drivers/scsi/raid_class.c

   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
  23 struct 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
  33 struct 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
  60 static 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
  80 static 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
  97 static 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
 114 static DECLARE_TRANSPORT_CLASS(raid_class,
 115                                "raid_devices",
 116                                raid_setup,
 117                                raid_remove,
 118                                NULL);
 119
 120 static 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
 131 static 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
 145 static 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
 162 static 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)                   \
 177 static 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)                         \
 187 raid_attr_show_internal(attr, %s, name,                                 \
 188         const char *name;                                               \
 189         code                                                            \
 190         name = raid_##states##_name(rd->attr);                          \
 191 )                                                                       \
 192 static DEVICE_ATTR(attr, S_IRUGO, raid_show_##attr, NULL)
 193
 194
 195 #define raid_attr_ro_internal(attr, code)                               \
 196 raid_attr_show_internal(attr, %d, rd->attr, code)                       \
 197 static 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
 210 raid_attr_ro_state(level);
 211 raid_attr_ro_fn(resync);
 212 raid_attr_ro_state_fn(state);
 213
 214 static 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
 223 int 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
 252 err_out:
 253         list_del(&rc->node);
 254         rd->component_count--;
 255         put_device(component_dev);
 256         kfree(rc);
 257         return err;
 258 }
 259 EXPORT_SYMBOL(raid_component_add);
 260
 261 struct raid_template *
 262 raid_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 }
 288 EXPORT_SYMBOL(raid_class_attach);
 289
 290 void
 291 raid_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 }
 299 EXPORT_SYMBOL(raid_class_release);
 300
 301 static __init int raid_init(void)
 302 {
 303         return transport_class_register(&raid_class);
 304 }
 305
 306 static __exit void raid_exit(void)
 307 {
 308         transport_class_unregister(&raid_class);
 309 }
 310
 311 MODULE_AUTHOR("James Bottomley");
 312 MODULE_DESCRIPTION("RAID device class");
 313 MODULE_LICENSE("GPL");
 314
 315 module_init(raid_init);
 316 module_exit(raid_exit);
 317