drivers/scsi/raid_class.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * raid_class.c - implementation of a simple raid visualisation class
   4  *
   5  * Copyright (c) 2005 - James Bottomley <James.Bottomley@steeleye.com>
   6  *
   7  * This class is designed to allow raid attributes to be visualised and
   8  * manipulated in a form independent of the underlying raid.  Ultimately this
   9  * should work for both hardware and software raids.
  10  */
  11 #include <linux/init.h>
  12 #include <linux/module.h>
  13 #include <linux/list.h>
  14 #include <linux/slab.h>
  15 #include <linux/string.h>
  16 #include <linux/raid_class.h>
  17 #include <scsi/scsi_device.h>
  18 #include <scsi/scsi_host.h>
  19
  20 #define RAID_NUM_ATTRS  3
  21
  22 struct raid_internal {
  23         struct raid_template r;
  24         struct raid_function_template *f;
  25         /* The actual attributes */
  26         struct device_attribute private_attrs[RAID_NUM_ATTRS];
  27         /* The array of null terminated pointers to attributes
  28          * needed by scsi_sysfs.c */
  29         struct device_attribute *attrs[RAID_NUM_ATTRS + 1];
  30 };
  31
  32 struct raid_component {
  33         struct list_head node;
  34         struct device dev;
  35         int num;
  36 };
  37
  38 #define to_raid_internal(tmpl)  container_of(tmpl, struct raid_internal, r)
  39
  40 #define tc_to_raid_internal(tcont) ({                                   \
  41         struct raid_template *r =                                       \
  42                 container_of(tcont, struct raid_template, raid_attrs);  \
  43         to_raid_internal(r);                                            \
  44 })
  45
  46 #define ac_to_raid_internal(acont) ({                                   \
  47         struct transport_container *tc =                                \
  48                 container_of(acont, struct transport_container, ac);    \
  49         tc_to_raid_internal(tc);                                        \
  50 })
  51
  52 #define device_to_raid_internal(dev) ({                         \
  53         struct attribute_container *ac =                                \
  54                 attribute_container_classdev_to_container(dev); \
  55         ac_to_raid_internal(ac);                                        \
  56 })
  57
  58
  59 static int raid_match(struct attribute_container *cont, struct device *dev)
  60 {
  61         /* We have to look for every subsystem that could house
  62          * emulated RAID devices, so start with SCSI */
  63         struct raid_internal *i = ac_to_raid_internal(cont);
  64
  65         if (IS_ENABLED(CONFIG_SCSI) && scsi_is_sdev_device(dev)) {
  66                 struct scsi_device *sdev = to_scsi_device(dev);
  67
  68                 if (i->f->cookie != sdev->host->hostt)
  69                         return 0;
  70
  71                 return i->f->is_raid(dev);
  72         }
  73         /* FIXME: look at other subsystems too */
  74         return 0;
  75 }
  76
  77 static int raid_setup(struct transport_container *tc, struct device *dev,
  78                        struct device *cdev)
  79 {
  80         struct raid_data *rd;
  81
  82         BUG_ON(dev_get_drvdata(cdev));
  83
  84         rd = kzalloc(sizeof(*rd), GFP_KERNEL);
  85         if (!rd)
  86                 return -ENOMEM;
  87
  88         INIT_LIST_HEAD(&rd->component_list);
  89         dev_set_drvdata(cdev, rd);
  90
  91         return 0;
  92 }
  93
  94 static int raid_remove(struct transport_container *tc, struct device *dev,
  95                        struct device *cdev)
  96 {
  97         struct raid_data *rd = dev_get_drvdata(cdev);
  98         struct raid_component *rc, *next;
  99         dev_printk(KERN_ERR, dev, "RAID REMOVE\n");
 100         dev_set_drvdata(cdev, NULL);
 101         list_for_each_entry_safe(rc, next, &rd->component_list, node) {
