drivers/nvdimm/btt_devs.c

   1 /*
   2  * Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of version 2 of the GNU General Public License as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  */
  13 #include <linux/blkdev.h>
  14 #include <linux/device.h>
  15 #include <linux/genhd.h>
  16 #include <linux/sizes.h>
  17 #include <linux/slab.h>
  18 #include <linux/fs.h>
  19 #include <linux/mm.h>
  20 #include "nd-core.h"
  21 #include "btt.h"
  22 #include "nd.h"
  23
  24 static void __nd_btt_detach_ndns(struct nd_btt *nd_btt)
  25 {
  26         struct nd_namespace_common *ndns = nd_btt->ndns;
  27
  28         dev_WARN_ONCE(&nd_btt->dev, !mutex_is_locked(&ndns->dev.mutex)
  29                         || ndns->claim != &nd_btt->dev,
  30                         "%s: invalid claim\n", __func__);
  31         ndns->claim = NULL;
  32         nd_btt->ndns = NULL;
  33         put_device(&ndns->dev);
  34 }
  35
  36 static void nd_btt_detach_ndns(struct nd_btt *nd_btt)
  37 {
  38         struct nd_namespace_common *ndns = nd_btt->ndns;
  39
  40         if (!ndns)
  41                 return;
  42         get_device(&ndns->dev);
  43         device_lock(&ndns->dev);
  44         __nd_btt_detach_ndns(nd_btt);
  45         device_unlock(&ndns->dev);
  46         put_device(&ndns->dev);
  47 }
  48
  49 static bool __nd_btt_attach_ndns(struct nd_btt *nd_btt,
  50                 struct nd_namespace_common *ndns)
  51 {
  52         if (ndns->claim)
  53                 return false;
  54         dev_WARN_ONCE(&nd_btt->dev, !mutex_is_locked(&ndns->dev.mutex)
  55                         || nd_btt->ndns,
  56                         "%s: invalid claim\n", __func__);
  57         ndns->claim = &nd_btt->dev;
  58         nd_btt->ndns = ndns;
  59         get_device(&ndns->dev);
  60         return true;
  61 }
  62
  63 static bool nd_btt_attach_ndns(struct nd_btt *nd_btt,
  64                 struct nd_namespace_common *ndns)
  65 {
  66         bool claimed;
  67
  68         device_lock(&ndns->dev);
  69         claimed = __nd_btt_attach_ndns(nd_btt, ndns);
  70         device_unlock(&ndns->dev);
  71         return claimed;
  72 }
  73
  74 static void nd_btt_release(struct device *dev)
  75 {
  76         struct nd_region *nd_region = to_nd_region(dev->parent);
  77         struct nd_btt *nd_btt = to_nd_btt(dev);
  78
  79         dev_dbg(dev, "%s\n", __func__);
  80         nd_btt_detach_ndns(nd_btt);
  81         ida_simple_remove(&nd_region->btt_ida, nd_btt->id);
  82         kfree(nd_btt->uuid);
  83         kfree(nd_btt);
  84 }
  85
  86 static struct device_type nd_btt_device_type = {
  87         .name = "nd_btt",
  88         .release = nd_btt_release,
  89 };
  90
  91 bool is_nd_btt(struct device *dev)
  92 {
  93         return dev->type == &nd_btt_device_type;
  94 }
  95 EXPORT_SYMBOL(is_nd_btt);
  96
  97 struct nd_btt *to_nd_btt(struct device *dev)
  98 {
  99         struct nd_btt *nd_btt = container_of(dev, struct nd_btt, dev);
 100
 101         WARN_ON(!is_nd_btt(dev));
 102         return nd_btt;
 103 }
 104 EXPORT_SYMBOL(to_nd_btt);
 105
 106 static const unsigned long btt_lbasize_supported[] = { 512, 4096, 0 };
 107
 108 static ssize_t sector_size_show(struct device *dev,
 109                 struct device_attribute *attr, char *buf)
 110 {
 111         struct nd_btt *nd_btt = to_nd_btt(dev);
 112
 113         return nd_sector_size_show(nd_btt->lbasize, btt_lbasize_supported, buf);
 114 }
 115
 116 static ssize_t sector_size_store(struct device *dev,
 117                 struct device_attribute *attr, const char *buf, size_t len)
 118 {
 119         struct nd_btt *nd_btt = to_nd_btt(dev);
 120         ssize_t rc;
 121
 122         device_lock(dev);
 123         nvdimm_bus_lock(dev);
 124         rc = nd_sector_size_store(dev, buf, &nd_btt->lbasize,
 125                         btt_lbasize_supported);
