drivers/nvdimm/btt.c

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This source file includes following definitions.
to_dev
adjust_initial_offset
arena_read_bytes
arena_write_bytes
btt_info_write
btt_info_read
__btt_map_write
btt_map_write
btt_map_read
btt_log_group_read
arena_debugfs_init
btt_debugfs_init
log_seq
btt_log_get_old
btt_log_read
__btt_log_write
btt_flog_write
btt_map_init
btt_log_init
to_namespace_offset
arena_clear_freelist_error
btt_freelist_init
ent_is_padding
log_set_indices
btt_rtt_init
btt_maplocks_init
alloc_arena
free_arenas
parse_arena_meta
discover_arenas
create_arenas
btt_arena_write_layout
btt_meta_init
btt_meta_size
lba_to_arena
lock_map
unlock_map
btt_data_read
btt_data_write
zero_fill_data
btt_rw_integrity
btt_rw_integrity
btt_read_pg
btt_is_badblock
btt_write_pg
btt_do_bvec
btt_make_request
btt_rw_page
btt_getgeo
btt_blk_init
btt_blk_cleanup
btt_init
btt_fini
nvdimm_namespace_attach_btt
nvdimm_namespace_detach_btt
nd_btt_init
nd_btt_exit
   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Block Translation Table
   4  * Copyright (c) 2014-2015, Intel Corporation.
   5  */
   6 #include <linux/highmem.h>
   7 #include <linux/debugfs.h>
   8 #include <linux/blkdev.h>
   9 #include <linux/module.h>
  10 #include <linux/device.h>
  11 #include <linux/mutex.h>
  12 #include <linux/hdreg.h>
  13 #include <linux/genhd.h>
  14 #include <linux/sizes.h>
  15 #include <linux/ndctl.h>
  16 #include <linux/fs.h>
  17 #include <linux/nd.h>
  18 #include <linux/backing-dev.h>
  19 #include "btt.h"
  20 #include "nd.h"
  21 
  22 enum log_ent_request {
  23         LOG_NEW_ENT = 0,
  24         LOG_OLD_ENT
  25 };
  26 
  27 static struct device *to_dev(struct arena_info *arena)
  28 {
  29         return &arena->nd_btt->dev;
  30 }
  31 
  32 static u64 adjust_initial_offset(struct nd_btt *nd_btt, u64 offset)
  33 {
  34         return offset + nd_btt->initial_offset;
  35 }
  36 
  37 static int arena_read_bytes(struct arena_info *arena, resource_size_t offset,
  38                 void *buf, size_t n, unsigned long flags)
  39 {
  40         struct nd_btt *nd_btt = arena->nd_btt;
  41         struct nd_namespace_common *ndns = nd_btt->ndns;
  42 
  43         /* arena offsets may be shifted from the base of the device */
  44         offset = adjust_initial_offset(nd_btt, offset);
  45         return nvdimm_read_bytes(ndns, offset, buf, n, flags);
  46 }
  47 
  48 static int arena_write_bytes(struct arena_info *arena, resource_size_t offset,
  49                 void *buf, size_t n, unsigned long flags)
  50 {
  51         struct nd_btt *nd_btt = arena->nd_btt;
  52         struct nd_namespace_common *ndns = nd_btt->ndns;
  53 
  54         /* arena offsets may be shifted from the base of the device */
  55         offset = adjust_initial_offset(nd_btt, offset);
  56         return nvdimm_write_bytes(ndns, offset, buf, n, flags);
  57 }
  58 
  59 static int btt_info_write(struct arena_info *arena, struct btt_sb *super)
  60 {
  61         int ret;
  62 
  63         /*
  64          * infooff and info2off should always be at least 512B aligned.
  65          * We rely on that to make sure rw_bytes does error clearing
  66          * correctly, so make sure that is the case.
  67          */
  68         dev_WARN_ONCE(to_dev(arena), !IS_ALIGNED(arena->infooff, 512),
  69                 "arena->infooff: %#llx is unaligned\n", arena->infooff);
  70         dev_WARN_ONCE(to_dev(arena), !IS_ALIGNED(arena->info2off, 512),
  71                 "arena->info2off: %#llx is unaligned\n", arena->info2off);
  72 
  73         ret = arena_write_bytes(arena, arena->info2off, super,
  74                         sizeof(struct btt_sb), 0);
  75         if (ret)
  76                 return ret;
  77 
  78         return arena_write_bytes(arena, arena->infooff, super,
  79                         sizeof(struct btt_sb), 0);
  80 }
  81 
  82 static int btt_info_read(struct arena_info *arena, struct btt_sb *super)
  83 {
  84         return arena_read_bytes(arena, arena->infooff, super,
  85                         sizeof(struct btt_sb), 0);
  86 }
  87 
  88 /*
  89  * 'raw' version of btt_map write
  90  * Assumptions:
  91  *   mapping is in little-endian
  92  *   mapping contains 'E' and 'Z' flags as desired
  93  */
  94 static int __btt_map_write(struct arena_info *arena, u32 lba, __le32 mapping,
  95                 unsigned long flags)
  96 {
  97         u64 ns_off = arena->mapoff + (lba * MAP_ENT_SIZE);
  98 
  99         if (unlikely(lba >= arena->external_nlba))
 100                 dev_err_ratelimited(to_dev(arena),
 101                         "%s: lba %#x out of range (max: %#x)\n",
 102                         __func__, lba, arena->external_nlba);
 103         return arena_write_bytes(arena, ns_off, &mapping, MAP_ENT_SIZE, flags);
 104 }
 105 
 106 static int btt_map_write(struct arena_info *arena, u32 lba, u32 mapping,
 107                         u32 z_flag, u32 e_flag, unsigned long rwb_flags)
 108 {
 109         u32 ze;
 110         __le32 mapping_le;
 111 
 112         /*
 113          * This 'mapping' is supposed to be just the LBA mapping, without
 114          * any flags set, so strip the flag bits.
 115          */
 116         mapping = ent_lba(mapping);
 117 
 118         ze = (z_flag << 1) + e_flag;
 119         switch (ze) {
 120         case 0:
 121                 /*
 122                  * We want to set neither of the Z or E flags, and
 123                  * in the actual layout, this means setting the bit
 124                  * positions of both to '1' to indicate a 'normal'
 125                  * map entry
 126                  */
 127                 mapping |= MAP_ENT_NORMAL;
 128                 break;
 129         case 1:
 130                 mapping |= (1 << MAP_ERR_SHIFT);
 131                 break;
 132         case 2:
 133                 mapping |= (1 << MAP_TRIM_SHIFT);
 134                 break;
 135         default:
 136                 /*
 137                  * The case where Z and E are both sent in as '1' could be
 138                  * construed as a valid 'normal' case, but we decide not to,
 139                  * to avoid confusion
 140                  */
 141                 dev_err_ratelimited(to_dev(arena),
 142                         "Invalid use of Z and E flags\n");
 143                 return -EIO;
 144         }
 145 
 146         mapping_le = cpu_to_le32(mapping);
 147         return __btt_map_write(arena, lba, mapping_le, rwb_flags);
 148 }
 149 
 150 static int btt_map_read(struct arena_info *arena, u32 lba, u32 *mapping,
 151                         int *trim, int *error, unsigned long rwb_flags)
 152 {
 153         int ret;
 154         __le32 in;
 155         u32 raw_mapping, postmap, ze, z_flag, e_flag;
 156         u64 ns_off = arena->mapoff + (lba * MAP_ENT_SIZE);
 157 
 158         if (unlikely(lba >= arena->external_nlba))
 159                 dev_err_ratelimited(to_dev(arena),
 160                         "%s: lba %#x out of range (max: %#x)\n",
 161                         __func__, lba, arena->external_nlba);
 162 
 163         ret = arena_read_bytes(arena, ns_off, &in, MAP_ENT_SIZE, rwb_flags);
 164         if (ret)
 165                 return ret;
 166 
 167         raw_mapping = le32_to_cpu(in);
 168 
 169         z_flag = ent_z_flag(raw_mapping);
 170         e_flag = ent_e_flag(raw_mapping);
 171         ze = (z_flag << 1) + e_flag;
 172         postmap = ent_lba(raw_mapping);
 173 
 174         /* Reuse the {z,e}_flag variables for *trim and *error */
 175         z_flag = 0;
 176         e_flag = 0;
 177 
 178         switch (ze) {
 179         case 0:
 180                 /* Initial state. Return postmap = premap */
 181                 *mapping = lba;
 182                 break;
 183         case 1:
 184                 *mapping = postmap;
 185                 e_flag = 1;
 186                 break;
 187         case 2:
 188                 *mapping = postmap;
 189                 z_flag = 1;
 190                 break;
 191         case 3:
 192                 *mapping = postmap;
 193                 break;
 194         default:
 195                 return -EIO;
 196         }
 197 
 198         if (trim)
 199                 *trim = z_flag;
 200         if (error)
 201                 *error = e_flag;
 202 
 203         return ret;
 204 }
 205 
 206 static int btt_log_group_read(struct arena_info *arena, u32 lane,
