drivers/lightnvm/pblk-write.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-write.c - pblk's write path from write buffer to media
  16  */
  17
  18 #include "pblk.h"
  19
  20 static void pblk_sync_line(struct pblk *pblk, struct pblk_line *line)
  21 {
  22 #ifdef CONFIG_NVM_DEBUG
  23         atomic_long_inc(&pblk->sync_writes);
  24 #endif
  25
  26         /* Counter protected by rb sync lock */
  27         line->left_ssecs--;
  28 }
  29
  30 static unsigned long pblk_end_w_bio(struct pblk *pblk, struct nvm_rq *rqd,
  31                                     struct pblk_c_ctx *c_ctx)
  32 {
  33         struct nvm_tgt_dev *dev = pblk->dev;
  34         struct bio *original_bio;
  35         unsigned long ret;
  36         int i;
  37
  38         for (i = 0; i < c_ctx->nr_valid; i++) {
  39                 struct pblk_w_ctx *w_ctx;
  40                 struct ppa_addr p;
  41                 struct pblk_line *line;
  42
  43                 w_ctx = pblk_rb_w_ctx(&pblk->rwb, c_ctx->sentry + i);
  44
  45                 p = rqd->ppa_list[i];
  46                 line = &pblk->lines[pblk_dev_ppa_to_line(p)];
  47                 pblk_sync_line(pblk, line);
  48
  49                 while ((original_bio = bio_list_pop(&w_ctx->bios)))
  50                         bio_endio(original_bio);
  51         }
  52
  53 #ifdef CONFIG_NVM_DEBUG
  54         atomic_long_add(c_ctx->nr_valid, &pblk->compl_writes);
  55 #endif
  56
  57         ret = pblk_rb_sync_advance(&pblk->rwb, c_ctx->nr_valid);
  58
  59         if (rqd->meta_list)
  60                 nvm_dev_dma_free(dev->parent, rqd->meta_list,
  61                                                         rqd->dma_meta_list);
  62
  63         bio_put(rqd->bio);
  64         pblk_free_rqd(pblk, rqd, WRITE);
  65
  66         return ret;
  67 }
  68
  69 static unsigned long pblk_end_queued_w_bio(struct pblk *pblk,
  70                                            struct nvm_rq *rqd,
  71                                            struct pblk_c_ctx *c_ctx)
  72 {
  73         list_del(&c_ctx->list);
  74         return pblk_end_w_bio(pblk, rqd, c_ctx);
  75 }
  76
  77 static void pblk_complete_write(struct pblk *pblk, struct nvm_rq *rqd,
  78                                 struct pblk_c_ctx *c_ctx)
  79 {
  80         struct pblk_c_ctx *c, *r;
  81         unsigned long flags;
  82         unsigned long pos;
  83
  84 #ifdef CONFIG_NVM_DEBUG
  85         atomic_long_sub(c_ctx->nr_valid, &pblk->inflight_writes);
  86 #endif
  87
  88         pblk_up_rq(pblk, rqd->ppa_list, rqd->nr_ppas, c_ctx->lun_bitmap);
  89
  90         pos = pblk_rb_sync_init(&pblk->rwb, &flags);
  91         if (pos == c_ctx->sentry) {
  92                 pos = pblk_end_w_bio(pblk, rqd, c_ctx);
  93
  94 retry:
  95                 list_for_each_entry_safe(c, r, &pblk->compl_list, list) {
  96                         rqd = nvm_rq_from_c_ctx(c);
  97                         if (c->sentry == pos) {
  98                                 pos = pblk_end_queued_w_bio(pblk, rqd, c);
  99                                 goto retry;
 100                         }
 101                 }
 102         } else {
 103                 WARN_ON(nvm_rq_from_c_ctx(c_ctx) != rqd);
 104                 list_add_tail(&c_ctx->list, &pblk->compl_list);
 105         }
 106         pblk_rb_sync_end(&pblk->rwb, &flags);
 107 }
 108
 109 /* When a write fails, we are not sure whether the block has grown bad or a page
 110  * range is more susceptible to write errors. If a high number of pages fail, we
 111  * assume that the block is bad and we mark it accordingly. In all cases, we
 112  * remap and resubmit the failed entries as fast as possible; if a flush is
 113  * waiting on a completion, the whole stack would stall otherwise.
