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 unsigned long pblk_end_w_bio(struct pblk *pblk, struct nvm_rq *rqd,
  21                                     struct pblk_c_ctx *c_ctx)
  22 {
  23         struct bio *original_bio;
  24         struct pblk_rb *rwb = &pblk->rwb;
  25         unsigned long ret;
  26         int i;
  27
  28         for (i = 0; i < c_ctx->nr_valid; i++) {
  29                 struct pblk_w_ctx *w_ctx;
  30                 int pos = c_ctx->sentry + i;
  31                 int flags;
  32
  33                 w_ctx = pblk_rb_w_ctx(rwb, pos);
  34                 flags = READ_ONCE(w_ctx->flags);
  35
  36                 if (flags & PBLK_FLUSH_ENTRY) {
  37                         flags &= ~PBLK_FLUSH_ENTRY;
  38                         /* Release flags on context. Protect from writes */
  39                         smp_store_release(&w_ctx->flags, flags);
  40
  41 #ifdef CONFIG_NVM_PBLK_DEBUG
  42                         atomic_dec(&rwb->inflight_flush_point);
  43 #endif
  44                 }
  45
  46                 while ((original_bio = bio_list_pop(&w_ctx->bios)))
  47                         bio_endio(original_bio);
  48         }
  49
  50         if (c_ctx->nr_padded)
  51                 pblk_bio_free_pages(pblk, rqd->bio, c_ctx->nr_valid,
  52                                                         c_ctx->nr_padded);
  53
  54 #ifdef CONFIG_NVM_PBLK_DEBUG
  55         atomic_long_add(rqd->nr_ppas, &pblk->sync_writes);
  56 #endif
  57
  58         ret = pblk_rb_sync_advance(&pblk->rwb, c_ctx->nr_valid);
  59
  60         bio_put(rqd->bio);
  61         pblk_free_rqd(pblk, rqd, PBLK_WRITE);
  62
  63         return ret;
  64 }
  65
  66 static unsigned long pblk_end_queued_w_bio(struct pblk *pblk,
  67                                            struct nvm_rq *rqd,
  68                                            struct pblk_c_ctx *c_ctx)
  69 {
  70         list_del(&c_ctx->list);
  71         return pblk_end_w_bio(pblk, rqd, c_ctx);
  72 }
  73
  74 static void pblk_complete_write(struct pblk *pblk, struct nvm_rq *rqd,
  75                                 struct pblk_c_ctx *c_ctx)
  76 {
  77         struct pblk_c_ctx *c, *r;
  78         unsigned long flags;
  79         unsigned long pos;
  80
  81 #ifdef CONFIG_NVM_PBLK_DEBUG
  82         atomic_long_sub(c_ctx->nr_valid, &pblk->inflight_writes);
  83 #endif
  84
  85         pblk_up_rq(pblk, rqd->ppa_list, rqd->nr_ppas, c_ctx->lun_bitmap);
  86
  87         pos = pblk_rb_sync_init(&pblk->rwb, &flags);
  88         if (pos == c_ctx->sentry) {
  89                 pos = pblk_end_w_bio(pblk, rqd, c_ctx);
  90
  91 retry:
  92                 list_for_each_entry_safe(c, r, &pblk->compl_list, list) {
  93                         rqd = nvm_rq_from_c_ctx(c);
  94                         if (c->sentry == pos) {
  95                                 pos = pblk_end_queued_w_bio(pblk, rqd, c);
  96                                 goto retry;
  97                         }
  98                 }
  99         } else {
 100                 WARN_ON(nvm_rq_from_c_ctx(c_ctx) != rqd);
 101                 list_add_tail(&c_ctx->list, &pblk->compl_list);
 102         }
 103         pblk_rb_sync_end(&pblk->rwb, &flags);
 104 }
 105
 106 /* Map remaining sectors in chunk, starting from ppa */
 107 static void pblk_map_remaining(struct pblk *pblk, struct ppa_addr *ppa)
 108 {
 109         struct nvm_tgt_dev *dev = pblk->dev;
