drivers/nvdimm/region_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/scatterlist.h>
  14 #include <linux/highmem.h>
  15 #include <linux/sched.h>
  16 #include <linux/slab.h>
  17 #include <linux/sort.h>
  18 #include <linux/io.h>
  19 #include <linux/nd.h>
  20 #include "nd-core.h"
  21 #include "nd.h"
  22
  23 static DEFINE_IDA(region_ida);
  24
  25 static void nd_region_release(struct device *dev)
  26 {
  27         struct nd_region *nd_region = to_nd_region(dev);
  28         u16 i;
  29
  30         for (i = 0; i < nd_region->ndr_mappings; i++) {
  31                 struct nd_mapping *nd_mapping = &nd_region->mapping[i];
  32                 struct nvdimm *nvdimm = nd_mapping->nvdimm;
  33
  34                 put_device(&nvdimm->dev);
  35         }
  36         free_percpu(nd_region->lane);
  37         ida_simple_remove(&region_ida, nd_region->id);
  38         if (is_nd_blk(dev))
  39                 kfree(to_nd_blk_region(dev));
  40         else
  41                 kfree(nd_region);
  42 }
  43
  44 static struct device_type nd_blk_device_type = {
  45         .name = "nd_blk",
  46         .release = nd_region_release,
  47 };
  48
  49 static struct device_type nd_pmem_device_type = {
  50         .name = "nd_pmem",
  51         .release = nd_region_release,
  52 };
  53
  54 static struct device_type nd_volatile_device_type = {
  55         .name = "nd_volatile",
  56         .release = nd_region_release,
  57 };
  58
  59 bool is_nd_pmem(struct device *dev)
  60 {
  61         return dev ? dev->type == &nd_pmem_device_type : false;
  62 }
  63
  64 bool is_nd_blk(struct device *dev)
  65 {
  66         return dev ? dev->type == &nd_blk_device_type : false;
  67 }
  68
  69 struct nd_region *to_nd_region(struct device *dev)
  70 {
  71         struct nd_region *nd_region = container_of(dev, struct nd_region, dev);
  72
  73         WARN_ON(dev->type->release != nd_region_release);
  74         return nd_region;
  75 }
  76 EXPORT_SYMBOL_GPL(to_nd_region);
  77
  78 struct nd_blk_region *to_nd_blk_region(struct device *dev)
  79 {
  80         struct nd_region *nd_region = to_nd_region(dev);
  81
  82         WARN_ON(!is_nd_blk(dev));
  83         return container_of(nd_region, struct nd_blk_region, nd_region);
  84 }
  85 EXPORT_SYMBOL_GPL(to_nd_blk_region);
  86
  87 void *nd_region_provider_data(struct nd_region *nd_region)
  88 {
  89         return nd_region->provider_data;
  90 }
  91 EXPORT_SYMBOL_GPL(nd_region_provider_data);
  92
  93 void *nd_blk_region_provider_data(struct nd_blk_region *ndbr)
  94 {
  95         return ndbr->blk_provider_data;
  96 }
  97 EXPORT_SYMBOL_GPL(nd_blk_region_provider_data);
  98
  99 void nd_blk_region_set_provider_data(struct nd_blk_region *ndbr, void *data)
 100 {
 101         ndbr->blk_provider_data = data;
 102 }
 103 EXPORT_SYMBOL_GPL(nd_blk_region_set_provider_data);
 104
 105 /**
 106  * nd_region_to_nstype() - region to an integer namespace type
 107  * @nd_region: region-device to interrogate
 108  *
 109  * This is the 'nstype' attribute of a region as well, an input to the
 110  * MODALIAS for namespace devices, and bit number for a nvdimm_bus to match
 111  * namespace devices with namespace drivers.
