raid_class.c

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/*
 * raid_class.c - implementation of a simple raid visualisation class
 *
 * Copyright (c) 2005 - James Bottomley <[email protected]>
 *
 * This file is licensed under GPLv2
 *
 * This class is designed to allow raid attributes to be visualised and
 * manipulated in a form independent of the underlying raid.  Ultimately this
 * should work for both hardware and software raids.
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/raid_class.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>

#define RAID_NUM_ATTRS  3

struct raid_internal {
    struct raid_template r;
    struct raid_function_template *f;
    /* The actual attributes */
    struct device_attribute private_attrs[RAID_NUM_ATTRS];
    /* The array of null terminated pointers to attributes 
     * needed by scsi_sysfs.c */
    struct device_attribute *attrs[RAID_NUM_ATTRS + 1];
};

struct raid_component {
    struct list_head node;
    struct device dev;
    int num;
};

#define to_raid_internal(tmpl)  container_of(tmpl, struct raid_internal, r)

#define tc_to_raid_internal(tcont) ({                   \
    struct raid_template *r =                   \
        container_of(tcont, struct raid_template, raid_attrs);  \
    to_raid_internal(r);                        \
})

#define ac_to_raid_internal(acont) ({                   \
    struct transport_container *tc =                \
        container_of(acont, struct transport_container, ac);    \
    tc_to_raid_internal(tc);                    \
})

#define device_to_raid_internal(dev) ({             \
    struct attribute_container *ac =                \
        attribute_container_classdev_to_container(dev); \
    ac_to_raid_internal(ac);                    \
})
    

static int raid_match(struct attribute_container *cont, struct device *dev)
{
    /* We have to look for every subsystem that could house
     * emulated RAID devices, so start with SCSI */
    struct raid_internal *i = ac_to_raid_internal(cont);

#if defined(CONFIG_SCSI) || defined(CONFIG_SCSI_MODULE)
    if (scsi_is_sdev_device(dev)) {
        struct scsi_device *sdev = to_scsi_device(dev);

        if (i->f->cookie != sdev->host->hostt)
            return 0;

        return i->f->is_raid(dev);
    }
#endif
    /* FIXME: look at other subsystems too */
    return 0;
}

static int raid_setup(struct transport_container *tc, struct device *dev,
               struct device *cdev)
{
    struct raid_data *rd;

    BUG_ON(dev_get_drvdata(cdev));

    rd = kzalloc(sizeof(*rd), GFP_KERNEL);
    if (!rd)
        return -ENOMEM;

    INIT_LIST_HEAD(&rd->component_list);
    dev_set_drvdata(cdev, rd);
        
    return 0;
}

static int raid_remove(struct transport_container *tc, struct device *dev,
               struct device *cdev)
{
    struct raid_data *rd = dev_get_drvdata(cdev);
    struct raid_component *rc, *next;
    dev_printk(KERN_ERR, dev, "RAID REMOVE\n");
    dev_set_drvdata(cdev, NULL);
    list_for_each_entry_safe(rc, next, &rd->component_list, node) {
        list_del(&rc->node);
        dev_printk(KERN_ERR, rc->dev.parent, "RAID COMPONENT REMOVE\n");
        device_unregister(&rc->dev);
    }
    dev_printk(KERN_ERR, dev, "RAID REMOVE DONE\n");
    kfree(rd);
    return 0;
}

static DECLARE_TRANSPORT_CLASS(raid_class,
                   "raid_devices",
                   raid_setup,
                   raid_remove,
                   NULL);

static const struct {
    enum raid_state value;
    char        *name;
} raid_states[] = {
    { RAID_STATE_UNKNOWN, "unknown" },
    { RAID_STATE_ACTIVE, "active" },
    { RAID_STATE_DEGRADED, "degraded" },
    { RAID_STATE_RESYNCING, "resyncing" },
    { RAID_STATE_OFFLINE, "offline" },
};

static const char *raid_state_name(enum raid_state state)
{
    int i;
    char *name = NULL;

    for (i = 0; i < ARRAY_SIZE(raid_states); i++) {
        if (raid_states[i].value == state) {
            name = raid_states[i].name;
            break;
        }
    }
    return name;
}

static struct {
    enum raid_level value;
    char *name;
} raid_levels[] = {
    { RAID_LEVEL_UNKNOWN, "unknown" },
    { RAID_LEVEL_LINEAR, "linear" },
    { RAID_LEVEL_0, "raid0" },
    { RAID_LEVEL_1, "raid1" },
    { RAID_LEVEL_10, "raid10" },
    { RAID_LEVEL_1E, "raid1e" },
    { RAID_LEVEL_3, "raid3" },
    { RAID_LEVEL_4, "raid4" },
    { RAID_LEVEL_5, "raid5" },
    { RAID_LEVEL_50, "raid50" },
    { RAID_LEVEL_6, "raid6" },
};

static const char *raid_level_name(enum raid_level level)
{
    int i;
    char *name = NULL;

    for (i = 0; i < ARRAY_SIZE(raid_levels); i++) {
        if (raid_levels[i].value == level) {
            name = raid_levels[i].name;
            break;
        }
    }
    return name;
}