 110         struct nvm_geo *geo = &dev->geo;
 111         struct pblk_line *line;
 112         struct ppa_addr map_ppa = *ppa;
 113         u64 paddr;
 114         int done = 0;
 115
 116         line = &pblk->lines[pblk_ppa_to_line(*ppa)];
 117         spin_lock(&line->lock);
 118
 119         while (!done)  {
 120                 paddr = pblk_dev_ppa_to_line_addr(pblk, map_ppa);
 121
 122                 if (!test_and_set_bit(paddr, line->map_bitmap))
 123                         line->left_msecs--;
 124
 125                 if (!test_and_set_bit(paddr, line->invalid_bitmap))
 126                         le32_add_cpu(line->vsc, -1);
 127
 128                 if (geo->version == NVM_OCSSD_SPEC_12) {
 129                         map_ppa.ppa++;
 130                         if (map_ppa.g.pg == geo->num_pg)
 131                                 done = 1;
 132                 } else {
 133                         map_ppa.m.sec++;
 134                         if (map_ppa.m.sec == geo->clba)
 135                                 done = 1;
 136                 }
 137         }
 138
 139         line->w_err_gc->has_write_err = 1;
 140         spin_unlock(&line->lock);
 141 }
 142
 143 static void pblk_prepare_resubmit(struct pblk *pblk, unsigned int sentry,
 144                                   unsigned int nr_entries)
 145 {
 146         struct pblk_rb *rb = &pblk->rwb;
 147         struct pblk_rb_entry *entry;
 148         struct pblk_line *line;
 149         struct pblk_w_ctx *w_ctx;
 150         struct ppa_addr ppa_l2p;
 151         int flags;
 152         unsigned int pos, i;
 153
 154         spin_lock(&pblk->trans_lock);
 155         pos = sentry;
 156         for (i = 0; i < nr_entries; i++) {
 157                 entry = &rb->entries[pos];
 158                 w_ctx = &entry->w_ctx;
 159
 160                 /* Check if the lba has been overwritten */
 161                 ppa_l2p = pblk_trans_map_get(pblk, w_ctx->lba);
 162                 if (!pblk_ppa_comp(ppa_l2p, entry->cacheline))
 163                         w_ctx->lba = ADDR_EMPTY;
 164
 165                 /* Mark up the entry as submittable again */
 166                 flags = READ_ONCE(w_ctx->flags);
 167                 flags |= PBLK_WRITTEN_DATA;
 168                 /* Release flags on write context. Protect from writes */
 169                 smp_store_release(&w_ctx->flags, flags);
 170
 171                 /* Decrese the reference count to the line as we will
 172                  * re-map these entries
 173                  */
 174                 line = &pblk->lines[pblk_ppa_to_line(w_ctx->ppa)];
 175                 kref_put(&line->ref, pblk_line_put);
 176
 177                 pos = (pos + 1) & (rb->nr_entries - 1);
 178         }
 179         spin_unlock(&pblk->trans_lock);
 180 }
 181
 182 static void pblk_queue_resubmit(struct pblk *pblk, struct pblk_c_ctx *c_ctx)
 183 {
 184         struct pblk_c_ctx *r_ctx;
 185
 186         r_ctx = kzalloc(sizeof(struct pblk_c_ctx), GFP_KERNEL);
 187         if (!r_ctx)
 188                 return;
 189
 190         r_ctx->lun_bitmap = NULL;
 191         r_ctx->sentry = c_ctx->sentry;
 192         r_ctx->nr_valid = c_ctx->nr_valid;
 193         r_ctx->nr_padded = c_ctx->nr_padded;
 194
 195         spin_lock(&pblk->resubmit_lock);
 196         list_add_tail(&r_ctx->list, &pblk->resubmit_list);
 197         spin_unlock(&pblk->resubmit_lock);
 198
 199 #ifdef CONFIG_NVM_PBLK_DEBUG