 112  */
 113 int nd_region_to_nstype(struct nd_region *nd_region)
 114 {
 115         if (is_nd_pmem(&nd_region->dev)) {
 116                 u16 i, alias;
 117
 118                 for (i = 0, alias = 0; i < nd_region->ndr_mappings; i++) {
 119                         struct nd_mapping *nd_mapping = &nd_region->mapping[i];
 120                         struct nvdimm *nvdimm = nd_mapping->nvdimm;
 121
 122                         if (nvdimm->flags & NDD_ALIASING)
 123                                 alias++;
 124                 }
 125                 if (alias)
 126                         return ND_DEVICE_NAMESPACE_PMEM;
 127                 else
 128                         return ND_DEVICE_NAMESPACE_IO;
 129         } else if (is_nd_blk(&nd_region->dev)) {
 130                 return ND_DEVICE_NAMESPACE_BLK;
 131         }
 132
 133         return 0;
 134 }
 135 EXPORT_SYMBOL(nd_region_to_nstype);
 136
 137 static int is_uuid_busy(struct device *dev, void *data)
 138 {
 139         struct nd_region *nd_region = to_nd_region(dev->parent);
 140         u8 *uuid = data;
 141
 142         switch (nd_region_to_nstype(nd_region)) {
 143         case ND_DEVICE_NAMESPACE_PMEM: {
 144                 struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);
 145
 146                 if (!nspm->uuid)
 147                         break;
 148                 if (memcmp(uuid, nspm->uuid, NSLABEL_UUID_LEN) == 0)
 149                         return -EBUSY;
 150                 break;
 151         }
 152         case ND_DEVICE_NAMESPACE_BLK: {
 153                 struct nd_namespace_blk *nsblk = to_nd_namespace_blk(dev);
 154
 155                 if (!nsblk->uuid)
 156                         break;
 157                 if (memcmp(uuid, nsblk->uuid, NSLABEL_UUID_LEN) == 0)
 158                         return -EBUSY;
 159                 break;
 160         }
 161         default:
 162                 break;
 163         }
 164
 165         return 0;
 166 }
 167
 168 static int is_namespace_uuid_busy(struct device *dev, void *data)
 169 {
 170         if (is_nd_pmem(dev) || is_nd_blk(dev))
 171                 return device_for_each_child(dev, data, is_uuid_busy);
 172         return 0;
 173 }
 174
 175 /**
 176  * nd_is_uuid_unique - verify that no other namespace has @uuid
 177  * @dev: any device on a nvdimm_bus
 178  * @uuid: uuid to check
 179  */
 180 bool nd_is_uuid_unique(struct device *dev, u8 *uuid)
 181 {
 182         struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
 183
 184         if (!nvdimm_bus)
 185                 return false;
 186         WARN_ON_ONCE(!is_nvdimm_bus_locked(&nvdimm_bus->dev));
 187         if (device_for_each_child(&nvdimm_bus->dev, uuid,
 188                                 is_namespace_uuid_busy) != 0)
 189                 return false;
 190         return true;
 191 }
 192
 193 static ssize_t size_show(struct device *dev,
 194                 struct device_attribute *attr, char *buf)
 195 {
 196         struct nd_region *nd_region = to_nd_region(dev);
 197         unsigned long long size = 0;
 198
 199         if (is_nd_pmem(dev)) {
 200                 size = nd_region->ndr_size;
 201         } else if (nd_region->ndr_mappings == 1) {
 202                 struct nd_mapping *nd_mapping = &nd_region->mapping[0];
 203
 204                 size = nd_mapping->size;
 205         }
 206
 207         return sprintf(buf, "%llu\n", size);
 208 }
 209 static DEVICE_ATTR_RO(size);
 210
 211 static ssize_t mappings_show(struct device *dev,
 212                 struct device_attribute *attr, char *buf)
 213 {
 214         struct nd_region *nd_region = to_nd_region(dev);
 215
 216         return sprintf(buf, "%d\n", nd_region->ndr_mappings);
 217 }
 218 static DEVICE_ATTR_RO(mappings);
 219
 220 static ssize_t nstype_show(struct device *dev,
 221                 struct device_attribute *attr, char *buf)
 222 {
