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)
  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,
  38                                         pblk_addr_to_cacheline(ppa), bio_iter);
  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         int advanced_bio = 0;
  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                         continue;
  67                 }
  68
  69                 /* Try to read from write buffer. The address is later checked
  70                  * on the write buffer to prevent retrieving overwritten data.
  71                  */
  72                 if (pblk_addr_in_cache(p)) {
  73                         if (!pblk_read_from_cache(pblk, bio, lba, p, i)) {
  74                                 pblk_lookup_l2p_seq(pblk, &p, lba, 1);
  75                                 goto retry;
  76                         }
  77                         WARN_ON(test_and_set_bit(i, read_bitmap));
  78                         advanced_bio = 1;
  79                 } else {
  80                         /* Read from media non-cached sectors */
  81                         rqd->ppa_list[j++] = p;
  82                 }
  83
  84                 if (advanced_bio)
  85                         bio_advance(bio, PBLK_EXPOSED_PAGE_SIZE);
  86         }
  87
  88 #ifdef CONFIG_NVM_DEBUG
  89         atomic_long_add(nr_secs, &pblk->inflight_reads);
  90 #endif
  91 }
  92
  93 static int pblk_submit_read_io(struct pblk *pblk, struct nvm_rq *rqd)
  94 {
  95         int err;
  96
  97         rqd->flags = pblk_set_read_mode(pblk);
  98
  99         err = pblk_submit_io(pblk, rqd);
 100         if (err)
 101                 return NVM_IO_ERR;
 102
 103         return NVM_IO_OK;
 104 }
 105
 106 static void pblk_end_io_read(struct nvm_rq *rqd)
 107 {
 108         struct pblk *pblk = rqd->private;
 109         struct nvm_tgt_dev *dev = pblk->dev;
 110         struct pblk_r_ctx *r_ctx = nvm_rq_to_pdu(rqd);
 111         struct bio *bio = rqd->bio;
 112
 113         if (rqd->error)
 114                 pblk_log_read_err(pblk, rqd);
 115 #ifdef CONFIG_NVM_DEBUG
 116         else
 117                 WARN_ONCE(bio->bi_error, "pblk: corrupted read error\n");
 118 #endif
 119
 120         if (rqd->nr_ppas > 1)
 121                 nvm_dev_dma_free(dev->parent, rqd->ppa_list, rqd->dma_ppa_list);
 122
 123         bio_put(bio);
 124         if (r_ctx->orig_bio) {
 125 #ifdef CONFIG_NVM_DEBUG
 126                 WARN_ONCE(r_ctx->orig_bio->bi_error,
 127                                                 "pblk: corrupted read bio\n");
 128 #endif
 129                 bio_endio(r_ctx->orig_bio);
 130                 bio_put(r_ctx->orig_bio);
 131         }
 132
 133 #ifdef CONFIG_NVM_DEBUG
 134         atomic_long_add(rqd->nr_ppas, &pblk->sync_reads);
 135         atomic_long_sub(rqd->nr_ppas, &pblk->inflight_reads);
 136 #endif
 137
 138         pblk_free_rqd(pblk, rqd, READ);
 139 }
 140
 141 static int pblk_fill_partial_read_bio(struct pblk *pblk, struct nvm_rq *rqd,
 142                                       unsigned int bio_init_idx,
 143                                       unsigned long *read_bitmap)
 144 {
 145         struct bio *new_bio, *bio = rqd->bio;
 146         struct bio_vec src_bv, dst_bv;
 147         void *ppa_ptr = NULL;
 148         void *src_p, *dst_p;
 149         dma_addr_t dma_ppa_list = 0;
 150         int nr_secs = rqd->nr_ppas;
 151         int nr_holes = nr_secs - bitmap_weight(read_bitmap, nr_secs);
 152         int i, ret, hole;
 153         DECLARE_COMPLETION_ONSTACK(wait);
 154
 155         new_bio = bio_alloc(GFP_KERNEL, nr_holes);
 156         if (!new_bio) {
 157                 pr_err("pblk: could not alloc read bio\n");
 158                 return NVM_IO_ERR;
 159         }
 160
 161         if (pblk_bio_add_pages(pblk, new_bio, GFP_KERNEL, nr_holes))
 162                 goto err;
 163
