drivers/nvdimm/dimm_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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14 #include <linux/vmalloc.h>
  15 #include <linux/device.h>
  16 #include <linux/ndctl.h>
  17 #include <linux/slab.h>
  18 #include <linux/io.h>
  19 #include <linux/fs.h>
  20 #include <linux/mm.h>
  21 #include "nd-core.h"
  22 #include "label.h"
  23 #include "pmem.h"
  24 #include "nd.h"
  25
  26 static DEFINE_IDA(dimm_ida);
  27
  28 /*
  29  * Retrieve bus and dimm handle and return if this bus supports
  30  * get_config_data commands
  31  */
  32 int nvdimm_check_config_data(struct device *dev)
  33 {
  34         struct nvdimm *nvdimm = to_nvdimm(dev);
  35
  36         if (!nvdimm->cmd_mask ||
  37             !test_bit(ND_CMD_GET_CONFIG_DATA, &nvdimm->cmd_mask)) {
  38                 if (test_bit(NDD_ALIASING, &nvdimm->flags))
  39                         return -ENXIO;
  40                 else
  41                         return -ENOTTY;
  42         }
  43
  44         return 0;
  45 }
  46
  47 static int validate_dimm(struct nvdimm_drvdata *ndd)
  48 {
  49         int rc;
  50
  51         if (!ndd)
  52                 return -EINVAL;
  53
  54         rc = nvdimm_check_config_data(ndd->dev);
  55         if (rc)
  56                 dev_dbg(ndd->dev, "%pf: %s error: %d\n",
  57                                 __builtin_return_address(0), __func__, rc);
  58         return rc;
  59 }
  60
  61 /**
  62  * nvdimm_init_nsarea - determine the geometry of a dimm's namespace area
  63  * @nvdimm: dimm to initialize
  64  */
  65 int nvdimm_init_nsarea(struct nvdimm_drvdata *ndd)
  66 {
  67         struct nd_cmd_get_config_size *cmd = &ndd->nsarea;
  68         struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(ndd->dev);
  69         struct nvdimm_bus_descriptor *nd_desc;
  70         int rc = validate_dimm(ndd);
  71         int cmd_rc = 0;
  72
  73         if (rc)
  74                 return rc;
  75
  76         if (cmd->config_size)
  77                 return 0; /* already valid */
  78
  79         memset(cmd, 0, sizeof(*cmd));
  80         nd_desc = nvdimm_bus->nd_desc;
  81         rc = nd_desc->ndctl(nd_desc, to_nvdimm(ndd->dev),
  82                         ND_CMD_GET_CONFIG_SIZE, cmd, sizeof(*cmd), &cmd_rc);
  83         if (rc < 0)
  84                 return rc;
  85         return cmd_rc;
  86 }
  87
  88 int nvdimm_init_config_data(struct nvdimm_drvdata *ndd)
  89 {
  90         struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(ndd->dev);
  91         struct nd_cmd_get_config_data_hdr *cmd;
  92         struct nvdimm_bus_descriptor *nd_desc;
  93         int rc = validate_dimm(ndd);
  94         u32 max_cmd_size, config_size;
  95         size_t offset;
  96
  97         if (rc)
  98                 return rc;
  99
 100         if (ndd->data)
 101                 return 0;
 102
 103         if (ndd->nsarea.status || ndd->nsarea.max_xfer == 0
 104                         || ndd->nsarea.config_size < ND_LABEL_MIN_SIZE) {
 105                 dev_dbg(ndd->dev, "failed to init config data area: (%d:%d)\n",
 106                                 ndd->nsarea.max_xfer, ndd->nsarea.config_size);
 107                 return -ENXIO;
 108         }
 109
 110         ndd->data = kvmalloc(ndd->nsarea.config_size, GFP_KERNEL);
 111         if (!ndd->data)
 112                 return -ENOMEM;
 113
 114         max_cmd_size = min_t(u32, PAGE_SIZE, ndd->nsarea.max_xfer);
 115         cmd = kzalloc(max_cmd_size + sizeof(*cmd), GFP_KERNEL);
 116         if (!cmd)
 117                 return -ENOMEM;
 118
 119         nd_desc = nvdimm_bus->nd_desc;
 120         for (config_size = ndd->nsarea.config_size, offset = 0;