 223         struct nd_region *nd_region = to_nd_region(dev);
 224
 225         return sprintf(buf, "%d\n", nd_region_to_nstype(nd_region));
 226 }
 227 static DEVICE_ATTR_RO(nstype);
 228
 229 static ssize_t set_cookie_show(struct device *dev,
 230                 struct device_attribute *attr, char *buf)
 231 {
 232         struct nd_region *nd_region = to_nd_region(dev);
 233         struct nd_interleave_set *nd_set = nd_region->nd_set;
 234
 235         if (is_nd_pmem(dev) && nd_set)
 236                 /* pass, should be precluded by region_visible */;
 237         else
 238                 return -ENXIO;
 239
 240         return sprintf(buf, "%#llx\n", nd_set->cookie);
 241 }
 242 static DEVICE_ATTR_RO(set_cookie);
 243
 244 resource_size_t nd_region_available_dpa(struct nd_region *nd_region)
 245 {
 246         resource_size_t blk_max_overlap = 0, available, overlap;
 247         int i;
 248
 249         WARN_ON(!is_nvdimm_bus_locked(&nd_region->dev));
 250
 251  retry:
 252         available = 0;
 253         overlap = blk_max_overlap;
 254         for (i = 0; i < nd_region->ndr_mappings; i++) {
 255                 struct nd_mapping *nd_mapping = &nd_region->mapping[i];
 256                 struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
 257
 258                 /* if a dimm is disabled the available capacity is zero */
 259                 if (!ndd)
 260                         return 0;
 261
 262                 if (is_nd_pmem(&nd_region->dev)) {
 263                         available += nd_pmem_available_dpa(nd_region,
 264                                         nd_mapping, &overlap);
 265                         if (overlap > blk_max_overlap) {
 266                                 blk_max_overlap = overlap;
 267                                 goto retry;
 268                         }
 269                 } else if (is_nd_blk(&nd_region->dev)) {
 270                         available += nd_blk_available_dpa(nd_mapping);
 271                 }
 272         }
 273
 274         return available;
 275 }
 276
 277 static ssize_t available_size_show(struct device *dev,
 278                 struct device_attribute *attr, char *buf)
 279 {
 280         struct nd_region *nd_region = to_nd_region(dev);
 281         unsigned long long available = 0;
 282
 283         /*
 284          * Flush in-flight updates and grab a snapshot of the available
 285          * size.  Of course, this value is potentially invalidated the
 286          * memory nvdimm_bus_lock() is dropped, but that's userspace's
 287          * problem to not race itself.
 288          */
 289         nvdimm_bus_lock(dev);
 290         wait_nvdimm_bus_probe_idle(dev);
 291         available = nd_region_available_dpa(nd_region);
 292         nvdimm_bus_unlock(dev);
 293
 294         return sprintf(buf, "%llu\n", available);
 295 }
 296 static DEVICE_ATTR_RO(available_size);
 297
 298 static ssize_t init_namespaces_show(struct device *dev,
 299                 struct device_attribute *attr, char *buf)
 300 {
 301         struct nd_region_namespaces *num_ns = dev_get_drvdata(dev);
 302         ssize_t rc;
 303
 304         nvdimm_bus_lock(dev);
 305         if (num_ns)
 306                 rc = sprintf(buf, "%d/%d\n", num_ns->active, num_ns->count);
 307         else
 308                 rc = -ENXIO;
 309         nvdimm_bus_unlock(dev);
 310
 311         return rc;
 312 }
 313 static DEVICE_ATTR_RO(init_namespaces);
 314
 315 static ssize_t namespace_seed_show(struct device *dev,
 316                 struct device_attribute *attr, char *buf)
 317 {
 318         struct nd_region *nd_region = to_nd_region(dev);
 319         ssize_t rc;
 320
 321         nvdimm_bus_lock(dev);
 322         if (nd_region->ns_seed)
 323                 rc = sprintf(buf, "%s\n", dev_name(nd_region->ns_seed));
 324         else
 325                 rc = sprintf(buf, "\n");
 326         nvdimm_bus_unlock(dev);
 327         return rc;
