root/drivers/lightnvm/pblk-read.c

DEFINITIONS

1. pblk_read_from_cache
2. pblk_read_ppalist_rq
3. pblk_read_check_seq
4. pblk_read_check_rand
5. pblk_end_user_read
6. __pblk_end_io_read
7. pblk_end_io_read
8. pblk_read_rq
9. pblk_submit_read
10. read_ppalist_rq_gc
11. read_rq_gc
12. pblk_submit_read_gc

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2016 CNEX Labs
   4  * Initial release: Javier Gonzalez <javier@cnexlabs.com>
   5  *                  Matias Bjorling <matias@cnexlabs.com>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License version
   9  * 2 as published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * General Public License for more details.
  15  *
  16  * pblk-read.c - pblk's read path
  17  */
  18 
  19 #include "pblk.h"
  20 
  21 /*
  22  * There is no guarantee that the value read from cache has not been updated and
  23  * resides at another location in the cache. We guarantee though that if the
  24  * value is read from the cache, it belongs to the mapped lba. In order to
  25  * guarantee and order between writes and reads are ordered, a flush must be
  26  * issued.
  27  */
  28 static int pblk_read_from_cache(struct pblk *pblk, struct bio *bio,
  29                                 sector_t lba, struct ppa_addr ppa)
  30 {
  31 #ifdef CONFIG_NVM_PBLK_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 }
  39 
  40 static int pblk_read_ppalist_rq(struct pblk *pblk, struct nvm_rq *rqd,
  41                                  struct bio *bio, sector_t blba,
  42                                  bool *from_cache)
  43 {
  44         void *meta_list = rqd->meta_list;
  45         int nr_secs, i;
  46 
  47 retry:
  48         nr_secs = pblk_lookup_l2p_seq(pblk, rqd->ppa_list, blba, rqd->nr_ppas,
  49                                         from_cache);
  50 
  51         if (!*from_cache)
  52                 goto end;
  53 
  54         for (i = 0; i < nr_secs; i++) {
  55                 struct pblk_sec_meta *meta = pblk_get_meta(pblk, meta_list, i);
  56                 sector_t lba = blba + i;
  57 
  58                 if (pblk_ppa_empty(rqd->ppa_list[i])) {
  59                         __le64 addr_empty = cpu_to_le64(ADDR_EMPTY);
  60 
  61                         meta->lba = addr_empty;
  62                 } else if (pblk_addr_in_cache(rqd->ppa_list[i])) {
  63                         /*
  64                          * Try to read from write buffer. The address is later
  65                          * checked on the write buffer to prevent retrieving
  66                          * overwritten data.
  67                          */
  68                         if (!pblk_read_from_cache(pblk, bio, lba,
  69                                                         rqd->ppa_list[i])) {
  70                                 if (i == 0) {
  71                                         /*
  72                                          * We didn't call with bio_advance()
  73                                          * yet, so we can just retry.
  74                                          */
  75                                         goto retry;
  76                                 } else {
  77                                         /*
  78                                          * We already call bio_advance()
  79                                          * so we cannot retry and we need
  80                                          * to quit that function in order
  81                                          * to allow caller to handle the bio
  82                                          * splitting in the current sector
  83                                          * position.
