drivers/lightnvm/pblk-write.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2016 CNEX Labs
   4  * Initial release: Javier Gonzalez <[email protected]>
   5  *                  Matias Bjorling <[email protected]>
   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 {
 110         struct pblk_line *line;
 111         struct ppa_addr map_ppa = *ppa;
 112         u64 paddr;
 113         int done = 0;
 114
 115         line = pblk_ppa_to_line(pblk, *ppa);
 116         spin_lock(&line->lock);
 117
 118         while (!done)  {
 119                 paddr = pblk_dev_ppa_to_line_addr(pblk, map_ppa);
 120
 121                 if (!test_and_set_bit(paddr, line->map_bitmap))
 122                         line->left_msecs--;
 123
 124                 if (!test_and_set_bit(paddr, line->invalid_bitmap))
 125                         le32_add_cpu(line->vsc, -1);
 126
 127                 done = nvm_next_ppa_in_chk(pblk->dev, &map_ppa);
 128         }
 129
 130         line->w_err_gc->has_write_err = 1;
 131         spin_unlock(&line->lock);
 132 }
 133
 134 static void pblk_prepare_resubmit(struct pblk *pblk, unsigned int sentry,
 135                                   unsigned int nr_entries)
 136 {
 137         struct pblk_rb *rb = &pblk->rwb;
 138         struct pblk_rb_entry *entry;
 139         struct pblk_line *line;
 140         struct pblk_w_ctx *w_ctx;
 141         struct ppa_addr ppa_l2p;
 142         int flags;
 143         unsigned int i;
 144
 145         spin_lock(&pblk->trans_lock);
 146         for (i = 0; i < nr_entries; i++) {
 147                 entry = &rb->entries[pblk_rb_ptr_wrap(rb, sentry, i)];
 148                 w_ctx = &entry->w_ctx;
 149
 150                 /* Check if the lba has been overwritten */
 151                 ppa_l2p = pblk_trans_map_get(pblk, w_ctx->lba);
 152                 if (!pblk_ppa_comp(ppa_l2p, entry->cacheline))
 153                         w_ctx->lba = ADDR_EMPTY;
 154
 155                 /* Mark up the entry as submittable again */
 156                 flags = READ_ONCE(w_ctx->flags);
 157                 flags |= PBLK_WRITTEN_DATA;
 158                 /* Release flags on write context. Protect from writes */
 159                 smp_store_release(&w_ctx->flags, flags);
 160
 161                 /* Decrease the reference count to the line as we will
 162                  * re-map these entries
 163                  */
 164                 line = pblk_ppa_to_line(pblk, w_ctx->ppa);
 165                 kref_put(&line->ref, pblk_line_put);
 166         }
 167         spin_unlock(&pblk->trans_lock);
 168 }
 169
 170 static void pblk_queue_resubmit(struct pblk *pblk, struct pblk_c_ctx *c_ctx)
 171 {
 172         struct pblk_c_ctx *r_ctx;
 173
 174         r_ctx = kzalloc(sizeof(struct pblk_c_ctx), GFP_KERNEL);
 175         if (!r_ctx)
 176                 return;
 177
 178         r_ctx->lun_bitmap = NULL;
 179         r_ctx->sentry = c_ctx->sentry;
 180         r_ctx->nr_valid = c_ctx->nr_valid;
 181         r_ctx->nr_padded = c_ctx->nr_padded;
 182
 183         spin_lock(&pblk->resubmit_lock);
 184         list_add_tail(&r_ctx->list, &pblk->resubmit_list);
 185         spin_unlock(&pblk->resubmit_lock);
 186
 187 #ifdef CONFIG_NVM_PBLK_DEBUG
 188         atomic_long_add(c_ctx->nr_valid, &pblk->recov_writes);
 189 #endif
 190 }
 191
