")                                       \
                                                                        \
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] == '\n') && (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\n");
sdev_rd_attr (queue_depth, "%d\n");
sdev_rd_attr (type, "%d\n");
sdev_rd_attr (scsi_level, "%d\n");
sdev_rd_attr (vendor, "%.8s\n");
sdev_rd_attr (model, "%.16s\n");
sdev_rd_attr (rev, "%.4s\n");

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\n", sdev->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\n", &timeout);
        sdev->timeout = 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] == '\n') {
                        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\n", 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\n", 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\n", (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\n", 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 "\n", 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\n", 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 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);
        if (retval < 0)
                return retval;

        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_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 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;

        if ((error = scsi_device_set_state(sdev, SDEV_RUNNING)) != 0)
                return error;

        error = device_add(&sdev->sdev_gendev);
        if (error) {
                put_device(sdev->sdev_gendev.parent);
                printk(KERN_INFO "error 1\n");
                return error;
        }
        error = device_add(&sdev->sdev_dev);
        if (error) {
                printk(KERN_INFO "error 2\n");
                goto clean_device;
        }

        /* take a reference for the sdev_dev; this is
         * released by the sdev_class .release */
        get_device(&sdev->sdev_gendev);

        /* 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);
        else
                error = device_create_file(&sdev->sdev_gendev, &dev_attr_queue_depth);
        if (error) {
                __scsi_remove_device(sdev);
                goto out;
        }
        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) {
                __scsi_remove_device(sdev);
                goto out;
        }

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

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

        /* we're treating error on bsg register as non-fatal, so pretend
         * nothing went wrong */
        error = 0;

        /* 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) {
                                __scsi_remove_device(sdev);
                                goto out;
                        }
                }
        }

        transport_add_device(&sdev->sdev_gendev);
 out:
        return error;

 clean_device:
        scsi_device_set_state(sdev, SDEV_CANCEL);

        device_del(&sdev->sdev_gendev);
        transport_destroy_device(&sdev->sdev_gendev);
        put_device(&sdev->sdev_gendev);

        return error;
}

void __scsi_remove_device(struct scsi_device *sdev)
{
        struct device *dev = &sdev->sdev_gendev;

        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);
        scsi_device_set_state(sdev, SDEV_DEL);
        if (sdev->host->hostt->slave_destroy)
                sdev->host->hostt->slave_destroy(sdev);
        transport_destroy_device(dev);
        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 ||
                    sdev->sdev_state == SDEV_DEL)
                        continue;
                spin_unlock_irqrestore(shost->host_lock, flags);
                scsi_remove_device(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)
{
        struct device *rdev;

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

        rdev = get_device(dev);
        device_for_each_child(dev, NULL, __remove_child);
        put_device(rdev);
}
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);


static struct device_attribute *class_attr_overridden(
                struct device_attribute **attrs,
                struct device_attribute *attr)
{
        int i;

        if (!attrs)
                return NULL;
        for (i = 0; attrs[i]; i++)
                if (!strcmp(attrs[i]->attr.name, attr->attr.name))
                        return attrs[i];
        return NULL;
}

static int class_attr_add(struct device *classdev,
                struct device_attribute *attr)
{
        struct device_attribute *base_attr;

        /*
         * Spare the caller from having to copy things it's not interested in.
         */
        base_attr = class_attr_overridden(scsi_sysfs_shost_attrs, attr);
        if (base_attr) {
                /* extend permissions */
                attr->attr.mode |= base_attr->attr.mode;

                /* override null show/store with default */
                if (!attr->show)
                        attr->show = base_attr->show;
                if (!attr->store)
                        attr->store = base_attr->store;
        }

        return device_create_file(classdev, attr);
}

/**
 * scsi_sysfs_add_host - add scsi host to subsystem
 * @shost:     scsi host struct to add to subsystem
 * @dev:       parent struct device pointer
 **/
int scsi_sysfs_add_host(struct Scsi_Host *shost)
{
        int error, i;

        if (shost->hostt->shost_attrs) {
                for (i = 0; shost->hostt->shost_attrs[i]; i++) {
                        error = class_attr_add(&shost->shost_dev,
                                        shost->hostt->shost_attrs[i]);
                        if (error)
                                return error;
                }
        }

        for (i = 0; scsi_sysfs_shost_attrs[i]; i++) {
                if (!class_attr_overridden(shost->hostt->shost_attrs,
                                        scsi_sysfs_shost_attrs[i])) {
                        error = device_create_file(&shost->shost_dev,
                                        scsi_sysfs_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;
        sprintf(sdev->sdev_gendev.bus_id,"%d:%d:%d:%d",
                sdev->host->host_no, sdev->channel, sdev->id,
                sdev->lun);
        
        device_initialize(&sdev->sdev_dev);
        sdev->sdev_dev.parent = &sdev->sdev_gendev;
        sdev->sdev_dev.class = &sdev_class;
        snprintf(sdev->sdev_dev.bus_id, BUS_ID_SIZE,
                 "%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, }, }, }, };