 102                 list_del(&rc->node);
 103                 dev_printk(KERN_ERR, rc->dev.parent, "RAID COMPONENT REMOVE\n");
 104                 device_unregister(&rc->dev);
 105         }
 106         dev_printk(KERN_ERR, dev, "RAID REMOVE DONE\n");
 107         kfree(rd);
 108         return 0;
 109 }
 110
 111 static DECLARE_TRANSPORT_CLASS(raid_class,
 112                                "raid_devices",
 113                                raid_setup,
 114                                raid_remove,
 115                                NULL);
 116
 117 static const struct {
 118         enum raid_state value;
 119         char            *name;
 120 } raid_states[] = {
 121         { RAID_STATE_UNKNOWN, "unknown" },
 122         { RAID_STATE_ACTIVE, "active" },
 123         { RAID_STATE_DEGRADED, "degraded" },
 124         { RAID_STATE_RESYNCING, "resyncing" },
 125         { RAID_STATE_OFFLINE, "offline" },
 126 };
 127
 128 static const char *raid_state_name(enum raid_state state)
 129 {
 130         int i;
 131         char *name = NULL;
 132
 133         for (i = 0; i < ARRAY_SIZE(raid_states); i++) {
 134                 if (raid_states[i].value == state) {
 135                         name = raid_states[i].name;
 136                         break;
 137                 }
 138         }
 139         return name;
 140 }
 141
 142 static struct {
 143         enum raid_level value;
 144         char *name;
 145 } raid_levels[] = {
 146         { RAID_LEVEL_UNKNOWN, "unknown" },
 147         { RAID_LEVEL_LINEAR, "linear" },
 148         { RAID_LEVEL_0, "raid0" },
 149         { RAID_LEVEL_1, "raid1" },
 150         { RAID_LEVEL_10, "raid10" },
 151         { RAID_LEVEL_1E, "raid1e" },
 152         { RAID_LEVEL_3, "raid3" },
 153         { RAID_LEVEL_4, "raid4" },
 154         { RAID_LEVEL_5, "raid5" },
 155         { RAID_LEVEL_50, "raid50" },
 156         { RAID_LEVEL_6, "raid6" },
 157         { RAID_LEVEL_JBOD, "jbod" },
 158 };
 159
 160 static const char *raid_level_name(enum raid_level level)
 161 {
 162         int i;
 163         char *name = NULL;
 164
 165         for (i = 0; i < ARRAY_SIZE(raid_levels); i++) {
 166                 if (raid_levels[i].value == level) {
 167                         name = raid_levels[i].name;
 168                         break;
 169                 }
 170         }
 171         return name;
 172 }
 173
 174 #define raid_attr_show_internal(attr, fmt, var, code)                   \
 175 static ssize_t raid_show_##attr(struct device *dev,                     \
 176                                 struct device_attribute *attr,          \
 177                                 char *buf)                              \
 178 {                                                                       \
 179         struct raid_data *rd = dev_get_drvdata(dev);                    \
 180         code                                                            \
 181         return snprintf(buf, 20, #fmt "\n", var);                       \
 182 }
 183
 184 #define raid_attr_ro_states(attr, states, code)                         \
 185 raid_attr_show_internal(attr, %s, name,                                 \
 186         const char *name;                                               \
 187         code                                                            \
 188         name = raid_##states##_name(rd->attr);                          \
 189 )                                                                       \
 190 static DEVICE_ATTR(attr, S_IRUGO, raid_show_##attr, NULL)
 191
 192
 193 #define raid_attr_ro_internal(attr, code)                               \
 194 raid_attr_show_internal(attr, %d, rd->attr, code)                       \
 195 static DEVICE_ATTR(attr, S_IRUGO, raid_show_##attr, NULL)
 196
 197 #define ATTR_CODE(attr)                                                 \