 164         if (nr_holes != new_bio->bi_vcnt) {
 165                 pr_err("pblk: malformed bio\n");
 166                 goto err;
 167         }
 168
 169         new_bio->bi_iter.bi_sector = 0; /* internal bio */
 170         bio_set_op_attrs(new_bio, REQ_OP_READ, 0);
 171         new_bio->bi_private = &wait;
 172         new_bio->bi_end_io = pblk_end_bio_sync;
 173
 174         rqd->bio = new_bio;
 175         rqd->nr_ppas = nr_holes;
 176         rqd->end_io = NULL;
 177
 178         if (unlikely(nr_secs > 1 && nr_holes == 1)) {
 179                 ppa_ptr = rqd->ppa_list;
 180                 dma_ppa_list = rqd->dma_ppa_list;
 181                 rqd->ppa_addr = rqd->ppa_list[0];
 182         }
 183
 184         ret = pblk_submit_read_io(pblk, rqd);
 185         if (ret) {
 186                 bio_put(rqd->bio);
 187                 pr_err("pblk: read IO submission failed\n");
 188                 goto err;
 189         }
 190
 191         if (!wait_for_completion_io_timeout(&wait,
 192                                 msecs_to_jiffies(PBLK_COMMAND_TIMEOUT_MS))) {
 193                 pr_err("pblk: partial read I/O timed out\n");
 194         }
 195
 196         if (rqd->error) {
 197                 atomic_long_inc(&pblk->read_failed);
 198 #ifdef CONFIG_NVM_DEBUG
 199                 pblk_print_failed_rqd(pblk, rqd, rqd->error);
 200 #endif
 201         }
 202
 203         if (unlikely(nr_secs > 1 && nr_holes == 1)) {
 204                 rqd->ppa_list = ppa_ptr;
 205                 rqd->dma_ppa_list = dma_ppa_list;
 206         }
 207
 208         /* Fill the holes in the original bio */
 209         i = 0;
 210         hole = find_first_zero_bit(read_bitmap, nr_secs);
 211         do {
 212                 src_bv = new_bio->bi_io_vec[i++];
 213                 dst_bv = bio->bi_io_vec[bio_init_idx + hole];
 214
 215                 src_p = kmap_atomic(src_bv.bv_page);
 216                 dst_p = kmap_atomic(dst_bv.bv_page);
 217
 218                 memcpy(dst_p + dst_bv.bv_offset,
 219                         src_p + src_bv.bv_offset,
 220                         PBLK_EXPOSED_PAGE_SIZE);
 221
 222                 kunmap_atomic(src_p);
 223                 kunmap_atomic(dst_p);
 224
 225                 mempool_free(src_bv.bv_page, pblk->page_pool);
 226
 227                 hole = find_next_zero_bit(read_bitmap, nr_secs, hole + 1);
 228         } while (hole < nr_secs);
 229
 230         bio_put(new_bio);
 231
 232         /* Complete the original bio and associated request */
 233         rqd->bio = bio;
 234         rqd->nr_ppas = nr_secs;
 235         rqd->private = pblk;
 236
 237         bio_endio(bio);
 238         pblk_end_io_read(rqd);
 239         return NVM_IO_OK;
 240
 241 err:
 242         /* Free allocated pages in new bio */
 243         pblk_bio_free_pages(pblk, bio, 0, new_bio->bi_vcnt);
 244         rqd->private = pblk;
 245         pblk_end_io_read(rqd);
 246         return NVM_IO_ERR;
 247 }
 248
 249 static void pblk_read_rq(struct pblk *pblk, struct nvm_rq *rqd,
 250                          unsigned long *read_bitmap)
 251 {
 252         struct bio *bio = rqd->bio;
 253         struct ppa_addr ppa;
 254         sector_t lba = pblk_get_lba(bio);
 255
 256         /* logic error: lba out-of-bounds. Ignore read request */
 257         if (lba >= pblk->rl.nr_secs) {
 258                 WARN(1, "pblk: read lba out of bounds\n");
 259                 return;
 260         }
 261
 262         pblk_lookup_l2p_seq(pblk, &ppa, lba, 1);
 263
 264 #ifdef CONFIG_NVM_DEBUG
 265         atomic_long_inc(&pblk->inflight_reads);
 266 #endif
 267
 268 retry:
 269         if (pblk_ppa_empty(ppa)) {
 270                 WARN_ON(test_and_set_bit(0, read_bitmap));
 271                 return;
 272         }
 273
 274         /* Try to read from write buffer. The address is later checked on the
 275          * write buffer to prevent retrieving overwritten data.