 207                         struct log_group *log)
 208 {
 209         return arena_read_bytes(arena,
 210                         arena->logoff + (lane * LOG_GRP_SIZE), log,
 211                         LOG_GRP_SIZE, 0);
 212 }
 213 
 214 static struct dentry *debugfs_root;
 215 
 216 static void arena_debugfs_init(struct arena_info *a, struct dentry *parent,
 217                                 int idx)
 218 {
 219         char dirname[32];
 220         struct dentry *d;
 221 
 222         /* If for some reason, parent bttN was not created, exit */
 223         if (!parent)
 224                 return;
 225 
 226         snprintf(dirname, 32, "arena%d", idx);
 227         d = debugfs_create_dir(dirname, parent);
 228         if (IS_ERR_OR_NULL(d))
 229                 return;
 230         a->debugfs_dir = d;
 231 
 232         debugfs_create_x64("size", S_IRUGO, d, &a->size);
 233         debugfs_create_x64("external_lba_start", S_IRUGO, d,
 234                                 &a->external_lba_start);
 235         debugfs_create_x32("internal_nlba", S_IRUGO, d, &a->internal_nlba);
 236         debugfs_create_u32("internal_lbasize", S_IRUGO, d,
 237                                 &a->internal_lbasize);
 238         debugfs_create_x32("external_nlba", S_IRUGO, d, &a->external_nlba);
 239         debugfs_create_u32("external_lbasize", S_IRUGO, d,
 240                                 &a->external_lbasize);
 241         debugfs_create_u32("nfree", S_IRUGO, d, &a->nfree);
 242         debugfs_create_u16("version_major", S_IRUGO, d, &a->version_major);
 243         debugfs_create_u16("version_minor", S_IRUGO, d, &a->version_minor);
 244         debugfs_create_x64("nextoff", S_IRUGO, d, &a->nextoff);
 245         debugfs_create_x64("infooff", S_IRUGO, d, &a->infooff);
 246         debugfs_create_x64("dataoff", S_IRUGO, d, &a->dataoff);
 247         debugfs_create_x64("mapoff", S_IRUGO, d, &a->mapoff);
 248         debugfs_create_x64("logoff", S_IRUGO, d, &a->logoff);
 249         debugfs_create_x64("info2off", S_IRUGO, d, &a->info2off);
 250         debugfs_create_x32("flags", S_IRUGO, d, &a->flags);
 251         debugfs_create_u32("log_index_0", S_IRUGO, d, &a->log_index[0]);
 252         debugfs_create_u32("log_index_1", S_IRUGO, d, &a->log_index[1]);
 253 }
 254 
 255 static void btt_debugfs_init(struct btt *btt)
 256 {
 257         int i = 0;
 258         struct arena_info *arena;
 259 
 260         btt->debugfs_dir = debugfs_create_dir(dev_name(&btt->nd_btt->dev),
 261                                                 debugfs_root);
 262         if (IS_ERR_OR_NULL(btt->debugfs_dir))
 263                 return;
 264 
 265         list_for_each_entry(arena, &btt->arena_list, list) {
 266                 arena_debugfs_init(arena, btt->debugfs_dir, i);
 267                 i++;
 268         }
 269 }
 270 
 271 static u32 log_seq(struct log_group *log, int log_idx)
 272 {
 273         return le32_to_cpu(log->ent[log_idx].seq);
 274 }
 275 
 276 /*
 277  * This function accepts two log entries, and uses the
 278  * sequence number to find the 'older' entry.
 279  * It also updates the sequence number in this old entry to
 280  * make it the 'new' one if the mark_flag is set.
 281  * Finally, it returns which of the entries was the older one.
 282  *
 283  * TODO The logic feels a bit kludge-y. make it better..
 284  */
 285 static int btt_log_get_old(struct arena_info *a, struct log_group *log)
 286 {
 287         int idx0 = a->log_index[0];
 288         int idx1 = a->log_index[1];
 289         int old;
 290 
 291         /*
 292          * the first ever time this is seen, the entry goes into [0]
 293          * the next time, the following logic works out to put this
 294          * (next) entry into [1]
 295          */
 296         if (log_seq(log, idx0) == 0) {
 297                 log->ent[idx0].seq = cpu_to_le32(1);
 298                 return 0;
 299         }
 300 
 301         if (log_seq(log, idx0) == log_seq(log, idx1))
 302                 return -EINVAL;
 303         if (log_seq(log, idx0) + log_seq(log, idx1) > 5)
 304                 return -EINVAL;
 305 
 306         if (log_seq(log, idx0) < log_seq(log, idx1)) {
 307                 if ((log_seq(log, idx1) - log_seq(log, idx0)) == 1)
 308                         old = 0;
 309                 else
 310                         old = 1;
 311         } else {
 312                 if ((log_seq(log, idx0) - log_seq(log, idx1)) == 1)
 313                         old = 1;
 314                 else
 315                         old = 0;
 316         }
 317 
 318         return old;
 319 }
 320 
 321 /*
 322  * This function copies the desired (old/new) log entry into ent if
 323  * it is not NULL. It returns the sub-slot number (0 or 1)
 324  * where the desired log entry was found. Negative return values
 325  * indicate errors.
 326  */
 327 static int btt_log_read(struct arena_info *arena, u32 lane,
 328                         struct log_entry *ent, int old_flag)
 329 {
 330         int ret;
 331         int old_ent, ret_ent;
 332         struct log_group log;
 333 
 334         ret = btt_log_group_read(arena, lane, &log);
 335         if (ret)
 336                 return -EIO;
 337 
 338         old_ent = btt_log_get_old(arena, &log);
 339         if (old_ent < 0 || old_ent > 1) {
 340                 dev_err(to_dev(arena),
 341                                 "log corruption (%d): lane %d seq [%d, %d]\n",
 342                                 old_ent, lane, log.ent[arena->log_index[0]].seq,
 343                                 log.ent[arena->log_index[1]].seq);
 344                 /* TODO set error state? */
 345                 return -EIO;
 346         }
 347 
 348         ret_ent = (old_flag ? old_ent : (1 - old_ent));
 349 
 350         if (ent != NULL)
 351                 memcpy(ent, &log.ent[arena->log_index[ret_ent]], LOG_ENT_SIZE);
 352 
 353         return ret_ent;
 354 }
 355 
 356 /*
 357  * This function commits a log entry to media
 358  * It does _not_ prepare the freelist entry for the next write
 359  * btt_flog_write is the wrapper for updating the freelist elements
 360  */
 361 static int __btt_log_write(struct arena_info *arena, u32 lane,
 362                         u32 sub, struct log_entry *ent, unsigned long flags)
 363 {
 364         int ret;
 365         u32 group_slot = arena->log_index[sub];
 366         unsigned int log_half = LOG_ENT_SIZE / 2;
 367         void *src = ent;
 368         u64 ns_off;
 369 
 370         ns_off = arena->logoff + (lane * LOG_GRP_SIZE) +
 371                 (group_slot * LOG_ENT_SIZE);
 372         /* split the 16B write into atomic, durable halves */
 373         ret = arena_write_bytes(arena, ns_off, src, log_half, flags);
 374         if (ret)
 375                 return ret;
 376 
 377         ns_off += log_half;
 378         src += log_half;
 379         return arena_write_bytes(arena, ns_off, src, log_half, flags);
 380 }
 381 
 382 static int btt_flog_write(struct arena_info *arena, u32 lane, u32 sub,
 383                         struct log_entry *ent)
 384 {
 385         int ret;
 386 
 387         ret = __btt_log_write(arena, lane, sub, ent, NVDIMM_IO_ATOMIC);
 388         if (ret)
 389                 return ret;
 390 
 391         /* prepare the next free entry */
 392         arena->freelist[lane].sub = 1 - arena->freelist[lane].sub;
 393         if (++(arena->freelist[lane].seq) == 4)
 394                 arena->freelist[lane].seq = 1;
 395         if (ent_e_flag(le32_to_cpu(ent->old_map)))
 396                 arena->freelist[lane].has_err = 1;
 397         arena->freelist[lane].block = ent_lba(le32_to_cpu(ent->old_map));
 398 
 399         return ret;
 400 }
 401 
 402 /*
 403  * This function initializes the BTT map to the initial state, which is
 404  * all-zeroes, and indicates an identity mapping
 405  */
 406 static int btt_map_init(struct arena_info *arena)
 407 {
 408         int ret = -EINVAL;
 409         void *zerobuf;
 410         size_t offset = 0;
 411         size_t chunk_size = SZ_2M;
 412         size_t mapsize = arena->logoff - arena->mapoff;
 413 
 414         zerobuf = kzalloc(chunk_size, GFP_KERNEL);
 415         if (!zerobuf)
 416                 return -ENOMEM;
 417 
 418         /*
 419          * mapoff should always be at least 512B  aligned. We rely on that to
 420          * make sure rw_bytes does error clearing correctly, so make sure that
 421          * is the case.
