drivers/lightnvm/pblk-write.c

   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-write.c - pblk's write path from write buffer to media
  17  */
  18
  19 #include "pblk.h"
  20 #include "pblk-trace.h"
  21
  22 static unsigned long pblk_end_w_bio(struct pblk *pblk, struct nvm_rq *rqd,
  23                                     struct pblk_c_ctx *c_ctx)
  24 {
  25         struct bio *original_bio;
  26         struct pblk_rb *rwb = &pblk->rwb;
  27         unsigned long ret;
  28         int i;
  29
  30         for (i = 0; i < c_ctx->nr_valid; i++) {
  31                 struct pblk_w_ctx *w_ctx;
  32                 int pos = c_ctx->sentry + i;
  33                 int flags;
  34
  35                 w_ctx = pblk_rb_w_ctx(rwb, pos);
  36                 flags = READ_ONCE(w_ctx->flags);
  37
  38                 if (flags & PBLK_FLUSH_ENTRY) {
  39                         flags &= ~PBLK_FLUSH_ENTRY;
  40                         /* Release flags on context. Protect from writes */
  41                         smp_store_release(&w_ctx->flags, flags);
  42
  43 #ifdef CONFIG_NVM_PBLK_DEBUG
  44                         atomic_dec(&rwb->inflight_flush_point);
  45 #endif
  46                 }
  47
  48                 while ((original_bio = bio_list_pop(&w_ctx->bios)))
  49                         bio_endio(original_bio);
  50         }
  51
  52         if (c_ctx->nr_padded)
  53                 pblk_bio_free_pages(pblk, rqd->bio, c_ctx->nr_valid,
  54                                                         c_ctx->nr_padded);
  55
  56 #ifdef CONFIG_NVM_PBLK_DEBUG
  57         atomic_long_add(rqd->nr_ppas, &pblk->sync_writes);
  58 #endif
  59
  60         ret = pblk_rb_sync_advance(&pblk->rwb, c_ctx->nr_valid);
  61
  62         bio_put(rqd->bio);
  63         pblk_free_rqd(pblk, rqd, PBLK_WRITE);
  64
  65         return ret;
  66 }
  67
  68 static unsigned long pblk_end_queued_w_bio(struct pblk *pblk,
  69                                            struct nvm_rq *rqd,
  70                                            struct pblk_c_ctx *c_ctx)
  71 {
  72         list_del(&c_ctx->list);
  73         return pblk_end_w_bio(pblk, rqd, c_ctx);
  74 }
  75
  76 static void pblk_complete_write(struct pblk *pblk, struct nvm_rq *rqd,
  77                                 struct pblk_c_ctx *c_ctx)
  78 {
  79         struct pblk_c_ctx *c, *r;
  80         unsigned long flags;
  81         unsigned long pos;
  82
  83 #ifdef CONFIG_NVM_PBLK_DEBUG
  84         atomic_long_sub(c_ctx->nr_valid, &pblk->inflight_writes);
  85 #endif
  86         pblk_up_rq(pblk, c_ctx->lun_bitmap);
  87
  88         pos = pblk_rb_sync_init(&pblk->rwb, &flags);
  89         if (pos == c_ctx->sentry) {
  90                 pos = pblk_end_w_bio(pblk, rqd, c_ctx);
  91
  92 retry:
  93                 list_for_each_entry_safe(c, r, &pblk->compl_list, list) {
  94                         rqd = nvm_rq_from_c_ctx(c);
  95                         if (c->sentry == pos) {
  96                                 pos = pblk_end_queued_w_bio(pblk, rqd, c);
  97                                 goto retry;
  98                         }
  99                 }
 100         } else {
 101                 WARN_ON(nvm_rq_from_c_ctx(c_ctx) != rqd);
 102                 list_add_tail(&c_ctx->list, &pblk->compl_list);
 103         }
 104         pblk_rb_sync_end(&pblk->rwb, &flags);
 105 }
 106
 107 /* Map remaining sectors in chunk, starting from ppa */