 192 static void pblk_submit_rec(struct work_struct *work)
 193 {
 194         struct pblk_rec_ctx *recovery =
 195                         container_of(work, struct pblk_rec_ctx, ws_rec);
 196         struct pblk *pblk = recovery->pblk;
 197         struct nvm_rq *rqd = recovery->rqd;
 198         struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 199         struct ppa_addr *ppa_list = nvm_rq_to_ppa_list(rqd);
 200
 201         pblk_log_write_err(pblk, rqd);
 202
 203         pblk_map_remaining(pblk, ppa_list);
 204         pblk_queue_resubmit(pblk, c_ctx);
 205
 206         pblk_up_rq(pblk, c_ctx->lun_bitmap);
 207         if (c_ctx->nr_padded)
 208                 pblk_bio_free_pages(pblk, rqd->bio, c_ctx->nr_valid,
 209                                                         c_ctx->nr_padded);
 210         bio_put(rqd->bio);
 211         pblk_free_rqd(pblk, rqd, PBLK_WRITE);
 212         mempool_free(recovery, &pblk->rec_pool);
 213
 214         atomic_dec(&pblk->inflight_io);
 215 }
 216
 217
 218 static void pblk_end_w_fail(struct pblk *pblk, struct nvm_rq *rqd)
 219 {
 220         struct pblk_rec_ctx *recovery;
 221
 222         recovery = mempool_alloc(&pblk->rec_pool, GFP_ATOMIC);
 223         if (!recovery) {
 224                 pblk_err(pblk, "could not allocate recovery work\n");
 225                 return;
 226         }
 227
 228         recovery->pblk = pblk;
 229         recovery->rqd = rqd;
 230
 231         INIT_WORK(&recovery->ws_rec, pblk_submit_rec);
 232         queue_work(pblk->close_wq, &recovery->ws_rec);
 233 }
 234
 235 static void pblk_end_io_write(struct nvm_rq *rqd)
 236 {
 237         struct pblk *pblk = rqd->private;
 238         struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 239
 240         if (rqd->error) {
 241                 pblk_end_w_fail(pblk, rqd);
 242                 return;
 243         } else {
 244                 if (trace_pblk_chunk_state_enabled())
 245                         pblk_check_chunk_state_update(pblk, rqd);
 246 #ifdef CONFIG_NVM_PBLK_DEBUG
 247                 WARN_ONCE(rqd->bio->bi_status, "pblk: corrupted write error\n");
 248 #endif
 249         }
 250
 251         pblk_complete_write(pblk, rqd, c_ctx);
 252         atomic_dec(&pblk->inflight_io);
 253 }
 254
 255 static void pblk_end_io_write_meta(struct nvm_rq *rqd)
 256 {
 257         struct pblk *pblk = rqd->private;
 258         struct pblk_g_ctx *m_ctx = nvm_rq_to_pdu(rqd);
 259         struct pblk_line *line = m_ctx->private;
 260         struct pblk_emeta *emeta = line->emeta;
 261         struct ppa_addr *ppa_list = nvm_rq_to_ppa_list(rqd);
 262         int sync;
 263
 264         pblk_up_chunk(pblk, ppa_list[0]);
 265
 266         if (rqd->error) {
 267                 pblk_log_write_err(pblk, rqd);
 268                 pblk_err(pblk, "metadata I/O failed. Line %d\n", line->id);
 269                 line->w_err_gc->has_write_err = 1;
 270         } else {
 271                 if (trace_pblk_chunk_state_enabled())
 272                         pblk_check_chunk_state_update(pblk, rqd);
 273         }
 274
 275         sync = atomic_add_return(rqd->nr_ppas, &emeta->sync);
 276         if (sync == emeta->nr_entries)
 277                 pblk_gen_run_ws(pblk, line, NULL, pblk_line_close_ws,
 278                                                 GFP_ATOMIC, pblk->close_wq);
