drivers/nvdimm/pmem.c

   1 /*
   2  * Persistent Memory Driver
   3  *
   4  * Copyright (c) 2014-2015, Intel Corporation.
   5  * Copyright (c) 2015, Christoph Hellwig <hch@lst.de>.
   6  * Copyright (c) 2015, Boaz Harrosh <boaz@plexistor.com>.
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms and conditions of the GNU General Public License,
  10  * version 2, as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope it will be useful, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15  * more details.
  16  */
  17
  18 #include <asm/cacheflush.h>
  19 #include <linux/blkdev.h>
  20 #include <linux/hdreg.h>
  21 #include <linux/init.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/module.h>
  24 #include <linux/moduleparam.h>
  25 #include <linux/badblocks.h>
  26 #include <linux/memremap.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/blk-mq.h>
  29 #include <linux/pfn_t.h>
  30 #include <linux/slab.h>
  31 #include <linux/uio.h>
  32 #include <linux/dax.h>
  33 #include <linux/nd.h>
  34 #include <linux/backing-dev.h>
  35 #include "pmem.h"
  36 #include "pfn.h"
  37 #include "nd.h"
  38 #include "nd-core.h"
  39
  40 static struct device *to_dev(struct pmem_device *pmem)
  41 {
  42         /*
  43          * nvdimm bus services need a 'dev' parameter, and we record the device
  44          * at init in bb.dev.
  45          */
  46         return pmem->bb.dev;
  47 }
  48
  49 static struct nd_region *to_region(struct pmem_device *pmem)
  50 {
  51         return to_nd_region(to_dev(pmem)->parent);
  52 }
  53
  54 static blk_status_t pmem_clear_poison(struct pmem_device *pmem,
  55                 phys_addr_t offset, unsigned int len)
  56 {
  57         struct device *dev = to_dev(pmem);
  58         sector_t sector;
  59         long cleared;
  60         blk_status_t rc = BLK_STS_OK;
  61
  62         sector = (offset - pmem->data_offset) / 512;
  63
  64         cleared = nvdimm_clear_poison(dev, pmem->phys_addr + offset, len);
  65         if (cleared < len)
  66                 rc = BLK_STS_IOERR;
  67         if (cleared > 0 && cleared / 512) {
  68                 cleared /= 512;
  69                 dev_dbg(dev, "%s: %#llx clear %ld sector%s\n", __func__,
  70                                 (unsigned long long) sector, cleared,
  71                                 cleared > 1 ? "s" : "");
  72                 badblocks_clear(&pmem->bb, sector, cleared);
  73                 if (pmem->bb_state)
  74                         sysfs_notify_dirent(pmem->bb_state);
  75         }
  76
  77         arch_invalidate_pmem(pmem->virt_addr + offset, len);
  78
  79         return rc;
  80 }
  81
  82 static void write_pmem(void *pmem_addr, struct page *page,
  83                 unsigned int off, unsigned int len)
  84 {
  85         unsigned int chunk;
  86         void *mem;
  87
  88         while (len) {
  89                 mem = kmap_atomic(page);
  90                 chunk = min_t(unsigned int, len, PAGE_SIZE);
  91                 memcpy_flushcache(pmem_addr, mem + off, chunk);
  92                 kunmap_atomic(mem);
  93                 len -= chunk;
  94                 off = 0;
  95                 page++;
  96                 pmem_addr += PAGE_SIZE;
  97         }
  98 }
  99
 100 static blk_status_t read_pmem(struct page *page, unsigned int off,
 101                 void *pmem_addr, unsigned int len)
 102 {
 103         unsigned int chunk;
 104         int rc;
 105         void *mem;
 106
 107         while (len) {
 108                 mem = kmap_atomic(page);
 109                 chunk = min_t(unsigned int, len, PAGE_SIZE);
 110                 rc = memcpy_mcsafe(mem + off, pmem_addr, chunk);
 111                 kunmap_atomic(mem);
 112                 if (rc)
 113                         return BLK_STS_IOERR;
 114                 len -= chunk;
 115                 off = 0;
 116                 page++;
 117                 pmem_addr += PAGE_SIZE;
 118         }
 119         return BLK_STS_OK;
 120 }
 121
 122 static blk_status_t pmem_do_bvec(struct pmem_device *pmem, struct page *page,
 123                         unsigned int len, unsigned int off, bool is_write,
 124                         sector_t sector)
 125 {
 126         blk_status_t rc = BLK_STS_OK;
 127         bool bad_pmem = false;
 128         phys_addr_t pmem_off = sector * 512 + pmem->data_offset;
 129         void *pmem_addr = pmem->virt_addr + pmem_off;
 130
 131         if (unlikely(is_bad_pmem(&pmem->bb, sector, len)))
 132                 bad_pmem = true;
 133
 134         if (!is_write) {
 135                 if (unlikely(bad_pmem))
 136                         rc = BLK_STS_IOERR;
 137                 else {
 138                         rc = read_pmem(page, off, pmem_addr, len);
 139                         flush_dcache_page(page);
 140                 }
 141         } else {
 142                 /*
 143                  * Note that we write the data both before and after
 144                  * clearing poison.  The write before clear poison
 145                  * handles situations where the latest written data is
 146                  * preserved and the clear poison operation simply marks
 147                  * the address range as valid without changing the data.