 108 static void pblk_map_remaining(struct pblk *pblk, struct ppa_addr *ppa,
 109                 int rqd_ppas)
 110 {
 111         struct pblk_line *line;
 112         struct ppa_addr map_ppa = *ppa;
 113         __le64 addr_empty = cpu_to_le64(ADDR_EMPTY);
 114         __le64 *lba_list;
 115         u64 paddr;
 116         int done = 0;
 117         int n = 0;
 118
 119         line = pblk_ppa_to_line(pblk, *ppa);
 120         lba_list = emeta_to_lbas(pblk, line->emeta->buf);
 121
 122         spin_lock(&line->lock);
 123
 124         while (!done)  {
 125                 paddr = pblk_dev_ppa_to_line_addr(pblk, map_ppa);
 126
 127                 if (!test_and_set_bit(paddr, line->map_bitmap))
 128                         line->left_msecs--;
 129
 130                 if (n < rqd_ppas && lba_list[paddr] != addr_empty)
 131                         line->nr_valid_lbas--;
 132
 133                 lba_list[paddr] = addr_empty;
 134
 135                 if (!test_and_set_bit(paddr, line->invalid_bitmap))
 136                         le32_add_cpu(line->vsc, -1);
 137
 138                 done = nvm_next_ppa_in_chk(pblk->dev, &map_ppa);
 139
 140                 n++;
 141         }
 142
 143         line->w_err_gc->has_write_err = 1;
 144         spin_unlock(&line->lock);
 145 }
 146
 147 static void pblk_prepare_resubmit(struct pblk *pblk, unsigned int sentry,
 148                                   unsigned int nr_entries)
 149 {
 150         struct pblk_rb *rb = &pblk->rwb;
 151         struct pblk_rb_entry *entry;
 152         struct pblk_line *line;
 153         struct pblk_w_ctx *w_ctx;
 154         struct ppa_addr ppa_l2p;
 155         int flags;
 156         unsigned int i;
 157
 158         spin_lock(&pblk->trans_lock);
 159         for (i = 0; i < nr_entries; i++) {
 160                 entry = &rb->entries[pblk_rb_ptr_wrap(rb, sentry, i)];
 161                 w_ctx = &entry->w_ctx;
 162
 163                 /* Check if the lba has been overwritten */
 164                 if (w_ctx->lba != ADDR_EMPTY) {
 165                         ppa_l2p = pblk_trans_map_get(pblk, w_ctx->lba);
 166                         if (!pblk_ppa_comp(ppa_l2p, entry->cacheline))
 167                                 w_ctx->lba = ADDR_EMPTY;
 168                 }
 169
 170                 /* Mark up the entry as submittable again */
 171                 flags = READ_ONCE(w_ctx->flags);
 172                 flags |= PBLK_WRITTEN_DATA;
 173                 /* Release flags on write context. Protect from writes */
 174                 smp_store_release(&w_ctx->flags, flags);
 175
 176                 /* Decrease the reference count to the line as we will
 177                  * re-map these entries
 178                  */
 179                 line = pblk_ppa_to_line(pblk, w_ctx->ppa);
 180                 atomic_dec(&line->sec_to_update);
 181                 kref_put(&line->ref, pblk_line_put);
 182         }
 183         spin_unlock(&pblk->trans_lock);
 184 }
 185
 186 static void pblk_queue_resubmit(struct pblk *pblk, struct pblk_c_ctx *c_ctx)
 187 {
 188         struct pblk_c_ctx *r_ctx;
 189
 190         r_ctx = kzalloc(sizeof(struct pblk_c_ctx), GFP_KERNEL);
 191         if (!r_ctx)
 192                 return;
 193
 194         r_ctx->lun_bitmap = NULL;
 195         r_ctx->sentry = c_ctx->sentry;
 196         r_ctx->nr_valid = c_ctx->nr_valid;
 197         r_ctx->nr_padded = c_ctx->nr_padded;
 198
