drivers/lightnvm/pblk-read.c

   1 /*
   2  * Copyright (C) 2016 CNEX Labs
   3  * Initial release: Javier Gonzalez <javier@cnexlabs.com>
   4  *                  Matias Bjorling <matias@cnexlabs.com>
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License version
   8  * 2 as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * pblk-read.c - pblk's read path
  16  */
  17
  18 #include "pblk.h"
  19
  20 /*
  21  * There is no guarantee that the value read from cache has not been updated and
  22  * resides at another location in the cache. We guarantee though that if the
  23  * value is read from the cache, it belongs to the mapped lba. In order to
  24  * guarantee and order between writes and reads are ordered, a flush must be
  25  * issued.
  26  */
  27 static int pblk_read_from_cache(struct pblk *pblk, struct bio *bio,
  28                                 sector_t lba, struct ppa_addr ppa,
  29                                 int bio_iter, bool advanced_bio)
  30 {
  31 #ifdef CONFIG_NVM_DEBUG
  32         /* Callers must ensure that the ppa points to a cache address */
  33         BUG_ON(pblk_ppa_empty(ppa));
  34         BUG_ON(!pblk_addr_in_cache(ppa));
  35 #endif
  36
  37         return pblk_rb_copy_to_bio(&pblk->rwb, bio, lba, ppa,
  38                                                 bio_iter, advanced_bio);
  39 }
  40
  41 static void pblk_read_ppalist_rq(struct pblk *pblk, struct nvm_rq *rqd,
  42                                  unsigned long *read_bitmap)
  43 {
  44         struct bio *bio = rqd->bio;
  45         struct ppa_addr ppas[PBLK_MAX_REQ_ADDRS];
  46         sector_t blba = pblk_get_lba(bio);
  47         int nr_secs = rqd->nr_ppas;
  48         bool advanced_bio = false;
  49         int i, j = 0;
  50
  51         /* logic error: lba out-of-bounds. Ignore read request */
  52         if (blba + nr_secs >= pblk->rl.nr_secs) {
  53                 WARN(1, "pblk: read lbas out of bounds\n");
  54                 return;
  55         }
  56
  57         pblk_lookup_l2p_seq(pblk, ppas, blba, nr_secs);
  58
  59         for (i = 0; i < nr_secs; i++) {
  60                 struct ppa_addr p = ppas[i];
  61                 sector_t lba = blba + i;
  62
  63 retry:
  64                 if (pblk_ppa_empty(p)) {
  65                         WARN_ON(test_and_set_bit(i, read_bitmap));
  66
  67                         if (unlikely(!advanced_bio)) {
  68                                 bio_advance(bio, (i) * PBLK_EXPOSED_PAGE_SIZE);
  69                                 advanced_bio = true;
  70                         }
  71
  72                         goto next;
  73                 }
  74
  75                 /* Try to read from write buffer. The address is later checked
  76                  * on the write buffer to prevent retrieving overwritten data.
  77                  */
  78                 if (pblk_addr_in_cache(p)) {
  79                         if (!pblk_read_from_cache(pblk, bio, lba, p, i,
  80                                                                 advanced_bio)) {
  81                                 pblk_lookup_l2p_seq(pblk, &p, lba, 1);
  82                                 goto retry;
  83                         }
  84                         WARN_ON(test_and_set_bit(i, read_bitmap));
  85                         advanced_bio = true;
  86 #ifdef CONFIG_NVM_DEBUG
  87                         atomic_long_inc(&pblk->cache_reads);
  88 #endif
  89                 } else {
  90                         /* Read from media non-cached sectors */
  91                         rqd->ppa_list[j++] = p;
  92                 }
  93
  94 next:
  95                 if (advanced_bio)
  96                         bio_advance(bio, PBLK_EXPOSED_PAGE_SIZE);
  97         }
  98
  99         if (pblk_io_aligned(pblk, nr_secs))
 100                 rqd->flags = pblk_set_read_mode(pblk, PBLK_READ_SEQUENTIAL);
 101         else
 102                 rqd->flags = pblk_set_read_mode(pblk, PBLK_READ_RANDOM);
 103
 104 #ifdef CONFIG_NVM_DEBUG