 121                         config_size; config_size -= cmd->in_length,
 122                         offset += cmd->in_length) {
 123                 cmd->in_length = min(config_size, max_cmd_size);
 124                 cmd->in_offset = offset;
 125                 rc = nd_desc->ndctl(nd_desc, to_nvdimm(ndd->dev),
 126                                 ND_CMD_GET_CONFIG_DATA, cmd,
 127                                 cmd->in_length + sizeof(*cmd), NULL);
 128                 if (rc || cmd->status) {
 129                         rc = -ENXIO;
 130                         break;
 131                 }
 132                 memcpy(ndd->data + offset, cmd->out_buf, cmd->in_length);
 133         }
 134         dev_dbg(ndd->dev, "%s: len: %zu rc: %d\n", __func__, offset, rc);
 135         kfree(cmd);
 136
 137         return rc;
 138 }
 139
 140 int nvdimm_set_config_data(struct nvdimm_drvdata *ndd, size_t offset,
 141                 void *buf, size_t len)
 142 {
 143         int rc = validate_dimm(ndd);
 144         size_t max_cmd_size, buf_offset;
 145         struct nd_cmd_set_config_hdr *cmd;
 146         struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(ndd->dev);
 147         struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;
 148
 149         if (rc)
 150                 return rc;
 151
 152         if (!ndd->data)
 153                 return -ENXIO;
 154
 155         if (offset + len > ndd->nsarea.config_size)
 156                 return -ENXIO;
 157
 158         max_cmd_size = min_t(u32, PAGE_SIZE, len);
 159         max_cmd_size = min_t(u32, max_cmd_size, ndd->nsarea.max_xfer);
 160         cmd = kzalloc(max_cmd_size + sizeof(*cmd) + sizeof(u32), GFP_KERNEL);
 161         if (!cmd)
 162                 return -ENOMEM;
 163
 164         for (buf_offset = 0; len; len -= cmd->in_length,
 165                         buf_offset += cmd->in_length) {
 166                 size_t cmd_size;
 167                 u32 *status;
 168
 169                 cmd->in_offset = offset + buf_offset;
 170                 cmd->in_length = min(max_cmd_size, len);
 171                 memcpy(cmd->in_buf, buf + buf_offset, cmd->in_length);
 172
 173                 /* status is output in the last 4-bytes of the command buffer */
 174                 cmd_size = sizeof(*cmd) + cmd->in_length + sizeof(u32);
 175                 status = ((void *) cmd) + cmd_size - sizeof(u32);
 176
 177                 rc = nd_desc->ndctl(nd_desc, to_nvdimm(ndd->dev),
 178                                 ND_CMD_SET_CONFIG_DATA, cmd, cmd_size, NULL);
 179                 if (rc || *status) {
 180                         rc = rc ? rc : -ENXIO;
 181                         break;
 182                 }
 183         }
 184         kfree(cmd);
 185
 186         return rc;
 187 }
 188
 189 void nvdimm_set_aliasing(struct device *dev)
 190 {
 191         struct nvdimm *nvdimm = to_nvdimm(dev);
 192
 193         set_bit(NDD_ALIASING, &nvdimm->flags);
 194 }
 195
 196 void nvdimm_set_locked(struct device *dev)
 197 {
 198         struct nvdimm *nvdimm = to_nvdimm(dev);
 199
 200         set_bit(NDD_LOCKED, &nvdimm->flags);
 201 }
 202
 203 void nvdimm_clear_locked(struct device *dev)
 204 {
 205         struct nvdimm *nvdimm = to_nvdimm(dev);
 206
 207         clear_bit(NDD_LOCKED, &nvdimm->flags);
 208 }
 209
 210 static void nvdimm_release(struct device *dev)
 211 {
 212         struct nvdimm *nvdimm = to_nvdimm(dev);
 213
 214         ida_simple_remove(&dimm_ida, nvdimm->id);
 215         kfree(nvdimm);
 216 }
 217
 218 static struct device_type nvdimm_device_type = {
 219         .name = "nvdimm",
 220         .release = nvdimm_release,
 221 };
 222
 223 bool is_nvdimm(struct device *dev)
