linux/drivers/scsi/raid_class.c
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   1/*
   2 * raid_class.c - implementation of a simple raid visualisation class
   3 *
   4 * Copyright (c) 2005 - James Bottomley <James.Bottomley@steeleye.com>
   5 *
   6 * This file is licensed under GPLv2
   7 *
   8 * This class is designed to allow raid attributes to be visualised and
   9 * manipulated in a form independent of the underlying raid.  Ultimately this
  10 * should work for both hardware and software raids.
  11 */
  12#include <linux/init.h>
  13#include <linux/module.h>
  14#include <linux/list.h>
  15#include <linux/slab.h>
  16#include <linux/string.h>
  17#include <linux/raid_class.h>
  18#include <scsi/scsi_device.h>
  19#include <scsi/scsi_host.h>
  20
  21#define RAID_NUM_ATTRS  3
  22
  23struct raid_internal {
  24        struct raid_template r;
  25        struct raid_function_template *f;
  26        /* The actual attributes */
  27        struct device_attribute private_attrs[RAID_NUM_ATTRS];
  28        /* The array of null terminated pointers to attributes 
  29         * needed by scsi_sysfs.c */
  30        struct device_attribute *attrs[RAID_NUM_ATTRS + 1];
  31};
  32
  33struct raid_component {
  34        struct list_head node;
  35        struct device dev;
  36        int num;
  37};
  38
  39#define to_raid_internal(tmpl)  container_of(tmpl, struct raid_internal, r)
  40
  41#define tc_to_raid_internal(tcont) ({                                   \
  42        struct raid_template *r =                                       \
  43                container_of(tcont, struct raid_template, raid_attrs);  \
  44        to_raid_internal(r);                                            \
  45})
  46
  47#define ac_to_raid_internal(acont) ({                                   \
  48        struct transport_container *tc =                                \
  49                container_of(acont, struct transport_container, ac);    \
  50        tc_to_raid_internal(tc);                                        \
  51})
  52
  53#define device_to_raid_internal(dev) ({                         \
  54        struct attribute_container *ac =                                \
  55                attribute_container_classdev_to_container(dev); \
  56        ac_to_raid_internal(ac);                                        \
  57})
  58        
  59
  60static int raid_match(struct attribute_container *cont, struct device *dev)
  61{
  62        /* We have to look for every subsystem that could house
  63         * emulated RAID devices, so start with SCSI */
  64        struct raid_internal *i = ac_to_raid_internal(cont);
  65
  66#if defined(CONFIG_SCSI) || defined(CONFIG_SCSI_MODULE)
  67        if (scsi_is_sdev_device(dev)) {
  68                struct scsi_device *sdev = to_scsi_device(dev);
  69
  70                if (i->f->cookie != sdev->host->hostt)
  71                        return 0;
  72
  73                return i->f->is_raid(dev);
  74        }
  75#endif
  76        /* FIXME: look at other subsystems too */
  77        return 0;
  78}
  79
  80static int raid_setup(struct transport_container *tc, struct device *dev,
  81                       struct device *cdev)
  82{
  83        struct raid_data *rd;
  84
  85        BUG_ON(dev_get_drvdata(cdev));
  86
  87        rd = kzalloc(sizeof(*rd), GFP_KERNEL);
  88        if (!rd)
  89                return -ENOMEM;
  90
  91        INIT_LIST_HEAD(&rd->component_list);
  92        dev_set_drvdata(cdev, rd);
  93                
  94        return 0;
  95}
  96
  97static int raid_remove(struct transport_container *tc, struct device *dev,
  98                       struct device *cdev)
  99{
 100        struct raid_data *rd = dev_get_drvdata(cdev);
 101        struct raid_component *rc, *next;
 102        dev_printk(KERN_ERR, dev, "RAID REMOVE\n");