 199         spin_lock(&pblk->resubmit_lock);
 200         list_add_tail(&r_ctx->list, &pblk->resubmit_list);
 201         spin_unlock(&pblk->resubmit_lock);
 202
 203 #ifdef CONFIG_NVM_PBLK_DEBUG
 204         atomic_long_add(c_ctx->nr_valid, &pblk->recov_writes);
 205 #endif
 206 }
 207
 208 static void pblk_submit_rec(struct work_struct *work)
 209 {
 210         struct pblk_rec_ctx *recovery =
 211                         container_of(work, struct pblk_rec_ctx, ws_rec);
 212         struct pblk *pblk = recovery->pblk;
 213         struct nvm_rq *rqd = recovery->rqd;
 214         struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 215         struct ppa_addr *ppa_list = nvm_rq_to_ppa_list(rqd);
 216
 217         pblk_log_write_err(pblk, rqd);
 218
 219         pblk_map_remaining(pblk, ppa_list, rqd->nr_ppas);
 220         pblk_queue_resubmit(pblk, c_ctx);
 221
 222         pblk_up_rq(pblk, c_ctx->lun_bitmap);
 223         if (c_ctx->nr_padded)
 224                 pblk_bio_free_pages(pblk, rqd->bio, c_ctx->nr_valid,
 225                                                         c_ctx->nr_padded);
 226         bio_put(rqd->bio);
 227         pblk_free_rqd(pblk, rqd, PBLK_WRITE);
 228         mempool_free(recovery, &pblk->rec_pool);
 229
 230         atomic_dec(&pblk->inflight_io);
 231 }
 232
 233
 234 static void pblk_end_w_fail(struct pblk *pblk, struct nvm_rq *rqd)
 235 {
 236         struct pblk_rec_ctx *recovery;
 237
 238         recovery = mempool_alloc(&pblk->rec_pool, GFP_ATOMIC);
 239         if (!recovery) {
 240                 pblk_err(pblk, "could not allocate recovery work\n");
 241                 return;
 242         }
 243
 244         recovery->pblk = pblk;
 245         recovery->rqd = rqd;
 246
 247         INIT_WORK(&recovery->ws_rec, pblk_submit_rec);
 248         queue_work(pblk->close_wq, &recovery->ws_rec);
 249 }
 250
 251 static void pblk_end_io_write(struct nvm_rq *rqd)
 252 {
 253         struct pblk *pblk = rqd->private;
 254         struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 255
 256         if (rqd->error) {
 257                 pblk_end_w_fail(pblk, rqd);
 258                 return;
 259         } else {
 260                 if (trace_pblk_chunk_state_enabled())
 261                         pblk_check_chunk_state_update(pblk, rqd);
 262 #ifdef CONFIG_NVM_PBLK_DEBUG
 263                 WARN_ONCE(rqd->bio->bi_status, "pblk: corrupted write error\n");
 264 #endif
 265         }
 266
 267         pblk_complete_write(pblk, rqd, c_ctx);
 268         atomic_dec(&pblk->inflight_io);
 269 }
 270
 271 static void pblk_end_io_write_meta(struct nvm_rq *rqd)
 272 {
 273         struct pblk *pblk = rqd->private;
 274         struct pblk_g_ctx *m_ctx = nvm_rq_to_pdu(rqd);
 275         struct pblk_line *line = m_ctx->private;
 276         struct pblk_emeta *emeta = line->emeta;
 277         struct ppa_addr *ppa_list = nvm_rq_to_ppa_list(rqd);
 278         int sync;
 279
 280         pblk_up_chunk(pblk, ppa_list[0]);
 281
 282         if (rqd->error) {
 283                 pblk_log_write_err(pblk, rqd);
 284                 pblk_err(pblk, "metadata I/O failed. Line %d\n", line->id);
 285                 line->w_err_gc->has_write_err = 1;
 286         } else {
 287                 if (trace_pblk_chunk_state_enabled())
 288                         pblk_check_chunk_state_update(pblk, rqd);
 289         }
 290
 291         sync = atomic_add_return(rqd->nr_ppas, &emeta->sync);