  84                                          */
  85                                         nr_secs = i;
  86                                         goto end;
  87                                 }
  88                         }
  89                         meta->lba = cpu_to_le64(lba);
  90 #ifdef CONFIG_NVM_PBLK_DEBUG
  91                         atomic_long_inc(&pblk->cache_reads);
  92 #endif
  93                 }
  94                 bio_advance(bio, PBLK_EXPOSED_PAGE_SIZE);
  95         }
  96 
  97 end:
  98         if (pblk_io_aligned(pblk, nr_secs))
  99                 rqd->is_seq = 1;
 100 
 101 #ifdef CONFIG_NVM_PBLK_DEBUG
 102         atomic_long_add(nr_secs, &pblk->inflight_reads);
 103 #endif
 104 
 105         return nr_secs;
 106 }
 107 
 108 
 109 static void pblk_read_check_seq(struct pblk *pblk, struct nvm_rq *rqd,
 110                                 sector_t blba)
 111 {
 112         void *meta_list = rqd->meta_list;
 113         int nr_lbas = rqd->nr_ppas;
 114         int i;
 115 
 116         if (!pblk_is_oob_meta_supported(pblk))
 117                 return;
 118 
 119         for (i = 0; i < nr_lbas; i++) {
 120                 struct pblk_sec_meta *meta = pblk_get_meta(pblk, meta_list, i);
 121                 u64 lba = le64_to_cpu(meta->lba);
 122 
 123                 if (lba == ADDR_EMPTY)
 124                         continue;
 125 
 126                 if (lba != blba + i) {
 127 #ifdef CONFIG_NVM_PBLK_DEBUG
 128                         struct ppa_addr *ppa_list = nvm_rq_to_ppa_list(rqd);
 129 
 130                         print_ppa(pblk, &ppa_list[i], "seq", i);
 131 #endif
 132                         pblk_err(pblk, "corrupted read LBA (%llu/%llu)\n",
 133                                                         lba, (u64)blba + i);
 134                         WARN_ON(1);
 135                 }
 136         }
 137 }
 138 
 139 /*
 140  * There can be holes in the lba list.
 141  */
 142 static void pblk_read_check_rand(struct pblk *pblk, struct nvm_rq *rqd,
 143                                  u64 *lba_list, int nr_lbas)
 144 {
 145         void *meta_lba_list = rqd->meta_list;
 146         int i, j;
 147 
 148         if (!pblk_is_oob_meta_supported(pblk))
 149                 return;
 150 
 151         for (i = 0, j = 0; i < nr_lbas; i++) {
 152                 struct pblk_sec_meta *meta = pblk_get_meta(pblk,
 153                                                            meta_lba_list, j);
 154                 u64 lba = lba_list[i];
 155                 u64 meta_lba;
 156 
 157                 if (lba == ADDR_EMPTY)
 158                         continue;
 159 
 160                 meta_lba = le64_to_cpu(meta->lba);
 161 
 162                 if (lba != meta_lba) {
 163 #ifdef CONFIG_NVM_PBLK_DEBUG
 164                         struct ppa_addr *ppa_list = nvm_rq_to_ppa_list(rqd);
 165 
 166                         print_ppa(pblk, &ppa_list[j], "rnd", j);
 167 #endif
 168                         pblk_err(pblk, "corrupted read LBA (%llu/%llu)\n",
 169                                                         meta_lba, lba);
 170                         WARN_ON(1);
 171                 }
 172 
 173                 j++;
 174         }
 175 
 176         WARN_ONCE(j != rqd->nr_ppas, "pblk: corrupted random request\n");
 177 }
 178 
 179 static void pblk_end_user_read(struct bio *bio, int error)
 180 {
 181         if (error && error != NVM_RSP_WARN_HIGHECC)
 182                 bio_io_error(bio);
 183         else
 184                 bio_endio(bio);
 185 }
 186 
 187 static void __pblk_end_io_read(struct pblk *pblk, struct nvm_rq *rqd,