 328 }
 329 static DEVICE_ATTR_RO(namespace_seed);
 330
 331 static ssize_t btt_seed_show(struct device *dev,
 332                 struct device_attribute *attr, char *buf)
 333 {
 334         struct nd_region *nd_region = to_nd_region(dev);
 335         ssize_t rc;
 336
 337         nvdimm_bus_lock(dev);
 338         if (nd_region->btt_seed)
 339                 rc = sprintf(buf, "%s\n", dev_name(nd_region->btt_seed));
 340         else
 341                 rc = sprintf(buf, "\n");
 342         nvdimm_bus_unlock(dev);
 343
 344         return rc;
 345 }
 346 static DEVICE_ATTR_RO(btt_seed);
 347
 348 static ssize_t pfn_seed_show(struct device *dev,
 349                 struct device_attribute *attr, char *buf)
 350 {
 351         struct nd_region *nd_region = to_nd_region(dev);
 352         ssize_t rc;
 353
 354         nvdimm_bus_lock(dev);
 355         if (nd_region->pfn_seed)
 356                 rc = sprintf(buf, "%s\n", dev_name(nd_region->pfn_seed));
 357         else
 358                 rc = sprintf(buf, "\n");
 359         nvdimm_bus_unlock(dev);
 360
 361         return rc;
 362 }
 363 static DEVICE_ATTR_RO(pfn_seed);
 364
 365 static ssize_t read_only_show(struct device *dev,
 366                 struct device_attribute *attr, char *buf)
 367 {
 368         struct nd_region *nd_region = to_nd_region(dev);
 369
 370         return sprintf(buf, "%d\n", nd_region->ro);
 371 }
 372
 373 static ssize_t read_only_store(struct device *dev,
 374                 struct device_attribute *attr, const char *buf, size_t len)
 375 {
 376         bool ro;
 377         int rc = strtobool(buf, &ro);
 378         struct nd_region *nd_region = to_nd_region(dev);
 379
 380         if (rc)
 381                 return rc;
 382
 383         nd_region->ro = ro;
 384         return len;
 385 }
 386 static DEVICE_ATTR_RW(read_only);
 387
 388 static struct attribute *nd_region_attributes[] = {
 389         &dev_attr_size.attr,
 390         &dev_attr_nstype.attr,
 391         &dev_attr_mappings.attr,
 392         &dev_attr_btt_seed.attr,
 393         &dev_attr_pfn_seed.attr,
 394         &dev_attr_read_only.attr,
 395         &dev_attr_set_cookie.attr,
 396         &dev_attr_available_size.attr,
 397         &dev_attr_namespace_seed.attr,
 398         &dev_attr_init_namespaces.attr,
 399         NULL,
 400 };
 401
 402 static umode_t region_visible(struct kobject *kobj, struct attribute *a, int n)
 403 {
 404         struct device *dev = container_of(kobj, typeof(*dev), kobj);
 405         struct nd_region *nd_region = to_nd_region(dev);
 406         struct nd_interleave_set *nd_set = nd_region->nd_set;
 407         int type = nd_region_to_nstype(nd_region);
 408
 409         if (a != &dev_attr_set_cookie.attr
 410                         && a != &dev_attr_available_size.attr)
 411                 return a->mode;
 412
 413         if ((type == ND_DEVICE_NAMESPACE_PMEM
 414                                 || type == ND_DEVICE_NAMESPACE_BLK)
 415                         && a == &dev_attr_available_size.attr)
 416                 return a->mode;
 417         else if (is_nd_pmem(dev) && nd_set)
 418                 return a->mode;
 419
 420         return 0;
 421 }
 422
 423 struct attribute_group nd_region_attribute_group = {
 424         .attrs = nd_region_attributes,
 425         .is_visible = region_visible,
 426 };
 427 EXPORT_SYMBOL_GPL(nd_region_attribute_group);
 428
 429 u64 nd_region_interleave_set_cookie(struct nd_region *nd_region)
 430 {
 431         struct nd_interleave_set *nd_set = nd_region->nd_set;
 432
 433         if (nd_set)
 434                 return nd_set->cookie;
 435         return 0;
 436 }
 437
 438 /*
 439  * Upon successful probe/remove, take/release a reference on the
 440  * associated interleave set (if present), and plant new btt + namespace
 441  * seeds.  Also, on the removal of a BLK region, notify the provider to
 442  * disable the region.
