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, 520, 528,
 107         4096, 4104, 4160, 4224, 0 };
 108
 109 static ssize_t sector_size_show(struct device *dev,
 110                 struct device_attribute *attr, char *buf)
 111 {
 112         struct nd_btt *nd_btt = to_nd_btt(dev);
 113
 114         return nd_sector_size_show(nd_btt->lbasize, btt_lbasize_supported, buf);
 115 }
 116
 117 static ssize_t sector_size_store(struct device *dev,
 118                 struct device_attribute *attr, const char *buf, size_t len)
 119 {
 120         struct nd_btt *nd_btt = to_nd_btt(dev);
 121         ssize_t rc;
 122
 123         device_lock(dev);
 124         nvdimm_bus_lock(dev);
 125         rc = nd_sector_size_store(dev, buf, &nd_btt->lbasize,
 126                         btt_lbasize_supported);
 127         dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 128                         rc, buf, buf[len - 1] == '\n' ? "" : "\n");
 129         nvdimm_bus_unlock(dev);
 130         device_unlock(dev);
 131
 132         return rc ? rc : len;
 133 }
 134 static DEVICE_ATTR_RW(sector_size);
 135
 136 static ssize_t uuid_show(struct device *dev,
 137                 struct device_attribute *attr, char *buf)
 138 {
 139         struct nd_btt *nd_btt = to_nd_btt(dev);
 140
 141         if (nd_btt->uuid)
 142                 return sprintf(buf, "%pUb\n", nd_btt->uuid);
 143         return sprintf(buf, "\n");
 144 }
 145
 146 static ssize_t uuid_store(struct device *dev,
 147                 struct device_attribute *attr, const char *buf, size_t len)
 148 {
 149         struct nd_btt *nd_btt = to_nd_btt(dev);
 150         ssize_t rc;
 151
 152         device_lock(dev);
 153         rc = nd_uuid_store(dev, &nd_btt->uuid, buf, len);
 154         dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 155                         rc, buf, buf[len - 1] == '\n' ? "" : "\n");
 156         device_unlock(dev);
 157
 158         return rc ? rc : len;
 159 }
 160 static DEVICE_ATTR_RW(uuid);
 161
 162 static ssize_t namespace_show(struct device *dev,
 163                 struct device_attribute *attr, char *buf)
 164 {
 165         struct nd_btt *nd_btt = to_nd_btt(dev);
 166         ssize_t rc;
 167
 168         nvdimm_bus_lock(dev);
 169         rc = sprintf(buf, "%s\n", nd_btt->ndns
 170                         ? dev_name(&nd_btt->ndns->dev) : "");
 171         nvdimm_bus_unlock(dev);
 172         return rc;
 173 }
 174
 175 static int namespace_match(struct device *dev, void *data)
 176 {
 177         char *name = data;
 178
 179         return strcmp(name, dev_name(dev)) == 0;
 180 }
 181
 182 static bool is_nd_btt_idle(struct device *dev)
 183 {
 184         struct nd_region *nd_region = to_nd_region(dev->parent);
 185         struct nd_btt *nd_btt = to_nd_btt(dev);
 186
 187         if (nd_region->btt_seed == dev || nd_btt->ndns || dev->driver)
 188                 return false;
 189         return true;
 190 }
 191
 192 static ssize_t __namespace_store(struct device *dev,
 193                 struct device_attribute *attr, const char *buf, size_t len)
 194 {
 195         struct nd_btt *nd_btt = to_nd_btt(dev);
 196         struct nd_namespace_common *ndns;
 197         struct device *found;
 198         char *name;
 199
 200         if (dev->driver) {
 201                 dev_dbg(dev, "%s: -EBUSY\n", __func__);
 202                 return -EBUSY;
 203         }
 204
 205         name = kstrndup(buf, len, GFP_KERNEL);
 206         if (!name)
 207                 return -ENOMEM;
 208         strim(name);
 209
 210         if (strncmp(name, "namespace", 9) == 0 || strcmp(name, "") == 0)
 211                 /* pass */;
 212         else {
 213                 len = -EINVAL;
 214                 goto out;
 215         }
 216
 217         ndns = nd_btt->ndns;
 218         if (strcmp(name, "") == 0) {
 219                 /* detach the namespace and destroy / reset the btt device */
 220                 nd_btt_detach_ndns(nd_btt);
 221                 if (is_nd_btt_idle(dev))
 222                         nd_device_unregister(dev, ND_ASYNC);
 223                 else {
 224                         nd_btt->lbasize = 0;
 225                         kfree(nd_btt->uuid);
 226                         nd_btt->uuid = NULL;
 227                 }
