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