 188                                bool put_line)
 189 {
 190         struct nvm_tgt_dev *dev = pblk->dev;
 191         struct pblk_g_ctx *r_ctx = nvm_rq_to_pdu(rqd);
 192         struct bio *int_bio = rqd->bio;
 193         unsigned long start_time = r_ctx->start_time;
 194 
 195         generic_end_io_acct(dev->q, REQ_OP_READ, &pblk->disk->part0, start_time);
 196 
 197         if (rqd->error)
 198                 pblk_log_read_err(pblk, rqd);
 199 
 200         pblk_read_check_seq(pblk, rqd, r_ctx->lba);
 201         bio_put(int_bio);
 202 
 203         if (put_line)
 204                 pblk_rq_to_line_put(pblk, rqd);
 205 
 206 #ifdef CONFIG_NVM_PBLK_DEBUG
 207         atomic_long_add(rqd->nr_ppas, &pblk->sync_reads);
 208         atomic_long_sub(rqd->nr_ppas, &pblk->inflight_reads);
 209 #endif
 210 
 211         pblk_free_rqd(pblk, rqd, PBLK_READ);
 212         atomic_dec(&pblk->inflight_io);
 213 }
 214 
 215 static void pblk_end_io_read(struct nvm_rq *rqd)
 216 {
 217         struct pblk *pblk = rqd->private;
 218         struct pblk_g_ctx *r_ctx = nvm_rq_to_pdu(rqd);
 219         struct bio *bio = (struct bio *)r_ctx->private;
 220 
 221         pblk_end_user_read(bio, rqd->error);
 222         __pblk_end_io_read(pblk, rqd, true);
 223 }
 224 
 225 static void pblk_read_rq(struct pblk *pblk, struct nvm_rq *rqd, struct bio *bio,
 226                          sector_t lba, bool *from_cache)
 227 {
 228         struct pblk_sec_meta *meta = pblk_get_meta(pblk, rqd->meta_list, 0);
 229         struct ppa_addr ppa;
 230 
 231         pblk_lookup_l2p_seq(pblk, &ppa, lba, 1, from_cache);
 232 
 233 #ifdef CONFIG_NVM_PBLK_DEBUG
 234         atomic_long_inc(&pblk->inflight_reads);
 235 #endif
 236 
 237 retry:
 238         if (pblk_ppa_empty(ppa)) {
 239                 __le64 addr_empty = cpu_to_le64(ADDR_EMPTY);
 240 
 241                 meta->lba = addr_empty;
 242                 return;
 243         }
 244 
 245         /* Try to read from write buffer. The address is later checked on the
 246          * write buffer to prevent retrieving overwritten data.
 247          */
 248         if (pblk_addr_in_cache(ppa)) {
 249                 if (!pblk_read_from_cache(pblk, bio, lba, ppa)) {
 250                         pblk_lookup_l2p_seq(pblk, &ppa, lba, 1, from_cache);
 251                         goto retry;
 252                 }
 253 
 254                 meta->lba = cpu_to_le64(lba);
 255 
 256 #ifdef CONFIG_NVM_PBLK_DEBUG
 257                 atomic_long_inc(&pblk->cache_reads);
 258 #endif
 259         } else {
 260                 rqd->ppa_addr = ppa;
 261         }
 262 }
 263 
 264 void pblk_submit_read(struct pblk *pblk, struct bio *bio)
 265 {
 266         struct nvm_tgt_dev *dev = pblk->dev;
 267         struct request_queue *q = dev->q;
 268         sector_t blba = pblk_get_lba(bio);
 269         unsigned int nr_secs = pblk_get_secs(bio);
 270         bool from_cache;
 271         struct pblk_g_ctx *r_ctx;
 272         struct nvm_rq *rqd;
 273         struct bio *int_bio, *split_bio;
 274 
 275         generic_start_io_acct(q, REQ_OP_READ, bio_sectors(bio),
 276                               &pblk->disk->part0);
 277 
 278         rqd = pblk_alloc_rqd(pblk, PBLK_READ);
 279 
 280         rqd->opcode = NVM_OP_PREAD;
 281         rqd->nr_ppas = nr_secs;
 282         rqd->private = pblk;
 283         rqd->end_io = pblk_end_io_read;
 284 
 285         r_ctx = nvm_rq_to_pdu(rqd);
 286         r_ctx->start_time = jiffies;
 287         r_ctx->lba = blba;
 288 
 289         if (pblk_alloc_rqd_meta(pblk, rqd)) {
 290                 bio_io_error(bio);
 291                 pblk_free_rqd(pblk, rqd, PBLK_READ);