 292         if (sync == emeta->nr_entries)
 293                 pblk_gen_run_ws(pblk, line, NULL, pblk_line_close_ws,
 294                                                 GFP_ATOMIC, pblk->close_wq);
 295
 296         pblk_free_rqd(pblk, rqd, PBLK_WRITE_INT);
 297
 298         atomic_dec(&pblk->inflight_io);
 299 }
 300
 301 static int pblk_alloc_w_rq(struct pblk *pblk, struct nvm_rq *rqd,
 302                            unsigned int nr_secs, nvm_end_io_fn(*end_io))
 303 {
 304         /* Setup write request */
 305         rqd->opcode = NVM_OP_PWRITE;
 306         rqd->nr_ppas = nr_secs;
 307         rqd->is_seq = 1;
 308         rqd->private = pblk;
 309         rqd->end_io = end_io;
 310
 311         return pblk_alloc_rqd_meta(pblk, rqd);
 312 }
 313
 314 static int pblk_setup_w_rq(struct pblk *pblk, struct nvm_rq *rqd,
 315                            struct ppa_addr *erase_ppa)
 316 {
 317         struct pblk_line_meta *lm = &pblk->lm;
 318         struct pblk_line *e_line = pblk_line_get_erase(pblk);
 319         struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 320         unsigned int valid = c_ctx->nr_valid;
 321         unsigned int padded = c_ctx->nr_padded;
 322         unsigned int nr_secs = valid + padded;
 323         unsigned long *lun_bitmap;
 324         int ret;
 325
 326         lun_bitmap = kzalloc(lm->lun_bitmap_len, GFP_KERNEL);
 327         if (!lun_bitmap)
 328                 return -ENOMEM;
 329         c_ctx->lun_bitmap = lun_bitmap;
 330
 331         ret = pblk_alloc_w_rq(pblk, rqd, nr_secs, pblk_end_io_write);
 332         if (ret) {
 333                 kfree(lun_bitmap);
 334                 return ret;
 335         }
 336
 337         if (likely(!e_line || !atomic_read(&e_line->left_eblks)))
 338                 ret = pblk_map_rq(pblk, rqd, c_ctx->sentry, lun_bitmap,
 339                                                         valid, 0);
 340         else
 341                 ret = pblk_map_erase_rq(pblk, rqd, c_ctx->sentry, lun_bitmap,
 342                                                         valid, erase_ppa);
 343
 344         return ret;
 345 }
 346
 347 static int pblk_calc_secs_to_sync(struct pblk *pblk, unsigned int secs_avail,
 348                                   unsigned int secs_to_flush)
 349 {
 350         int secs_to_sync;
 351
 352         secs_to_sync = pblk_calc_secs(pblk, secs_avail, secs_to_flush, true);
 353
 354 #ifdef CONFIG_NVM_PBLK_DEBUG
 355         if ((!secs_to_sync && secs_to_flush)
 356                         || (secs_to_sync < 0)
 357                         || (secs_to_sync > secs_avail && !secs_to_flush)) {
 358                 pblk_err(pblk, "bad sector calculation (a:%d,s:%d,f:%d)\n",
 359                                 secs_avail, secs_to_sync, secs_to_flush);
 360         }
 361 #endif
 362
 363         return secs_to_sync;
 364 }
 365
 366 int pblk_submit_meta_io(struct pblk *pblk, struct pblk_line *meta_line)
 367 {
 368         struct nvm_tgt_dev *dev = pblk->dev;
 369         struct nvm_geo *geo = &dev->geo;
 370         struct pblk_line_mgmt *l_mg = &pblk->l_mg;
 371         struct pblk_line_meta *lm = &pblk->lm;
 372         struct pblk_emeta *emeta = meta_line->emeta;
 373         struct ppa_addr *ppa_list;
 374         struct pblk_g_ctx *m_ctx;
 375         struct bio *bio;
 376         struct nvm_rq *rqd;
 377         void *data;
 378         u64 paddr;
 379         int rq_ppas = pblk->min_write_pgs;
 380         int id = meta_line->id;