 114  */
 115 static void pblk_end_w_fail(struct pblk *pblk, struct nvm_rq *rqd)
 116 {
 117         void *comp_bits = &rqd->ppa_status;
 118         struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 119         struct pblk_rec_ctx *recovery;
 120         struct ppa_addr *ppa_list = rqd->ppa_list;
 121         int nr_ppas = rqd->nr_ppas;
 122         unsigned int c_entries;
 123         int bit, ret;
 124
 125         if (unlikely(nr_ppas == 1))
 126                 ppa_list = &rqd->ppa_addr;
 127
 128         recovery = mempool_alloc(pblk->rec_pool, GFP_ATOMIC);
 129         if (!recovery) {
 130                 pr_err("pblk: could not allocate recovery context\n");
 131                 return;
 132         }
 133         INIT_LIST_HEAD(&recovery->failed);
 134
 135         bit = -1;
 136         while ((bit = find_next_bit(comp_bits, nr_ppas, bit + 1)) < nr_ppas) {
 137                 struct pblk_rb_entry *entry;
 138                 struct ppa_addr ppa;
 139
 140                 /* Logic error */
 141                 if (bit > c_ctx->nr_valid) {
 142                         WARN_ONCE(1, "pblk: corrupted write request\n");
 143                         mempool_free(recovery, pblk->rec_pool);
 144                         goto out;
 145                 }
 146
 147                 ppa = ppa_list[bit];
 148                 entry = pblk_rb_sync_scan_entry(&pblk->rwb, &ppa);
 149                 if (!entry) {
 150                         pr_err("pblk: could not scan entry on write failure\n");
 151                         mempool_free(recovery, pblk->rec_pool);
 152                         goto out;
 153                 }
 154
 155                 /* The list is filled first and emptied afterwards. No need for
 156                  * protecting it with a lock
 157                  */
 158                 list_add_tail(&entry->index, &recovery->failed);
 159         }
 160
 161         c_entries = find_first_bit(comp_bits, nr_ppas);
 162         ret = pblk_recov_setup_rq(pblk, c_ctx, recovery, comp_bits, c_entries);
 163         if (ret) {
 164                 pr_err("pblk: could not recover from write failure\n");
 165                 mempool_free(recovery, pblk->rec_pool);
 166                 goto out;
 167         }
 168
 169         INIT_WORK(&recovery->ws_rec, pblk_submit_rec);
 170         queue_work(pblk->kw_wq, &recovery->ws_rec);
 171
 172 out:
 173         pblk_complete_write(pblk, rqd, c_ctx);
 174 }
 175
 176 static void pblk_end_io_write(struct nvm_rq *rqd)
 177 {
 178         struct pblk *pblk = rqd->private;
 179         struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 180
 181         if (rqd->error) {
 182                 pblk_log_write_err(pblk, rqd);
 183                 return pblk_end_w_fail(pblk, rqd);
 184         }
 185 #ifdef CONFIG_NVM_DEBUG
 186         else
 187                 WARN_ONCE(rqd->bio->bi_status, "pblk: corrupted write error\n");
 188 #endif
 189
 190         pblk_complete_write(pblk, rqd, c_ctx);
 191 }
 192
 193 static void pblk_end_io_write_meta(struct nvm_rq *rqd)
 194 {
 195         struct pblk *pblk = rqd->private;
 196         struct nvm_tgt_dev *dev = pblk->dev;
 197         struct nvm_geo *geo = &dev->geo;
 198         struct pblk_g_ctx *m_ctx = nvm_rq_to_pdu(rqd);
 199         struct pblk_line *line = m_ctx->private;
 200         struct pblk_emeta *emeta = line->emeta;
 201         int pos = pblk_ppa_to_pos(geo, rqd->ppa_list[0]);
 202         struct pblk_lun *rlun = &pblk->luns[pos];
 203         int sync;
 204
 205         up(&rlun->wr_sem);
 206
 207         if (rqd->error) {
 208                 pblk_log_write_err(pblk, rqd);
 209                 pr_err("pblk: metadata I/O failed\n");
 210         }
 211 #ifdef CONFIG_NVM_DEBUG
 212         else
 213                 WARN_ONCE(rqd->bio->bi_status, "pblk: corrupted write error\n");
 214 #endif
 215
 216         sync = atomic_add_return(rqd->nr_ppas, &emeta->sync);
 217         if (sync == emeta->nr_entries)
 218                 pblk_line_run_ws(pblk, line, NULL, pblk_line_close_ws);
 219
 220         bio_put(rqd->bio);
 221         pblk_free_rqd(pblk, rqd, READ);
 222 }
 223
 224 static int pblk_alloc_w_rq(struct pblk *pblk, struct nvm_rq *rqd,
 225                            unsigned int nr_secs,
 226                            nvm_end_io_fn(*end_io))
 227 {
 228         struct nvm_tgt_dev *dev = pblk->dev;
 229
 230         /* Setup write request */