 292                 return;
 293         }
 294 
 295         /* Clone read bio to deal internally with:
 296          * -read errors when reading from drive
 297          * -bio_advance() calls during cache reads
 298          */
 299         int_bio = bio_clone_fast(bio, GFP_KERNEL, &pblk_bio_set);
 300 
 301         if (nr_secs > 1)
 302                 nr_secs = pblk_read_ppalist_rq(pblk, rqd, int_bio, blba,
 303                                                 &from_cache);
 304         else
 305                 pblk_read_rq(pblk, rqd, int_bio, blba, &from_cache);
 306 
 307 split_retry:
 308         r_ctx->private = bio; /* original bio */
 309         rqd->bio = int_bio; /* internal bio */
 310 
 311         if (from_cache && nr_secs == rqd->nr_ppas) {
 312                 /* All data was read from cache, we can complete the IO. */
 313                 pblk_end_user_read(bio, 0);
 314                 atomic_inc(&pblk->inflight_io);
 315                 __pblk_end_io_read(pblk, rqd, false);
 316         } else if (nr_secs != rqd->nr_ppas) {
 317                 /* The read bio request could be partially filled by the write
 318                  * buffer, but there are some holes that need to be read from
 319                  * the drive. In order to handle this, we will use block layer
 320                  * mechanism to split this request in to smaller ones and make
 321                  * a chain of it.
 322                  */
 323                 split_bio = bio_split(bio, nr_secs * NR_PHY_IN_LOG, GFP_KERNEL,
 324                                         &pblk_bio_set);
 325                 bio_chain(split_bio, bio);
 326                 generic_make_request(bio);
 327 
 328                 /* New bio contains first N sectors of the previous one, so
 329                  * we can continue to use existing rqd, but we need to shrink
 330                  * the number of PPAs in it. New bio is also guaranteed that
 331                  * it contains only either data from cache or from drive, newer
 332                  * mix of them.
 333                  */
 334                 bio = split_bio;
 335                 rqd->nr_ppas = nr_secs;
 336                 if (rqd->nr_ppas == 1)
 337                         rqd->ppa_addr = rqd->ppa_list[0];
 338 
 339                 /* Recreate int_bio - existing might have some needed internal
 340                  * fields modified already.
 341                  */
 342                 bio_put(int_bio);
 343                 int_bio = bio_clone_fast(bio, GFP_KERNEL, &pblk_bio_set);
 344                 goto split_retry;
 345         } else if (pblk_submit_io(pblk, rqd, NULL)) {
 346                 /* Submitting IO to drive failed, let's report an error */
 347                 rqd->error = -ENODEV;
 348                 pblk_end_io_read(rqd);
 349         }
 350 }
 351 
 352 static int read_ppalist_rq_gc(struct pblk *pblk, struct nvm_rq *rqd,
 353                               struct pblk_line *line, u64 *lba_list,
 354                               u64 *paddr_list_gc, unsigned int nr_secs)
 355 {
 356         struct ppa_addr ppa_list_l2p[NVM_MAX_VLBA];
 357         struct ppa_addr ppa_gc;
 358         int valid_secs = 0;
 359         int i;
 360 
 361         pblk_lookup_l2p_rand(pblk, ppa_list_l2p, lba_list, nr_secs);
 362 
 363         for (i = 0; i < nr_secs; i++) {
 364                 if (lba_list[i] == ADDR_EMPTY)
 365                         continue;
 366 
 367                 ppa_gc = addr_to_gen_ppa(pblk, paddr_list_gc[i], line->id);
 368                 if (!pblk_ppa_comp(ppa_list_l2p[i], ppa_gc)) {