 381         int rq_len;
 382         int i, j;
 383         int ret;
 384
 385         rqd = pblk_alloc_rqd(pblk, PBLK_WRITE_INT);
 386
 387         m_ctx = nvm_rq_to_pdu(rqd);
 388         m_ctx->private = meta_line;
 389
 390         rq_len = rq_ppas * geo->csecs;
 391         data = ((void *)emeta->buf) + emeta->mem;
 392
 393         bio = pblk_bio_map_addr(pblk, data, rq_ppas, rq_len,
 394                                         l_mg->emeta_alloc_type, GFP_KERNEL);
 395         if (IS_ERR(bio)) {
 396                 pblk_err(pblk, "failed to map emeta io");
 397                 ret = PTR_ERR(bio);
 398                 goto fail_free_rqd;
 399         }
 400         bio->bi_iter.bi_sector = 0; /* internal bio */
 401         bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
 402         rqd->bio = bio;
 403
 404         ret = pblk_alloc_w_rq(pblk, rqd, rq_ppas, pblk_end_io_write_meta);
 405         if (ret)
 406                 goto fail_free_bio;
 407
 408         ppa_list = nvm_rq_to_ppa_list(rqd);
 409         for (i = 0; i < rqd->nr_ppas; ) {
 410                 spin_lock(&meta_line->lock);
 411                 paddr = __pblk_alloc_page(pblk, meta_line, rq_ppas);
 412                 spin_unlock(&meta_line->lock);
 413                 for (j = 0; j < rq_ppas; j++, i++, paddr++)
 414                         ppa_list[i] = addr_to_gen_ppa(pblk, paddr, id);
 415         }
 416
 417         spin_lock(&l_mg->close_lock);
 418         emeta->mem += rq_len;
 419         if (emeta->mem >= lm->emeta_len[0])
 420                 list_del(&meta_line->list);
 421         spin_unlock(&l_mg->close_lock);
 422
 423         pblk_down_chunk(pblk, ppa_list[0]);
 424
 425         ret = pblk_submit_io(pblk, rqd);
 426         if (ret) {
 427                 pblk_err(pblk, "emeta I/O submission failed: %d\n", ret);
 428                 goto fail_rollback;
 429         }
 430
 431         return NVM_IO_OK;
 432
 433 fail_rollback:
 434         pblk_up_chunk(pblk, ppa_list[0]);
 435         spin_lock(&l_mg->close_lock);
 436         pblk_dealloc_page(pblk, meta_line, rq_ppas);
 437         list_add(&meta_line->list, &meta_line->list);
 438         spin_unlock(&l_mg->close_lock);
 439 fail_free_bio:
 440         bio_put(bio);
 441 fail_free_rqd:
 442         pblk_free_rqd(pblk, rqd, PBLK_WRITE_INT);
 443         return ret;
 444 }
 445
 446 static inline bool pblk_valid_meta_ppa(struct pblk *pblk,
 447                                        struct pblk_line *meta_line,
 448                                        struct nvm_rq *data_rqd)
 449 {
 450         struct nvm_tgt_dev *dev = pblk->dev;
 451         struct nvm_geo *geo = &dev->geo;
 452         struct pblk_c_ctx *data_c_ctx = nvm_rq_to_pdu(data_rqd);
 453         struct pblk_line *data_line = pblk_line_get_data(pblk);
 454         struct ppa_addr ppa, ppa_opt;
 455         u64 paddr;
 456         int pos_opt;
 457
 458         /* Schedule a metadata I/O that is half the distance from the data I/O
 459          * with regards to the number of LUNs forming the pblk instance. This
 460          * balances LUN conflicts across every I/O.
 461          *
 462          * When the LUN configuration changes (e.g., due to GC), this distance
 463          * can align, which would result on metadata and data I/Os colliding. In
 464          * this case, modify the distance to not be optimal, but move the
 465          * optimal in the right direction.
