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