 422          */
 423         dev_WARN_ONCE(to_dev(arena), !IS_ALIGNED(arena->mapoff, 512),
 424                 "arena->mapoff: %#llx is unaligned\n", arena->mapoff);
 425 
 426         while (mapsize) {
 427                 size_t size = min(mapsize, chunk_size);
 428 
 429                 dev_WARN_ONCE(to_dev(arena), size < 512,
 430                         "chunk size: %#zx is unaligned\n", size);
 431                 ret = arena_write_bytes(arena, arena->mapoff + offset, zerobuf,
 432                                 size, 0);
 433                 if (ret)
 434                         goto free;
 435 
 436                 offset += size;
 437                 mapsize -= size;
 438                 cond_resched();
 439         }
 440 
 441  free:
 442         kfree(zerobuf);
 443         return ret;
 444 }
 445 
 446 /*
 447  * This function initializes the BTT log with 'fake' entries pointing
 448  * to the initial reserved set of blocks as being free
 449  */
 450 static int btt_log_init(struct arena_info *arena)
 451 {
 452         size_t logsize = arena->info2off - arena->logoff;
 453         size_t chunk_size = SZ_4K, offset = 0;
 454         struct log_entry ent;
 455         void *zerobuf;
 456         int ret;
 457         u32 i;
 458 
 459         zerobuf = kzalloc(chunk_size, GFP_KERNEL);
 460         if (!zerobuf)
 461                 return -ENOMEM;
 462         /*
 463          * logoff should always be at least 512B  aligned. We rely on that to
 464          * make sure rw_bytes does error clearing correctly, so make sure that
 465          * is the case.
 466          */
 467         dev_WARN_ONCE(to_dev(arena), !IS_ALIGNED(arena->logoff, 512),
 468                 "arena->logoff: %#llx is unaligned\n", arena->logoff);
 469 
 470         while (logsize) {
 471                 size_t size = min(logsize, chunk_size);
 472 
 473                 dev_WARN_ONCE(to_dev(arena), size < 512,
 474                         "chunk size: %#zx is unaligned\n", size);
 475                 ret = arena_write_bytes(arena, arena->logoff + offset, zerobuf,
 476                                 size, 0);
 477                 if (ret)
 478                         goto free;
 479 
 480                 offset += size;
 481                 logsize -= size;
 482                 cond_resched();
 483         }
 484 
 485         for (i = 0; i < arena->nfree; i++) {
 486                 ent.lba = cpu_to_le32(i);
 487                 ent.old_map = cpu_to_le32(arena->external_nlba + i);
 488                 ent.new_map = cpu_to_le32(arena->external_nlba + i);
 489                 ent.seq = cpu_to_le32(LOG_SEQ_INIT);
 490                 ret = __btt_log_write(arena, i, 0, &ent, 0);
 491                 if (ret)
 492                         goto free;
 493         }
 494 
 495  free:
 496         kfree(zerobuf);
 497         return ret;
 498 }
 499 
 500 static u64 to_namespace_offset(struct arena_info *arena, u64 lba)
 501 {
 502         return arena->dataoff + ((u64)lba * arena->internal_lbasize);
 503 }
 504 
 505 static int arena_clear_freelist_error(struct arena_info *arena, u32 lane)
 506 {
 507         int ret = 0;
 508 
 509         if (arena->freelist[lane].has_err) {
 510                 void *zero_page = page_address(ZERO_PAGE(0));
 511                 u32 lba = arena->freelist[lane].block;
 512                 u64 nsoff = to_namespace_offset(arena, lba);
 513                 unsigned long len = arena->sector_size;
 514 
 515                 mutex_lock(&arena->err_lock);
 516 
 517                 while (len) {
 518                         unsigned long chunk = min(len, PAGE_SIZE);
 519 
 520                         ret = arena_write_bytes(arena, nsoff, zero_page,
 521                                 chunk, 0);
 522                         if (ret)
 523                                 break;
 524                         len -= chunk;
 525                         nsoff += chunk;
 526                         if (len == 0)
 527                                 arena->freelist[lane].has_err = 0;
 528                 }
 529                 mutex_unlock(&arena->err_lock);
 530         }
 531         return ret;
 532 }
 533 
 534 static int btt_freelist_init(struct arena_info *arena)
 535 {
 536         int new, ret;
 537         struct log_entry log_new;
 538         u32 i, map_entry, log_oldmap, log_newmap;
 539 
 540         arena->freelist = kcalloc(arena->nfree, sizeof(struct free_entry),
 541                                         GFP_KERNEL);
 542         if (!arena->freelist)
 543                 return -ENOMEM;
 544 
 545         for (i = 0; i < arena->nfree; i++) {
 546                 new = btt_log_read(arena, i, &log_new, LOG_NEW_ENT);
 547                 if (new < 0)
 548                         return new;
 549 
 550                 /* old and new map entries with any flags stripped out */
 551                 log_oldmap = ent_lba(le32_to_cpu(log_new.old_map));
 552                 log_newmap = ent_lba(le32_to_cpu(log_new.new_map));
 553 
 554                 /* sub points to the next one to be overwritten */
 555                 arena->freelist[i].sub = 1 - new;
 556                 arena->freelist[i].seq = nd_inc_seq(le32_to_cpu(log_new.seq));
 557                 arena->freelist[i].block = log_oldmap;
 558 
 559                 /*
 560                  * FIXME: if error clearing fails during init, we want to make
 561                  * the BTT read-only
 562                  */
 563                 if (ent_e_flag(le32_to_cpu(log_new.old_map)) &&
 564                     !ent_normal(le32_to_cpu(log_new.old_map))) {
 565                         arena->freelist[i].has_err = 1;
 566                         ret = arena_clear_freelist_error(arena, i);
 567                         if (ret)
 568                                 dev_err_ratelimited(to_dev(arena),
 569                                         "Unable to clear known errors\n");
 570                 }
 571 
 572                 /* This implies a newly created or untouched flog entry */
 573                 if (log_oldmap == log_newmap)
 574                         continue;
 575 
 576                 /* Check if map recovery is needed */
 577                 ret = btt_map_read(arena, le32_to_cpu(log_new.lba), &map_entry,
 578                                 NULL, NULL, 0);
 579                 if (ret)
 580                         return ret;
 581 
 582                 /*
 583                  * The map_entry from btt_read_map is stripped of any flag bits,
 584                  * so use the stripped out versions from the log as well for
 585                  * testing whether recovery is needed. For restoration, use the
 586                  * 'raw' version of the log entries as that captured what we
 587                  * were going to write originally.
 588                  */
 589                 if ((log_newmap != map_entry) && (log_oldmap == map_entry)) {
 590                         /*
 591                          * Last transaction wrote the flog, but wasn't able
 592                          * to complete the map write. So fix up the map.
 593                          */
 594                         ret = btt_map_write(arena, le32_to_cpu(log_new.lba),
 595                                         le32_to_cpu(log_new.new_map), 0, 0, 0);
 596                         if (ret)
 597                                 return ret;
 598                 }
 599         }
 600 
 601         return 0;
 602 }
 603 
 604 static bool ent_is_padding(struct log_entry *ent)
 605 {
 606         return (ent->lba == 0) && (ent->old_map == 0) && (ent->new_map == 0)
 607                 && (ent->seq == 0);
 608 }
 609 
 610 /*
 611  * Detecting valid log indices: We read a log group (see the comments in btt.h
 612  * for a description of a 'log_group' and its 'slots'), and iterate over its
 613  * four slots. We expect that a padding slot will be all-zeroes, and use this
 614  * to detect a padding slot vs. an actual entry.
 615  *
 616  * If a log_group is in the initial state, i.e. hasn't been used since the
 617  * creation of this BTT layout, it will have three of the four slots with
 618  * zeroes. We skip over these log_groups for the detection of log_index. If
 619  * all log_groups are in the initial state (i.e. the BTT has never been
 620  * written to), it is safe to assume the 'new format' of log entries in slots
 621  * (0, 1).