 228                 goto out;
 229         } else if (ndns) {
 230                 dev_dbg(dev, "namespace already set to: %s\n",
 231                                 dev_name(&ndns->dev));
 232                 len = -EBUSY;
 233                 goto out;
 234         }
 235
 236         found = device_find_child(dev->parent, name, namespace_match);
 237         if (!found) {
 238                 dev_dbg(dev, "'%s' not found under %s\n", name,
 239                                 dev_name(dev->parent));
 240                 len = -ENODEV;
 241                 goto out;
 242         }
 243
 244         ndns = to_ndns(found);
 245         if (__nvdimm_namespace_capacity(ndns) < SZ_16M) {
 246                 dev_dbg(dev, "%s too small to host btt\n", name);
 247                 len = -ENXIO;
 248                 goto out_attach;
 249         }
 250
 251         WARN_ON_ONCE(!is_nvdimm_bus_locked(&nd_btt->dev));
 252         if (!nd_btt_attach_ndns(nd_btt, ndns)) {
 253                 dev_dbg(dev, "%s already claimed\n",
 254                                 dev_name(&ndns->dev));
 255                 len = -EBUSY;
 256         }
 257
 258  out_attach:
 259         put_device(&ndns->dev); /* from device_find_child */
 260  out:
 261         kfree(name);
 262         return len;
 263 }
 264
 265 static ssize_t namespace_store(struct device *dev,
 266                 struct device_attribute *attr, const char *buf, size_t len)
 267 {
 268         ssize_t rc;
 269
 270         nvdimm_bus_lock(dev);
 271         device_lock(dev);
 272         rc = __namespace_store(dev, attr, buf, len);
 273         dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 274                         rc, buf, buf[len - 1] == '\n' ? "" : "\n");
 275         device_unlock(dev);
 276         nvdimm_bus_unlock(dev);
 277
 278         return rc;
 279 }
 280 static DEVICE_ATTR_RW(namespace);
 281
 282 static struct attribute *nd_btt_attributes[] = {
 283         &dev_attr_sector_size.attr,
 284         &dev_attr_namespace.attr,
 285         &dev_attr_uuid.attr,
 286         NULL,
 287 };
 288
 289 static struct attribute_group nd_btt_attribute_group = {
 290         .attrs = nd_btt_attributes,
 291 };
 292
 293 static const struct attribute_group *nd_btt_attribute_groups[] = {
 294         &nd_btt_attribute_group,
 295         &nd_device_attribute_group,
 296         &nd_numa_attribute_group,
 297         NULL,
 298 };
 299
 300 static struct device *__nd_btt_create(struct nd_region *nd_region,
 301                 unsigned long lbasize, u8 *uuid,
 302                 struct nd_namespace_common *ndns)
 303 {
 304         struct nd_btt *nd_btt;
 305         struct device *dev;
 306
 307         nd_btt = kzalloc(sizeof(*nd_btt), GFP_KERNEL);
 308         if (!nd_btt)
 309                 return NULL;
 310
 311         nd_btt->id = ida_simple_get(&nd_region->btt_ida, 0, 0, GFP_KERNEL);
 312         if (nd_btt->id < 0) {
 313                 kfree(nd_btt);
 314                 return NULL;
 315         }
 316
 317         nd_btt->lbasize = lbasize;
 318         if (uuid)
 319                 uuid = kmemdup(uuid, 16, GFP_KERNEL);
 320         nd_btt->uuid = uuid;
 321         dev = &nd_btt->dev;
 322         dev_set_name(dev, "btt%d.%d", nd_region->id, nd_btt->id);
 323         dev->parent = &nd_region->dev;
 324         dev->type = &nd_btt_device_type;
 325         dev->groups = nd_btt_attribute_groups;
 326         device_initialize(&nd_btt->dev);
 327         if (ndns && !__nd_btt_attach_ndns(nd_btt, ndns)) {
 328                 dev_dbg(&ndns->dev, "%s failed, already claimed by %s\n",
 329                                 __func__, dev_name(ndns->claim));
 330                 put_device(dev);
 331                 return NULL;
 332         }
 333         return dev;
 334 }
 335
 336 struct device *nd_btt_create(struct nd_region *nd_region)
 337 {
 338         struct device *dev = __nd_btt_create(nd_region, 0, NULL, NULL);
 339
 340         if (dev)
 341                 __nd_device_register(dev);
 342         return dev;
 343 }
 344
 345 /*
 346  * nd_btt_sb_checksum: compute checksum for btt info block
 347  *
 348  * Returns a fletcher64 checksum of everything in the given info block
 349  * except the last field (since that's where the checksum lives).