 126         dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 127                         rc, buf, buf[len - 1] == '\n' ? "" : "\n");
 128         nvdimm_bus_unlock(dev);
 129         device_unlock(dev);
 130
 131         return rc ? rc : len;
 132 }
 133 static DEVICE_ATTR_RW(sector_size);
 134
 135 static ssize_t uuid_show(struct device *dev,
 136                 struct device_attribute *attr, char *buf)
 137 {
 138         struct nd_btt *nd_btt = to_nd_btt(dev);
 139
 140         if (nd_btt->uuid)
 141                 return sprintf(buf, "%pUb\n", nd_btt->uuid);
 142         return sprintf(buf, "\n");
 143 }
 144
 145 static ssize_t uuid_store(struct device *dev,
 146                 struct device_attribute *attr, const char *buf, size_t len)
 147 {
 148         struct nd_btt *nd_btt = to_nd_btt(dev);
 149         ssize_t rc;
 150
 151         device_lock(dev);
 152         rc = nd_uuid_store(dev, &nd_btt->uuid, buf, len);
 153         dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 154                         rc, buf, buf[len - 1] == '\n' ? "" : "\n");
 155         device_unlock(dev);
 156
 157         return rc ? rc : len;
 158 }
 159 static DEVICE_ATTR_RW(uuid);
 160
 161 static ssize_t namespace_show(struct device *dev,
 162                 struct device_attribute *attr, char *buf)
 163 {
 164         struct nd_btt *nd_btt = to_nd_btt(dev);
 165         ssize_t rc;
 166
 167         nvdimm_bus_lock(dev);
 168         rc = sprintf(buf, "%s\n", nd_btt->ndns
 169                         ? dev_name(&nd_btt->ndns->dev) : "");
 170         nvdimm_bus_unlock(dev);
 171         return rc;
 172 }
 173
 174 static int namespace_match(struct device *dev, void *data)
 175 {
 176         char *name = data;
 177
 178         return strcmp(name, dev_name(dev)) == 0;
 179 }
 180
 181 static bool is_nd_btt_idle(struct device *dev)
 182 {
 183         struct nd_region *nd_region = to_nd_region(dev->parent);
 184         struct nd_btt *nd_btt = to_nd_btt(dev);
 185
 186         if (nd_region->btt_seed == dev || nd_btt->ndns || dev->driver)
 187                 return false;
 188         return true;
 189 }
 190
 191 static ssize_t __namespace_store(struct device *dev,
 192                 struct device_attribute *attr, const char *buf, size_t len)
 193 {
 194         struct nd_btt *nd_btt = to_nd_btt(dev);
 195         struct nd_namespace_common *ndns;
 196         struct device *found;
 197         char *name;
 198
 199         if (dev->driver) {
 200                 dev_dbg(dev, "%s: -EBUSY\n", __func__);
 201                 return -EBUSY;
 202         }
 203
 204         name = kstrndup(buf, len, GFP_KERNEL);
 205         if (!name)
 206                 return -ENOMEM;
 207         strim(name);
 208
 209         if (strncmp(name, "namespace", 9) == 0 || strcmp(name, "") == 0)
 210                 /* pass */;
 211         else {
 212                 len = -EINVAL;
 213                 goto out;
 214         }
 215
 216         ndns = nd_btt->ndns;
 217         if (strcmp(name, "") == 0) {
 218                 /* detach the namespace and destroy / reset the btt device */
 219                 nd_btt_detach_ndns(nd_btt);
 220                 if (is_nd_btt_idle(dev))
 221                         nd_device_unregister(dev, ND_ASYNC);
 222                 else {
 223                         nd_btt->lbasize = 0;
 224                         kfree(nd_btt->uuid);
 225                         nd_btt->uuid = NULL;
 226                 }
 227                 goto out;
 228         } else if (ndns) {
 229                 dev_dbg(dev, "namespace already set to: %s\n",
 230                                 dev_name(&ndns->dev));
 231                 len = -EBUSY;
 232                 goto out;
 233         }
 234
 235         found = device_find_child(dev->parent, name, namespace_match);
 236         if (!found) {