 622  */
 623 static int log_set_indices(struct arena_info *arena)
 624 {
 625         bool idx_set = false, initial_state = true;
 626         int ret, log_index[2] = {-1, -1};
 627         u32 i, j, next_idx = 0;
 628         struct log_group log;
 629         u32 pad_count = 0;
 630 
 631         for (i = 0; i < arena->nfree; i++) {
 632                 ret = btt_log_group_read(arena, i, &log);
 633                 if (ret < 0)
 634                         return ret;
 635 
 636                 for (j = 0; j < 4; j++) {
 637                         if (!idx_set) {
 638                                 if (ent_is_padding(&log.ent[j])) {
 639                                         pad_count++;
 640                                         continue;
 641                                 } else {
 642                                         /* Skip if index has been recorded */
 643                                         if ((next_idx == 1) &&
 644                                                 (j == log_index[0]))
 645                                                 continue;
 646                                         /* valid entry, record index */
 647                                         log_index[next_idx] = j;
 648                                         next_idx++;
 649                                 }
 650                                 if (next_idx == 2) {
 651                                         /* two valid entries found */
 652                                         idx_set = true;
 653                                 } else if (next_idx > 2) {
 654                                         /* too many valid indices */
 655                                         return -ENXIO;
 656                                 }
 657                         } else {
 658                                 /*
 659                                  * once the indices have been set, just verify
 660                                  * that all subsequent log groups are either in
 661                                  * their initial state or follow the same
 662                                  * indices.
 663                                  */
 664                                 if (j == log_index[0]) {
 665                                         /* entry must be 'valid' */
 666                                         if (ent_is_padding(&log.ent[j]))
 667                                                 return -ENXIO;
 668                                 } else if (j == log_index[1]) {
 669                                         ;
 670                                         /*
 671                                          * log_index[1] can be padding if the
 672                                          * lane never got used and it is still
 673                                          * in the initial state (three 'padding'
 674                                          * entries)
 675                                          */
 676                                 } else {
 677                                         /* entry must be invalid (padding) */
 678                                         if (!ent_is_padding(&log.ent[j]))
 679                                                 return -ENXIO;
 680                                 }
 681                         }
 682                 }
 683                 /*
 684                  * If any of the log_groups have more than one valid,
 685                  * non-padding entry, then the we are no longer in the
 686                  * initial_state
 687                  */
 688                 if (pad_count < 3)
 689                         initial_state = false;
 690                 pad_count = 0;
 691         }
 692 
 693         if (!initial_state && !idx_set)
 694                 return -ENXIO;
 695 
 696         /*
 697          * If all the entries in the log were in the initial state,
 698          * assume new padding scheme
 699          */
 700         if (initial_state)
 701                 log_index[1] = 1;
 702 
 703         /*
 704          * Only allow the known permutations of log/padding indices,
 705          * i.e. (0, 1), and (0, 2)
 706          */
 707         if ((log_index[0] == 0) && ((log_index[1] == 1) || (log_index[1] == 2)))
 708                 ; /* known index possibilities */
 709         else {
 710                 dev_err(to_dev(arena), "Found an unknown padding scheme\n");
 711                 return -ENXIO;
 712         }
 713 
 714         arena->log_index[0] = log_index[0];
 715         arena->log_index[1] = log_index[1];
 716         dev_dbg(to_dev(arena), "log_index_0 = %d\n", log_index[0]);
 717         dev_dbg(to_dev(arena), "log_index_1 = %d\n", log_index[1]);
 718         return 0;
 719 }
 720 
 721 static int btt_rtt_init(struct arena_info *arena)
 722 {
 723         arena->rtt = kcalloc(arena->nfree, sizeof(u32), GFP_KERNEL);
 724         if (arena->rtt == NULL)
 725                 return -ENOMEM;
 726 
 727         return 0;
 728 }
 729 
 730 static int btt_maplocks_init(struct arena_info *arena)
 731 {
 732         u32 i;
 733 
 734         arena->map_locks = kcalloc(arena->nfree, sizeof(struct aligned_lock),
 735                                 GFP_KERNEL);
 736         if (!arena->map_locks)
 737                 return -ENOMEM;
 738 
 739         for (i = 0; i < arena->nfree; i++)
 740                 spin_lock_init(&arena->map_locks[i].lock);
 741 
 742         return 0;
 743 }
 744 
 745 static struct arena_info *alloc_arena(struct btt *btt, size_t size,
 746                                 size_t start, size_t arena_off)
 747 {
 748         struct arena_info *arena;
 749         u64 logsize, mapsize, datasize;
 750         u64 available = size;
 751 
 752         arena = kzalloc(sizeof(struct arena_info), GFP_KERNEL);
 753         if (!arena)
 754                 return NULL;
 755         arena->nd_btt = btt->nd_btt;
 756         arena->sector_size = btt->sector_size;
 757         mutex_init(&arena->err_lock);
 758 
 759         if (!size)
 760                 return arena;
 761 
 762         arena->size = size;
 763         arena->external_lba_start = start;
 764         arena->external_lbasize = btt->lbasize;
 765         arena->internal_lbasize = roundup(arena->external_lbasize,
 766                                         INT_LBASIZE_ALIGNMENT);
 767         arena->nfree = BTT_DEFAULT_NFREE;
 768         arena->version_major = btt->nd_btt->version_major;
 769         arena->version_minor = btt->nd_btt->version_minor;
 770 
 771         if (available % BTT_PG_SIZE)
 772                 available -= (available % BTT_PG_SIZE);
 773 
 774         /* Two pages are reserved for the super block and its copy */
 775         available -= 2 * BTT_PG_SIZE;
 776 
 777         /* The log takes a fixed amount of space based on nfree */
 778         logsize = roundup(arena->nfree * LOG_GRP_SIZE, BTT_PG_SIZE);
 779         available -= logsize;
 780 
 781         /* Calculate optimal split between map and data area */
 782         arena->internal_nlba = div_u64(available - BTT_PG_SIZE,
 783                         arena->internal_lbasize + MAP_ENT_SIZE);
 784         arena->external_nlba = arena->internal_nlba - arena->nfree;
 785 
 786         mapsize = roundup((arena->external_nlba * MAP_ENT_SIZE), BTT_PG_SIZE);
 787         datasize = available - mapsize;
 788 
 789         /* 'Absolute' values, relative to start of storage space */
 790         arena->infooff = arena_off;
 791         arena->dataoff = arena->infooff + BTT_PG_SIZE;
 792         arena->mapoff = arena->dataoff + datasize;
 793         arena->logoff = arena->mapoff + mapsize;
 794         arena->info2off = arena->logoff + logsize;
 795 
 796         /* Default log indices are (0,1) */
 797         arena->log_index[0] = 0;
 798         arena->log_index[1] = 1;
 799         return arena;
 800 }
 801 
 802 static void free_arenas(struct btt *btt)
 803 {
 804         struct arena_info *arena, *next;
 805 
 806         list_for_each_entry_safe(arena, next, &btt->arena_list, list) {
 807                 list_del(&arena->list);
 808                 kfree(arena->rtt);
 809                 kfree(arena->map_locks);
 810                 kfree(arena->freelist);
 811                 debugfs_remove_recursive(arena->debugfs_dir);
 812                 kfree(arena);
 813         }
 814 }
 815 
 816 /*
 817  * This function reads an existing valid btt superblock and
 818  * populates the corresponding arena_info struct
 819  */
 820 static void parse_arena_meta(struct arena_info *arena, struct btt_sb *super,
 821                                 u64 arena_off)
 822 {
 823         arena->internal_nlba = le32_to_cpu(super->internal_nlba);
 824         arena->internal_lbasize = le32_to_cpu(super->internal_lbasize);
 825         arena->external_nlba = le32_to_cpu(super->external_nlba);
 826         arena->external_lbasize = le32_to_cpu(super->external_lbasize);