 198         struct raid_internal *i = device_to_raid_internal(dev);         \
 199         if (i->f->get_##attr)                                           \
 200                 i->f->get_##attr(dev->parent);
 201
 202 #define raid_attr_ro(attr)      raid_attr_ro_internal(attr, )
 203 #define raid_attr_ro_fn(attr)   raid_attr_ro_internal(attr, ATTR_CODE(attr))
 204 #define raid_attr_ro_state(attr)        raid_attr_ro_states(attr, attr, )
 205 #define raid_attr_ro_state_fn(attr)     raid_attr_ro_states(attr, attr, ATTR_CODE(attr))
 206
 207
 208 raid_attr_ro_state(level);
 209 raid_attr_ro_fn(resync);
 210 raid_attr_ro_state_fn(state);
 211
 212 static void raid_component_release(struct device *dev)
 213 {
 214         struct raid_component *rc =
 215                 container_of(dev, struct raid_component, dev);
 216         dev_printk(KERN_ERR, rc->dev.parent, "COMPONENT RELEASE\n");
 217         put_device(rc->dev.parent);
 218         kfree(rc);
 219 }
 220
 221 int raid_component_add(struct raid_template *r,struct device *raid_dev,
 222                        struct device *component_dev)
 223 {
 224         struct device *cdev =
 225                 attribute_container_find_class_device(&r->raid_attrs.ac,
 226                                                       raid_dev);
 227         struct raid_component *rc;
 228         struct raid_data *rd = dev_get_drvdata(cdev);
 229         int err;
 230
 231         rc = kzalloc(sizeof(*rc), GFP_KERNEL);
 232         if (!rc)
 233                 return -ENOMEM;
 234
 235         INIT_LIST_HEAD(&rc->node);
 236         device_initialize(&rc->dev);
 237         rc->dev.release = raid_component_release;
 238         rc->dev.parent = get_device(component_dev);
 239         rc->num = rd->component_count++;
 240
 241         dev_set_name(&rc->dev, "component-%d", rc->num);
 242         list_add_tail(&rc->node, &rd->component_list);
 243         rc->dev.class = &raid_class.class;
 244         err = device_add(&rc->dev);
 245         if (err)
 246                 goto err_out;
 247
 248         return 0;
 249
 250 err_out:
 251         list_del(&rc->node);
 252         rd->component_count--;
 253         put_device(component_dev);
 254         kfree(rc);
 255         return err;
 256 }
 257 EXPORT_SYMBOL(raid_component_add);
 258
 259 struct raid_template *
 260 raid_class_attach(struct raid_function_template *ft)
 261 {
 262         struct raid_internal *i = kzalloc(sizeof(struct raid_internal),
 263                                           GFP_KERNEL);
 264         int count = 0;
 265
 266         if (unlikely(!i))
 267                 return NULL;
 268
 269         i->f = ft;
 270
 271         i->r.raid_attrs.ac.class = &raid_class.class;
 272         i->r.raid_attrs.ac.match = raid_match;
 273         i->r.raid_attrs.ac.attrs = &i->attrs[0];
 274
 275         attribute_container_register(&i->r.raid_attrs.ac);
 276
 277         i->attrs[count++] = &dev_attr_level;
 278         i->attrs[count++] = &dev_attr_resync;
 279         i->attrs[count++] = &dev_attr_state;
 280
 281         i->attrs[count] = NULL;
 282         BUG_ON(count > RAID_NUM_ATTRS);
 283
 284         return &i->r;
 285 }
 286 EXPORT_SYMBOL(raid_class_attach);
 287
 288 void
 289 raid_class_release(struct raid_template *r)
 290 {
 291         struct raid_internal *i = to_raid_internal(r);
 292
 293         BUG_ON(attribute_container_unregister(&i->r.raid_attrs.ac));
 294
 295         kfree(i);
 296 }
 297 EXPORT_SYMBOL(raid_class_release);
 298
 299 static __init int raid_init(void)
 300 {
 301         return transport_class_register(&raid_class);
 302 }
 303
 304 static __exit void raid_exit(void)
 305 {
 306         transport_class_unregister(&raid_class);
 307 }
 308
 309 MODULE_AUTHOR("James Bottomley");
 310 MODULE_DESCRIPTION("RAID device class");
 311 MODULE_LICENSE("GPL");
 312
 313 module_init(raid_init);
 314 module_exit(raid_exit);
 315