 103        dev_set_drvdata(cdev, NULL);
 104        list_for_each_entry_safe(rc, next, &rd->component_list, node) {
 105                list_del(&rc->node);
 106                dev_printk(KERN_ERR, rc->dev.parent, "RAID COMPONENT REMOVE\n");
 107                device_unregister(&rc->dev);
 108        }
 109        dev_printk(KERN_ERR, dev, "RAID REMOVE DONE\n");
 110        kfree(rd);
 111        return 0;
 112}
 113
 114static DECLARE_TRANSPORT_CLASS(raid_class,
 115                               "raid_devices",
 116                               raid_setup,
 117                               raid_remove,
 118                               NULL);
 119
 120static const struct {
 121        enum raid_state value;
 122        char            *name;
 123} raid_states[] = {
 124        { RAID_STATE_UNKNOWN, "unknown" },
 125        { RAID_STATE_ACTIVE, "active" },
 126        { RAID_STATE_DEGRADED, "degraded" },
 127        { RAID_STATE_RESYNCING, "resyncing" },
 128        { RAID_STATE_OFFLINE, "offline" },
 129};
 130
 131static const char *raid_state_name(enum raid_state state)
 132{
 133        int i;
 134        char *name = NULL;
 135
 136        for (i = 0; i < ARRAY_SIZE(raid_states); i++) {
 137                if (raid_states[i].value == state) {
 138                        name = raid_states[i].name;
 139                        break;
 140                }
 141        }
 142        return name;
 143}
 144
 145static struct {
 146        enum raid_level value;
 147        char *name;
 148} raid_levels[] = {
 149        { RAID_LEVEL_UNKNOWN, "unknown" },
 150        { RAID_LEVEL_LINEAR, "linear" },
 151        { RAID_LEVEL_0, "raid0" },
 152        { RAID_LEVEL_1, "raid1" },
 153        { RAID_LEVEL_10, "raid10" },
 154        { RAID_LEVEL_1E, "raid1e" },
 155        { RAID_LEVEL_3, "raid3" },
 156        { RAID_LEVEL_4, "raid4" },
 157        { RAID_LEVEL_5, "raid5" },
 158        { RAID_LEVEL_50, "raid50" },
 159        { RAID_LEVEL_6, "raid6" },
 160};
 161
 162static const char *raid_level_name(enum raid_level level)
 163{
 164        int i;
 165        char *name = NULL;
 166
 167        for (i = 0; i < ARRAY_SIZE(raid_levels); i++) {
 168                if (raid_levels[i].value == level) {
 169                        name = raid_levels[i].name;
 170                        break;
 171                }
 172        }
 173        return name;
 174}
 175
 176#define raid_attr_show_internal(attr, fmt, var, code)                   \
 177static ssize_t raid_show_##attr(struct device *dev,                     \
 178                                struct device_attribute *attr,          \
 179                                char *buf)                              \
 180{                                                                       \
 181        struct raid_data *rd = dev_get_drvdata(dev);                    \
 182        code                                                            \
 183        return snprintf(buf, 20, #fmt "\n", var);                       \
 184}
 185
 186#define raid_attr_ro_states(attr, states, code)                         \
 187raid_attr_show_internal(attr, %s, name,                                 \
 188        const char *name;                                               \
 189        code                                                            \
 190        name = raid_##states##_name(rd->attr);                          \
 191)                                                                       \
 192static DEVICE_ATTR(attr, S_IRUGO, raid_show_##attr, NULL)
 193
 194
 195#define raid_attr_ro_internal(attr, code)                               \
 196raid_attr_show_internal(attr, %d, rd->attr, code)                       \
 197static DEVICE_ATTR(attr, S_IRUGO, raid_show_##attr, NULL)
 198
 199#define ATTR_CODE(attr)                                                 \