 827         arena->nfree = le32_to_cpu(super->nfree);
 828         arena->version_major = le16_to_cpu(super->version_major);
 829         arena->version_minor = le16_to_cpu(super->version_minor);
 830 
 831         arena->nextoff = (super->nextoff == 0) ? 0 : (arena_off +
 832                         le64_to_cpu(super->nextoff));
 833         arena->infooff = arena_off;
 834         arena->dataoff = arena_off + le64_to_cpu(super->dataoff);
 835         arena->mapoff = arena_off + le64_to_cpu(super->mapoff);
 836         arena->logoff = arena_off + le64_to_cpu(super->logoff);
 837         arena->info2off = arena_off + le64_to_cpu(super->info2off);
 838 
 839         arena->size = (le64_to_cpu(super->nextoff) > 0)
 840                 ? (le64_to_cpu(super->nextoff))
 841                 : (arena->info2off - arena->infooff + BTT_PG_SIZE);
 842 
 843         arena->flags = le32_to_cpu(super->flags);
 844 }
 845 
 846 static int discover_arenas(struct btt *btt)
 847 {
 848         int ret = 0;
 849         struct arena_info *arena;
 850         struct btt_sb *super;
 851         size_t remaining = btt->rawsize;
 852         u64 cur_nlba = 0;
 853         size_t cur_off = 0;
 854         int num_arenas = 0;
 855 
 856         super = kzalloc(sizeof(*super), GFP_KERNEL);
 857         if (!super)
 858                 return -ENOMEM;
 859 
 860         while (remaining) {
 861                 /* Alloc memory for arena */
 862                 arena = alloc_arena(btt, 0, 0, 0);
 863                 if (!arena) {
 864                         ret = -ENOMEM;
 865                         goto out_super;
 866                 }
 867 
 868                 arena->infooff = cur_off;
 869                 ret = btt_info_read(arena, super);
 870                 if (ret)
 871                         goto out;
 872 
 873                 if (!nd_btt_arena_is_valid(btt->nd_btt, super)) {
 874                         if (remaining == btt->rawsize) {
 875                                 btt->init_state = INIT_NOTFOUND;
 876                                 dev_info(to_dev(arena), "No existing arenas\n");
 877                                 goto out;
 878                         } else {
 879                                 dev_err(to_dev(arena),
 880                                                 "Found corrupted metadata!\n");
 881                                 ret = -ENODEV;
 882                                 goto out;
 883                         }
 884                 }
 885 
 886                 arena->external_lba_start = cur_nlba;
 887                 parse_arena_meta(arena, super, cur_off);
 888 
 889                 ret = log_set_indices(arena);
 890                 if (ret) {
 891                         dev_err(to_dev(arena),
 892                                 "Unable to deduce log/padding indices\n");
 893                         goto out;
 894                 }
 895 
 896                 ret = btt_freelist_init(arena);
 897                 if (ret)
 898                         goto out;
 899 
 900                 ret = btt_rtt_init(arena);
 901                 if (ret)
 902                         goto out;
 903 
 904                 ret = btt_maplocks_init(arena);
 905                 if (ret)
 906                         goto out;
 907 
 908                 list_add_tail(&arena->list, &btt->arena_list);
 909 
 910                 remaining -= arena->size;
 911                 cur_off += arena->size;
 912                 cur_nlba += arena->external_nlba;
 913                 num_arenas++;
 914 
 915                 if (arena->nextoff == 0)
 916                         break;
 917         }
 918         btt->num_arenas = num_arenas;
 919         btt->nlba = cur_nlba;
 920         btt->init_state = INIT_READY;
 921 
 922         kfree(super);
 923         return ret;
 924 
 925  out:
 926         kfree(arena);
 927         free_arenas(btt);
 928  out_super:
 929         kfree(super);
 930         return ret;
 931 }
 932 
 933 static int create_arenas(struct btt *btt)
 934 {
 935         size_t remaining = btt->rawsize;
 936         size_t cur_off = 0;
 937 
 938         while (remaining) {
 939                 struct arena_info *arena;
 940                 size_t arena_size = min_t(u64, ARENA_MAX_SIZE, remaining);
 941 
 942                 remaining -= arena_size;
 943                 if (arena_size < ARENA_MIN_SIZE)
 944                         break;
 945 
 946                 arena = alloc_arena(btt, arena_size, btt->nlba, cur_off);
 947                 if (!arena) {
 948                         free_arenas(btt);
 949                         return -ENOMEM;
 950                 }
 951                 btt->nlba += arena->external_nlba;
 952                 if (remaining >= ARENA_MIN_SIZE)
 953                         arena->nextoff = arena->size;
 954                 else
 955                         arena->nextoff = 0;
 956                 cur_off += arena_size;
 957                 list_add_tail(&arena->list, &btt->arena_list);
 958         }
 959 
 960         return 0;
 961 }
 962 
 963 /*
 964  * This function completes arena initialization by writing
 965  * all the metadata.
 966  * It is only called for an uninitialized arena when a write
 967  * to that arena occurs for the first time.
 968  */
 969 static int btt_arena_write_layout(struct arena_info *arena)
 970 {
 971         int ret;
 972         u64 sum;
 973         struct btt_sb *super;
 974         struct nd_btt *nd_btt = arena->nd_btt;
 975         const u8 *parent_uuid = nd_dev_to_uuid(&nd_btt->ndns->dev);
 976 
 977         ret = btt_map_init(arena);
 978         if (ret)
 979                 return ret;
 980 
 981         ret = btt_log_init(arena);
 982         if (ret)
 983                 return ret;
 984 
 985         super = kzalloc(sizeof(struct btt_sb), GFP_NOIO);
 986         if (!super)
 987                 return -ENOMEM;
 988 
 989         strncpy(super->signature, BTT_SIG, BTT_SIG_LEN);
 990         memcpy(super->uuid, nd_btt->uuid, 16);
 991         memcpy(super->parent_uuid, parent_uuid, 16);
 992         super->flags = cpu_to_le32(arena->flags);
 993         super->version_major = cpu_to_le16(arena->version_major);
 994         super->version_minor = cpu_to_le16(arena->version_minor);
 995         super->external_lbasize = cpu_to_le32(arena->external_lbasize);
 996         super->external_nlba = cpu_to_le32(arena->external_nlba);
 997         super->internal_lbasize = cpu_to_le32(arena->internal_lbasize);
 998         super->internal_nlba = cpu_to_le32(arena->internal_nlba);
 999         super->nfree = cpu_to_le32(arena->nfree);
1000         super->infosize = cpu_to_le32(sizeof(struct btt_sb));
1001         super->nextoff = cpu_to_le64(arena->nextoff);
1002         /*
1003          * Subtract arena->infooff (arena start) so numbers are relative
1004          * to 'this' arena
1005          */
1006         super->dataoff = cpu_to_le64(arena->dataoff - arena->infooff);
1007         super->mapoff = cpu_to_le64(arena->mapoff - arena->infooff);
1008         super->logoff = cpu_to_le64(arena->logoff - arena->infooff);
1009         super->info2off = cpu_to_le64(arena->info2off - arena->infooff);
1010 
1011         super->flags = 0;
1012         sum = nd_sb_checksum((struct nd_gen_sb *) super);
1013         super->checksum = cpu_to_le64(sum);
1014 
1015         ret = btt_info_write(arena, super);
1016 
1017         kfree(super);
1018         return ret;
1019 }
1020 
1021 /*
1022  * This function completes the initialization for the BTT namespace
1023  * such that it is ready to accept IOs
1024  */
1025 static int btt_meta_init(struct btt *btt)
1026 {
1027         int ret = 0;
1028         struct arena_info *arena;
1029 
1030         mutex_lock(&btt->init_lock);
1031         list_for_each_entry(arena, &btt->arena_list, list) {
1032                 ret = btt_arena_write_layout(arena);
1033                 if (ret)
1034                         goto unlock;
1035 
1036                 ret = btt_freelist_init(arena);
1037                 if (ret)
1038                         goto unlock;
1039 
1040                 ret = btt_rtt_init(arena);
1041                 if (ret)
1042                         goto unlock;
1043 
1044                 ret = btt_maplocks_init(arena);
1045                 if (ret)
1046                         goto unlock;
1047         }
1048 
1049         btt->init_state = INIT_READY;
1050 
1051  unlock:
1052         mutex_unlock(&btt->init_lock);
1053         return ret;
1054 }
1055 
1056 static u32 btt_meta_size(struct btt *btt)
1057 {
1058         return btt->lbasize - btt->sector_size;
1059 }
1060 
1061 /*
1062  * This function calculates the arena in which the given LBA lies
1063  * by doing a linear walk. This is acceptable since we expect only
1064  * a few arenas. If we have backing devices that get much larger,
1065  * we can construct a balanced binary tree of arenas at init time
1066  * so that this range search becomes faster.
