linux/drivers/scsi/raid_class.c
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   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
  22struct 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
  32struct 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
  59static 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
  77static 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
  94static 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
 111static DECLARE_TRANSPORT_CLASS(raid_class,
 112                               "raid_devices",
 113                               raid_setup,
 114                               raid_remove,
 115                               NULL);
 116
 117static 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
 128static 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
 142static 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
 160static 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)                   \
 175static 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)                         \
 185raid_attr_show_internal(attr, %s, name,                                 \
 186        const char *name;                                               \
 187        code                                                            \
 188        name = raid_##states##_name(rd->attr);                          \
 189)                                                                       \
 190static DEVICE_ATTR(attr, S_IRUGO, raid_show_##attr, NULL)
 191
 192
 193#define raid_attr_ro_internal(attr, code)                               \
 194raid_attr_show_internal(attr, %d, rd->attr, code)                       \
 195static 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
 208raid_attr_ro_state(level);
 209raid_attr_ro_fn(resync);
 210raid_attr_ro_state_fn(state);
 211
 212static 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
 221int 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
 250err_out:
 251        list_del(&rc->node);
 252        rd->component_count--;
 253        put_device(component_dev);
 254        kfree(rc);
 255        return err;
 256}
 257EXPORT_SYMBOL(raid_component_add);
 258
 259struct raid_template *
 260raid_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}
 286EXPORT_SYMBOL(raid_class_attach);
 287
 288void
 289raid_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}
 297EXPORT_SYMBOL(raid_class_release);
 298
 299static __init int raid_init(void)
 300{
 301        return transport_class_register(&raid_class);
 302}
 303
 304static __exit void raid_exit(void)
 305{
 306        transport_class_unregister(&raid_class);
 307}
 308
 309MODULE_AUTHOR("James Bottomley");
 310MODULE_DESCRIPTION("RAID device class");
 311MODULE_LICENSE("GPL");
 312
 313module_init(raid_init);
 314module_exit(raid_exit);
 315
 316