 237                 dev_dbg(dev, "'%s' not found under %s\n", name,
 238                                 dev_name(dev->parent));
 239                 len = -ENODEV;
 240                 goto out;
 241         }
 242
 243         ndns = to_ndns(found);
 244         if (__nvdimm_namespace_capacity(ndns) < SZ_16M) {
 245                 dev_dbg(dev, "%s too small to host btt\n", name);
 246                 len = -ENXIO;
 247                 goto out_attach;
 248         }
 249
 250         WARN_ON_ONCE(!is_nvdimm_bus_locked(&nd_btt->dev));
 251         if (!nd_btt_attach_ndns(nd_btt, ndns)) {
 252                 dev_dbg(dev, "%s already claimed\n",
 253                                 dev_name(&ndns->dev));
 254                 len = -EBUSY;
 255         }
 256
 257  out_attach:
 258         put_device(&ndns->dev); /* from device_find_child */
 259  out:
 260         kfree(name);
 261         return len;
 262 }
 263
 264 static ssize_t namespace_store(struct device *dev,
 265                 struct device_attribute *attr, const char *buf, size_t len)
 266 {
 267         ssize_t rc;
 268
 269         nvdimm_bus_lock(dev);
 270         device_lock(dev);
 271         rc = __namespace_store(dev, attr, buf, len);
 272         dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 273                         rc, buf, buf[len - 1] == '\n' ? "" : "\n");
 274         device_unlock(dev);
 275         nvdimm_bus_unlock(dev);
 276
 277         return rc;
 278 }
 279 static DEVICE_ATTR_RW(namespace);
 280
 281 static struct attribute *nd_btt_attributes[] = {
 282         &dev_attr_sector_size.attr,
 283         &dev_attr_namespace.attr,
 284         &dev_attr_uuid.attr,
 285         NULL,
 286 };
 287
 288 static struct attribute_group nd_btt_attribute_group = {
 289         .attrs = nd_btt_attributes,
 290 };
 291
 292 static const struct attribute_group *nd_btt_attribute_groups[] = {
 293         &nd_btt_attribute_group,
 294         &nd_device_attribute_group,
 295         NULL,
 296 };
 297
 298 static struct device *__nd_btt_create(struct nd_region *nd_region,
 299                 unsigned long lbasize, u8 *uuid,
 300                 struct nd_namespace_common *ndns)
 301 {
 302         struct nd_btt *nd_btt;
 303         struct device *dev;
 304
 305         nd_btt = kzalloc(sizeof(*nd_btt), GFP_KERNEL);
 306         if (!nd_btt)
 307                 return NULL;
 308
 309         nd_btt->id = ida_simple_get(&nd_region->btt_ida, 0, 0, GFP_KERNEL);
 310         if (nd_btt->id < 0) {
 311                 kfree(nd_btt);
 312                 return NULL;
 313         }
 314
 315         nd_btt->lbasize = lbasize;
 316         if (uuid)
 317                 uuid = kmemdup(uuid, 16, GFP_KERNEL);
 318         nd_btt->uuid = uuid;
 319         dev = &nd_btt->dev;
 320         dev_set_name(dev, "btt%d.%d", nd_region->id, nd_btt->id);
 321         dev->parent = &nd_region->dev;
 322         dev->type = &nd_btt_device_type;
 323         dev->groups = nd_btt_attribute_groups;
 324         device_initialize(&nd_btt->dev);
 325         if (ndns && !__nd_btt_attach_ndns(nd_btt, ndns)) {
 326                 dev_dbg(&ndns->dev, "%s failed, already claimed by %s\n",
 327                                 __func__, dev_name(ndns->claim));
 328                 put_device(dev);
 329                 return NULL;
 330         }
 331         return dev;
 332 }
 333
 334 struct device *nd_btt_create(struct nd_region *nd_region)
 335 {
 336         struct device *dev = __nd_btt_create(nd_region, 0, NULL, NULL);
 337
 338         if (dev)
 339                 __nd_device_register(dev);
 340         return dev;
 341 }
 342
 343 /*
 344  * nd_btt_sb_checksum: compute checksum for btt info block
 345  *
 346  * Returns a fletcher64 checksum of everything in the given info block
 347  * except the last field (since that's where the checksum lives).