 200         atomic_long_add(c_ctx->nr_valid, &pblk->recov_writes);
 201 #endif
 202 }
 203
 204 static void pblk_submit_rec(struct work_struct *work)
 205 {
 206         struct pblk_rec_ctx *recovery =
 207                         container_of(work, struct pblk_rec_ctx, ws_rec);
 208         struct pblk *pblk = recovery->pblk;
 209         struct nvm_rq *rqd = recovery->rqd;
 210         struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 211         struct ppa_addr *ppa_list;
 212
 213         pblk_log_write_err(pblk, rqd);
 214
 215         if (rqd->nr_ppas == 1)
 216                 ppa_list = &rqd->ppa_addr;
 217         else
 218                 ppa_list = rqd->ppa_list;
 219
 220         pblk_map_remaining(pblk, ppa_list);
 221         pblk_queue_resubmit(pblk, c_ctx);
 222
 223         pblk_up_rq(pblk, rqd->ppa_list, rqd->nr_ppas, c_ctx->lun_bitmap);
 224         if (c_ctx->nr_padded)
 225                 pblk_bio_free_pages(pblk, rqd->bio, c_ctx->nr_valid,
 226                                                         c_ctx->nr_padded);
 227         bio_put(rqd->bio);
 228         pblk_free_rqd(pblk, rqd, PBLK_WRITE);
 229         mempool_free(recovery, &pblk->rec_pool);
 230
 231         atomic_dec(&pblk->inflight_io);
 232 }
 233
 234
 235 static void pblk_end_w_fail(struct pblk *pblk, struct nvm_rq *rqd)
 236 {
 237         struct pblk_rec_ctx *recovery;
 238
 239         recovery = mempool_alloc(&pblk->rec_pool, GFP_ATOMIC);
 240         if (!recovery) {
 241                 pblk_err(pblk, "could not allocate recovery work\n");
 242                 return;
 243         }
 244
 245         recovery->pblk = pblk;
 246         recovery->rqd = rqd;
 247
 248         INIT_WORK(&recovery->ws_rec, pblk_submit_rec);
 249         queue_work(pblk->close_wq, &recovery->ws_rec);
 250 }
 251
 252 static void pblk_end_io_write(struct nvm_rq *rqd)
 253 {
 254         struct pblk *pblk = rqd->private;
 255         struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 256
 257         if (rqd->error) {
 258                 pblk_end_w_fail(pblk, rqd);
 259                 return;
 260         }
 261 #ifdef CONFIG_NVM_PBLK_DEBUG
 262         else
 263                 WARN_ONCE(rqd->bio->bi_status, "pblk: corrupted write error\n");
 264 #endif
 265
 266         pblk_complete_write(pblk, rqd, c_ctx);
 267         atomic_dec(&pblk->inflight_io);
 268 }
 269
 270 static void pblk_end_io_write_meta(struct nvm_rq *rqd)
 271 {
 272         struct pblk *pblk = rqd->private;
 273         struct pblk_g_ctx *m_ctx = nvm_rq_to_pdu(rqd);
 274         struct pblk_line *line = m_ctx->private;
 275         struct pblk_emeta *emeta = line->emeta;
 276         int sync;
 277
 278         pblk_up_page(pblk, rqd->ppa_list, rqd->nr_ppas);
 279
 280         if (rqd->error) {
 281                 pblk_log_write_err(pblk, rqd);
 282                 pblk_err(pblk, "metadata I/O failed. Line %d\n", line->id);
 283                 line->w_err_gc->has_write_err = 1;
 284         }
 285
 286         sync = atomic_add_return(rqd->nr_ppas, &emeta->sync);
 287         if (sync == emeta->nr_entries)
 288                 pblk_gen_run_ws(pblk, line, NULL, pblk_line_close_ws,
 289                                                 GFP_ATOMIC, pblk->close_wq);
 290
 291         pblk_free_rqd(pblk, rqd, PBLK_WRITE_INT);
 292
 293         atomic_dec(&pblk->inflight_io);
 294 }
 295
 296 static int pblk_alloc_w_rq(struct pblk *pblk, struct nvm_rq *rqd,