 369                         paddr_list_gc[i] = lba_list[i] = ADDR_EMPTY;
 370                         continue;
 371                 }
 372 
 373                 rqd->ppa_list[valid_secs++] = ppa_list_l2p[i];
 374         }
 375 
 376 #ifdef CONFIG_NVM_PBLK_DEBUG
 377         atomic_long_add(valid_secs, &pblk->inflight_reads);
 378 #endif
 379 
 380         return valid_secs;
 381 }
 382 
 383 static int read_rq_gc(struct pblk *pblk, struct nvm_rq *rqd,
 384                       struct pblk_line *line, sector_t lba,
 385                       u64 paddr_gc)
 386 {
 387         struct ppa_addr ppa_l2p, ppa_gc;
 388         int valid_secs = 0;
 389 
 390         if (lba == ADDR_EMPTY)
 391                 goto out;
 392 
 393         /* logic error: lba out-of-bounds */
 394         if (lba >= pblk->capacity) {
 395                 WARN(1, "pblk: read lba out of bounds\n");
 396                 goto out;
 397         }
 398 
 399         spin_lock(&pblk->trans_lock);
 400         ppa_l2p = pblk_trans_map_get(pblk, lba);
 401         spin_unlock(&pblk->trans_lock);
 402 
 403         ppa_gc = addr_to_gen_ppa(pblk, paddr_gc, line->id);
 404         if (!pblk_ppa_comp(ppa_l2p, ppa_gc))
 405                 goto out;
 406 
 407         rqd->ppa_addr = ppa_l2p;
 408         valid_secs = 1;
 409 
 410 #ifdef CONFIG_NVM_PBLK_DEBUG
 411         atomic_long_inc(&pblk->inflight_reads);
 412 #endif
 413 
 414 out:
 415         return valid_secs;
 416 }
 417 
 418 int pblk_submit_read_gc(struct pblk *pblk, struct pblk_gc_rq *gc_rq)
 419 {
 420         struct nvm_rq rqd;
 421         int ret = NVM_IO_OK;
 422 
 423         memset(&rqd, 0, sizeof(struct nvm_rq));
 424 
 425         ret = pblk_alloc_rqd_meta(pblk, &rqd);
 426         if (ret)
 427                 return ret;
 428 
 429         if (gc_rq->nr_secs > 1) {
 430                 gc_rq->secs_to_gc = read_ppalist_rq_gc(pblk, &rqd, gc_rq->line,
 431                                                         gc_rq->lba_list,
 432                                                         gc_rq->paddr_list,
 433                                                         gc_rq->nr_secs);
 434                 if (gc_rq->secs_to_gc == 1)
 435                         rqd.ppa_addr = rqd.ppa_list[0];
 436         } else {
 437                 gc_rq->secs_to_gc = read_rq_gc(pblk, &rqd, gc_rq->line,
 438                                                         gc_rq->lba_list[0],
 439                                                         gc_rq->paddr_list[0]);
 440         }
 441 
 442         if (!(gc_rq->secs_to_gc))
 443                 goto out;
 444 
 445         rqd.opcode = NVM_OP_PREAD;
 446         rqd.nr_ppas = gc_rq->secs_to_gc;
 447 
 448         if (pblk_submit_io_sync(pblk, &rqd, gc_rq->data)) {
 449                 ret = -EIO;
 450                 goto err_free_dma;
 451         }
 452 
 453         pblk_read_check_rand(pblk, &rqd, gc_rq->lba_list, gc_rq->nr_secs);
 454 
 455         atomic_dec(&pblk->inflight_io);
 456 
 457         if (rqd.error) {
 458                 atomic_long_inc(&pblk->read_failed_gc);
 459 #ifdef CONFIG_NVM_PBLK_DEBUG
 460                 pblk_print_failed_rqd(pblk, &rqd, rqd.error);
 461 #endif
 462         }
 463 
 464 #ifdef CONFIG_NVM_PBLK_DEBUG
 465         atomic_long_add(gc_rq->secs_to_gc, &pblk->sync_reads);
 466         atomic_long_add(gc_rq->secs_to_gc, &pblk->recov_gc_reads);
 467         atomic_long_sub(gc_rq->secs_to_gc, &pblk->inflight_reads);
 468 #endif
 469 
 470 out:
 471         pblk_free_rqd_meta(pblk, &rqd);
 472         return ret;
 473 
 474 err_free_dma:
 475         pblk_free_rqd_meta(pblk, &rqd);
 476         return ret;
 477 }