 443  */
 444 static void nd_region_notify_driver_action(struct nvdimm_bus *nvdimm_bus,
 445                 struct device *dev, bool probe)
 446 {
 447         struct nd_region *nd_region;
 448
 449         if (!probe && (is_nd_pmem(dev) || is_nd_blk(dev))) {
 450                 int i;
 451
 452                 nd_region = to_nd_region(dev);
 453                 for (i = 0; i < nd_region->ndr_mappings; i++) {
 454                         struct nd_mapping *nd_mapping = &nd_region->mapping[i];
 455                         struct nvdimm_drvdata *ndd = nd_mapping->ndd;
 456                         struct nvdimm *nvdimm = nd_mapping->nvdimm;
 457
 458                         kfree(nd_mapping->labels);
 459                         nd_mapping->labels = NULL;
 460                         put_ndd(ndd);
 461                         nd_mapping->ndd = NULL;
 462                         if (ndd)
 463                                 atomic_dec(&nvdimm->busy);
 464                 }
 465
 466                 if (is_nd_pmem(dev))
 467                         return;
 468
 469                 to_nd_blk_region(dev)->disable(nvdimm_bus, dev);
 470         }
 471         if (dev->parent && is_nd_blk(dev->parent) && probe) {
 472                 nd_region = to_nd_region(dev->parent);
 473                 nvdimm_bus_lock(dev);
 474                 if (nd_region->ns_seed == dev)
 475                         nd_region_create_blk_seed(nd_region);
 476                 nvdimm_bus_unlock(dev);
 477         }
 478         if (is_nd_btt(dev) && probe) {
 479                 struct nd_btt *nd_btt = to_nd_btt(dev);
 480
 481                 nd_region = to_nd_region(dev->parent);
 482                 nvdimm_bus_lock(dev);
 483                 if (nd_region->btt_seed == dev)
 484                         nd_region_create_btt_seed(nd_region);
 485                 if (nd_region->ns_seed == &nd_btt->ndns->dev &&
 486                                 is_nd_blk(dev->parent))
 487                         nd_region_create_blk_seed(nd_region);
 488                 nvdimm_bus_unlock(dev);
 489         }
 490 }
 491
 492 void nd_region_probe_success(struct nvdimm_bus *nvdimm_bus, struct device *dev)
 493 {
 494         nd_region_notify_driver_action(nvdimm_bus, dev, true);
 495 }
 496
 497 void nd_region_disable(struct nvdimm_bus *nvdimm_bus, struct device *dev)
 498 {
 499         nd_region_notify_driver_action(nvdimm_bus, dev, false);
 500 }
 501
 502 static ssize_t mappingN(struct device *dev, char *buf, int n)
 503 {
 504         struct nd_region *nd_region = to_nd_region(dev);
 505         struct nd_mapping *nd_mapping;
 506         struct nvdimm *nvdimm;
 507
 508         if (n >= nd_region->ndr_mappings)
 509                 return -ENXIO;
 510         nd_mapping = &nd_region->mapping[n];
 511         nvdimm = nd_mapping->nvdimm;
 512
 513         return sprintf(buf, "%s,%llu,%llu\n", dev_name(&nvdimm->dev),
 514                         nd_mapping->start, nd_mapping->size);
 515 }
 516
 517 #define REGION_MAPPING(idx) \
 518 static ssize_t mapping##idx##_show(struct device *dev,          \
 519                 struct device_attribute *attr, char *buf)       \
 520 {                                                               \
 521         return mappingN(dev, buf, idx);                         \
 522 }                                                               \
 523 static DEVICE_ATTR_RO(mapping##idx)
 524
 525 /*
 526  * 32 should be enough for a while, even in the presence of socket
 527  * interleave a 32-way interleave set is a degenerate case.