 231         rqd->opcode = NVM_OP_PWRITE;
 232         rqd->nr_ppas = nr_secs;
 233         rqd->flags = pblk_set_progr_mode(pblk, WRITE);
 234         rqd->private = pblk;
 235         rqd->end_io = end_io;
 236
 237         rqd->meta_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
 238                                                         &rqd->dma_meta_list);
 239         if (!rqd->meta_list)
 240                 return -ENOMEM;
 241
 242         if (unlikely(nr_secs == 1))
 243                 return 0;
 244
 245         rqd->ppa_list = rqd->meta_list + pblk_dma_meta_size;
 246         rqd->dma_ppa_list = rqd->dma_meta_list + pblk_dma_meta_size;
 247
 248         return 0;
 249 }
 250
 251 static int pblk_setup_w_rq(struct pblk *pblk, struct nvm_rq *rqd,
 252                            struct pblk_c_ctx *c_ctx, struct ppa_addr *erase_ppa)
 253 {
 254         struct pblk_line_meta *lm = &pblk->lm;
 255         struct pblk_line *e_line = pblk_line_get_erase(pblk);
 256         unsigned int valid = c_ctx->nr_valid;
 257         unsigned int padded = c_ctx->nr_padded;
 258         unsigned int nr_secs = valid + padded;
 259         unsigned long *lun_bitmap;
 260         int ret = 0;
 261
 262         lun_bitmap = kzalloc(lm->lun_bitmap_len, GFP_KERNEL);
 263         if (!lun_bitmap)
 264                 return -ENOMEM;
 265         c_ctx->lun_bitmap = lun_bitmap;
 266
 267         ret = pblk_alloc_w_rq(pblk, rqd, nr_secs, pblk_end_io_write);
 268         if (ret) {
 269                 kfree(lun_bitmap);
 270                 return ret;
 271         }
 272
 273         if (likely(!atomic_read(&e_line->left_eblks) || !e_line))
 274                 pblk_map_rq(pblk, rqd, c_ctx->sentry, lun_bitmap, valid, 0);
 275         else
 276                 pblk_map_erase_rq(pblk, rqd, c_ctx->sentry, lun_bitmap,
 277                                                         valid, erase_ppa);
 278
 279         return 0;
 280 }
 281
 282 int pblk_setup_w_rec_rq(struct pblk *pblk, struct nvm_rq *rqd,
 283                         struct pblk_c_ctx *c_ctx)
 284 {
 285         struct pblk_line_meta *lm = &pblk->lm;
 286         unsigned long *lun_bitmap;
 287         int ret;
 288
 289         lun_bitmap = kzalloc(lm->lun_bitmap_len, GFP_KERNEL);
 290         if (!lun_bitmap)
 291                 return -ENOMEM;
 292
 293         c_ctx->lun_bitmap = lun_bitmap;
 294
 295         ret = pblk_alloc_w_rq(pblk, rqd, rqd->nr_ppas, pblk_end_io_write);
 296         if (ret)
 297                 return ret;
 298
 299         pblk_map_rq(pblk, rqd, c_ctx->sentry, lun_bitmap, c_ctx->nr_valid, 0);
 300
 301         rqd->ppa_status = (u64)0;
 302         rqd->flags = pblk_set_progr_mode(pblk, WRITE);
 303
 304         return ret;
 305 }
 306
 307 static int pblk_calc_secs_to_sync(struct pblk *pblk, unsigned int secs_avail,
 308                                   unsigned int secs_to_flush)
 309 {
 310         int secs_to_sync;
 311
 312         secs_to_sync = pblk_calc_secs(pblk, secs_avail, secs_to_flush);
 313
 314 #ifdef CONFIG_NVM_DEBUG
 315         if ((!secs_to_sync && secs_to_flush)
 316                         || (secs_to_sync < 0)
 317                         || (secs_to_sync > secs_avail && !secs_to_flush)) {
 318                 pr_err("pblk: bad sector calculation (a:%d,s:%d,f:%d)\n",
 319                                 secs_avail, secs_to_sync, secs_to_flush);
 320         }
 321 #endif
 322
 323         return secs_to_sync;
 324 }
 325
 326 static inline int pblk_valid_meta_ppa(struct pblk *pblk,
 327                                       struct pblk_line *meta_line,
 328                                       struct ppa_addr *ppa_list, int nr_ppas)
 329 {
 330         struct nvm_tgt_dev *dev = pblk->dev;
 331         struct nvm_geo *geo = &dev->geo;
 332         struct pblk_line *data_line;
 333         struct ppa_addr ppa, ppa_opt;
 334         u64 paddr;
 335         int i;
 336
 337         data_line = &pblk->lines[pblk_dev_ppa_to_line(ppa_list[0])];
 338         paddr = pblk_lookup_page(pblk, meta_line);
 339         ppa = addr_to_gen_ppa(pblk, paddr, 0);
 340
 341         if (test_bit(pblk_ppa_to_pos(geo, ppa), data_line->blk_bitmap))
 342                 return 1;
 343
 344         /* Schedule a metadata I/O that is half the distance from the data I/O
 345          * with regards to the number of LUNs forming the pblk instance. This
 346          * balances LUN conflicts across every I/O.