 279
 280         pblk_free_rqd(pblk, rqd, PBLK_WRITE_INT);
 281
 282         atomic_dec(&pblk->inflight_io);
 283 }
 284
 285 static int pblk_alloc_w_rq(struct pblk *pblk, struct nvm_rq *rqd,
 286                            unsigned int nr_secs, nvm_end_io_fn(*end_io))
 287 {
 288         /* Setup write request */
 289         rqd->opcode = NVM_OP_PWRITE;
 290         rqd->nr_ppas = nr_secs;
 291         rqd->is_seq = 1;
 292         rqd->private = pblk;
 293         rqd->end_io = end_io;
 294
 295         return pblk_alloc_rqd_meta(pblk, rqd);
 296 }
 297
 298 static int pblk_setup_w_rq(struct pblk *pblk, struct nvm_rq *rqd,
 299                            struct ppa_addr *erase_ppa)
 300 {
 301         struct pblk_line_meta *lm = &pblk->lm;
 302         struct pblk_line *e_line = pblk_line_get_erase(pblk);
 303         struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 304         unsigned int valid = c_ctx->nr_valid;
 305         unsigned int padded = c_ctx->nr_padded;
 306         unsigned int nr_secs = valid + padded;
 307         unsigned long *lun_bitmap;
 308         int ret;
 309
 310         lun_bitmap = kzalloc(lm->lun_bitmap_len, GFP_KERNEL);
 311         if (!lun_bitmap)
 312                 return -ENOMEM;
 313         c_ctx->lun_bitmap = lun_bitmap;
 314
 315         ret = pblk_alloc_w_rq(pblk, rqd, nr_secs, pblk_end_io_write);
 316         if (ret) {
 317                 kfree(lun_bitmap);
 318                 return ret;
 319         }
 320
 321         if (likely(!e_line || !atomic_read(&e_line->left_eblks)))
 322                 pblk_map_rq(pblk, rqd, c_ctx->sentry, lun_bitmap, valid, 0);
 323         else
 324                 pblk_map_erase_rq(pblk, rqd, c_ctx->sentry, lun_bitmap,
 325                                                         valid, erase_ppa);
 326
 327         return 0;
 328 }
 329
 330 static int pblk_calc_secs_to_sync(struct pblk *pblk, unsigned int secs_avail,
 331                                   unsigned int secs_to_flush)
 332 {
 333         int secs_to_sync;
 334
 335         secs_to_sync = pblk_calc_secs(pblk, secs_avail, secs_to_flush);
 336
 337 #ifdef CONFIG_NVM_PBLK_DEBUG
 338         if ((!secs_to_sync && secs_to_flush)
 339                         || (secs_to_sync < 0)
 340                         || (secs_to_sync > secs_avail && !secs_to_flush)) {
 341                 pblk_err(pblk, "bad sector calculation (a:%d,s:%d,f:%d)\n",
 342                                 secs_avail, secs_to_sync, secs_to_flush);
 343         }
 344 #endif
 345
 346         return secs_to_sync;
 347 }
 348
 349 int pblk_submit_meta_io(struct pblk *pblk, struct pblk_line *meta_line)
 350 {
 351         struct nvm_tgt_dev *dev = pblk->dev;
 352         struct nvm_geo *geo = &dev->geo;
 353         struct pblk_line_mgmt *l_mg = &pblk->l_mg;
 354         struct pblk_line_meta *lm = &pblk->lm;
 355         struct pblk_emeta *emeta = meta_line->emeta;
 356         struct ppa_addr *ppa_list;
 357         struct pblk_g_ctx *m_ctx;
 358         struct bio *bio;
 359         struct nvm_rq *rqd;
 360         void *data;
 361         u64 paddr;
 362         int rq_ppas = pblk->min_write_pgs;
 363         int id = meta_line->id;
 364         int rq_len;
 365         int i, j;
 366         int ret;
 367
 368         rqd = pblk_alloc_rqd(pblk, PBLK_WRITE_INT);