 105         atomic_long_add(nr_secs, &pblk->inflight_reads);
 106 #endif
 107 }
 108
 109 static int pblk_submit_read_io(struct pblk *pblk, struct nvm_rq *rqd)
 110 {
 111         int err;
 112
 113         err = pblk_submit_io(pblk, rqd);
 114         if (err)
 115                 return NVM_IO_ERR;
 116
 117         return NVM_IO_OK;
 118 }
 119
 120 static void pblk_end_io_read(struct nvm_rq *rqd)
 121 {
 122         struct pblk *pblk = rqd->private;
 123         struct nvm_tgt_dev *dev = pblk->dev;
 124         struct pblk_g_ctx *r_ctx = nvm_rq_to_pdu(rqd);
 125         struct bio *bio = rqd->bio;
 126
 127         if (rqd->error)
 128                 pblk_log_read_err(pblk, rqd);
 129 #ifdef CONFIG_NVM_DEBUG
 130         else
 131                 WARN_ONCE(bio->bi_status, "pblk: corrupted read error\n");
 132 #endif
 133
 134         nvm_dev_dma_free(dev->parent, rqd->meta_list, rqd->dma_meta_list);
 135
 136         bio_put(bio);
 137         if (r_ctx->private) {
 138                 struct bio *orig_bio = r_ctx->private;
 139
 140 #ifdef CONFIG_NVM_DEBUG
 141                 WARN_ONCE(orig_bio->bi_status, "pblk: corrupted read bio\n");
 142 #endif
 143                 bio_endio(orig_bio);
 144                 bio_put(orig_bio);
 145         }
 146
 147 #ifdef CONFIG_NVM_DEBUG
 148         atomic_long_add(rqd->nr_ppas, &pblk->sync_reads);
 149         atomic_long_sub(rqd->nr_ppas, &pblk->inflight_reads);
 150 #endif
 151
 152         pblk_free_rqd(pblk, rqd, READ);
 153         atomic_dec(&pblk->inflight_io);
 154 }
 155
 156 static int pblk_fill_partial_read_bio(struct pblk *pblk, struct nvm_rq *rqd,
 157                                       unsigned int bio_init_idx,
 158                                       unsigned long *read_bitmap)
 159 {
 160         struct bio *new_bio, *bio = rqd->bio;
 161         struct bio_vec src_bv, dst_bv;
 162         void *ppa_ptr = NULL;
 163         void *src_p, *dst_p;
 164         dma_addr_t dma_ppa_list = 0;
 165         int nr_secs = rqd->nr_ppas;
 166         int nr_holes = nr_secs - bitmap_weight(read_bitmap, nr_secs);
 167         int i, ret, hole;
 168         DECLARE_COMPLETION_ONSTACK(wait);
 169
 170         new_bio = bio_alloc(GFP_KERNEL, nr_holes);
 171         if (!new_bio) {
 172                 pr_err("pblk: could not alloc read bio\n");
 173                 return NVM_IO_ERR;
 174         }
 175
 176         if (pblk_bio_add_pages(pblk, new_bio, GFP_KERNEL, nr_holes))
 177                 goto err;
 178
 179         if (nr_holes != new_bio->bi_vcnt) {
 180                 pr_err("pblk: malformed bio\n");
 181                 goto err;
 182         }
 183
 184         new_bio->bi_iter.bi_sector = 0; /* internal bio */
 185         bio_set_op_attrs(new_bio, REQ_OP_READ, 0);
 186         new_bio->bi_private = &wait;
 187         new_bio->bi_end_io = pblk_end_bio_sync;
 188
 189         rqd->bio = new_bio;
 190         rqd->nr_ppas = nr_holes;
 191         rqd->flags = pblk_set_read_mode(pblk, PBLK_READ_RANDOM);
 192         rqd->end_io = NULL;
 193
 194         if (unlikely(nr_secs > 1 && nr_holes == 1)) {
 195                 ppa_ptr = rqd->ppa_list;
 196                 dma_ppa_list = rqd->dma_ppa_list;
 197                 rqd->ppa_addr = rqd->ppa_list[0];
 198         }
 199
 200         ret = pblk_submit_read_io(pblk, rqd);
 201         if (ret) {
 202                 bio_put(rqd->bio);
 203                 pr_err("pblk: read IO submission failed\n");
 204                 goto err;
 205         }
 206
 207         if (!wait_for_completion_io_timeout(&wait,
 208                                 msecs_to_jiffies(PBLK_COMMAND_TIMEOUT_MS))) {
 209                 pr_err("pblk: partial read I/O timed out\n");
 210         }
 211
 212         if (rqd->error) {
 213                 atomic_long_inc(&pblk->read_failed);
 214 #ifdef CONFIG_NVM_DEBUG
 215                 pblk_print_failed_rqd(pblk, rqd, rqd->error);
 216 #endif
 217         }
 218
 219         if (unlikely(nr_secs > 1 && nr_holes == 1)) {
 220                 rqd->ppa_list = ppa_ptr;