 347          *
 348          * When the LUN configuration changes (e.g., due to GC), this distance
 349          * can align, which would result on a LUN deadlock. In this case, modify
 350          * the distance to not be optimal, but allow metadata I/Os to succeed.
 351          */
 352         ppa_opt = addr_to_gen_ppa(pblk, paddr + data_line->meta_distance, 0);
 353         if (unlikely(ppa_opt.ppa == ppa.ppa)) {
 354                 data_line->meta_distance--;
 355                 return 0;
 356         }
 357
 358         for (i = 0; i < nr_ppas; i += pblk->min_write_pgs)
 359                 if (ppa_list[i].g.ch == ppa_opt.g.ch &&
 360                                         ppa_list[i].g.lun == ppa_opt.g.lun)
 361                         return 1;
 362
 363         if (test_bit(pblk_ppa_to_pos(geo, ppa_opt), data_line->blk_bitmap)) {
 364                 for (i = 0; i < nr_ppas; i += pblk->min_write_pgs)
 365                         if (ppa_list[i].g.ch == ppa.g.ch &&
 366                                                 ppa_list[i].g.lun == ppa.g.lun)
 367                                 return 0;
 368
 369                 return 1;
 370         }
 371
 372         return 0;
 373 }
 374
 375 int pblk_submit_meta_io(struct pblk *pblk, struct pblk_line *meta_line)
 376 {
 377         struct nvm_tgt_dev *dev = pblk->dev;
 378         struct nvm_geo *geo = &dev->geo;
 379         struct pblk_line_mgmt *l_mg = &pblk->l_mg;
 380         struct pblk_line_meta *lm = &pblk->lm;
 381         struct pblk_emeta *emeta = meta_line->emeta;
 382         struct pblk_g_ctx *m_ctx;
 383         struct pblk_lun *rlun;
 384         struct bio *bio;
 385         struct nvm_rq *rqd;
 386         void *data;
 387         u64 paddr;
 388         int rq_ppas = pblk->min_write_pgs;
 389         int id = meta_line->id;
 390         int rq_len;
 391         int i, j;
 392         int ret;
 393
 394         rqd = pblk_alloc_rqd(pblk, READ);
 395         if (IS_ERR(rqd)) {
 396                 pr_err("pblk: cannot allocate write req.\n");
 397                 return PTR_ERR(rqd);
 398         }
 399         m_ctx = nvm_rq_to_pdu(rqd);
 400         m_ctx->private = meta_line;
 401
 402         rq_len = rq_ppas * geo->sec_size;
 403         data = ((void *)emeta->buf) + emeta->mem;
 404
 405         bio = pblk_bio_map_addr(pblk, data, rq_ppas, rq_len, GFP_KERNEL);
 406         if (IS_ERR(bio)) {
 407                 ret = PTR_ERR(bio);
 408                 goto fail_free_rqd;
 409         }
 410         bio->bi_iter.bi_sector = 0; /* internal bio */
 411         bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
 412         rqd->bio = bio;
 413
 414         ret = pblk_alloc_w_rq(pblk, rqd, rq_ppas, pblk_end_io_write_meta);
 415         if (ret)
 416                 goto fail_free_bio;
 417
 418         for (i = 0; i < rqd->nr_ppas; ) {
 419                 spin_lock(&meta_line->lock);
 420                 paddr = __pblk_alloc_page(pblk, meta_line, rq_ppas);
 421                 spin_unlock(&meta_line->lock);
 422                 for (j = 0; j < rq_ppas; j++, i++, paddr++)
 423                         rqd->ppa_list[i] = addr_to_gen_ppa(pblk, paddr, id);
 424         }
 425
 426         rlun = &pblk->luns[pblk_ppa_to_pos(geo, rqd->ppa_list[0])];
 427         ret = down_timeout(&rlun->wr_sem, msecs_to_jiffies(5000));
 428         if (ret) {
 429                 pr_err("pblk: lun semaphore timed out (%d)\n", ret);
 430                 goto fail_free_bio;
 431         }
 432
 433         emeta->mem += rq_len;
 434         if (emeta->mem >= lm->emeta_len[0]) {
 435                 spin_lock(&l_mg->close_lock);