 200        struct raid_internal *i = device_to_raid_internal(dev);         \
 201        if (i->f->get_##attr)                                           \
 202                i->f->get_##attr(dev->parent);
 203
 204#define raid_attr_ro(attr)      raid_attr_ro_internal(attr, )
 205#define raid_attr_ro_fn(attr)   raid_attr_ro_internal(attr, ATTR_CODE(attr))
 206#define raid_attr_ro_state(attr)        raid_attr_ro_states(attr, attr, )
 207#define raid_attr_ro_state_fn(attr)     raid_attr_ro_states(attr, attr, ATTR_CODE(attr))
 208
 209
 210raid_attr_ro_state(level);
 211raid_attr_ro_fn(resync);
 212raid_attr_ro_state_fn(state);
 213
 214static void raid_component_release(struct device *dev)
 215{
 216        struct raid_component *rc =
 217                container_of(dev, struct raid_component, dev);
 218        dev_printk(KERN_ERR, rc->dev.parent, "COMPONENT RELEASE\n");
 219        put_device(rc->dev.parent);
 220        kfree(rc);
 221}
 222
 223int raid_component_add(struct raid_template *r,struct device *raid_dev,
 224                       struct device *component_dev)
 225{
 226        struct device *cdev =
 227                attribute_container_find_class_device(&r->raid_attrs.ac,
 228                                                      raid_dev);
 229        struct raid_component *rc;
 230        struct raid_data *rd = dev_get_drvdata(cdev);
 231        int err;
 232
 233        rc = kzalloc(sizeof(*rc), GFP_KERNEL);
 234        if (!rc)
 235                return -ENOMEM;
 236
 237        INIT_LIST_HEAD(&rc->node);
 238        device_initialize(&rc->dev);
 239        rc->dev.release = raid_component_release;
 240        rc->dev.parent = get_device(component_dev);
 241        rc->num = rd->component_count++;
 242
 243        dev_set_name(&rc->dev, "component-%d", rc->num);
 244        list_add_tail(&rc->node, &rd->component_list);
 245        rc->dev.class = &raid_class.class;
 246        err = device_add(&rc->dev);
 247        if (err)
 248                goto err_out;
 249
 250        return 0;
 251
 252err_out:
 253        list_del(&rc->node);
 254        rd->component_count--;
 255        put_device(component_dev);
 256        kfree(rc);
 257        return err;
 258}
 259EXPORT_SYMBOL(raid_component_add);
 260
 261struct raid_template *
 262raid_class_attach(struct raid_function_template *ft)
 263{
 264        struct raid_internal *i = kzalloc(sizeof(struct raid_internal),
 265                                          GFP_KERNEL);
 266        int count = 0;
 267
 268        if (unlikely(!i))
 269                return NULL;
 270
 271        i->f = ft;
 272
 273        i->r.raid_attrs.ac.class = &raid_class.class;
 274        i->r.raid_attrs.ac.match = raid_match;
 275        i->r.raid_attrs.ac.attrs = &i->attrs[0];
 276
 277        attribute_container_register(&i->r.raid_attrs.ac);
 278
 279        i->attrs[count++] = &dev_attr_level;
 280        i->attrs[count++] = &dev_attr_resync;
 281        i->attrs[count++] = &dev_attr_state;
 282
 283        i->attrs[count] = NULL;
 284        BUG_ON(count > RAID_NUM_ATTRS);
 285
 286        return &i->r;
 287}
 288EXPORT_SYMBOL(raid_class_attach);
 289
 290void
 291raid_class_release(struct raid_template *r)
 292{
 293        struct raid_internal *i = to_raid_internal(r);
 294
 295        BUG_ON(attribute_container_unregister(&i->r.raid_attrs.ac));
 296
 297        kfree(i);
 298}
 299EXPORT_SYMBOL(raid_class_release);
 300
 301static __init int raid_init(void)
 302{
 303        return transport_class_register(&raid_class);
 304}
 305
 306static __exit void raid_exit(void)
 307{
 308        transport_class_unregister(&raid_class);
 309}
 310
 311MODULE_AUTHOR("James Bottomley");
 312MODULE_DESCRIPTION("RAID device class");
 313MODULE_LICENSE("GPL");
 314
 315module_init(raid_init);
 316module_exit(raid_exit);
 317
 318
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