 221                 rqd->dma_ppa_list = dma_ppa_list;
 222         }
 223
 224         /* Fill the holes in the original bio */
 225         i = 0;
 226         hole = find_first_zero_bit(read_bitmap, nr_secs);
 227         do {
 228                 src_bv = new_bio->bi_io_vec[i++];
 229                 dst_bv = bio->bi_io_vec[bio_init_idx + hole];
 230
 231                 src_p = kmap_atomic(src_bv.bv_page);
 232                 dst_p = kmap_atomic(dst_bv.bv_page);
 233
 234                 memcpy(dst_p + dst_bv.bv_offset,
 235                         src_p + src_bv.bv_offset,
 236                         PBLK_EXPOSED_PAGE_SIZE);
 237
 238                 kunmap_atomic(src_p);
 239                 kunmap_atomic(dst_p);
 240
 241                 mempool_free(src_bv.bv_page, pblk->page_pool);
 242
 243                 hole = find_next_zero_bit(read_bitmap, nr_secs, hole + 1);
 244         } while (hole < nr_secs);
 245
 246         bio_put(new_bio);
 247
 248         /* Complete the original bio and associated request */
 249         rqd->bio = bio;
 250         rqd->nr_ppas = nr_secs;
 251         rqd->private = pblk;
 252
 253         bio_endio(bio);
 254         pblk_end_io_read(rqd);
 255         return NVM_IO_OK;
 256
 257 err:
 258         /* Free allocated pages in new bio */
 259         pblk_bio_free_pages(pblk, bio, 0, new_bio->bi_vcnt);
 260         rqd->private = pblk;
 261         pblk_end_io_read(rqd);
 262         return NVM_IO_ERR;
 263 }
 264
 265 static void pblk_read_rq(struct pblk *pblk, struct nvm_rq *rqd,
 266                          unsigned long *read_bitmap)
 267 {
 268         struct bio *bio = rqd->bio;
 269         struct ppa_addr ppa;
 270         sector_t lba = pblk_get_lba(bio);
 271
 272         /* logic error: lba out-of-bounds. Ignore read request */
 273         if (lba >= pblk->rl.nr_secs) {
 274                 WARN(1, "pblk: read lba out of bounds\n");
 275                 return;
 276         }
 277
 278         pblk_lookup_l2p_seq(pblk, &ppa, lba, 1);
 279
 280 #ifdef CONFIG_NVM_DEBUG
 281         atomic_long_inc(&pblk->inflight_reads);
 282 #endif
 283
 284 retry:
 285         if (pblk_ppa_empty(ppa)) {
 286                 WARN_ON(test_and_set_bit(0, read_bitmap));
 287                 return;
 288         }
 289
 290         /* Try to read from write buffer. The address is later checked on the
 291          * write buffer to prevent retrieving overwritten data.
 292          */
 293         if (pblk_addr_in_cache(ppa)) {
 294                 if (!pblk_read_from_cache(pblk, bio, lba, ppa, 0, 1)) {
 295                         pblk_lookup_l2p_seq(pblk, &ppa, lba, 1);
 296                         goto retry;
 297                 }
 298                 WARN_ON(test_and_set_bit(0, read_bitmap));
 299 #ifdef CONFIG_NVM_DEBUG
 300                         atomic_long_inc(&pblk->cache_reads);
 301 #endif
 302         } else {
 303                 rqd->ppa_addr = ppa;
 304         }
 305
 306         rqd->flags = pblk_set_read_mode(pblk, PBLK_READ_RANDOM);
 307 }
 308
 309 int pblk_submit_read(struct pblk *pblk, struct bio *bio)
 310 {
 311         struct nvm_tgt_dev *dev = pblk->dev;
 312         unsigned int nr_secs = pblk_get_secs(bio);
 313         struct nvm_rq *rqd;
 314         unsigned long read_bitmap; /* Max 64 ppas per request */
 315         unsigned int bio_init_idx;
 316         int ret = NVM_IO_ERR;
 317
 318         if (nr_secs > PBLK_MAX_REQ_ADDRS)
 319                 return NVM_IO_ERR;
 320
 321         bitmap_zero(&read_bitmap, nr_secs);
 322
 323         rqd = pblk_alloc_rqd(pblk, READ);
 324         if (IS_ERR(rqd)) {
 325                 pr_err_ratelimited("pblk: not able to alloc rqd");
 326                 return NVM_IO_ERR;
 327         }
 328
 329         rqd->opcode = NVM_OP_PREAD;
 330         rqd->bio = bio;
 331         rqd->nr_ppas = nr_secs;
 332         rqd->private = pblk;
 333         rqd->end_io = pblk_end_io_read;
 334
 335         /* Save the index for this bio's start. This is needed in case
 336          * we need to fill a partial read.