1067  */
1068 static int lba_to_arena(struct btt *btt, sector_t sector, __u32 *premap,
1069                                 struct arena_info **arena)
1070 {
1071         struct arena_info *arena_list;
1072         __u64 lba = div_u64(sector << SECTOR_SHIFT, btt->sector_size);
1073 
1074         list_for_each_entry(arena_list, &btt->arena_list, list) {
1075                 if (lba < arena_list->external_nlba) {
1076                         *arena = arena_list;
1077                         *premap = lba;
1078                         return 0;
1079                 }
1080                 lba -= arena_list->external_nlba;
1081         }
1082 
1083         return -EIO;
1084 }
1085 
1086 /*
1087  * The following (lock_map, unlock_map) are mostly just to improve
1088  * readability, since they index into an array of locks
1089  */
1090 static void lock_map(struct arena_info *arena, u32 premap)
1091                 __acquires(&arena->map_locks[idx].lock)
1092 {
1093         u32 idx = (premap * MAP_ENT_SIZE / L1_CACHE_BYTES) % arena->nfree;
1094 
1095         spin_lock(&arena->map_locks[idx].lock);
1096 }
1097 
1098 static void unlock_map(struct arena_info *arena, u32 premap)
1099                 __releases(&arena->map_locks[idx].lock)
1100 {
1101         u32 idx = (premap * MAP_ENT_SIZE / L1_CACHE_BYTES) % arena->nfree;
1102 
1103         spin_unlock(&arena->map_locks[idx].lock);
1104 }
1105 
1106 static int btt_data_read(struct arena_info *arena, struct page *page,
1107                         unsigned int off, u32 lba, u32 len)
1108 {
1109         int ret;
1110         u64 nsoff = to_namespace_offset(arena, lba);
1111         void *mem = kmap_atomic(page);
1112 
1113         ret = arena_read_bytes(arena, nsoff, mem + off, len, NVDIMM_IO_ATOMIC);
1114         kunmap_atomic(mem);
1115 
1116         return ret;
1117 }
1118 
1119 static int btt_data_write(struct arena_info *arena, u32 lba,
1120                         struct page *page, unsigned int off, u32 len)
1121 {
1122         int ret;
1123         u64 nsoff = to_namespace_offset(arena, lba);
1124         void *mem = kmap_atomic(page);
1125 
1126         ret = arena_write_bytes(arena, nsoff, mem + off, len, NVDIMM_IO_ATOMIC);
1127         kunmap_atomic(mem);
1128 
1129         return ret;
1130 }
1131 
1132 static void zero_fill_data(struct page *page, unsigned int off, u32 len)
1133 {
1134         void *mem = kmap_atomic(page);
1135 
1136         memset(mem + off, 0, len);
1137         kunmap_atomic(mem);
1138 }
1139 
1140 #ifdef CONFIG_BLK_DEV_INTEGRITY
1141 static int btt_rw_integrity(struct btt *btt, struct bio_integrity_payload *bip,
1142                         struct arena_info *arena, u32 postmap, int rw)
1143 {
1144         unsigned int len = btt_meta_size(btt);
1145         u64 meta_nsoff;
1146         int ret = 0;
1147 
1148         if (bip == NULL)
1149                 return 0;
1150 
1151         meta_nsoff = to_namespace_offset(arena, postmap) + btt->sector_size;
1152 
1153         while (len) {
1154                 unsigned int cur_len;
1155                 struct bio_vec bv;
1156                 void *mem;
1157 
1158                 bv = bvec_iter_bvec(bip->bip_vec, bip->bip_iter);
1159                 /*
1160                  * The 'bv' obtained from bvec_iter_bvec has its .bv_len and
1161                  * .bv_offset already adjusted for iter->bi_bvec_done, and we
1162                  * can use those directly
1163                  */
1164 
1165                 cur_len = min(len, bv.bv_len);
1166                 mem = kmap_atomic(bv.bv_page);
1167                 if (rw)
1168                         ret = arena_write_bytes(arena, meta_nsoff,
1169                                         mem + bv.bv_offset, cur_len,
1170                                         NVDIMM_IO_ATOMIC);
1171                 else
1172                         ret = arena_read_bytes(arena, meta_nsoff,
1173                                         mem + bv.bv_offset, cur_len,
1174                                         NVDIMM_IO_ATOMIC);
1175 
1176                 kunmap_atomic(mem);
1177                 if (ret)
1178                         return ret;
1179 
1180                 len -= cur_len;
1181                 meta_nsoff += cur_len;
1182                 if (!bvec_iter_advance(bip->bip_vec, &bip->bip_iter, cur_len))
1183                         return -EIO;
1184         }
1185 
1186         return ret;
1187 }
1188 
1189 #else /* CONFIG_BLK_DEV_INTEGRITY */
1190 static int btt_rw_integrity(struct btt *btt, struct bio_integrity_payload *bip,
1191                         struct arena_info *arena, u32 postmap, int rw)
1192 {
1193         return 0;
1194 }
1195 #endif
1196 
1197 static int btt_read_pg(struct btt *btt, struct bio_integrity_payload *bip,
1198                         struct page *page, unsigned int off, sector_t sector,
1199                         unsigned int len)
1200 {
1201         int ret = 0;
1202         int t_flag, e_flag;
1203         struct arena_info *arena = NULL;
1204         u32 lane = 0, premap, postmap;
1205 
1206         while (len) {
1207                 u32 cur_len;
1208 
1209                 lane = nd_region_acquire_lane(btt->nd_region);
1210 
1211                 ret = lba_to_arena(btt, sector, &premap, &arena);
1212                 if (ret)
1213                         goto out_lane;
1214 
1215                 cur_len = min(btt->sector_size, len);
1216 
1217                 ret = btt_map_read(arena, premap, &postmap, &t_flag, &e_flag,
1218                                 NVDIMM_IO_ATOMIC);
1219                 if (ret)
1220                         goto out_lane;
1221 
1222                 /*
1223                  * We loop to make sure that the post map LBA didn't change
1224                  * from under us between writing the RTT and doing the actual
1225                  * read.
1226                  */
1227                 while (1) {
1228                         u32 new_map;
1229                         int new_t, new_e;
1230 
1231                         if (t_flag) {
1232                                 zero_fill_data(page, off, cur_len);
1233                                 goto out_lane;
1234                         }
1235 
1236                         if (e_flag) {
1237                                 ret = -EIO;
1238                                 goto out_lane;
1239                         }
1240 
1241                         arena->rtt[lane] = RTT_VALID | postmap;
1242                         /*
1243                          * Barrier to make sure this write is not reordered
1244                          * to do the verification map_read before the RTT store
1245                          */
1246                         barrier();
1247 
1248                         ret = btt_map_read(arena, premap, &new_map, &new_t,
1249                                                 &new_e, NVDIMM_IO_ATOMIC);
1250                         if (ret)
1251                                 goto out_rtt;
1252 
1253                         if ((postmap == new_map) && (t_flag == new_t) &&
1254                                         (e_flag == new_e))
1255                                 break;
1256 
1257                         postmap = new_map;
1258                         t_flag = new_t;
1259                         e_flag = new_e;
1260                 }
1261 
1262                 ret = btt_data_read(arena, page, off, postmap, cur_len);
1263                 if (ret) {
1264                         /* Media error - set the e_flag */
1265                         if (btt_map_write(arena, premap, postmap, 0, 1, NVDIMM_IO_ATOMIC))
1266                                 dev_warn_ratelimited(to_dev(arena),
1267                                         "Error persistently tracking bad blocks at %#x\n",
1268                                         premap);
1269                         goto out_rtt;
1270                 }
1271 
1272                 if (bip) {
1273                         ret = btt_rw_integrity(btt, bip, arena, postmap, READ);
1274                         if (ret)
1275                                 goto out_rtt;
1276                 }
1277 
1278                 arena->rtt[lane] = RTT_INVALID;
1279                 nd_region_release_lane(btt->nd_region, lane);
1280 
1281                 len -= cur_len;
1282                 off += cur_len;
1283                 sector += btt->sector_size >> SECTOR_SHIFT;
1284         }
1285 
1286         return 0;
1287 
1288  out_rtt:
1289         arena->rtt[lane] = RTT_INVALID;
1290  out_lane:
1291         nd_region_release_lane(btt->nd_region, lane);
1292         return ret;
1293 }
1294 
1295 /*
1296  * Normally, arena_{read,write}_bytes will take care of the initial offset
1297  * adjustment, but in the case of btt_is_badblock, where we query is_bad_pmem,
1298  * we need the final, raw namespace offset here
1299  */
1300 static bool btt_is_badblock(struct btt *btt, struct arena_info *arena,
1301                 u32 postmap)
1302 {
1303         u64 nsoff = adjust_initial_offset(arena->nd_btt,
1304                         to_namespace_offset(arena, postmap));
1305         sector_t phys_sector = nsoff >> 9;
1306 
1307         return is_bad_pmem(btt->phys_bb, phys_sector, arena->internal_lbasize);
1308 }
1309 
1310 static int btt_write_pg(struct btt *btt, struct bio_integrity_payload *bip,
1311                         sector_t sector, struct page *page, unsigned int off,
1312                         unsigned int len)
1313 {
1314         int ret = 0;
1315         struct arena_info *arena = NULL;
1316         u32 premap = 0, old_postmap, new_postmap, lane = 0, i;
1317         struct log_entry log;
1318         int sub;
1319 
1320         while (len) {
1321                 u32 cur_len;
1322                 int e_flag;
1323 
1324  retry:
1325                 lane = nd_region_acquire_lane(btt->nd_region);
1326 
1327                 ret = lba_to_arena(btt, sector, &premap, &arena);
1328                 if (ret)
1329                         goto out_lane;
1330                 cur_len = min(btt->sector_size, len);
1331 