 276          */
 277         if (pblk_addr_in_cache(ppa)) {
 278                 if (!pblk_read_from_cache(pblk, bio, lba, ppa, 0)) {
 279                         pblk_lookup_l2p_seq(pblk, &ppa, lba, 1);
 280                         goto retry;
 281                 }
 282                 WARN_ON(test_and_set_bit(0, read_bitmap));
 283         } else {
 284                 rqd->ppa_addr = ppa;
 285         }
 286 }
 287
 288 int pblk_submit_read(struct pblk *pblk, struct bio *bio)
 289 {
 290         struct nvm_tgt_dev *dev = pblk->dev;
 291         unsigned int nr_secs = pblk_get_secs(bio);
 292         struct nvm_rq *rqd;
 293         unsigned long read_bitmap; /* Max 64 ppas per request */
 294         unsigned int bio_init_idx;
 295         int ret = NVM_IO_ERR;
 296
 297         if (nr_secs > PBLK_MAX_REQ_ADDRS)
 298                 return NVM_IO_ERR;
 299
 300         bitmap_zero(&read_bitmap, nr_secs);
 301
 302         rqd = pblk_alloc_rqd(pblk, READ);
 303         if (IS_ERR(rqd)) {
 304                 pr_err_ratelimited("pblk: not able to alloc rqd");
 305                 return NVM_IO_ERR;
 306         }
 307
 308         rqd->opcode = NVM_OP_PREAD;
 309         rqd->bio = bio;
 310         rqd->nr_ppas = nr_secs;
 311         rqd->private = pblk;
 312         rqd->end_io = pblk_end_io_read;
 313
 314         /* Save the index for this bio's start. This is needed in case
 315          * we need to fill a partial read.
 316          */
 317         bio_init_idx = pblk_get_bi_idx(bio);
 318
 319         if (nr_secs > 1) {
 320                 rqd->ppa_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
 321                                                 &rqd->dma_ppa_list);
 322                 if (!rqd->ppa_list) {
 323                         pr_err("pblk: not able to allocate ppa list\n");
 324                         goto fail_rqd_free;
 325                 }
 326
 327                 pblk_read_ppalist_rq(pblk, rqd, &read_bitmap);
 328         } else {
 329                 pblk_read_rq(pblk, rqd, &read_bitmap);
 330         }
 331
 332         bio_get(bio);
 333         if (bitmap_full(&read_bitmap, nr_secs)) {
 334                 bio_endio(bio);
 335                 pblk_end_io_read(rqd);
 336                 return NVM_IO_OK;
 337         }
 338
 339         /* All sectors are to be read from the device */
 340         if (bitmap_empty(&read_bitmap, rqd->nr_ppas)) {
 341                 struct bio *int_bio = NULL;
 342                 struct pblk_r_ctx *r_ctx = nvm_rq_to_pdu(rqd);
 343
 344                 /* Clone read bio to deal with read errors internally */
 345                 int_bio = bio_clone_bioset(bio, GFP_KERNEL, fs_bio_set);
 346                 if (!int_bio) {
 347                         pr_err("pblk: could not clone read bio\n");
 348                         return NVM_IO_ERR;
 349                 }
 350
 351                 rqd->bio = int_bio;
 352                 r_ctx->orig_bio = bio;
 353
 354                 ret = pblk_submit_read_io(pblk, rqd);
 355                 if (ret) {
 356                         pr_err("pblk: read IO submission failed\n");
 357                         if (int_bio)
 358                                 bio_put(int_bio);
 359                         return ret;
 360                 }
 361
 362                 return NVM_IO_OK;
 363         }
 364
 365         /* The read bio request could be partially filled by the write buffer,
 366          * but there are some holes that need to be read from the drive.
 367          */
 368         ret = pblk_fill_partial_read_bio(pblk, rqd, bio_init_idx, &read_bitmap);
 369         if (ret) {
 370                 pr_err("pblk: failed to perform partial read\n");
 371                 return ret;
 372         }
 373
 374         return NVM_IO_OK;
 375
 376 fail_rqd_free:
 377         pblk_free_rqd(pblk, rqd, READ);
 378         return ret;
 379 }
 380
 381 static int read_ppalist_rq_gc(struct pblk *pblk, struct nvm_rq *rqd,
 382                               struct pblk_line *line, u64 *lba_list,
 383                               unsigned int nr_secs)
 384 {
 385         struct ppa_addr ppas[PBLK_MAX_REQ_ADDRS];
 386         int valid_secs = 0;
 387         int i;
 388
 389         pblk_lookup_l2p_rand(pblk, ppas, lba_list, nr_secs);
 390
 391         for (i = 0; i < nr_secs; i++) {
 392                 if (pblk_addr_in_cache(ppas[i]) || ppas[i].g.blk != line->id ||
 393                                                 pblk_ppa_empty(ppas[i])) {
 394                         lba_list[i] = ADDR_EMPTY;
 395                         continue;
 396                 }
 397
 398                 rqd->ppa_list[valid_secs++] = ppas[i];