 436                 list_del(&meta_line->list);
 437                 WARN(!bitmap_full(meta_line->map_bitmap, lm->sec_per_line),
 438                                 "pblk: corrupt meta line %d\n", meta_line->id);
 439                 spin_unlock(&l_mg->close_lock);
 440         }
 441
 442         ret = pblk_submit_io(pblk, rqd);
 443         if (ret) {
 444                 pr_err("pblk: emeta I/O submission failed: %d\n", ret);
 445                 goto fail_rollback;
 446         }
 447
 448         return NVM_IO_OK;
 449
 450 fail_rollback:
 451         spin_lock(&l_mg->close_lock);
 452         pblk_dealloc_page(pblk, meta_line, rq_ppas);
 453         list_add(&meta_line->list, &meta_line->list);
 454         spin_unlock(&l_mg->close_lock);
 455 fail_free_bio:
 456         bio_put(bio);
 457 fail_free_rqd:
 458         pblk_free_rqd(pblk, rqd, READ);
 459         return ret;
 460 }
 461
 462 static int pblk_sched_meta_io(struct pblk *pblk, struct ppa_addr *prev_list,
 463                                int prev_n)
 464 {
 465         struct pblk_line_meta *lm = &pblk->lm;
 466         struct pblk_line_mgmt *l_mg = &pblk->l_mg;
 467         struct pblk_line *meta_line;
 468
 469         spin_lock(&l_mg->close_lock);
 470 retry:
 471         if (list_empty(&l_mg->emeta_list)) {
 472                 spin_unlock(&l_mg->close_lock);
 473                 return 0;
 474         }
 475         meta_line = list_first_entry(&l_mg->emeta_list, struct pblk_line, list);
 476         if (bitmap_full(meta_line->map_bitmap, lm->sec_per_line))
 477                 goto retry;
 478         spin_unlock(&l_mg->close_lock);
 479
 480         if (!pblk_valid_meta_ppa(pblk, meta_line, prev_list, prev_n))
 481                 return 0;
 482
 483         return pblk_submit_meta_io(pblk, meta_line);
 484 }
 485
 486 static int pblk_submit_io_set(struct pblk *pblk, struct nvm_rq *rqd)
 487 {
 488         struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 489         struct ppa_addr erase_ppa;
 490         int err;
 491
 492         ppa_set_empty(&erase_ppa);
 493
 494         /* Assign lbas to ppas and populate request structure */
 495         err = pblk_setup_w_rq(pblk, rqd, c_ctx, &erase_ppa);
 496         if (err) {
 497                 pr_err("pblk: could not setup write request: %d\n", err);
 498                 return NVM_IO_ERR;
 499         }
 500
 501         if (likely(ppa_empty(erase_ppa))) {
 502                 /* Submit metadata write for previous data line */
 503                 err = pblk_sched_meta_io(pblk, rqd->ppa_list, rqd->nr_ppas);
 504                 if (err) {
 505                         pr_err("pblk: metadata I/O submission failed: %d", err);
 506                         return NVM_IO_ERR;
 507                 }
 508
 509                 /* Submit data write for current data line */
 510                 err = pblk_submit_io(pblk, rqd);
 511                 if (err) {
 512                         pr_err("pblk: data I/O submission failed: %d\n", err);
 513                         return NVM_IO_ERR;
 514                 }
 515         } else {
 516                 /* Submit data write for current data line */
 517                 err = pblk_submit_io(pblk, rqd);
 518                 if (err) {
 519                         pr_err("pblk: data I/O submission failed: %d\n", err);
 520                         return NVM_IO_ERR;
 521                 }
 522
 523                 /* Submit available erase for next data line */
 524                 if (pblk_blk_erase_async(pblk, erase_ppa)) {
 525                         struct pblk_line *e_line = pblk_line_get_erase(pblk);