 148                  * In this case application software can assume that an
 149                  * interrupted write will either return the new good
 150                  * data or an error.
 151                  *
 152                  * However, if pmem_clear_poison() leaves the data in an
 153                  * indeterminate state we need to perform the write
 154                  * after clear poison.
 155                  */
 156                 flush_dcache_page(page);
 157                 write_pmem(pmem_addr, page, off, len);
 158                 if (unlikely(bad_pmem)) {
 159                         rc = pmem_clear_poison(pmem, pmem_off, len);
 160                         write_pmem(pmem_addr, page, off, len);
 161                 }
 162         }
 163
 164         return rc;
 165 }
 166
 167 /* account for REQ_FLUSH rename, replace with REQ_PREFLUSH after v4.8-rc1 */
 168 #ifndef REQ_FLUSH
 169 #define REQ_FLUSH REQ_PREFLUSH
 170 #endif
 171
 172 static blk_qc_t pmem_make_request(struct request_queue *q, struct bio *bio)
 173 {
 174         blk_status_t rc = 0;
 175         bool do_acct;
 176         unsigned long start;
 177         struct bio_vec bvec;
 178         struct bvec_iter iter;
 179         struct pmem_device *pmem = q->queuedata;
 180         struct nd_region *nd_region = to_region(pmem);
 181
 182         if (bio->bi_opf & REQ_FLUSH)
 183                 nvdimm_flush(nd_region);
 184
 185         do_acct = nd_iostat_start(bio, &start);
 186         bio_for_each_segment(bvec, bio, iter) {
 187                 rc = pmem_do_bvec(pmem, bvec.bv_page, bvec.bv_len,
 188                                 bvec.bv_offset, op_is_write(bio_op(bio)),
 189                                 iter.bi_sector);
 190                 if (rc) {
 191                         bio->bi_status = rc;
 192                         break;
 193                 }
 194         }
 195         if (do_acct)
 196                 nd_iostat_end(bio, start);
 197
 198         if (bio->bi_opf & REQ_FUA)
 199                 nvdimm_flush(nd_region);
 200
 201         bio_endio(bio);
 202         return BLK_QC_T_NONE;
 203 }
 204
 205 static int pmem_rw_page(struct block_device *bdev, sector_t sector,
 206                        struct page *page, bool is_write)
 207 {
 208         struct pmem_device *pmem = bdev->bd_queue->queuedata;
 209         blk_status_t rc;
 210
 211         rc = pmem_do_bvec(pmem, page, hpage_nr_pages(page) * PAGE_SIZE,
 212                           0, is_write, sector);
 213
 214         /*
 215          * The ->rw_page interface is subtle and tricky.  The core
 216          * retries on any error, so we can only invoke page_endio() in
 217          * the successful completion case.  Otherwise, we'll see crashes
 218          * caused by double completion.
 219          */
 220         if (rc == 0)
 221                 page_endio(page, is_write, 0);
 222
 223         return blk_status_to_errno(rc);
 224 }
 225
 226 /* see "strong" declaration in tools/testing/nvdimm/pmem-dax.c */
 227 __weak long __pmem_direct_access(struct pmem_device *pmem, pgoff_t pgoff,
 228                 long nr_pages, void **kaddr, pfn_t *pfn)
 229 {
 230         resource_size_t offset = PFN_PHYS(pgoff) + pmem->data_offset;
 231
 232         if (unlikely(is_bad_pmem(&pmem->bb, PFN_PHYS(pgoff) / 512,
 233                                         PFN_PHYS(nr_pages))))
 234                 return -EIO;
 235         *kaddr = pmem->virt_addr + offset;
 236         *pfn = phys_to_pfn_t(pmem->phys_addr + offset, pmem->pfn_flags);
 237
 238         /*
 239          * If badblocks are present, limit known good range to the
 240          * requested range.