 348  */
 349 u64 nd_btt_sb_checksum(struct btt_sb *btt_sb)
 350 {
 351         u64 sum, sum_save;
 352
 353         sum_save = btt_sb->checksum;
 354         btt_sb->checksum = 0;
 355         sum = nd_fletcher64(btt_sb, sizeof(*btt_sb), 1);
 356         btt_sb->checksum = sum_save;
 357         return sum;
 358 }
 359 EXPORT_SYMBOL(nd_btt_sb_checksum);
 360
 361 static int __nd_btt_probe(struct nd_btt *nd_btt,
 362                 struct nd_namespace_common *ndns, struct btt_sb *btt_sb)
 363 {
 364         u64 checksum;
 365
 366         if (!btt_sb || !ndns || !nd_btt)
 367                 return -ENODEV;
 368
 369         if (nvdimm_read_bytes(ndns, SZ_4K, btt_sb, sizeof(*btt_sb)))
 370                 return -ENXIO;
 371
 372         if (nvdimm_namespace_capacity(ndns) < SZ_16M)
 373                 return -ENXIO;
 374
 375         if (memcmp(btt_sb->signature, BTT_SIG, BTT_SIG_LEN) != 0)
 376                 return -ENODEV;
 377
 378         checksum = le64_to_cpu(btt_sb->checksum);
 379         btt_sb->checksum = 0;
 380         if (checksum != nd_btt_sb_checksum(btt_sb))
 381                 return -ENODEV;
 382         btt_sb->checksum = cpu_to_le64(checksum);
 383
 384         nd_btt->lbasize = le32_to_cpu(btt_sb->external_lbasize);
 385         nd_btt->uuid = kmemdup(btt_sb->uuid, 16, GFP_KERNEL);
 386         if (!nd_btt->uuid)
 387                 return -ENOMEM;
 388
 389         __nd_device_register(&nd_btt->dev);
 390
 391         return 0;
 392 }
 393
 394 int nd_btt_probe(struct nd_namespace_common *ndns, void *drvdata)
 395 {
 396         int rc;
 397         struct device *dev;
 398         struct btt_sb *btt_sb;
 399         struct nd_region *nd_region = to_nd_region(ndns->dev.parent);
 400
 401         if (ndns->force_raw)
 402                 return -ENODEV;
 403
 404         nvdimm_bus_lock(&ndns->dev);
 405         dev = __nd_btt_create(nd_region, 0, NULL, ndns);
 406         nvdimm_bus_unlock(&ndns->dev);
 407         if (!dev)
 408                 return -ENOMEM;
 409         dev_set_drvdata(dev, drvdata);
 410         btt_sb = kzalloc(sizeof(*btt_sb), GFP_KERNEL);
 411         rc = __nd_btt_probe(to_nd_btt(dev), ndns, btt_sb);
 412         kfree(btt_sb);
 413         dev_dbg(&ndns->dev, "%s: btt: %s\n", __func__,
 414                         rc == 0 ? dev_name(dev) : "<none>");
 415         if (rc < 0) {
 416                 __nd_btt_detach_ndns(to_nd_btt(dev));
 417                 put_device(dev);
 418         }
 419
 420         return rc;
 421 }
 422 EXPORT_SYMBOL(nd_btt_probe);