 466          */
 467         paddr = pblk_lookup_page(pblk, meta_line);
 468         ppa = addr_to_gen_ppa(pblk, paddr, 0);
 469         ppa_opt = addr_to_gen_ppa(pblk, paddr + data_line->meta_distance, 0);
 470         pos_opt = pblk_ppa_to_pos(geo, ppa_opt);
 471
 472         if (test_bit(pos_opt, data_c_ctx->lun_bitmap) ||
 473                                 test_bit(pos_opt, data_line->blk_bitmap))
 474                 return true;
 475
 476         if (unlikely(pblk_ppa_comp(ppa_opt, ppa)))
 477                 data_line->meta_distance--;
 478
 479         return false;
 480 }
 481
 482 static struct pblk_line *pblk_should_submit_meta_io(struct pblk *pblk,
 483                                                     struct nvm_rq *data_rqd)
 484 {
 485         struct pblk_line_meta *lm = &pblk->lm;
 486         struct pblk_line_mgmt *l_mg = &pblk->l_mg;
 487         struct pblk_line *meta_line;
 488
 489         spin_lock(&l_mg->close_lock);
 490         if (list_empty(&l_mg->emeta_list)) {
 491                 spin_unlock(&l_mg->close_lock);
 492                 return NULL;
 493         }
 494         meta_line = list_first_entry(&l_mg->emeta_list, struct pblk_line, list);
 495         if (meta_line->emeta->mem >= lm->emeta_len[0]) {
 496                 spin_unlock(&l_mg->close_lock);
 497                 return NULL;
 498         }
 499         spin_unlock(&l_mg->close_lock);
 500
 501         if (!pblk_valid_meta_ppa(pblk, meta_line, data_rqd))
 502                 return NULL;
 503
 504         return meta_line;
 505 }
 506
 507 static int pblk_submit_io_set(struct pblk *pblk, struct nvm_rq *rqd)
 508 {
 509         struct ppa_addr erase_ppa;
 510         struct pblk_line *meta_line;
 511         int err;
 512
 513         pblk_ppa_set_empty(&erase_ppa);
 514
 515         /* Assign lbas to ppas and populate request structure */
 516         err = pblk_setup_w_rq(pblk, rqd, &erase_ppa);
 517         if (err) {
 518                 pblk_err(pblk, "could not setup write request: %d\n", err);
 519                 return NVM_IO_ERR;
 520         }
 521
 522         meta_line = pblk_should_submit_meta_io(pblk, rqd);
 523
 524         /* Submit data write for current data line */
 525         err = pblk_submit_io(pblk, rqd);
 526         if (err) {
 527                 pblk_err(pblk, "data I/O submission failed: %d\n", err);
 528                 return NVM_IO_ERR;
 529         }
 530
 531         if (!pblk_ppa_empty(erase_ppa)) {
 532                 /* Submit erase for next data line */
 533                 if (pblk_blk_erase_async(pblk, erase_ppa)) {
 534                         struct pblk_line *e_line = pblk_line_get_erase(pblk);
 535                         struct nvm_tgt_dev *dev = pblk->dev;
 536                         struct nvm_geo *geo = &dev->geo;
 537                         int bit;
 538
 539                         atomic_inc(&e_line->left_eblks);
 540                         bit = pblk_ppa_to_pos(geo, erase_ppa);
 541                         WARN_ON(!test_and_clear_bit(bit, e_line->erase_bitmap));
 542                 }
 543         }
 544
 545         if (meta_line) {
 546                 /* Submit metadata write for previous data line */
 547                 err = pblk_submit_meta_io(pblk, meta_line);
 548                 if (err) {
 549                         pblk_err(pblk, "metadata I/O submission failed: %d",
 550                                         err);
 551                         return NVM_IO_ERR;
 552                 }
 553         }
 554
 555         return NVM_IO_OK;
 556 }
 557
 558 static void pblk_free_write_rqd(struct pblk *pblk, struct nvm_rq *rqd)
 559 {
 560         struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 561         struct bio *bio = rqd->bio;