 350  */
 351 u64 nd_btt_sb_checksum(struct btt_sb *btt_sb)
 352 {
 353         u64 sum;
 354         __le64 sum_save;
 355
 356         sum_save = btt_sb->checksum;
 357         btt_sb->checksum = 0;
 358         sum = nd_fletcher64(btt_sb, sizeof(*btt_sb), 1);
 359         btt_sb->checksum = sum_save;
 360         return sum;
 361 }
 362 EXPORT_SYMBOL(nd_btt_sb_checksum);
 363
 364 static int __nd_btt_probe(struct nd_btt *nd_btt,
 365                 struct nd_namespace_common *ndns, struct btt_sb *btt_sb)
 366 {
 367         u64 checksum;
 368
 369         if (!btt_sb || !ndns || !nd_btt)
 370                 return -ENODEV;
 371
 372         if (nvdimm_read_bytes(ndns, SZ_4K, btt_sb, sizeof(*btt_sb)))
 373                 return -ENXIO;
 374
 375         if (nvdimm_namespace_capacity(ndns) < SZ_16M)
 376                 return -ENXIO;
 377
 378         if (memcmp(btt_sb->signature, BTT_SIG, BTT_SIG_LEN) != 0)
 379                 return -ENODEV;
 380
 381         checksum = le64_to_cpu(btt_sb->checksum);
 382         btt_sb->checksum = 0;
 383         if (checksum != nd_btt_sb_checksum(btt_sb))
 384                 return -ENODEV;
 385         btt_sb->checksum = cpu_to_le64(checksum);
 386
 387         nd_btt->lbasize = le32_to_cpu(btt_sb->external_lbasize);
 388         nd_btt->uuid = kmemdup(btt_sb->uuid, 16, GFP_KERNEL);
 389         if (!nd_btt->uuid)
 390                 return -ENOMEM;
 391
 392         __nd_device_register(&nd_btt->dev);
 393
 394         return 0;
 395 }
 396
 397 int nd_btt_probe(struct nd_namespace_common *ndns, void *drvdata)
 398 {
 399         int rc;
 400         struct device *dev;
 401         struct btt_sb *btt_sb;
 402         struct nd_region *nd_region = to_nd_region(ndns->dev.parent);
 403
 404         if (ndns->force_raw)
 405                 return -ENODEV;
 406
 407         nvdimm_bus_lock(&ndns->dev);
 408         dev = __nd_btt_create(nd_region, 0, NULL, ndns);
 409         nvdimm_bus_unlock(&ndns->dev);
 410         if (!dev)
 411                 return -ENOMEM;
 412         dev_set_drvdata(dev, drvdata);
 413         btt_sb = kzalloc(sizeof(*btt_sb), GFP_KERNEL);
 414         rc = __nd_btt_probe(to_nd_btt(dev), ndns, btt_sb);
 415         kfree(btt_sb);
 416         dev_dbg(&ndns->dev, "%s: btt: %s\n", __func__,
 417                         rc == 0 ? dev_name(dev) : "<none>");
 418         if (rc < 0) {
 419                 __nd_btt_detach_ndns(to_nd_btt(dev));
 420                 put_device(dev);
 421         }
 422
 423         return rc;
 424 }
 425 EXPORT_SYMBOL(nd_btt_probe);