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 class_device_attribute private_attrs[RAID_NUM_ATTRS];
  28         /* The array of null terminated pointers to attributes
  29          * needed by scsi_sysfs.c */
  30         struct class_device_attribute *attrs[RAID_NUM_ATTRS + 1];
  31 };
  32
  33 struct raid_component {
  34         struct list_head node;
  35         struct class_device cdev;
  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 class_device_to_raid_internal(cdev) ({                          \
  54         struct attribute_container *ac =                                \
  55                 attribute_container_classdev_to_container(cdev);        \
  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 (scsi_is_sdev_device(dev)) {
  67                 struct scsi_device *sdev = to_scsi_device(dev);
  68
  69                 if (i->f->cookie != sdev->host->hostt)
  70                         return 0;
  71
  72                 return i->f->is_raid(dev);
  73         }
  74         /* FIXME: look at other subsystems too */
  75         return 0;
  76 }
  77
  78 static int raid_setup(struct transport_container *tc, struct device *dev,
  79                        struct class_device *cdev)
  80 {
  81         struct raid_data *rd;
  82
  83         BUG_ON(class_get_devdata(cdev));
  84
  85         rd = kzalloc(sizeof(*rd), GFP_KERNEL);
  86         if (!rd)
  87                 return -ENOMEM;
  88
  89         INIT_LIST_HEAD(&rd->component_list);
  90         class_set_devdata(cdev, rd);
  91
  92         return 0;
  93 }
  94
  95 static int raid_remove(struct transport_container *tc, struct device *dev,
  96                        struct class_device *cdev)
  97 {
  98         struct raid_data *rd = class_get_devdata(cdev);
  99         struct raid_component *rc, *next;
 100         dev_printk(KERN_ERR, dev, "RAID REMOVE\n");
 101         class_set_devdata(cdev, NULL);
 102         list_for_each_entry_safe(rc, next, &rd->component_list, node) {
 103                 list_del(&rc->node);
 104                 dev_printk(KERN_ERR, rc->cdev.dev, "RAID COMPONENT REMOVE\n");
 105                 class_device_unregister(&rc->cdev);
 106         }
 107         dev_printk(KERN_ERR, dev, "RAID REMOVE DONE\n");
 108         kfree(rd);
 109         return 0;
 110 }
 111
 112 static DECLARE_TRANSPORT_CLASS(raid_class,
 113                                "raid_devices",
 114                                raid_setup,
 115                                raid_remove,
 116                                NULL);
 117
 118 static struct {
 119         enum raid_state value;
 120         char            *name;
 121 } raid_states[] = {
 122         { RAID_STATE_UNKNOWN, "unknown" },
 123         { RAID_STATE_ACTIVE, "active" },
 124         { RAID_STATE_DEGRADED, "degraded" },
 125         { RAID_STATE_RESYNCING, "resyncing" },
 126         { RAID_STATE_OFFLINE, "offline" },
 127 };
 128
 129 static const char *raid_state_name(enum raid_state state)
 130 {
 131         int i;
 132         char *name = NULL;
 133
 134         for (i = 0; i < sizeof(raid_states)/sizeof(raid_states[0]); i++) {
 135                 if (raid_states[i].value == state) {
 136                         name = raid_states[i].name;
 137                         break;
 138                 }
 139         }
 140         return name;
 141 }
 142
 143 static struct {
 144         enum raid_level value;
 145         char *name;
 146 } raid_levels[] = {
 147         { RAID_LEVEL_UNKNOWN, "unknown" },
 148         { RAID_LEVEL_LINEAR, "linear" },
 149         { RAID_LEVEL_0, "raid0" },
 150         { RAID_LEVEL_1, "raid1" },
 151         { RAID_LEVEL_3, "raid3" },
 152         { RAID_LEVEL_4, "raid4" },
 153         { RAID_LEVEL_5, "raid5" },
 154         { RAID_LEVEL_6, "raid6" },
 155 };
 156
 157 static const char *raid_level_name(enum raid_level level)
 158 {
 159         int i;
 160         char *name = NULL;
 161
 162         for (i = 0; i < sizeof(raid_levels)/sizeof(raid_levels[0]); i++) {
 163                 if (raid_levels[i].value == level) {
 164                         name = raid_levels[i].name;
 165                         break;
 166                 }
 167         }
 168         return name;
 169 }
 170
 171 #define raid_attr_show_internal(attr, fmt, var, code)                   \
 172 static ssize_t raid_show_##attr(struct class_device *cdev, char *buf)   \
 173 {                                                                       \
 174         struct raid_data *rd = class_get_devdata(cdev);                 \
 175         code                                                            \
 176         return snprintf(buf, 20, #fmt "\n", var);                       \
