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