 241          */
 242         if (unlikely(pmem->bb.count))
 243                 return nr_pages;
 244         return PHYS_PFN(pmem->size - pmem->pfn_pad - offset);
 245 }
 246
 247 static const struct block_device_operations pmem_fops = {
 248         .owner =                THIS_MODULE,
 249         .rw_page =              pmem_rw_page,
 250         .revalidate_disk =      nvdimm_revalidate_disk,
 251 };
 252
 253 static long pmem_dax_direct_access(struct dax_device *dax_dev,
 254                 pgoff_t pgoff, long nr_pages, void **kaddr, pfn_t *pfn)
 255 {
 256         struct pmem_device *pmem = dax_get_private(dax_dev);
 257
 258         return __pmem_direct_access(pmem, pgoff, nr_pages, kaddr, pfn);
 259 }
 260
 261 static size_t pmem_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff,
 262                 void *addr, size_t bytes, struct iov_iter *i)
 263 {
 264         return copy_from_iter_flushcache(addr, bytes, i);
 265 }
 266
 267 static const struct dax_operations pmem_dax_ops = {
 268         .direct_access = pmem_dax_direct_access,
 269         .copy_from_iter = pmem_copy_from_iter,
 270 };
 271
 272 static const struct attribute_group *pmem_attribute_groups[] = {
 273         &dax_attribute_group,
 274         NULL,
 275 };
 276
 277 static void pmem_release_queue(void *q)
 278 {
 279         blk_cleanup_queue(q);
 280 }
 281
 282 static void pmem_freeze_queue(void *q)
 283 {
 284         blk_freeze_queue_start(q);
 285 }
 286
 287 static void pmem_release_disk(void *__pmem)
 288 {
 289         struct pmem_device *pmem = __pmem;
 290
 291         kill_dax(pmem->dax_dev);
 292         put_dax(pmem->dax_dev);
 293         del_gendisk(pmem->disk);
 294         put_disk(pmem->disk);
 295 }
 296
 297 static int pmem_attach_disk(struct device *dev,
 298                 struct nd_namespace_common *ndns)
 299 {
 300         struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 301         struct nd_region *nd_region = to_nd_region(dev->parent);
 302         struct vmem_altmap __altmap, *altmap = NULL;
 303         int nid = dev_to_node(dev), fua, wbc;
 304         struct resource *res = &nsio->res;
 305         struct nd_pfn *nd_pfn = NULL;
 306         struct dax_device *dax_dev;
 307         struct nd_pfn_sb *pfn_sb;
 308         struct pmem_device *pmem;
 309         struct resource pfn_res;
 310         struct request_queue *q;
 311         struct device *gendev;
 312         struct gendisk *disk;
 313         void *addr;
 314
 315         /* while nsio_rw_bytes is active, parse a pfn info block if present */
 316         if (is_nd_pfn(dev)) {
 317                 nd_pfn = to_nd_pfn(dev);
 318                 altmap = nvdimm_setup_pfn(nd_pfn, &pfn_res, &__altmap);
 319                 if (IS_ERR(altmap))
 320                         return PTR_ERR(altmap);
 321         }
 322
 323         /* we're attaching a block device, disable raw namespace access */
 324         devm_nsio_disable(dev, nsio);
 325
 326         pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
 327         if (!pmem)
 328                 return -ENOMEM;
 329
 330         dev_set_drvdata(dev, pmem);
 331         pmem->phys_addr = res->start;
 332         pmem->size = resource_size(res);
 333         fua = nvdimm_has_flush(nd_region);
 334         if (!IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) || fua < 0) {
 335                 dev_warn(dev, "unable to guarantee persistence of writes\n");
 336                 fua = 0;
 337         }
 338         wbc = nvdimm_has_cache(nd_region) &&
 339                 !test_bit(ND_REGION_PERSIST_CACHE, &nd_region->flags);
 340
 341         if (!devm_request_mem_region(dev, res->start, resource_size(res),
 342                                 dev_name(&ndns->dev))) {
 343                 dev_warn(dev, "could not reserve region %pR\n", res);
 344                 return -EBUSY;
 345         }
 346
 347         q = blk_alloc_queue_node(GFP_KERNEL, dev_to_node(dev));
 348         if (!q)
 349                 return -ENOMEM;