 369
 370         m_ctx = nvm_rq_to_pdu(rqd);
 371         m_ctx->private = meta_line;
 372
 373         rq_len = rq_ppas * geo->csecs;
 374         data = ((void *)emeta->buf) + emeta->mem;
 375
 376         bio = pblk_bio_map_addr(pblk, data, rq_ppas, rq_len,
 377                                         l_mg->emeta_alloc_type, GFP_KERNEL);
 378         if (IS_ERR(bio)) {
 379                 pblk_err(pblk, "failed to map emeta io");
 380                 ret = PTR_ERR(bio);
 381                 goto fail_free_rqd;
 382         }
 383         bio->bi_iter.bi_sector = 0; /* internal bio */
 384         bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
 385         rqd->bio = bio;
 386
 387         ret = pblk_alloc_w_rq(pblk, rqd, rq_ppas, pblk_end_io_write_meta);
 388         if (ret)
 389                 goto fail_free_bio;
 390
 391         ppa_list = nvm_rq_to_ppa_list(rqd);
 392         for (i = 0; i < rqd->nr_ppas; ) {
 393                 spin_lock(&meta_line->lock);
 394                 paddr = __pblk_alloc_page(pblk, meta_line, rq_ppas);
 395                 spin_unlock(&meta_line->lock);
 396                 for (j = 0; j < rq_ppas; j++, i++, paddr++)
 397                         ppa_list[i] = addr_to_gen_ppa(pblk, paddr, id);
 398         }
 399
 400         spin_lock(&l_mg->close_lock);
 401         emeta->mem += rq_len;
 402         if (emeta->mem >= lm->emeta_len[0])
 403                 list_del(&meta_line->list);
 404         spin_unlock(&l_mg->close_lock);
 405
 406         pblk_down_chunk(pblk, ppa_list[0]);
 407
 408         ret = pblk_submit_io(pblk, rqd);
 409         if (ret) {
 410                 pblk_err(pblk, "emeta I/O submission failed: %d\n", ret);
 411                 goto fail_rollback;
 412         }
 413
 414         return NVM_IO_OK;
 415
 416 fail_rollback:
 417         pblk_up_chunk(pblk, ppa_list[0]);
 418         spin_lock(&l_mg->close_lock);
 419         pblk_dealloc_page(pblk, meta_line, rq_ppas);
 420         list_add(&meta_line->list, &meta_line->list);
 421         spin_unlock(&l_mg->close_lock);
 422 fail_free_bio:
 423         bio_put(bio);
 424 fail_free_rqd:
 425         pblk_free_rqd(pblk, rqd, PBLK_WRITE_INT);
 426         return ret;
 427 }
 428
 429 static inline bool pblk_valid_meta_ppa(struct pblk *pblk,
 430                                        struct pblk_line *meta_line,
 431                                        struct nvm_rq *data_rqd)
 432 {
 433         struct nvm_tgt_dev *dev = pblk->dev;
 434         struct nvm_geo *geo = &dev->geo;
 435         struct pblk_c_ctx *data_c_ctx = nvm_rq_to_pdu(data_rqd);
 436         struct pblk_line *data_line = pblk_line_get_data(pblk);
 437         struct ppa_addr ppa, ppa_opt;
 438         u64 paddr;
 439         int pos_opt;
 440
 441         /* Schedule a metadata I/O that is half the distance from the data I/O
 442          * with regards to the number of LUNs forming the pblk instance. This
 443          * balances LUN conflicts across every I/O.
 444          *
 445          * When the LUN configuration changes (e.g., due to GC), this distance
 446          * can align, which would result on metadata and data I/Os colliding. In
 447          * this case, modify the distance to not be optimal, but move the
 448          * optimal in the right direction.