 528  */
 529 REGION_MAPPING(0);
 530 REGION_MAPPING(1);
 531 REGION_MAPPING(2);
 532 REGION_MAPPING(3);
 533 REGION_MAPPING(4);
 534 REGION_MAPPING(5);
 535 REGION_MAPPING(6);
 536 REGION_MAPPING(7);
 537 REGION_MAPPING(8);
 538 REGION_MAPPING(9);
 539 REGION_MAPPING(10);
 540 REGION_MAPPING(11);
 541 REGION_MAPPING(12);
 542 REGION_MAPPING(13);
 543 REGION_MAPPING(14);
 544 REGION_MAPPING(15);
 545 REGION_MAPPING(16);
 546 REGION_MAPPING(17);
 547 REGION_MAPPING(18);
 548 REGION_MAPPING(19);
 549 REGION_MAPPING(20);
 550 REGION_MAPPING(21);
 551 REGION_MAPPING(22);
 552 REGION_MAPPING(23);
 553 REGION_MAPPING(24);
 554 REGION_MAPPING(25);
 555 REGION_MAPPING(26);
 556 REGION_MAPPING(27);
 557 REGION_MAPPING(28);
 558 REGION_MAPPING(29);
 559 REGION_MAPPING(30);
 560 REGION_MAPPING(31);
 561
 562 static umode_t mapping_visible(struct kobject *kobj, struct attribute *a, int n)
 563 {
 564         struct device *dev = container_of(kobj, struct device, kobj);
 565         struct nd_region *nd_region = to_nd_region(dev);
 566
 567         if (n < nd_region->ndr_mappings)
 568                 return a->mode;
 569         return 0;
 570 }
 571
 572 static struct attribute *mapping_attributes[] = {
 573         &dev_attr_mapping0.attr,
 574         &dev_attr_mapping1.attr,
 575         &dev_attr_mapping2.attr,
 576         &dev_attr_mapping3.attr,
 577         &dev_attr_mapping4.attr,
 578         &dev_attr_mapping5.attr,
 579         &dev_attr_mapping6.attr,
 580         &dev_attr_mapping7.attr,
 581         &dev_attr_mapping8.attr,
 582         &dev_attr_mapping9.attr,
 583         &dev_attr_mapping10.attr,
 584         &dev_attr_mapping11.attr,
 585         &dev_attr_mapping12.attr,
 586         &dev_attr_mapping13.attr,
 587         &dev_attr_mapping14.attr,
 588         &dev_attr_mapping15.attr,
 589         &dev_attr_mapping16.attr,
 590         &dev_attr_mapping17.attr,
 591         &dev_attr_mapping18.attr,
 592         &dev_attr_mapping19.attr,
 593         &dev_attr_mapping20.attr,
 594         &dev_attr_mapping21.attr,
 595         &dev_attr_mapping22.attr,
 596         &dev_attr_mapping23.attr,
 597         &dev_attr_mapping24.attr,
 598         &dev_attr_mapping25.attr,
 599         &dev_attr_mapping26.attr,
 600         &dev_attr_mapping27.attr,
 601         &dev_attr_mapping28.attr,
 602         &dev_attr_mapping29.attr,
 603         &dev_attr_mapping30.attr,
 604         &dev_attr_mapping31.attr,
 605         NULL,
 606 };
 607
 608 struct attribute_group nd_mapping_attribute_group = {
 609         .is_visible = mapping_visible,
 610         .attrs = mapping_attributes,
 611 };
 612 EXPORT_SYMBOL_GPL(nd_mapping_attribute_group);
 613
 614 int nd_blk_region_init(struct nd_region *nd_region)
 615 {
 616         struct device *dev = &nd_region->dev;
 617         struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
 618
 619         if (!is_nd_blk(dev))
 620                 return 0;
 621
 622         if (nd_region->ndr_mappings < 1) {
 623                 dev_err(dev, "invalid BLK region\n");
 624                 return -ENXIO;
 625         }
 626
 627         return to_nd_blk_region(dev)->enable(nvdimm_bus, dev);
 628 }
 629
 630 /**
 631  * nd_region_acquire_lane - allocate and lock a lane
 632  * @nd_region: region id and number of lanes possible
 633  *
 634  * A lane correlates to a BLK-data-window and/or a log slot in the BTT.