#define raid_attr_show_internal(attr, fmt, var, code)           \
static ssize_t raid_show_##attr(struct device *dev,             \
                struct device_attribute *attr,      \
                char *buf)              \
{                                   \
    struct raid_data *rd = dev_get_drvdata(dev);            \
    code                                \
    return snprintf(buf, 20, #fmt "\n", var);           \
}

#define raid_attr_ro_states(attr, states, code)             \
raid_attr_show_internal(attr, %s, name,                 \
    const char *name;                       \
    code                                \
    name = raid_##states##_name(rd->attr);              \
)                                   \
static DEVICE_ATTR(attr, S_IRUGO, raid_show_##attr, NULL)


#define raid_attr_ro_internal(attr, code)               \
raid_attr_show_internal(attr, %d, rd->attr, code)           \
static DEVICE_ATTR(attr, S_IRUGO, raid_show_##attr, NULL)

#define ATTR_CODE(attr)                         \
    struct raid_internal *i = device_to_raid_internal(dev);     \
    if (i->f->get_##attr)                       \
        i->f->get_##attr(dev->parent);

#define raid_attr_ro(attr)  raid_attr_ro_internal(attr, )
#define raid_attr_ro_fn(attr)   raid_attr_ro_internal(attr, ATTR_CODE(attr))
#define raid_attr_ro_state(attr)    raid_attr_ro_states(attr, attr, )
#define raid_attr_ro_state_fn(attr) raid_attr_ro_states(attr, attr, ATTR_CODE(attr))


raid_attr_ro_state(level);
raid_attr_ro_fn(resync);
raid_attr_ro_state_fn(state);

static void raid_component_release(struct device *dev)
{
    struct raid_component *rc =
        container_of(dev, struct raid_component, dev);
    dev_printk(KERN_ERR, rc->dev.parent, "COMPONENT RELEASE\n");
    put_device(rc->dev.parent);
    kfree(rc);
}

int raid_component_add(struct raid_template *r,struct device *raid_dev,
               struct device *component_dev)
{
    struct device *cdev =
        attribute_container_find_class_device(&r->raid_attrs.ac,
                              raid_dev);
    struct raid_component *rc;
    struct raid_data *rd = dev_get_drvdata(cdev);
    int err;

    rc = kzalloc(sizeof(*rc), GFP_KERNEL);
    if (!rc)
        return -ENOMEM;

    INIT_LIST_HEAD(&rc->node);
    device_initialize(&rc->dev);
    rc->dev.release = raid_component_release;
    rc->dev.parent = get_device(component_dev);
    rc->num = rd->component_count++;

    dev_set_name(&rc->dev, "component-%d", rc->num);
    list_add_tail(&rc->node, &rd->component_list);
    rc->dev.class = &raid_class.class;
    err = device_add(&rc->dev);
    if (err)
        goto err_out;

    return 0;

err_out:
    list_del(&rc->node);
    rd->component_count--;
    put_device(component_dev);
    kfree(rc);
    return err;
}
EXPORT_SYMBOL(raid_component_add);

struct raid_template *
raid_class_attach(struct raid_function_template *ft)
{
    struct raid_internal *i = kzalloc(sizeof(struct raid_internal),
                      GFP_KERNEL);
    int count = 0;

    if (unlikely(!i))
        return NULL;

    i->f = ft;

    i->r.raid_attrs.ac.class = &raid_class.class;
    i->r.raid_attrs.ac.match = raid_match;
    i->r.raid_attrs.ac.attrs = &i->attrs[0];

    attribute_container_register(&i->r.raid_attrs.ac);

    i->attrs[count++] = &dev_attr_level;
    i->attrs[count++] = &dev_attr_resync;
    i->attrs[count++] = &dev_attr_state;

    i->attrs[count] = NULL;
    BUG_ON(count > RAID_NUM_ATTRS);

    return &i->r;
}
EXPORT_SYMBOL(raid_class_attach);

void
raid_class_release(struct raid_template *r)
{
    struct raid_internal *i = to_raid_internal(r);

    BUG_ON(attribute_container_unregister(&i->r.raid_attrs.ac));

    kfree(i);
}
EXPORT_SYMBOL(raid_class_release);

static __init int raid_init(void)
{
    return transport_class_register(&raid_class);
}

static __exit void raid_exit(void)
{
    transport_class_unregister(&raid_class);
}

MODULE_AUTHOR("James Bottomley");
MODULE_DESCRIPTION("RAID device class");
MODULE_LICENSE("GPL");

module_init(raid_init);
module_exit(raid_exit);