 224 {
 225         return dev->type == &nvdimm_device_type;
 226 }
 227
 228 struct nvdimm *to_nvdimm(struct device *dev)
 229 {
 230         struct nvdimm *nvdimm = container_of(dev, struct nvdimm, dev);
 231
 232         WARN_ON(!is_nvdimm(dev));
 233         return nvdimm;
 234 }
 235 EXPORT_SYMBOL_GPL(to_nvdimm);
 236
 237 struct nvdimm *nd_blk_region_to_dimm(struct nd_blk_region *ndbr)
 238 {
 239         struct nd_region *nd_region = &ndbr->nd_region;
 240         struct nd_mapping *nd_mapping = &nd_region->mapping[0];
 241
 242         return nd_mapping->nvdimm;
 243 }
 244 EXPORT_SYMBOL_GPL(nd_blk_region_to_dimm);
 245
 246 unsigned long nd_blk_memremap_flags(struct nd_blk_region *ndbr)
 247 {
 248         /* pmem mapping properties are private to libnvdimm */
 249         return ARCH_MEMREMAP_PMEM;
 250 }
 251 EXPORT_SYMBOL_GPL(nd_blk_memremap_flags);
 252
 253 struct nvdimm_drvdata *to_ndd(struct nd_mapping *nd_mapping)
 254 {
 255         struct nvdimm *nvdimm = nd_mapping->nvdimm;
 256
 257         WARN_ON_ONCE(!is_nvdimm_bus_locked(&nvdimm->dev));
 258
 259         return dev_get_drvdata(&nvdimm->dev);
 260 }
 261 EXPORT_SYMBOL(to_ndd);
 262
 263 void nvdimm_drvdata_release(struct kref *kref)
 264 {
 265         struct nvdimm_drvdata *ndd = container_of(kref, typeof(*ndd), kref);
 266         struct device *dev = ndd->dev;
 267         struct resource *res, *_r;
 268
 269         dev_dbg(dev, "%s\n", __func__);
 270
 271         nvdimm_bus_lock(dev);
 272         for_each_dpa_resource_safe(ndd, res, _r)
 273                 nvdimm_free_dpa(ndd, res);
 274         nvdimm_bus_unlock(dev);
 275
 276         kvfree(ndd->data);
 277         kfree(ndd);
 278         put_device(dev);
 279 }
 280
 281 void get_ndd(struct nvdimm_drvdata *ndd)
 282 {
 283         kref_get(&ndd->kref);
 284 }
 285
 286 void put_ndd(struct nvdimm_drvdata *ndd)
 287 {
 288         if (ndd)
 289                 kref_put(&ndd->kref, nvdimm_drvdata_release);
 290 }
 291
 292 const char *nvdimm_name(struct nvdimm *nvdimm)
 293 {
 294         return dev_name(&nvdimm->dev);
 295 }
 296 EXPORT_SYMBOL_GPL(nvdimm_name);
 297
 298 struct kobject *nvdimm_kobj(struct nvdimm *nvdimm)
 299 {
 300         return &nvdimm->dev.kobj;
 301 }
 302 EXPORT_SYMBOL_GPL(nvdimm_kobj);
 303
 304 unsigned long nvdimm_cmd_mask(struct nvdimm *nvdimm)
 305 {
 306         return nvdimm->cmd_mask;
 307 }
 308 EXPORT_SYMBOL_GPL(nvdimm_cmd_mask);
 309
 310 void *nvdimm_provider_data(struct nvdimm *nvdimm)
 311 {
 312         if (nvdimm)
 313                 return nvdimm->provider_data;
 314         return NULL;
 315 }
 316 EXPORT_SYMBOL_GPL(nvdimm_provider_data);
 317
 318 static ssize_t commands_show(struct device *dev,
 319                 struct device_attribute *attr, char *buf)
 320 {
 321         struct nvdimm *nvdimm = to_nvdimm(dev);
 322         int cmd, len = 0;
 323
 324         if (!nvdimm->cmd_mask)
 325                 return sprintf(buf, "\n");
 326
 327         for_each_set_bit(cmd, &nvdimm->cmd_mask, BITS_PER_LONG)
 328                 len += sprintf(buf + len, "%s ", nvdimm_cmd_name(cmd));
 329         len += sprintf(buf + len, "\n");
 330         return len;
 331 }
 332 static DEVICE_ATTR_RO(commands);
 333
 334 static ssize_t state_show(struct device *dev, struct device_attribute *attr,
 335                 char *buf)
 336 {
 337         struct nvdimm *nvdimm = to_nvdimm(dev);
 338
 339         /*
 340          * The state may be in the process of changing, userspace should
 341          * quiesce probing if it wants a static answer
 342          */
 343         nvdimm_bus_lock(dev);
 344         nvdimm_bus_unlock(dev);
 345         return sprintf(buf, "%s\n", atomic_read(&nvdimm->busy)