1332                 if ((arena->flags & IB_FLAG_ERROR_MASK) != 0) {
1333                         ret = -EIO;
1334                         goto out_lane;
1335                 }
1336 
1337                 if (btt_is_badblock(btt, arena, arena->freelist[lane].block))
1338                         arena->freelist[lane].has_err = 1;
1339 
1340                 if (mutex_is_locked(&arena->err_lock)
1341                                 || arena->freelist[lane].has_err) {
1342                         nd_region_release_lane(btt->nd_region, lane);
1343 
1344                         ret = arena_clear_freelist_error(arena, lane);
1345                         if (ret)
1346                                 return ret;
1347 
1348                         /* OK to acquire a different lane/free block */
1349                         goto retry;
1350                 }
1351 
1352                 new_postmap = arena->freelist[lane].block;
1353 
1354                 /* Wait if the new block is being read from */
1355                 for (i = 0; i < arena->nfree; i++)
1356                         while (arena->rtt[i] == (RTT_VALID | new_postmap))
1357                                 cpu_relax();
1358 
1359 
1360                 if (new_postmap >= arena->internal_nlba) {
1361                         ret = -EIO;
1362                         goto out_lane;
1363                 }
1364 
1365                 ret = btt_data_write(arena, new_postmap, page, off, cur_len);
1366                 if (ret)
1367                         goto out_lane;
1368 
1369                 if (bip) {
1370                         ret = btt_rw_integrity(btt, bip, arena, new_postmap,
1371                                                 WRITE);
1372                         if (ret)
1373                                 goto out_lane;
1374                 }
1375 
1376                 lock_map(arena, premap);
1377                 ret = btt_map_read(arena, premap, &old_postmap, NULL, &e_flag,
1378                                 NVDIMM_IO_ATOMIC);
1379                 if (ret)
1380                         goto out_map;
1381                 if (old_postmap >= arena->internal_nlba) {
1382                         ret = -EIO;
1383                         goto out_map;
1384                 }
1385                 if (e_flag)
1386                         set_e_flag(old_postmap);
1387 
1388                 log.lba = cpu_to_le32(premap);
1389                 log.old_map = cpu_to_le32(old_postmap);
1390                 log.new_map = cpu_to_le32(new_postmap);
1391                 log.seq = cpu_to_le32(arena->freelist[lane].seq);
1392                 sub = arena->freelist[lane].sub;
1393                 ret = btt_flog_write(arena, lane, sub, &log);
1394                 if (ret)
1395                         goto out_map;
1396 
1397                 ret = btt_map_write(arena, premap, new_postmap, 0, 0,
1398                         NVDIMM_IO_ATOMIC);
1399                 if (ret)
1400                         goto out_map;
1401 
1402                 unlock_map(arena, premap);
1403                 nd_region_release_lane(btt->nd_region, lane);
1404 
1405                 if (e_flag) {
1406                         ret = arena_clear_freelist_error(arena, lane);
1407                         if (ret)
1408                                 return ret;
1409                 }
1410 
1411                 len -= cur_len;
1412                 off += cur_len;
1413                 sector += btt->sector_size >> SECTOR_SHIFT;
1414         }
1415 
1416         return 0;
1417 
1418  out_map:
1419         unlock_map(arena, premap);
1420  out_lane:
1421         nd_region_release_lane(btt->nd_region, lane);
1422         return ret;
1423 }
1424 
1425 static int btt_do_bvec(struct btt *btt, struct bio_integrity_payload *bip,
1426                         struct page *page, unsigned int len, unsigned int off,
1427                         unsigned int op, sector_t sector)
1428 {
1429         int ret;
1430 
1431         if (!op_is_write(op)) {
1432                 ret = btt_read_pg(btt, bip, page, off, sector, len);
1433                 flush_dcache_page(page);
1434         } else {
1435                 flush_dcache_page(page);
1436                 ret = btt_write_pg(btt, bip, sector, page, off, len);
1437         }
1438 
1439         return ret;
1440 }
1441 
1442 static blk_qc_t btt_make_request(struct request_queue *q, struct bio *bio)
1443 {
1444         struct bio_integrity_payload *bip = bio_integrity(bio);
1445         struct btt *btt = q->queuedata;
1446         struct bvec_iter iter;
1447         unsigned long start;
1448         struct bio_vec bvec;
1449         int err = 0;
1450         bool do_acct;
1451 
1452         if (!bio_integrity_prep(bio))
1453                 return BLK_QC_T_NONE;
1454 
1455         do_acct = nd_iostat_start(bio, &start);
1456         bio_for_each_segment(bvec, bio, iter) {
1457                 unsigned int len = bvec.bv_len;
1458 
1459                 if (len > PAGE_SIZE || len < btt->sector_size ||
1460                                 len % btt->sector_size) {
1461                         dev_err_ratelimited(&btt->nd_btt->dev,
1462                                 "unaligned bio segment (len: %d)\n", len);
1463                         bio->bi_status = BLK_STS_IOERR;
1464                         break;
1465                 }
1466 
1467                 err = btt_do_bvec(btt, bip, bvec.bv_page, len, bvec.bv_offset,
1468                                   bio_op(bio), iter.bi_sector);
1469                 if (err) {
1470                         dev_err(&btt->nd_btt->dev,
1471                                         "io error in %s sector %lld, len %d,\n",
1472                                         (op_is_write(bio_op(bio))) ? "WRITE" :
1473                                         "READ",
1474                                         (unsigned long long) iter.bi_sector, len);
1475                         bio->bi_status = errno_to_blk_status(err);
1476                         break;
1477                 }
1478         }
1479         if (do_acct)
1480                 nd_iostat_end(bio, start);
1481 
1482         bio_endio(bio);
1483         return BLK_QC_T_NONE;
1484 }
1485 
1486 static int btt_rw_page(struct block_device *bdev, sector_t sector,
1487                 struct page *page, unsigned int op)
1488 {
1489         struct btt *btt = bdev->bd_disk->private_data;
1490         int rc;
1491         unsigned int len;
1492 
1493         len = hpage_nr_pages(page) * PAGE_SIZE;
1494         rc = btt_do_bvec(btt, NULL, page, len, 0, op, sector);
1495         if (rc == 0)
1496                 page_endio(page, op_is_write(op), 0);
1497 
1498         return rc;
1499 }
1500 
1501 
1502 static int btt_getgeo(struct block_device *bd, struct hd_geometry *geo)
1503 {
1504         /* some standard values */
1505         geo->heads = 1 << 6;
1506         geo->sectors = 1 << 5;
1507         geo->cylinders = get_capacity(bd->bd_disk) >> 11;
1508         return 0;
1509 }
1510 
1511 static const struct block_device_operations btt_fops = {
1512         .owner =                THIS_MODULE,
1513         .rw_page =              btt_rw_page,
1514         .getgeo =               btt_getgeo,
1515         .revalidate_disk =      nvdimm_revalidate_disk,
1516 };
1517 
1518 static int btt_blk_init(struct btt *btt)
1519 {
1520         struct nd_btt *nd_btt = btt->nd_btt;
1521         struct nd_namespace_common *ndns = nd_btt->ndns;
1522 
1523         /* create a new disk and request queue for btt */
1524         btt->btt_queue = blk_alloc_queue(GFP_KERNEL);
1525         if (!btt->btt_queue)
1526                 return -ENOMEM;
1527 
1528         btt->btt_disk = alloc_disk(0);
1529         if (!btt->btt_disk) {
1530                 blk_cleanup_queue(btt->btt_queue);
1531                 return -ENOMEM;
1532         }
1533 
1534         nvdimm_namespace_disk_name(ndns, btt->btt_disk->disk_name);
1535         btt->btt_disk->first_minor = 0;
1536         btt->btt_disk->fops = &btt_fops;
1537         btt->btt_disk->private_data = btt;
1538         btt->btt_disk->queue = btt->btt_queue;
1539         btt->btt_disk->flags = GENHD_FL_EXT_DEVT;
1540         btt->btt_disk->queue->backing_dev_info->capabilities |=
1541                         BDI_CAP_SYNCHRONOUS_IO;
1542 
1543         blk_queue_make_request(btt->btt_queue, btt_make_request);
1544         blk_queue_logical_block_size(btt->btt_queue, btt->sector_size);
1545         blk_queue_max_hw_sectors(btt->btt_queue, UINT_MAX);
1546         blk_queue_flag_set(QUEUE_FLAG_NONROT, btt->btt_queue);
1547         btt->btt_queue->queuedata = btt;
1548 
1549         if (btt_meta_size(btt)) {
1550                 int rc = nd_integrity_init(btt->btt_disk, btt_meta_size(btt));
1551 
1552                 if (rc) {
1553                         del_gendisk(btt->btt_disk);
1554                         put_disk(btt->btt_disk);
1555                         blk_cleanup_queue(btt->btt_queue);
1556                         return rc;
1557                 }
1558         }
1559         set_capacity(btt->btt_disk, btt->nlba * btt->sector_size >> 9);
1560         device_add_disk(&btt->nd_btt->dev, btt->btt_disk, NULL);
1561         btt->nd_btt->size = btt->nlba * (u64)btt->sector_size;
1562         revalidate_disk(btt->btt_disk);
1563 
1564         return 0;
1565 }
1566 
1567 static void btt_blk_cleanup(struct btt *btt)
1568 {
1569         del_gendisk(btt->btt_disk);
1570         put_disk(btt->btt_disk);
1571         blk_cleanup_queue(btt->btt_queue);
1572 }
1573 
1574 /**
1575  * btt_init - initialize a block translation table for the given device
1576  * @nd_btt:     device with BTT geometry and backing device info
1577  * @rawsize:    raw size in bytes of the backing device
1578  * @lbasize:    lba size of the backing device
1579  * @uuid:       A uuid for the backing device - this is stored on media
1580  * @maxlane:    maximum number of parallel requests the device can handle
1581  *
1582  * Initialize a Block Translation Table on a backing device to provide
1583  * single sector power fail atomicity.