 635  * We optimize for the common case where there are 256 lanes, one
 636  * per-cpu.  For larger systems we need to lock to share lanes.  For now
 637  * this implementation assumes the cost of maintaining an allocator for
 638  * free lanes is on the order of the lock hold time, so it implements a
 639  * static lane = cpu % num_lanes mapping.
 640  *
 641  * In the case of a BTT instance on top of a BLK namespace a lane may be
 642  * acquired recursively.  We lock on the first instance.
 643  *
 644  * In the case of a BTT instance on top of PMEM, we only acquire a lane
 645  * for the BTT metadata updates.
 646  */
 647 unsigned int nd_region_acquire_lane(struct nd_region *nd_region)
 648 {
 649         unsigned int cpu, lane;
 650
 651         cpu = get_cpu();
 652         if (nd_region->num_lanes < nr_cpu_ids) {
 653                 struct nd_percpu_lane *ndl_lock, *ndl_count;
 654
 655                 lane = cpu % nd_region->num_lanes;
 656                 ndl_count = per_cpu_ptr(nd_region->lane, cpu);
 657                 ndl_lock = per_cpu_ptr(nd_region->lane, lane);
 658                 if (ndl_count->count++ == 0)
 659                         spin_lock(&ndl_lock->lock);
 660         } else
 661                 lane = cpu;
 662
 663         return lane;
 664 }
 665 EXPORT_SYMBOL(nd_region_acquire_lane);
 666
 667 void nd_region_release_lane(struct nd_region *nd_region, unsigned int lane)
 668 {
 669         if (nd_region->num_lanes < nr_cpu_ids) {
 670                 unsigned int cpu = get_cpu();
 671                 struct nd_percpu_lane *ndl_lock, *ndl_count;
 672
 673                 ndl_count = per_cpu_ptr(nd_region->lane, cpu);
 674                 ndl_lock = per_cpu_ptr(nd_region->lane, lane);
 675                 if (--ndl_count->count == 0)
 676                         spin_unlock(&ndl_lock->lock);
 677                 put_cpu();
 678         }
 679         put_cpu();
 680 }
 681 EXPORT_SYMBOL(nd_region_release_lane);
 682
 683 static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
 684                 struct nd_region_desc *ndr_desc, struct device_type *dev_type,
 685                 const char *caller)
 686 {
 687         struct nd_region *nd_region;
 688         struct device *dev;
 689         void *region_buf;
 690         unsigned int i;
 691         int ro = 0;
 692
 693         for (i = 0; i < ndr_desc->num_mappings; i++) {
 694                 struct nd_mapping *nd_mapping = &ndr_desc->nd_mapping[i];
 695                 struct nvdimm *nvdimm = nd_mapping->nvdimm;
 696
 697                 if ((nd_mapping->start | nd_mapping->size) % SZ_4K) {
 698                         dev_err(&nvdimm_bus->dev, "%s: %s mapping%d is not 4K aligned\n",
 699                                         caller, dev_name(&nvdimm->dev), i);
 700
 701                         return NULL;
 702                 }
 703
 704                 if (nvdimm->flags & NDD_UNARMED)
 705                         ro = 1;
 706         }
 707
 708         if (dev_type == &nd_blk_device_type) {
 709                 struct nd_blk_region_desc *ndbr_desc;
 710                 struct nd_blk_region *ndbr;
 711
 712                 ndbr_desc = to_blk_region_desc(ndr_desc);
 713                 ndbr = kzalloc(sizeof(*ndbr) + sizeof(struct nd_mapping)
 714                                 * ndr_desc->num_mappings,
 715                                 GFP_KERNEL);
 716                 if (ndbr) {
 717                         nd_region = &ndbr->nd_region;
 718                         ndbr->enable = ndbr_desc->enable;
 719                         ndbr->disable = ndbr_desc->disable;
 720                         ndbr->do_io = ndbr_desc->do_io;
 721                 }