 346                         ? "active" : "idle");
 347 }
 348 static DEVICE_ATTR_RO(state);
 349
 350 static ssize_t available_slots_show(struct device *dev,
 351                 struct device_attribute *attr, char *buf)
 352 {
 353         struct nvdimm_drvdata *ndd = dev_get_drvdata(dev);
 354         ssize_t rc;
 355         u32 nfree;
 356
 357         if (!ndd)
 358                 return -ENXIO;
 359
 360         nvdimm_bus_lock(dev);
 361         nfree = nd_label_nfree(ndd);
 362         if (nfree - 1 > nfree) {
 363                 dev_WARN_ONCE(dev, 1, "we ate our last label?\n");
 364                 nfree = 0;
 365         } else
 366                 nfree--;
 367         rc = sprintf(buf, "%d\n", nfree);
 368         nvdimm_bus_unlock(dev);
 369         return rc;
 370 }
 371 static DEVICE_ATTR_RO(available_slots);
 372
 373 static struct attribute *nvdimm_attributes[] = {
 374         &dev_attr_state.attr,
 375         &dev_attr_commands.attr,
 376         &dev_attr_available_slots.attr,
 377         NULL,
 378 };
 379
 380 struct attribute_group nvdimm_attribute_group = {
 381         .attrs = nvdimm_attributes,
 382 };
 383 EXPORT_SYMBOL_GPL(nvdimm_attribute_group);
 384
 385 struct nvdimm *nvdimm_create(struct nvdimm_bus *nvdimm_bus, void *provider_data,
 386                 const struct attribute_group **groups, unsigned long flags,
 387                 unsigned long cmd_mask, int num_flush,
 388                 struct resource *flush_wpq)
 389 {
 390         struct nvdimm *nvdimm = kzalloc(sizeof(*nvdimm), GFP_KERNEL);
 391         struct device *dev;
 392
 393         if (!nvdimm)
 394                 return NULL;
 395
 396         nvdimm->id = ida_simple_get(&dimm_ida, 0, 0, GFP_KERNEL);
 397         if (nvdimm->id < 0) {
 398                 kfree(nvdimm);
 399                 return NULL;
 400         }
 401         nvdimm->provider_data = provider_data;
 402         nvdimm->flags = flags;
 403         nvdimm->cmd_mask = cmd_mask;
 404         nvdimm->num_flush = num_flush;
 405         nvdimm->flush_wpq = flush_wpq;
 406         atomic_set(&nvdimm->busy, 0);
 407         dev = &nvdimm->dev;
 408         dev_set_name(dev, "nmem%d", nvdimm->id);
 409         dev->parent = &nvdimm_bus->dev;
 410         dev->type = &nvdimm_device_type;
 411         dev->devt = MKDEV(nvdimm_major, nvdimm->id);
 412         dev->groups = groups;
 413         nd_device_register(dev);
 414
 415         return nvdimm;
 416 }
 417 EXPORT_SYMBOL_GPL(nvdimm_create);
 418
 419 int alias_dpa_busy(struct device *dev, void *data)
 420 {
 421         resource_size_t map_end, blk_start, new;
 422         struct blk_alloc_info *info = data;
 423         struct nd_mapping *nd_mapping;
 424         struct nd_region *nd_region;
 425         struct nvdimm_drvdata *ndd;
 426         struct resource *res;
 427         int i;
 428
 429         if (!is_memory(dev))
 430                 return 0;
 431
 432         nd_region = to_nd_region(dev);
 433         for (i = 0; i < nd_region->ndr_mappings; i++) {
 434                 nd_mapping  = &nd_region->mapping[i];
 435                 if (nd_mapping->nvdimm == info->nd_mapping->nvdimm)
 436                         break;
 437         }
 438
 439         if (i >= nd_region->ndr_mappings)
 440                 return 0;
 441
 442         ndd = to_ndd(nd_mapping);
 443         map_end = nd_mapping->start + nd_mapping->size - 1;
 444         blk_start = nd_mapping->start;
 445
 446         /*
 447          * In the allocation case ->res is set to free space that we are
 448          * looking to validate against PMEM aliasing collision rules
 449          * (i.e. BLK is allocated after all aliased PMEM).