 337          */
 338         bio_init_idx = pblk_get_bi_idx(bio);
 339
 340         rqd->meta_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
 341                                                         &rqd->dma_meta_list);
 342         if (!rqd->meta_list) {
 343                 pr_err("pblk: not able to allocate ppa list\n");
 344                 goto fail_rqd_free;
 345         }
 346
 347         if (nr_secs > 1) {
 348                 rqd->ppa_list = rqd->meta_list + pblk_dma_meta_size;
 349                 rqd->dma_ppa_list = rqd->dma_meta_list + pblk_dma_meta_size;
 350
 351                 pblk_read_ppalist_rq(pblk, rqd, &read_bitmap);
 352         } else {
 353                 pblk_read_rq(pblk, rqd, &read_bitmap);
 354         }
 355
 356         bio_get(bio);
 357         if (bitmap_full(&read_bitmap, nr_secs)) {
 358                 bio_endio(bio);
 359                 atomic_inc(&pblk->inflight_io);
 360                 pblk_end_io_read(rqd);
 361                 return NVM_IO_OK;
 362         }
 363
 364         /* All sectors are to be read from the device */
 365         if (bitmap_empty(&read_bitmap, rqd->nr_ppas)) {
 366                 struct bio *int_bio = NULL;
 367                 struct pblk_g_ctx *r_ctx = nvm_rq_to_pdu(rqd);
 368
 369                 /* Clone read bio to deal with read errors internally */
 370                 int_bio = bio_clone_fast(bio, GFP_KERNEL, pblk_bio_set);
 371                 if (!int_bio) {
 372                         pr_err("pblk: could not clone read bio\n");
 373                         return NVM_IO_ERR;
 374                 }
 375
 376                 rqd->bio = int_bio;
 377                 r_ctx->private = bio;
 378
 379                 ret = pblk_submit_read_io(pblk, rqd);
 380                 if (ret) {
 381                         pr_err("pblk: read IO submission failed\n");
 382                         if (int_bio)
 383                                 bio_put(int_bio);
 384                         return ret;
 385                 }
 386
 387                 return NVM_IO_OK;
 388         }
 389
 390         /* The read bio request could be partially filled by the write buffer,
 391          * but there are some holes that need to be read from the drive.
 392          */
 393         ret = pblk_fill_partial_read_bio(pblk, rqd, bio_init_idx, &read_bitmap);
 394         if (ret) {
 395                 pr_err("pblk: failed to perform partial read\n");
 396                 return ret;
 397         }
 398
 399         return NVM_IO_OK;
 400
 401 fail_rqd_free:
 402         pblk_free_rqd(pblk, rqd, READ);
 403         return ret;
 404 }
 405
 406 static int read_ppalist_rq_gc(struct pblk *pblk, struct nvm_rq *rqd,
 407                               struct pblk_line *line, u64 *lba_list,
 408                               unsigned int nr_secs)
 409 {
 410         struct ppa_addr ppas[PBLK_MAX_REQ_ADDRS];
 411         int valid_secs = 0;
 412         int i;
 413
 414         pblk_lookup_l2p_rand(pblk, ppas, lba_list, nr_secs);
 415
 416         for (i = 0; i < nr_secs; i++) {
 417                 if (pblk_addr_in_cache(ppas[i]) || ppas[i].g.blk != line->id ||
 418                                                 pblk_ppa_empty(ppas[i])) {
 419                         lba_list[i] = ADDR_EMPTY;
 420                         continue;
 421                 }
 422
 423                 rqd->ppa_list[valid_secs++] = ppas[i];
 424         }
 425
 426 #ifdef CONFIG_NVM_DEBUG
 427         atomic_long_add(valid_secs, &pblk->inflight_reads);
 428 #endif
 429         return valid_secs;
 430 }
 431
 432 static int read_rq_gc(struct pblk *pblk, struct nvm_rq *rqd,
 433                       struct pblk_line *line, sector_t lba)
 434 {
 435         struct ppa_addr ppa;
 436         int valid_secs = 0;
 437
 438         if (lba == ADDR_EMPTY)
 439                 goto out;
 440
 441         /* logic error: lba out-of-bounds */
 442         if (lba >= pblk->rl.nr_secs) {
 443                 WARN(1, "pblk: read lba out of bounds\n");