 399         }
 400
 401 #ifdef CONFIG_NVM_DEBUG
 402         atomic_long_add(valid_secs, &pblk->inflight_reads);
 403 #endif
 404         return valid_secs;
 405 }
 406
 407 static int read_rq_gc(struct pblk *pblk, struct nvm_rq *rqd,
 408                       struct pblk_line *line, sector_t lba)
 409 {
 410         struct ppa_addr ppa;
 411         int valid_secs = 0;
 412
 413         if (lba == ADDR_EMPTY)
 414                 goto out;
 415
 416         /* logic error: lba out-of-bounds */
 417         if (lba >= pblk->rl.nr_secs) {
 418                 WARN(1, "pblk: read lba out of bounds\n");
 419                 goto out;
 420         }
 421
 422         spin_lock(&pblk->trans_lock);
 423         ppa = pblk_trans_map_get(pblk, lba);
 424         spin_unlock(&pblk->trans_lock);
 425
 426         /* Ignore updated values until the moment */
 427         if (pblk_addr_in_cache(ppa) || ppa.g.blk != line->id ||
 428                                                         pblk_ppa_empty(ppa))
 429                 goto out;
 430
 431         rqd->ppa_addr = ppa;
 432         valid_secs = 1;
 433
 434 #ifdef CONFIG_NVM_DEBUG
 435         atomic_long_inc(&pblk->inflight_reads);
 436 #endif
 437
 438 out:
 439         return valid_secs;
 440 }
 441
 442 int pblk_submit_read_gc(struct pblk *pblk, u64 *lba_list, void *data,
 443                         unsigned int nr_secs, unsigned int *secs_to_gc,
 444                         struct pblk_line *line)
 445 {
 446         struct nvm_tgt_dev *dev = pblk->dev;
 447         struct nvm_geo *geo = &dev->geo;
 448         struct request_queue *q = dev->q;
 449         struct bio *bio;
 450         struct nvm_rq rqd;
 451         int ret, data_len;
 452         DECLARE_COMPLETION_ONSTACK(wait);
 453
 454         memset(&rqd, 0, sizeof(struct nvm_rq));
 455
 456         if (nr_secs > 1) {
 457                 rqd.ppa_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
 458                                                         &rqd.dma_ppa_list);
 459                 if (!rqd.ppa_list)
 460                         return NVM_IO_ERR;
 461
 462                 *secs_to_gc = read_ppalist_rq_gc(pblk, &rqd, line, lba_list,
 463                                                                 nr_secs);
 464                 if (*secs_to_gc == 1) {
 465                         struct ppa_addr ppa;
 466
 467                         ppa = rqd.ppa_list[0];
 468                         nvm_dev_dma_free(dev->parent, rqd.ppa_list,
 469                                                         rqd.dma_ppa_list);
 470                         rqd.ppa_addr = ppa;
 471                 }
 472         } else {
 473                 *secs_to_gc = read_rq_gc(pblk, &rqd, line, lba_list[0]);
 474         }
 475
 476         if (!(*secs_to_gc))
 477                 goto out;
 478
 479         data_len = (*secs_to_gc) * geo->sec_size;
 480         bio = bio_map_kern(q, data, data_len, GFP_KERNEL);
 481         if (IS_ERR(bio)) {
 482                 pr_err("pblk: could not allocate GC bio (%lu)\n", PTR_ERR(bio));
 483                 goto err_free_dma;
 484         }
 485
 486         bio->bi_iter.bi_sector = 0; /* internal bio */
 487         bio_set_op_attrs(bio, REQ_OP_READ, 0);
 488
 489         rqd.opcode = NVM_OP_PREAD;
 490         rqd.end_io = pblk_end_io_sync;
 491         rqd.private = &wait;
 492         rqd.nr_ppas = *secs_to_gc;
 493         rqd.bio = bio;
 494
 495         ret = pblk_submit_read_io(pblk, &rqd);
 496         if (ret) {
 497                 bio_endio(bio);
 498                 pr_err("pblk: GC read request failed\n");
 499                 goto err_free_dma;
 500         }
 501
 502         if (!wait_for_completion_io_timeout(&wait,
 503                                 msecs_to_jiffies(PBLK_COMMAND_TIMEOUT_MS))) {
 504                 pr_err("pblk: GC read I/O timed out\n");
 505         }
 506
 507         if (rqd.error) {
 508                 atomic_long_inc(&pblk->read_failed_gc);
 509 #ifdef CONFIG_NVM_DEBUG
 510                 pblk_print_failed_rqd(pblk, &rqd, rqd.error);
 511 #endif
 512         }
 513
 514 #ifdef CONFIG_NVM_DEBUG
 515         atomic_long_add(*secs_to_gc, &pblk->sync_reads);
 516         atomic_long_add(*secs_to_gc, &pblk->recov_gc_reads);
 517         atomic_long_sub(*secs_to_gc, &pblk->inflight_reads);
 518 #endif
 519
 520 out:
 521         if (rqd.nr_ppas > 1)
 522                 nvm_dev_dma_free(dev->parent, rqd.ppa_list, rqd.dma_ppa_list);
 523         return NVM_IO_OK;
 524
 525 err_free_dma:
 526         if (rqd.nr_ppas > 1)
 527                 nvm_dev_dma_free(dev->parent, rqd.ppa_list, rqd.dma_ppa_list);
 528         return NVM_IO_ERR;
 529 }