 450          */
 451         if (info->res) {
 452                 if (info->res->start >= nd_mapping->start
 453                                 && info->res->start < map_end)
 454                         /* pass */;
 455                 else
 456                         return 0;
 457         }
 458
 459  retry:
 460         /*
 461          * Find the free dpa from the end of the last pmem allocation to
 462          * the end of the interleave-set mapping.
 463          */
 464         for_each_dpa_resource(ndd, res) {
 465                 if (strncmp(res->name, "pmem", 4) != 0)
 466                         continue;
 467                 if ((res->start >= blk_start && res->start < map_end)
 468                                 || (res->end >= blk_start
 469                                         && res->end <= map_end)) {
 470                         new = max(blk_start, min(map_end + 1, res->end + 1));
 471                         if (new != blk_start) {
 472                                 blk_start = new;
 473                                 goto retry;
 474                         }
 475                 }
 476         }
 477
 478         /* update the free space range with the probed blk_start */
 479         if (info->res && blk_start > info->res->start) {
 480                 info->res->start = max(info->res->start, blk_start);
 481                 if (info->res->start > info->res->end)
 482                         info->res->end = info->res->start - 1;
 483                 return 1;
 484         }
 485
 486         info->available -= blk_start - nd_mapping->start;
 487
 488         return 0;
 489 }
 490
 491 /**
 492  * nd_blk_available_dpa - account the unused dpa of BLK region
 493  * @nd_mapping: container of dpa-resource-root + labels
 494  *
 495  * Unlike PMEM, BLK namespaces can occupy discontiguous DPA ranges, but
 496  * we arrange for them to never start at an lower dpa than the last
 497  * PMEM allocation in an aliased region.
 498  */
 499 resource_size_t nd_blk_available_dpa(struct nd_region *nd_region)
 500 {
 501         struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(&nd_region->dev);
 502         struct nd_mapping *nd_mapping = &nd_region->mapping[0];
 503         struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
 504         struct blk_alloc_info info = {
 505                 .nd_mapping = nd_mapping,
 506                 .available = nd_mapping->size,
 507                 .res = NULL,
 508         };
 509         struct resource *res;
 510
 511         if (!ndd)
 512                 return 0;
 513
 514         device_for_each_child(&nvdimm_bus->dev, &info, alias_dpa_busy);
 515
 516         /* now account for busy blk allocations in unaliased dpa */
 517         for_each_dpa_resource(ndd, res) {
 518                 if (strncmp(res->name, "blk", 3) != 0)
 519                         continue;
 520                 info.available -= resource_size(res);
 521         }
 522
 523         return info.available;
 524 }
 525
 526 /**
 527  * nd_pmem_available_dpa - for the given dimm+region account unallocated dpa
 528  * @nd_mapping: container of dpa-resource-root + labels
 529  * @nd_region: constrain available space check to this reference region
 530  * @overlap: calculate available space assuming this level of overlap
 531  *
 532  * Validate that a PMEM label, if present, aligns with the start of an
 533  * interleave set and truncate the available size at the lowest BLK
 534  * overlap point.
 535  *
 536  * The expectation is that this routine is called multiple times as it
 537  * probes for the largest BLK encroachment for any single member DIMM of
 538  * the interleave set.  Once that value is determined the PMEM-limit for
 539  * the set can be established.