 444                 goto out;
 445         }
 446
 447         spin_lock(&pblk->trans_lock);
 448         ppa = pblk_trans_map_get(pblk, lba);
 449         spin_unlock(&pblk->trans_lock);
 450
 451         /* Ignore updated values until the moment */
 452         if (pblk_addr_in_cache(ppa) || ppa.g.blk != line->id ||
 453                                                         pblk_ppa_empty(ppa))
 454                 goto out;
 455
 456         rqd->ppa_addr = ppa;
 457         valid_secs = 1;
 458
 459 #ifdef CONFIG_NVM_DEBUG
 460         atomic_long_inc(&pblk->inflight_reads);
 461 #endif
 462
 463 out:
 464         return valid_secs;
 465 }
 466
 467 int pblk_submit_read_gc(struct pblk *pblk, u64 *lba_list, void *data,
 468                         unsigned int nr_secs, unsigned int *secs_to_gc,
 469                         struct pblk_line *line)
 470 {
 471         struct nvm_tgt_dev *dev = pblk->dev;
 472         struct nvm_geo *geo = &dev->geo;
 473         struct bio *bio;
 474         struct nvm_rq rqd;
 475         int ret, data_len;
 476         DECLARE_COMPLETION_ONSTACK(wait);
 477
 478         memset(&rqd, 0, sizeof(struct nvm_rq));
 479
 480         rqd.meta_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
 481                                                         &rqd.dma_meta_list);
 482         if (!rqd.meta_list)
 483                 return NVM_IO_ERR;
 484
 485         if (nr_secs > 1) {
 486                 rqd.ppa_list = rqd.meta_list + pblk_dma_meta_size;
 487                 rqd.dma_ppa_list = rqd.dma_meta_list + pblk_dma_meta_size;
 488
 489                 *secs_to_gc = read_ppalist_rq_gc(pblk, &rqd, line, lba_list,
 490                                                                 nr_secs);
 491                 if (*secs_to_gc == 1)
 492                         rqd.ppa_addr = rqd.ppa_list[0];
 493         } else {
 494                 *secs_to_gc = read_rq_gc(pblk, &rqd, line, lba_list[0]);
 495         }
 496
 497         if (!(*secs_to_gc))
 498                 goto out;
 499
 500         data_len = (*secs_to_gc) * geo->sec_size;
 501         bio = pblk_bio_map_addr(pblk, data, *secs_to_gc, data_len,
 502                                                 PBLK_KMALLOC_META, GFP_KERNEL);
 503         if (IS_ERR(bio)) {
 504                 pr_err("pblk: could not allocate GC bio (%lu)\n", PTR_ERR(bio));
 505                 goto err_free_dma;
 506         }
 507
 508         bio->bi_iter.bi_sector = 0; /* internal bio */
 509         bio_set_op_attrs(bio, REQ_OP_READ, 0);
 510
 511         rqd.opcode = NVM_OP_PREAD;
 512         rqd.end_io = pblk_end_io_sync;
 513         rqd.private = &wait;
 514         rqd.nr_ppas = *secs_to_gc;
 515         rqd.flags = pblk_set_read_mode(pblk, PBLK_READ_RANDOM);
 516         rqd.bio = bio;
 517
 518         ret = pblk_submit_read_io(pblk, &rqd);
 519         if (ret) {
 520                 bio_endio(bio);
 521                 pr_err("pblk: GC read request failed\n");
 522                 goto err_free_dma;
 523         }
 524
 525         if (!wait_for_completion_io_timeout(&wait,
 526                                 msecs_to_jiffies(PBLK_COMMAND_TIMEOUT_MS))) {
 527                 pr_err("pblk: GC read I/O timed out\n");
 528         }
 529         atomic_dec(&pblk->inflight_io);
 530
 531         if (rqd.error) {
 532                 atomic_long_inc(&pblk->read_failed_gc);
 533 #ifdef CONFIG_NVM_DEBUG
 534                 pblk_print_failed_rqd(pblk, &rqd, rqd.error);
 535 #endif
 536         }
 537
 538 #ifdef CONFIG_NVM_DEBUG
 539         atomic_long_add(*secs_to_gc, &pblk->sync_reads);
 540         atomic_long_add(*secs_to_gc, &pblk->recov_gc_reads);
 541         atomic_long_sub(*secs_to_gc, &pblk->inflight_reads);
 542 #endif
 543
 544 out:
 545         nvm_dev_dma_free(dev->parent, rqd.meta_list, rqd.dma_meta_list);
 546         return NVM_IO_OK;
 547
 548 err_free_dma:
 549         nvm_dev_dma_free(dev->parent, rqd.meta_list, rqd.dma_meta_list);
 550         return NVM_IO_ERR;
 551 }