 722                 region_buf = ndbr;
 723         } else {
 724                 nd_region = kzalloc(sizeof(struct nd_region)
 725                                 + sizeof(struct nd_mapping)
 726                                 * ndr_desc->num_mappings,
 727                                 GFP_KERNEL);
 728                 region_buf = nd_region;
 729         }
 730
 731         if (!region_buf)
 732                 return NULL;
 733         nd_region->id = ida_simple_get(&region_ida, 0, 0, GFP_KERNEL);
 734         if (nd_region->id < 0)
 735                 goto err_id;
 736
 737         nd_region->lane = alloc_percpu(struct nd_percpu_lane);
 738         if (!nd_region->lane)
 739                 goto err_percpu;
 740
 741         for (i = 0; i < nr_cpu_ids; i++) {
 742                 struct nd_percpu_lane *ndl;
 743
 744                 ndl = per_cpu_ptr(nd_region->lane, i);
 745                 spin_lock_init(&ndl->lock);
 746                 ndl->count = 0;
 747         }
 748
 749         memcpy(nd_region->mapping, ndr_desc->nd_mapping,
 750                         sizeof(struct nd_mapping) * ndr_desc->num_mappings);
 751         for (i = 0; i < ndr_desc->num_mappings; i++) {
 752                 struct nd_mapping *nd_mapping = &ndr_desc->nd_mapping[i];
 753                 struct nvdimm *nvdimm = nd_mapping->nvdimm;
 754
 755                 get_device(&nvdimm->dev);
 756         }
 757         nd_region->ndr_mappings = ndr_desc->num_mappings;
 758         nd_region->provider_data = ndr_desc->provider_data;
 759         nd_region->nd_set = ndr_desc->nd_set;
 760         nd_region->num_lanes = ndr_desc->num_lanes;
 761         nd_region->flags = ndr_desc->flags;
 762         nd_region->ro = ro;
 763         nd_region->numa_node = ndr_desc->numa_node;
 764         ida_init(&nd_region->ns_ida);
 765         ida_init(&nd_region->btt_ida);
 766         ida_init(&nd_region->pfn_ida);
 767         dev = &nd_region->dev;
 768         dev_set_name(dev, "region%d", nd_region->id);
 769         dev->parent = &nvdimm_bus->dev;
 770         dev->type = dev_type;
 771         dev->groups = ndr_desc->attr_groups;
 772         nd_region->ndr_size = resource_size(ndr_desc->res);
 773         nd_region->ndr_start = ndr_desc->res->start;
 774         nd_device_register(dev);
 775
 776         return nd_region;
 777
 778  err_percpu:
 779         ida_simple_remove(&region_ida, nd_region->id);
 780  err_id:
 781         kfree(region_buf);
 782         return NULL;
 783 }
 784
 785 struct nd_region *nvdimm_pmem_region_create(struct nvdimm_bus *nvdimm_bus,
 786                 struct nd_region_desc *ndr_desc)
 787 {
 788         ndr_desc->num_lanes = ND_MAX_LANES;
 789         return nd_region_create(nvdimm_bus, ndr_desc, &nd_pmem_device_type,
 790                         __func__);
 791 }
 792 EXPORT_SYMBOL_GPL(nvdimm_pmem_region_create);
 793
 794 struct nd_region *nvdimm_blk_region_create(struct nvdimm_bus *nvdimm_bus,
 795                 struct nd_region_desc *ndr_desc)
 796 {
 797         if (ndr_desc->num_mappings > 1)
 798                 return NULL;
 799         ndr_desc->num_lanes = min(ndr_desc->num_lanes, ND_MAX_LANES);
 800         return nd_region_create(nvdimm_bus, ndr_desc, &nd_blk_device_type,
 801                         __func__);
 802 }
 803 EXPORT_SYMBOL_GPL(nvdimm_blk_region_create);
 804
 805 struct nd_region *nvdimm_volatile_region_create(struct nvdimm_bus *nvdimm_bus,
 806                 struct nd_region_desc *ndr_desc)
 807 {
 808         ndr_desc->num_lanes = ND_MAX_LANES;
 809         return nd_region_create(nvdimm_bus, ndr_desc, &nd_volatile_device_type,
 810                         __func__);
 811 }
 812 EXPORT_SYMBOL_GPL(nvdimm_volatile_region_create);