 540  */
 541 resource_size_t nd_pmem_available_dpa(struct nd_region *nd_region,
 542                 struct nd_mapping *nd_mapping, resource_size_t *overlap)
 543 {
 544         resource_size_t map_start, map_end, busy = 0, available, blk_start;
 545         struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
 546         struct resource *res;
 547         const char *reason;
 548
 549         if (!ndd)
 550                 return 0;
 551
 552         map_start = nd_mapping->start;
 553         map_end = map_start + nd_mapping->size - 1;
 554         blk_start = max(map_start, map_end + 1 - *overlap);
 555         for_each_dpa_resource(ndd, res) {
 556                 if (res->start >= map_start && res->start < map_end) {
 557                         if (strncmp(res->name, "blk", 3) == 0)
 558                                 blk_start = min(blk_start,
 559                                                 max(map_start, res->start));
 560                         else if (res->end > map_end) {
 561                                 reason = "misaligned to iset";
 562                                 goto err;
 563                         } else
 564                                 busy += resource_size(res);
 565                 } else if (res->end >= map_start && res->end <= map_end) {
 566                         if (strncmp(res->name, "blk", 3) == 0) {
 567                                 /*
 568                                  * If a BLK allocation overlaps the start of
 569                                  * PMEM the entire interleave set may now only
 570                                  * be used for BLK.
 571                                  */
 572                                 blk_start = map_start;
 573                         } else
 574                                 busy += resource_size(res);
 575                 } else if (map_start > res->start && map_start < res->end) {
 576                         /* total eclipse of the mapping */
 577                         busy += nd_mapping->size;
 578                         blk_start = map_start;
 579                 }
 580         }
 581
 582         *overlap = map_end + 1 - blk_start;
 583         available = blk_start - map_start;
 584         if (busy < available)
 585                 return available - busy;
 586         return 0;
 587
 588  err:
 589         nd_dbg_dpa(nd_region, ndd, res, "%s\n", reason);
 590         return 0;
 591 }
 592
 593 void nvdimm_free_dpa(struct nvdimm_drvdata *ndd, struct resource *res)
 594 {
 595         WARN_ON_ONCE(!is_nvdimm_bus_locked(ndd->dev));
 596         kfree(res->name);
 597         __release_region(&ndd->dpa, res->start, resource_size(res));
 598 }
 599
 600 struct resource *nvdimm_allocate_dpa(struct nvdimm_drvdata *ndd,
 601                 struct nd_label_id *label_id, resource_size_t start,
 602                 resource_size_t n)
 603 {
 604         char *name = kmemdup(label_id, sizeof(*label_id), GFP_KERNEL);
 605         struct resource *res;
 606
 607         if (!name)
 608                 return NULL;
 609
 610         WARN_ON_ONCE(!is_nvdimm_bus_locked(ndd->dev));
 611         res = __request_region(&ndd->dpa, start, n, name, 0);
 612         if (!res)
 613                 kfree(name);
 614         return res;
 615 }
 616
 617 /**
 618  * nvdimm_allocated_dpa - sum up the dpa currently allocated to this label_id
 619  * @nvdimm: container of dpa-resource-root + labels
 620  * @label_id: dpa resource name of the form {pmem|blk}-<human readable uuid>
 621  */
 622 resource_size_t nvdimm_allocated_dpa(struct nvdimm_drvdata *ndd,
 623                 struct nd_label_id *label_id)
 624 {
 625         resource_size_t allocated = 0;
 626         struct resource *res;
 627
 628         for_each_dpa_resource(ndd, res)
 629                 if (strcmp(res->name, label_id->id) == 0)
 630                         allocated += resource_size(res);
 631
 632         return allocated;
 633 }
 634
 635 static int count_dimms(struct device *dev, void *c)
 636 {
 637         int *count = c;
 638
 639         if (is_nvdimm(dev))
 640                 (*count)++;
 641         return 0;
 642 }
 643
 644 int nvdimm_bus_check_dimm_count(struct nvdimm_bus *nvdimm_bus, int dimm_count)
 645 {
 646         int count = 0;
 647         /* Flush any possible dimm registration failures */
 648         nd_synchronize();
 649
 650         device_for_each_child(&nvdimm_bus->dev, &count, count_dimms);
 651         dev_dbg(&nvdimm_bus->dev, "%s: count: %d\n", __func__, count);
 652         if (count != dimm_count)
 653                 return -ENXIO;
 654         return 0;
 655 }
 656 EXPORT_SYMBOL_GPL(nvdimm_bus_check_dimm_count);
 657
 658 void __exit nvdimm_devs_exit(void)
 659 {
 660         ida_destroy(&dimm_ida);
 661 }