 350
 351         if (devm_add_action_or_reset(dev, pmem_release_queue, q))
 352                 return -ENOMEM;
 353
 354         pmem->pfn_flags = PFN_DEV;
 355         if (is_nd_pfn(dev)) {
 356                 addr = devm_memremap_pages(dev, &pfn_res, &q->q_usage_counter,
 357                                 altmap);
 358                 pfn_sb = nd_pfn->pfn_sb;
 359                 pmem->data_offset = le64_to_cpu(pfn_sb->dataoff);
 360                 pmem->pfn_pad = resource_size(res) - resource_size(&pfn_res);
 361                 pmem->pfn_flags |= PFN_MAP;
 362                 res = &pfn_res; /* for badblocks populate */
 363                 res->start += pmem->data_offset;
 364         } else if (pmem_should_map_pages(dev)) {
 365                 addr = devm_memremap_pages(dev, &nsio->res,
 366                                 &q->q_usage_counter, NULL);
 367                 pmem->pfn_flags |= PFN_MAP;
 368         } else
 369                 addr = devm_memremap(dev, pmem->phys_addr,
 370                                 pmem->size, ARCH_MEMREMAP_PMEM);
 371
 372         /*
 373          * At release time the queue must be frozen before
 374          * devm_memremap_pages is unwound
 375          */
 376         if (devm_add_action_or_reset(dev, pmem_freeze_queue, q))
 377                 return -ENOMEM;
 378
 379         if (IS_ERR(addr))
 380                 return PTR_ERR(addr);
 381         pmem->virt_addr = addr;
 382
 383         blk_queue_write_cache(q, wbc, fua);
 384         blk_queue_make_request(q, pmem_make_request);
 385         blk_queue_physical_block_size(q, PAGE_SIZE);
 386         blk_queue_logical_block_size(q, pmem_sector_size(ndns));
 387         blk_queue_max_hw_sectors(q, UINT_MAX);
 388         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
 389         queue_flag_set_unlocked(QUEUE_FLAG_DAX, q);
 390         q->queuedata = pmem;
 391
 392         disk = alloc_disk_node(0, nid);
 393         if (!disk)
 394                 return -ENOMEM;
 395         pmem->disk = disk;
 396
 397         disk->fops              = &pmem_fops;
 398         disk->queue             = q;
 399         disk->flags             = GENHD_FL_EXT_DEVT;
 400         disk->queue->backing_dev_info->capabilities |= BDI_CAP_SYNCHRONOUS_IO;
 401         nvdimm_namespace_disk_name(ndns, disk->disk_name);
 402         set_capacity(disk, (pmem->size - pmem->pfn_pad - pmem->data_offset)
 403                         / 512);
 404         if (devm_init_badblocks(dev, &pmem->bb))
 405                 return -ENOMEM;
 406         nvdimm_badblocks_populate(nd_region, &pmem->bb, res);
 407         disk->bb = &pmem->bb;
 408
 409         dax_dev = alloc_dax(pmem, disk->disk_name, &pmem_dax_ops);
 410         if (!dax_dev) {
 411                 put_disk(disk);
 412                 return -ENOMEM;
 413         }
 414         dax_write_cache(dax_dev, wbc);
 415         pmem->dax_dev = dax_dev;
 416
 417         gendev = disk_to_dev(disk);
 418         gendev->groups = pmem_attribute_groups;
 419
 420         device_add_disk(dev, disk);
 421         if (devm_add_action_or_reset(dev, pmem_release_disk, pmem))
 422                 return -ENOMEM;
 423
 424         revalidate_disk(disk);
 425
 426         pmem->bb_state = sysfs_get_dirent(disk_to_dev(disk)->kobj.sd,
 427                                           "badblocks");
 428         if (!pmem->bb_state)
 429                 dev_warn(dev, "'badblocks' notification disabled\n");
 430
 431         return 0;
 432 }
 433
 434 static int nd_pmem_probe(struct device *dev)
 435 {
 436         struct nd_namespace_common *ndns;
 437
 438         ndns = nvdimm_namespace_common_probe(dev);
 439         if (IS_ERR(ndns))
 440                 return PTR_ERR(ndns);
 441
 442         if (devm_nsio_enable(dev, to_nd_namespace_io(&ndns->dev)))
 443                 return -ENXIO;
 444
 445         if (is_nd_btt(dev))
 446                 return nvdimm_namespace_attach_btt(ndns);
 447
 448         if (is_nd_pfn(dev))