 526                         struct nvm_tgt_dev *dev = pblk->dev;
 527                         struct nvm_geo *geo = &dev->geo;
 528                         int bit;
 529
 530                         atomic_inc(&e_line->left_eblks);
 531                         bit = pblk_ppa_to_pos(geo, erase_ppa);
 532                         WARN_ON(!test_and_clear_bit(bit, e_line->erase_bitmap));
 533                 }
 534         }
 535
 536         return NVM_IO_OK;
 537 }
 538
 539 static void pblk_free_write_rqd(struct pblk *pblk, struct nvm_rq *rqd)
 540 {
 541         struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 542         struct bio *bio = rqd->bio;
 543
 544         if (c_ctx->nr_padded)
 545                 pblk_bio_free_pages(pblk, bio, rqd->nr_ppas, c_ctx->nr_padded);
 546 }
 547
 548 static int pblk_submit_write(struct pblk *pblk)
 549 {
 550         struct bio *bio;
 551         struct nvm_rq *rqd;
 552         unsigned int secs_avail, secs_to_sync, secs_to_com;
 553         unsigned int secs_to_flush;
 554         unsigned long pos;
 555
 556         /* If there are no sectors in the cache, flushes (bios without data)
 557          * will be cleared on the cache threads
 558          */
 559         secs_avail = pblk_rb_read_count(&pblk->rwb);
 560         if (!secs_avail)
 561                 return 1;
 562
 563         secs_to_flush = pblk_rb_sync_point_count(&pblk->rwb);
 564         if (!secs_to_flush && secs_avail < pblk->min_write_pgs)
 565                 return 1;
 566
 567         rqd = pblk_alloc_rqd(pblk, WRITE);
 568         if (IS_ERR(rqd)) {
 569                 pr_err("pblk: cannot allocate write req.\n");
 570                 return 1;
 571         }
 572
 573         bio = bio_alloc(GFP_KERNEL, pblk->max_write_pgs);
 574         if (!bio) {
 575                 pr_err("pblk: cannot allocate write bio\n");
 576                 goto fail_free_rqd;
 577         }
 578         bio->bi_iter.bi_sector = 0; /* internal bio */
 579         bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
 580         rqd->bio = bio;
 581
 582         secs_to_sync = pblk_calc_secs_to_sync(pblk, secs_avail, secs_to_flush);
 583         if (secs_to_sync > pblk->max_write_pgs) {
 584                 pr_err("pblk: bad buffer sync calculation\n");
 585                 goto fail_put_bio;
 586         }
 587
 588         secs_to_com = (secs_to_sync > secs_avail) ? secs_avail : secs_to_sync;
 589         pos = pblk_rb_read_commit(&pblk->rwb, secs_to_com);
 590
 591         if (pblk_rb_read_to_bio(&pblk->rwb, rqd, bio, pos, secs_to_sync,
 592                                                                 secs_avail)) {
 593                 pr_err("pblk: corrupted write bio\n");
 594                 goto fail_put_bio;
 595         }
 596
 597         if (pblk_submit_io_set(pblk, rqd))
 598                 goto fail_free_bio;
 599
 600 #ifdef CONFIG_NVM_DEBUG
 601         atomic_long_add(secs_to_sync, &pblk->sub_writes);
 602 #endif
 603
 604         return 0;
 605
 606 fail_free_bio:
 607         pblk_free_write_rqd(pblk, rqd);
 608 fail_put_bio:
 609         bio_put(bio);
 610 fail_free_rqd:
 611         pblk_free_rqd(pblk, rqd, WRITE);
 612
 613         return 1;
 614 }
 615
 616 int pblk_write_ts(void *data)
 617 {
 618         struct pblk *pblk = data;
 619
 620         while (!kthread_should_stop()) {
 621                 if (!pblk_submit_write(pblk))
 622                         continue;
 623                 set_current_state(TASK_INTERRUPTIBLE);
 624                 io_schedule();
 625         }
 626
 627         return 0;
 628 }