 449          */
 450         paddr = pblk_lookup_page(pblk, meta_line);
 451         ppa = addr_to_gen_ppa(pblk, paddr, 0);
 452         ppa_opt = addr_to_gen_ppa(pblk, paddr + data_line->meta_distance, 0);
 453         pos_opt = pblk_ppa_to_pos(geo, ppa_opt);
 454
 455         if (test_bit(pos_opt, data_c_ctx->lun_bitmap) ||
 456                                 test_bit(pos_opt, data_line->blk_bitmap))
 457                 return true;
 458
 459         if (unlikely(pblk_ppa_comp(ppa_opt, ppa)))
 460                 data_line->meta_distance--;
 461
 462         return false;
 463 }
 464
 465 static struct pblk_line *pblk_should_submit_meta_io(struct pblk *pblk,
 466                                                     struct nvm_rq *data_rqd)
 467 {
 468         struct pblk_line_meta *lm = &pblk->lm;
 469         struct pblk_line_mgmt *l_mg = &pblk->l_mg;
 470         struct pblk_line *meta_line;
 471
 472         spin_lock(&l_mg->close_lock);
 473         if (list_empty(&l_mg->emeta_list)) {
 474                 spin_unlock(&l_mg->close_lock);
 475                 return NULL;
 476         }
 477         meta_line = list_first_entry(&l_mg->emeta_list, struct pblk_line, list);
 478         if (meta_line->emeta->mem >= lm->emeta_len[0]) {
 479                 spin_unlock(&l_mg->close_lock);
 480                 return NULL;
 481         }
 482         spin_unlock(&l_mg->close_lock);
 483
 484         if (!pblk_valid_meta_ppa(pblk, meta_line, data_rqd))
 485                 return NULL;
 486
 487         return meta_line;
 488 }
 489
 490 static int pblk_submit_io_set(struct pblk *pblk, struct nvm_rq *rqd)
 491 {
 492         struct ppa_addr erase_ppa;
 493         struct pblk_line *meta_line;
 494         int err;
 495
 496         pblk_ppa_set_empty(&erase_ppa);
 497
 498         /* Assign lbas to ppas and populate request structure */
 499         err = pblk_setup_w_rq(pblk, rqd, &erase_ppa);
 500         if (err) {
 501                 pblk_err(pblk, "could not setup write request: %d\n", err);
 502                 return NVM_IO_ERR;
 503         }
 504
 505         meta_line = pblk_should_submit_meta_io(pblk, rqd);
 506
 507         /* Submit data write for current data line */
 508         err = pblk_submit_io(pblk, rqd);
 509         if (err) {
 510                 pblk_err(pblk, "data I/O submission failed: %d\n", err);
 511                 return NVM_IO_ERR;
 512         }
 513
 514         if (!pblk_ppa_empty(erase_ppa)) {
 515                 /* Submit erase for next data line */
 516                 if (pblk_blk_erase_async(pblk, erase_ppa)) {
 517                         struct pblk_line *e_line = pblk_line_get_erase(pblk);
 518                         struct nvm_tgt_dev *dev = pblk->dev;
 519                         struct nvm_geo *geo = &dev->geo;
 520                         int bit;
 521
 522                         atomic_inc(&e_line->left_eblks);
 523                         bit = pblk_ppa_to_pos(geo, erase_ppa);
 524                         WARN_ON(!test_and_clear_bit(bit, e_line->erase_bitmap));
 525                 }
 526         }
 527
 528         if (meta_line) {
 529                 /* Submit metadata write for previous data line */
 530                 err = pblk_submit_meta_io(pblk, meta_line);
 531                 if (err) {
 532                         pblk_err(pblk, "metadata I/O submission failed: %d",
 533                                         err);
 534                         return NVM_IO_ERR;
 535                 }
 536         }
 537
 538         return NVM_IO_OK;
 539 }
 540
 541 static void pblk_free_write_rqd(struct pblk *pblk, struct nvm_rq *rqd)
 542 {
 543         struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 544         struct bio *bio = rqd->bio;
 545
 546         if (c_ctx->nr_padded)