 449                 return pmem_attach_disk(dev, ndns);
 450
 451         /* if we find a valid info-block we'll come back as that personality */
 452         if (nd_btt_probe(dev, ndns) == 0 || nd_pfn_probe(dev, ndns) == 0
 453                         || nd_dax_probe(dev, ndns) == 0)
 454                 return -ENXIO;
 455
 456         /* ...otherwise we're just a raw pmem device */
 457         return pmem_attach_disk(dev, ndns);
 458 }
 459
 460 static int nd_pmem_remove(struct device *dev)
 461 {
 462         struct pmem_device *pmem = dev_get_drvdata(dev);
 463
 464         if (is_nd_btt(dev))
 465                 nvdimm_namespace_detach_btt(to_nd_btt(dev));
 466         else {
 467                 /*
 468                  * Note, this assumes device_lock() context to not race
 469                  * nd_pmem_notify()
 470                  */
 471                 sysfs_put(pmem->bb_state);
 472                 pmem->bb_state = NULL;
 473         }
 474         nvdimm_flush(to_nd_region(dev->parent));
 475
 476         return 0;
 477 }
 478
 479 static void nd_pmem_shutdown(struct device *dev)
 480 {
 481         nvdimm_flush(to_nd_region(dev->parent));
 482 }
 483
 484 static void nd_pmem_notify(struct device *dev, enum nvdimm_event event)
 485 {
 486         struct nd_region *nd_region;
 487         resource_size_t offset = 0, end_trunc = 0;
 488         struct nd_namespace_common *ndns;
 489         struct nd_namespace_io *nsio;
 490         struct resource res;
 491         struct badblocks *bb;
 492         struct kernfs_node *bb_state;
 493
 494         if (event != NVDIMM_REVALIDATE_POISON)
 495                 return;
 496
 497         if (is_nd_btt(dev)) {
 498                 struct nd_btt *nd_btt = to_nd_btt(dev);
 499
 500                 ndns = nd_btt->ndns;
 501                 nd_region = to_nd_region(ndns->dev.parent);
 502                 nsio = to_nd_namespace_io(&ndns->dev);
 503                 bb = &nsio->bb;
 504                 bb_state = NULL;
 505         } else {
 506                 struct pmem_device *pmem = dev_get_drvdata(dev);
 507
 508                 nd_region = to_region(pmem);
 509                 bb = &pmem->bb;
 510                 bb_state = pmem->bb_state;
 511
 512                 if (is_nd_pfn(dev)) {
 513                         struct nd_pfn *nd_pfn = to_nd_pfn(dev);
 514                         struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 515
 516                         ndns = nd_pfn->ndns;
 517                         offset = pmem->data_offset +
 518                                         __le32_to_cpu(pfn_sb->start_pad);
 519                         end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
 520                 } else {
 521                         ndns = to_ndns(dev);
 522                 }
 523
 524                 nsio = to_nd_namespace_io(&ndns->dev);
 525         }
 526
 527         res.start = nsio->res.start + offset;
 528         res.end = nsio->res.end - end_trunc;
 529         nvdimm_badblocks_populate(nd_region, bb, &res);
 530         if (bb_state)
 531                 sysfs_notify_dirent(bb_state);
 532 }
 533
 534 MODULE_ALIAS("pmem");
 535 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
 536 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM);
 537 static struct nd_device_driver nd_pmem_driver = {
 538         .probe = nd_pmem_probe,
 539         .remove = nd_pmem_remove,
 540         .notify = nd_pmem_notify,
 541         .shutdown = nd_pmem_shutdown,
 542         .drv = {
 543                 .name = "nd_pmem",
 544         },
 545         .type = ND_DRIVER_NAMESPACE_IO | ND_DRIVER_NAMESPACE_PMEM,
 546 };
 547
 548 static int __init pmem_init(void)
 549 {
 550         return nd_driver_register(&nd_pmem_driver);
 551 }
 552 module_init(pmem_init);
 553
 554 static void pmem_exit(void)
 555 {
 556         driver_unregister(&nd_pmem_driver.drv);
 557 }
 558 module_exit(pmem_exit);
 559
 560 MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
 561 MODULE_LICENSE("GPL v2");