 297                            unsigned int nr_secs,
 298                            nvm_end_io_fn(*end_io))
 299 {
 300         struct nvm_tgt_dev *dev = pblk->dev;
 301
 302         /* Setup write request */
 303         rqd->opcode = NVM_OP_PWRITE;
 304         rqd->nr_ppas = nr_secs;
 305         rqd->flags = pblk_set_progr_mode(pblk, PBLK_WRITE);
 306         rqd->private = pblk;
 307         rqd->end_io = end_io;
 308
 309         rqd->meta_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
 310                                                         &rqd->dma_meta_list);
 311         if (!rqd->meta_list)
 312                 return -ENOMEM;
 313
 314         rqd->ppa_list = rqd->meta_list + pblk_dma_meta_size;
 315         rqd->dma_ppa_list = rqd->dma_meta_list + pblk_dma_meta_size;
 316
 317         return 0;
 318 }
 319
 320 static int pblk_setup_w_rq(struct pblk *pblk, struct nvm_rq *rqd,
 321                            struct ppa_addr *erase_ppa)
 322 {
 323         struct pblk_line_meta *lm = &pblk->lm;
 324         struct pblk_line *e_line = pblk_line_get_erase(pblk);
 325         struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 326         unsigned int valid = c_ctx->nr_valid;
 327         unsigned int padded = c_ctx->nr_padded;
 328         unsigned int nr_secs = valid + padded;
 329         unsigned long *lun_bitmap;
 330         int ret;
 331
 332         lun_bitmap = kzalloc(lm->lun_bitmap_len, GFP_KERNEL);
 333         if (!lun_bitmap)
 334                 return -ENOMEM;
 335         c_ctx->lun_bitmap = lun_bitmap;
 336
 337         ret = pblk_alloc_w_rq(pblk, rqd, nr_secs, pblk_end_io_write);
 338         if (ret) {
 339                 kfree(lun_bitmap);
 340                 return ret;
 341         }
 342
 343         if (likely(!e_line || !atomic_read(&e_line->left_eblks)))
 344                 pblk_map_rq(pblk, rqd, c_ctx->sentry, lun_bitmap, valid, 0);
 345         else
 346                 pblk_map_erase_rq(pblk, rqd, c_ctx->sentry, lun_bitmap,
 347                                                         valid, erase_ppa);
 348
 349         return 0;
 350 }
 351
 352 static int pblk_calc_secs_to_sync(struct pblk *pblk, unsigned int secs_avail,
 353                                   unsigned int secs_to_flush)
 354 {
 355         int secs_to_sync;
 356
 357         secs_to_sync = pblk_calc_secs(pblk, secs_avail, secs_to_flush);
 358
 359 #ifdef CONFIG_NVM_PBLK_DEBUG
 360         if ((!secs_to_sync && secs_to_flush)
 361                         || (secs_to_sync < 0)
 362                         || (secs_to_sync > secs_avail && !secs_to_flush)) {
 363                 pblk_err(pblk, "bad sector calculation (a:%d,s:%d,f:%d)\n",
 364                                 secs_avail, secs_to_sync, secs_to_flush);
 365         }
 366 #endif
 367
 368         return secs_to_sync;
 369 }
 370
 371 int pblk_submit_meta_io(struct pblk *pblk, struct pblk_line *meta_line)
 372 {
 373         struct nvm_tgt_dev *dev = pblk->dev;
 374         struct nvm_geo *geo = &dev->geo;
 375         struct pblk_line_mgmt *l_mg = &pblk->l_mg;
 376         struct pblk_line_meta *lm = &pblk->lm;
 377         struct pblk_emeta *emeta = meta_line->emeta;
 378         struct pblk_g_ctx *m_ctx;
 379         struct bio *bio;
 380         struct nvm_rq *rqd;
 381         void *data;
 382         u64 paddr;
 383         int rq_ppas = pblk->min_write_pgs;
 384         int id = meta_line->id;