 177 }
 178
 179 #define raid_attr_ro_states(attr, states, code)                         \
 180 raid_attr_show_internal(attr, %s, name,                                 \
 181         const char *name;                                               \
 182         code                                                            \
 183         name = raid_##states##_name(rd->attr);                          \
 184 )                                                                       \
 185 static CLASS_DEVICE_ATTR(attr, S_IRUGO, raid_show_##attr, NULL)
 186
 187
 188 #define raid_attr_ro_internal(attr, code)                               \
 189 raid_attr_show_internal(attr, %d, rd->attr, code)                       \
 190 static CLASS_DEVICE_ATTR(attr, S_IRUGO, raid_show_##attr, NULL)
 191
 192 #define ATTR_CODE(attr)                                                 \
 193         struct raid_internal *i = class_device_to_raid_internal(cdev);  \
 194         if (i->f->get_##attr)                                           \
 195                 i->f->get_##attr(cdev->dev);
 196
 197 #define raid_attr_ro(attr)      raid_attr_ro_internal(attr, )
 198 #define raid_attr_ro_fn(attr)   raid_attr_ro_internal(attr, ATTR_CODE(attr))
 199 #define raid_attr_ro_state(attr)        raid_attr_ro_states(attr, attr, )
 200 #define raid_attr_ro_state_fn(attr)     raid_attr_ro_states(attr, attr, ATTR_CODE(attr))
 201
 202
 203 raid_attr_ro_state(level);
 204 raid_attr_ro_fn(resync);
 205 raid_attr_ro_state_fn(state);
 206
 207 static void raid_component_release(struct class_device *cdev)
 208 {
 209         struct raid_component *rc = container_of(cdev, struct raid_component,
 210                                                  cdev);
 211         dev_printk(KERN_ERR, rc->cdev.dev, "COMPONENT RELEASE\n");
 212         put_device(rc->cdev.dev);
 213         kfree(rc);
 214 }
 215
 216 void raid_component_add(struct raid_template *r,struct device *raid_dev,
 217                         struct device *component_dev)
 218 {
 219         struct class_device *cdev =
 220                 attribute_container_find_class_device(&r->raid_attrs.ac,
 221                                                       raid_dev);
 222         struct raid_component *rc;
 223         struct raid_data *rd = class_get_devdata(cdev);
 224
 225         rc = kzalloc(sizeof(*rc), GFP_KERNEL);
 226         if (!rc)
 227                 return;
 228
 229         INIT_LIST_HEAD(&rc->node);
 230         class_device_initialize(&rc->cdev);
 231         rc->cdev.release = raid_component_release;
 232         rc->cdev.dev = get_device(component_dev);
 233         rc->num = rd->component_count++;
 234
 235         snprintf(rc->cdev.class_id, sizeof(rc->cdev.class_id),
 236                  "component-%d", rc->num);
 237         list_add_tail(&rc->node, &rd->component_list);
 238         rc->cdev.parent = cdev;
 239         rc->cdev.class = &raid_class.class;
 240         class_device_add(&rc->cdev);
 241 }
 242 EXPORT_SYMBOL(raid_component_add);
 243
 244 struct raid_template *
 245 raid_class_attach(struct raid_function_template *ft)
 246 {
 247         struct raid_internal *i = kzalloc(sizeof(struct raid_internal),
 248                                           GFP_KERNEL);
 249         int count = 0;
 250
 251         if (unlikely(!i))
 252                 return NULL;
 253
 254         i->f = ft;
 255
 256         i->r.raid_attrs.ac.class = &raid_class.class;
 257         i->r.raid_attrs.ac.match = raid_match;
 258         i->r.raid_attrs.ac.attrs = &i->attrs[0];
 259
 260         attribute_container_register(&i->r.raid_attrs.ac);
 261
 262         i->attrs[count++] = &class_device_attr_level;
 263         i->attrs[count++] = &class_device_attr_resync;
 264         i->attrs[count++] = &class_device_attr_state;
 265
 266         i->attrs[count] = NULL;
 267         BUG_ON(count > RAID_NUM_ATTRS);
 268
 269         return &i->r;
 270 }
 271 EXPORT_SYMBOL(raid_class_attach);
 272
 273 void
 274 raid_class_release(struct raid_template *r)
 275 {
 276         struct raid_internal *i = to_raid_internal(r);
 277
 278         attribute_container_unregister(&i->r.raid_attrs.ac);
 279
 280         kfree(i);
 281 }
 282 EXPORT_SYMBOL(raid_class_release);
 283
 284 static __init int raid_init(void)
 285 {
 286         return transport_class_register(&raid_class);
 287 }
 288
 289 static __exit void raid_exit(void)
 290 {
 291         transport_class_unregister(&raid_class);
 292 }
 293
 294 MODULE_AUTHOR("James Bottomley");
 295 MODULE_DESCRIPTION("RAID device class");
 296 MODULE_LICENSE("GPL");
 297
 298 module_init(raid_init);
 299 module_exit(raid_exit);
 300