1584  *
1585  * Context:
1586  * Might sleep.
1587  *
1588  * Returns:
1589  * Pointer to a new struct btt on success, NULL on failure.
1590  */
1591 static struct btt *btt_init(struct nd_btt *nd_btt, unsigned long long rawsize,
1592                 u32 lbasize, u8 *uuid, struct nd_region *nd_region)
1593 {
1594         int ret;
1595         struct btt *btt;
1596         struct nd_namespace_io *nsio;
1597         struct device *dev = &nd_btt->dev;
1598 
1599         btt = devm_kzalloc(dev, sizeof(struct btt), GFP_KERNEL);
1600         if (!btt)
1601                 return NULL;
1602 
1603         btt->nd_btt = nd_btt;
1604         btt->rawsize = rawsize;
1605         btt->lbasize = lbasize;
1606         btt->sector_size = ((lbasize >= 4096) ? 4096 : 512);
1607         INIT_LIST_HEAD(&btt->arena_list);
1608         mutex_init(&btt->init_lock);
1609         btt->nd_region = nd_region;
1610         nsio = to_nd_namespace_io(&nd_btt->ndns->dev);
1611         btt->phys_bb = &nsio->bb;
1612 
1613         ret = discover_arenas(btt);
1614         if (ret) {
1615                 dev_err(dev, "init: error in arena_discover: %d\n", ret);
1616                 return NULL;
1617         }
1618 
1619         if (btt->init_state != INIT_READY && nd_region->ro) {
1620                 dev_warn(dev, "%s is read-only, unable to init btt metadata\n",
1621                                 dev_name(&nd_region->dev));
1622                 return NULL;
1623         } else if (btt->init_state != INIT_READY) {
1624                 btt->num_arenas = (rawsize / ARENA_MAX_SIZE) +
1625                         ((rawsize % ARENA_MAX_SIZE) ? 1 : 0);
1626                 dev_dbg(dev, "init: %d arenas for %llu rawsize\n",
1627                                 btt->num_arenas, rawsize);
1628 
1629                 ret = create_arenas(btt);
1630                 if (ret) {
1631                         dev_info(dev, "init: create_arenas: %d\n", ret);
1632                         return NULL;
1633                 }
1634 
1635                 ret = btt_meta_init(btt);
1636                 if (ret) {
1637                         dev_err(dev, "init: error in meta_init: %d\n", ret);
1638                         return NULL;
1639                 }
1640         }
1641 
1642         ret = btt_blk_init(btt);
1643         if (ret) {
1644                 dev_err(dev, "init: error in blk_init: %d\n", ret);
1645                 return NULL;
1646         }
1647 
1648         btt_debugfs_init(btt);
1649 
1650         return btt;
1651 }
1652 
1653 /**
1654  * btt_fini - de-initialize a BTT
1655  * @btt:        the BTT handle that was generated by btt_init
1656  *
1657  * De-initialize a Block Translation Table on device removal
1658  *
1659  * Context:
1660  * Might sleep.
1661  */
1662 static void btt_fini(struct btt *btt)
1663 {
1664         if (btt) {
1665                 btt_blk_cleanup(btt);
1666                 free_arenas(btt);
1667                 debugfs_remove_recursive(btt->debugfs_dir);
1668         }
1669 }
1670 
1671 int nvdimm_namespace_attach_btt(struct nd_namespace_common *ndns)
1672 {
1673         struct nd_btt *nd_btt = to_nd_btt(ndns->claim);
1674         struct nd_region *nd_region;
1675         struct btt_sb *btt_sb;
1676         struct btt *btt;
1677         size_t rawsize;
1678 
1679         if (!nd_btt->uuid || !nd_btt->ndns || !nd_btt->lbasize) {
1680                 dev_dbg(&nd_btt->dev, "incomplete btt configuration\n");
1681                 return -ENODEV;
1682         }
1683 
1684         btt_sb = devm_kzalloc(&nd_btt->dev, sizeof(*btt_sb), GFP_KERNEL);
1685         if (!btt_sb)
1686                 return -ENOMEM;
1687 
1688         /*
1689          * If this returns < 0, that is ok as it just means there wasn't
1690          * an existing BTT, and we're creating a new one. We still need to
1691          * call this as we need the version dependent fields in nd_btt to be
1692          * set correctly based on the holder class
1693          */
1694         nd_btt_version(nd_btt, ndns, btt_sb);
1695 
1696         rawsize = nvdimm_namespace_capacity(ndns) - nd_btt->initial_offset;
1697         if (rawsize < ARENA_MIN_SIZE) {
1698                 dev_dbg(&nd_btt->dev, "%s must be at least %ld bytes\n",
1699                                 dev_name(&ndns->dev),
1700                                 ARENA_MIN_SIZE + nd_btt->initial_offset);
1701                 return -ENXIO;
1702         }
1703         nd_region = to_nd_region(nd_btt->dev.parent);
1704         btt = btt_init(nd_btt, rawsize, nd_btt->lbasize, nd_btt->uuid,
1705                         nd_region);
1706         if (!btt)
1707                 return -ENOMEM;
1708         nd_btt->btt = btt;
1709 
1710         return 0;
1711 }
1712 EXPORT_SYMBOL(nvdimm_namespace_attach_btt);
1713 
1714 int nvdimm_namespace_detach_btt(struct nd_btt *nd_btt)
1715 {
1716         struct btt *btt = nd_btt->btt;
1717 
1718         btt_fini(btt);
1719         nd_btt->btt = NULL;
1720 
1721         return 0;
1722 }
1723 EXPORT_SYMBOL(nvdimm_namespace_detach_btt);
1724 
1725 static int __init nd_btt_init(void)
1726 {
1727         int rc = 0;
1728 
1729         debugfs_root = debugfs_create_dir("btt", NULL);
1730         if (IS_ERR_OR_NULL(debugfs_root))
1731                 rc = -ENXIO;
1732 
1733         return rc;
1734 }
1735 
1736 static void __exit nd_btt_exit(void)
1737 {
1738         debugfs_remove_recursive(debugfs_root);
1739 }
1740 
1741 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_BTT);
1742 MODULE_AUTHOR("Vishal Verma <vishal.l.verma@linux.intel.com>");
1743 MODULE_LICENSE("GPL v2");
1744 module_init(nd_btt_init);
1745 module_exit(nd_btt_exit);
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/nvdimm/btt.c

DEFINITIONS