 385         int rq_len;
 386         int i, j;
 387         int ret;
 388
 389         rqd = pblk_alloc_rqd(pblk, PBLK_WRITE_INT);
 390
 391         m_ctx = nvm_rq_to_pdu(rqd);
 392         m_ctx->private = meta_line;
 393
 394         rq_len = rq_ppas * geo->csecs;
 395         data = ((void *)emeta->buf) + emeta->mem;
 396
 397         bio = pblk_bio_map_addr(pblk, data, rq_ppas, rq_len,
 398                                         l_mg->emeta_alloc_type, GFP_KERNEL);
 399         if (IS_ERR(bio)) {
 400                 pblk_err(pblk, "failed to map emeta io");
 401                 ret = PTR_ERR(bio);
 402                 goto fail_free_rqd;
 403         }
 404         bio->bi_iter.bi_sector = 0; /* internal bio */
 405         bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
 406         rqd->bio = bio;
 407
 408         ret = pblk_alloc_w_rq(pblk, rqd, rq_ppas, pblk_end_io_write_meta);
 409         if (ret)
 410                 goto fail_free_bio;
 411
 412         for (i = 0; i < rqd->nr_ppas; ) {
 413                 spin_lock(&meta_line->lock);
 414                 paddr = __pblk_alloc_page(pblk, meta_line, rq_ppas);
 415                 spin_unlock(&meta_line->lock);
 416                 for (j = 0; j < rq_ppas; j++, i++, paddr++)
 417                         rqd->ppa_list[i] = addr_to_gen_ppa(pblk, paddr, id);
 418         }
 419
 420         emeta->mem += rq_len;
 421         if (emeta->mem >= lm->emeta_len[0]) {
 422                 spin_lock(&l_mg->close_lock);
 423                 list_del(&meta_line->list);
 424                 spin_unlock(&l_mg->close_lock);
 425         }
 426
 427         pblk_down_page(pblk, rqd->ppa_list, rqd->nr_ppas);
 428
 429         ret = pblk_submit_io(pblk, rqd);
 430         if (ret) {
 431                 pblk_err(pblk, "emeta I/O submission failed: %d\n", ret);
 432                 goto fail_rollback;
 433         }
 434
 435         return NVM_IO_OK;
 436
 437 fail_rollback:
 438         pblk_up_page(pblk, rqd->ppa_list, rqd->nr_ppas);
 439         spin_lock(&l_mg->close_lock);
 440         pblk_dealloc_page(pblk, meta_line, rq_ppas);
 441         list_add(&meta_line->list, &meta_line->list);
 442         spin_unlock(&l_mg->close_lock);
 443 fail_free_bio:
 444         bio_put(bio);
 445 fail_free_rqd:
 446         pblk_free_rqd(pblk, rqd, PBLK_WRITE_INT);
 447         return ret;
 448 }
 449
 450 static inline bool pblk_valid_meta_ppa(struct pblk *pblk,
 451                                        struct pblk_line *meta_line,
 452                                        struct nvm_rq *data_rqd)
 453 {
 454         struct nvm_tgt_dev *dev = pblk->dev;
 455         struct nvm_geo *geo = &dev->geo;
 456         struct pblk_c_ctx *data_c_ctx = nvm_rq_to_pdu(data_rqd);
 457         struct pblk_line *data_line = pblk_line_get_data(pblk);
 458         struct ppa_addr ppa, ppa_opt;
 459         u64 paddr;
 460         int pos_opt;
 461
 462         /* Schedule a metadata I/O that is half the distance from the data I/O
 463          * with regards to the number of LUNs forming the pblk instance. This
 464          * balances LUN conflicts across every I/O.
 465          *
 466          * When the LUN configuration changes (e.g., due to GC), this distance
 467          * can align, which would result on metadata and data I/Os colliding. In
 468          * this case, modify the distance to not be optimal, but move the
 469          * optimal in the right direction.