 547                 pblk_bio_free_pages(pblk, bio, c_ctx->nr_valid,
 548                                                         c_ctx->nr_padded);
 549 }
 550
 551 static int pblk_submit_write(struct pblk *pblk)
 552 {
 553         struct bio *bio;
 554         struct nvm_rq *rqd;
 555         unsigned int secs_avail, secs_to_sync, secs_to_com;
 556         unsigned int secs_to_flush;
 557         unsigned long pos;
 558         unsigned int resubmit;
 559
 560         spin_lock(&pblk->resubmit_lock);
 561         resubmit = !list_empty(&pblk->resubmit_list);
 562         spin_unlock(&pblk->resubmit_lock);
 563
 564         /* Resubmit failed writes first */
 565         if (resubmit) {
 566                 struct pblk_c_ctx *r_ctx;
 567
 568                 spin_lock(&pblk->resubmit_lock);
 569                 r_ctx = list_first_entry(&pblk->resubmit_list,
 570                                         struct pblk_c_ctx, list);
 571                 list_del(&r_ctx->list);
 572                 spin_unlock(&pblk->resubmit_lock);
 573
 574                 secs_avail = r_ctx->nr_valid;
 575                 pos = r_ctx->sentry;
 576
 577                 pblk_prepare_resubmit(pblk, pos, secs_avail);
 578                 secs_to_sync = pblk_calc_secs_to_sync(pblk, secs_avail,
 579                                 secs_avail);
 580
 581                 kfree(r_ctx);
 582         } else {
 583                 /* If there are no sectors in the cache,
 584                  * flushes (bios without data) will be cleared on
 585                  * the cache threads
 586                  */
 587                 secs_avail = pblk_rb_read_count(&pblk->rwb);
 588                 if (!secs_avail)
 589                         return 1;
 590
 591                 secs_to_flush = pblk_rb_flush_point_count(&pblk->rwb);
 592                 if (!secs_to_flush && secs_avail < pblk->min_write_pgs)
 593                         return 1;
 594
 595                 secs_to_sync = pblk_calc_secs_to_sync(pblk, secs_avail,
 596                                         secs_to_flush);
 597                 if (secs_to_sync > pblk->max_write_pgs) {
 598                         pblk_err(pblk, "bad buffer sync calculation\n");
 599                         return 1;
 600                 }
 601
 602                 secs_to_com = (secs_to_sync > secs_avail) ?
 603                         secs_avail : secs_to_sync;
 604                 pos = pblk_rb_read_commit(&pblk->rwb, secs_to_com);
 605         }
 606
 607         bio = bio_alloc(GFP_KERNEL, secs_to_sync);
 608
 609         bio->bi_iter.bi_sector = 0; /* internal bio */
 610         bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
 611
 612         rqd = pblk_alloc_rqd(pblk, PBLK_WRITE);
 613         rqd->bio = bio;
 614
 615         if (pblk_rb_read_to_bio(&pblk->rwb, rqd, pos, secs_to_sync,
 616                                                                 secs_avail)) {
 617                 pblk_err(pblk, "corrupted write bio\n");
 618                 goto fail_put_bio;
 619         }
 620
 621         if (pblk_submit_io_set(pblk, rqd))
 622                 goto fail_free_bio;
 623
 624 #ifdef CONFIG_NVM_PBLK_DEBUG
 625         atomic_long_add(secs_to_sync, &pblk->sub_writes);
 626 #endif
 627
 628         return 0;
 629
 630 fail_free_bio:
 631         pblk_free_write_rqd(pblk, rqd);
 632 fail_put_bio:
 633         bio_put(bio);
 634         pblk_free_rqd(pblk, rqd, PBLK_WRITE);
 635
 636         return 1;
 637 }
 638
 639 int pblk_write_ts(void *data)
 640 {
 641         struct pblk *pblk = data;
 642
 643         while (!kthread_should_stop()) {
 644                 if (!pblk_submit_write(pblk))
 645                         continue;
 646                 set_current_state(TASK_INTERRUPTIBLE);
 647                 io_schedule();
 648         }
 649
 650         return 0;
 651 }