 562
 563         if (c_ctx->nr_padded)
 564                 pblk_bio_free_pages(pblk, bio, c_ctx->nr_valid,
 565                                                         c_ctx->nr_padded);
 566 }
 567
 568 static int pblk_submit_write(struct pblk *pblk, int *secs_left)
 569 {
 570         struct bio *bio;
 571         struct nvm_rq *rqd;
 572         unsigned int secs_avail, secs_to_sync, secs_to_com;
 573         unsigned int secs_to_flush, packed_meta_pgs;
 574         unsigned long pos;
 575         unsigned int resubmit;
 576
 577         *secs_left = 0;
 578
 579         spin_lock(&pblk->resubmit_lock);
 580         resubmit = !list_empty(&pblk->resubmit_list);
 581         spin_unlock(&pblk->resubmit_lock);
 582
 583         /* Resubmit failed writes first */
 584         if (resubmit) {
 585                 struct pblk_c_ctx *r_ctx;
 586
 587                 spin_lock(&pblk->resubmit_lock);
 588                 r_ctx = list_first_entry(&pblk->resubmit_list,
 589                                         struct pblk_c_ctx, list);
 590                 list_del(&r_ctx->list);
 591                 spin_unlock(&pblk->resubmit_lock);
 592
 593                 secs_avail = r_ctx->nr_valid;
 594                 pos = r_ctx->sentry;
 595
 596                 pblk_prepare_resubmit(pblk, pos, secs_avail);
 597                 secs_to_sync = pblk_calc_secs_to_sync(pblk, secs_avail,
 598                                 secs_avail);
 599
 600                 kfree(r_ctx);
 601         } else {
 602                 /* If there are no sectors in the cache,
 603                  * flushes (bios without data) will be cleared on
 604                  * the cache threads
 605                  */
 606                 secs_avail = pblk_rb_read_count(&pblk->rwb);
 607                 if (!secs_avail)
 608                         return 0;
 609
 610                 secs_to_flush = pblk_rb_flush_point_count(&pblk->rwb);
 611                 if (!secs_to_flush && secs_avail < pblk->min_write_pgs_data)
 612                         return 0;
 613
 614                 secs_to_sync = pblk_calc_secs_to_sync(pblk, secs_avail,
 615                                         secs_to_flush);
 616                 if (secs_to_sync > pblk->max_write_pgs) {
 617                         pblk_err(pblk, "bad buffer sync calculation\n");
 618                         return 0;
 619                 }
 620
 621                 secs_to_com = (secs_to_sync > secs_avail) ?
 622                         secs_avail : secs_to_sync;
 623                 pos = pblk_rb_read_commit(&pblk->rwb, secs_to_com);
 624         }
 625
 626         packed_meta_pgs = (pblk->min_write_pgs - pblk->min_write_pgs_data);
 627         bio = bio_alloc(GFP_KERNEL, secs_to_sync + packed_meta_pgs);
 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         *secs_left = 1;
 649         return 0;
 650
 651 fail_free_bio:
 652         pblk_free_write_rqd(pblk, rqd);
 653 fail_put_bio:
 654         bio_put(bio);
 655         pblk_free_rqd(pblk, rqd, PBLK_WRITE);
 656
 657         return -EINTR;
 658 }
 659
 660 int pblk_write_ts(void *data)
 661 {
 662         struct pblk *pblk = data;
 663         int secs_left;
 664         int write_failure = 0;
 665
 666         while (!kthread_should_stop()) {
 667                 if (!write_failure) {
 668                         write_failure = pblk_submit_write(pblk, &secs_left);
 669
 670                         if (secs_left)
 671                                 continue;
 672                 }
 673                 set_current_state(TASK_INTERRUPTIBLE);
 674                 io_schedule();
 675         }
 676
 677         return 0;
 678 }