 470          */
 471         paddr = pblk_lookup_page(pblk, meta_line);
 472         ppa = addr_to_gen_ppa(pblk, paddr, 0);
 473         ppa_opt = addr_to_gen_ppa(pblk, paddr + data_line->meta_distance, 0);
 474         pos_opt = pblk_ppa_to_pos(geo, ppa_opt);
 475
 476         if (test_bit(pos_opt, data_c_ctx->lun_bitmap) ||
 477                                 test_bit(pos_opt, data_line->blk_bitmap))
 478                 return true;
 479
 480         if (unlikely(pblk_ppa_comp(ppa_opt, ppa)))
 481                 data_line->meta_distance--;
 482
 483         return false;
 484 }
 485
 486 static struct pblk_line *pblk_should_submit_meta_io(struct pblk *pblk,
 487                                                     struct nvm_rq *data_rqd)
 488 {
 489         struct pblk_line_meta *lm = &pblk->lm;
 490         struct pblk_line_mgmt *l_mg = &pblk->l_mg;
 491         struct pblk_line *meta_line;
 492
 493         spin_lock(&l_mg->close_lock);
 494 retry:
 495         if (list_empty(&l_mg->emeta_list)) {
 496                 spin_unlock(&l_mg->close_lock);
 497                 return NULL;
 498         }
 499         meta_line = list_first_entry(&l_mg->emeta_list, struct pblk_line, list);
 500         if (meta_line->emeta->mem >= lm->emeta_len[0])
 501                 goto retry;
 502         spin_unlock(&l_mg->close_lock);
 503
 504         if (!pblk_valid_meta_ppa(pblk, meta_line, data_rqd))
 505                 return NULL;
 506
 507         return meta_line;
 508 }
 509
 510 static int pblk_submit_io_set(struct pblk *pblk, struct nvm_rq *rqd)
 511 {
 512         struct ppa_addr erase_ppa;
 513         struct pblk_line *meta_line;
 514         int err;
 515
 516         pblk_ppa_set_empty(&erase_ppa);
 517
 518         /* Assign lbas to ppas and populate request structure */
 519         err = pblk_setup_w_rq(pblk, rqd, &erase_ppa);
 520         if (err) {
 521                 pblk_err(pblk, "could not setup write request: %d\n", err);
 522                 return NVM_IO_ERR;
 523         }
 524
 525         meta_line = pblk_should_submit_meta_io(pblk, rqd);
 526
 527         /* Submit data write for current data line */
 528         err = pblk_submit_io(pblk, rqd);
 529         if (err) {
 530                 pblk_err(pblk, "data I/O submission failed: %d\n", err);
 531                 return NVM_IO_ERR;
 532         }
 533
 534         if (!pblk_ppa_empty(erase_ppa)) {
 535                 /* Submit erase for next data line */
 536                 if (pblk_blk_erase_async(pblk, erase_ppa)) {
 537                         struct pblk_line *e_line = pblk_line_get_erase(pblk);
 538                         struct nvm_tgt_dev *dev = pblk->dev;
 539                         struct nvm_geo *geo = &dev->geo;
 540                         int bit;
 541
 542                         atomic_inc(&e_line->left_eblks);
 543                         bit = pblk_ppa_to_pos(geo, erase_ppa);
 544                         WARN_ON(!test_and_clear_bit(bit, e_line->erase_bitmap));
 545                 }
 546         }
 547
 548         if (meta_line) {
 549                 /* Submit metadata write for previous data line */
 550                 err = pblk_submit_meta_io(pblk, meta_line);
 551                 if (err) {
 552                         pblk_err(pblk, "metadata I/O submission failed: %d",
 553                                         err);
 554                         return NVM_IO_ERR;
 555                 }
 556         }
 557
 558         return NVM_IO_OK;
 559 }
 560
 561 static void pblk_free_write_rqd(struct pblk *pblk, struct nvm_rq *rqd)
 562 {
 563         struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 564         struct bio *bio = rqd->bio;
 565
 566         if (c_ctx->nr_padded)
 567                 pblk_bio_free_pages(pblk, bio, c_ctx->nr_valid,
 568                                                         c_ctx->nr_padded);
 569 }
 570
 571 static int pblk_submit_write(struct pblk *pblk)
 572 {
 573         struct bio *bio;
 574         struct nvm_rq *rqd;
 575         unsigned int secs_avail, secs_to_sync, secs_to_com;
 576         unsigned int secs_to_flush;
 577         unsigned long pos;
 578         unsigned int resubmit;
 579
 580         spin_lock(&pblk->resubmit_lock);
 581         resubmit = !list_empty(&pblk->resubmit_list);
 582         spin_unlock(&pblk->resubmit_lock);
 583
 584         /* Resubmit failed writes first */
 585         if (resubmit) {
 586                 struct pblk_c_ctx *r_ctx;
 587
 588                 spin_lock(&pblk->resubmit_lock);
 589                 r_ctx = list_first_entry(&pblk->resubmit_list,
 590                                         struct pblk_c_ctx, list);
 591                 list_del(&r_ctx->list);
 592                 spin_unlock(&pblk->resubmit_lock);
 593
 594                 secs_avail = r_ctx->nr_valid;
 595                 pos = r_ctx->sentry;
 596
 597                 pblk_prepare_resubmit(pblk, pos, secs_avail);
 598                 secs_to_sync = pblk_calc_secs_to_sync(pblk, secs_avail,
 599                                 secs_avail);
 600
 601                 kfree(r_ctx);
 602         } else {
 603                 /* If there are no sectors in the cache,
 604                  * flushes (bios without data) will be cleared on
 605                  * the cache threads
 606                  */
 607                 secs_avail = pblk_rb_read_count(&pblk->rwb);
 608                 if (!secs_avail)
 609                         return 1;
 610
 611                 secs_to_flush = pblk_rb_flush_point_count(&pblk->rwb);
 612                 if (!secs_to_flush && secs_avail < pblk->min_write_pgs)
 613                         return 1;
 614
 615                 secs_to_sync = pblk_calc_secs_to_sync(pblk, secs_avail,
 616                                         secs_to_flush);
 617                 if (secs_to_sync > pblk->max_write_pgs) {
 618                         pblk_err(pblk, "bad buffer sync calculation\n");
 619                         return 1;
 620                 }
 621
 622                 secs_to_com = (secs_to_sync > secs_avail) ?
 623                         secs_avail : secs_to_sync;
 624                 pos = pblk_rb_read_commit(&pblk->rwb, secs_to_com);
 625         }
 626
 627         bio = bio_alloc(GFP_KERNEL, secs_to_sync);
 628
 629         bio->bi_iter.bi_sector = 0; /* internal bio */
 630         bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
 631
 632         rqd = pblk_alloc_rqd(pblk, PBLK_WRITE);
 633         rqd->bio = bio;
 634
 635         if (pblk_rb_read_to_bio(&pblk->rwb, rqd, pos, secs_to_sync,
 636                                                                 secs_avail)) {
 637                 pblk_err(pblk, "corrupted write bio\n");
 638                 goto fail_put_bio;
 639         }
 640
 641         if (pblk_submit_io_set(pblk, rqd))
 642                 goto fail_free_bio;
 643
 644 #ifdef CONFIG_NVM_PBLK_DEBUG
 645         atomic_long_add(secs_to_sync, &pblk->sub_writes);
 646 #endif
 647
 648         return 0;
 649
 650 fail_free_bio:
 651         pblk_free_write_rqd(pblk, rqd);
 652 fail_put_bio:
 653         bio_put(bio);
 654         pblk_free_rqd(pblk, rqd, PBLK_WRITE);
 655
 656         return 1;
 657 }
 658
 659 int pblk_write_ts(void *data)
 660 {
 661         struct pblk *pblk = data;
 662
 663         while (!kthread_should_stop()) {
 664                 if (!pblk_submit_write(pblk))
 665                         continue;
 666                 set_current_state(TASK_INTERRUPTIBLE);
 667                 io_schedule();
 668         }
 669
 670         return 0;
 671 }