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                 if (w_ctx->lba != ADDR_EMPTY) {
 162                         ppa_l2p = pblk_trans_map_get(pblk, w_ctx->lba);
 163                         if (!pblk_ppa_comp(ppa_l2p, entry->cacheline))
 164                                 w_ctx->lba = ADDR_EMPTY;
 165                 }
 166
 167                 /* Mark up the entry as submittable again */
 168                 flags = READ_ONCE(w_ctx->flags);
 169                 flags |= PBLK_WRITTEN_DATA;
 170                 /* Release flags on write context. Protect from writes */
 171                 smp_store_release(&w_ctx->flags, flags);
 172
 173                 /* Decrese the reference count to the line as we will
 174                  * re-map these entries
 175                  */
 176                 line = &pblk->lines[pblk_ppa_to_line(w_ctx->ppa)];
 177                 kref_put(&line->ref, pblk_line_put);
 178
 179                 pos = (pos + 1) & (rb->nr_entries - 1);
 180         }
 181         spin_unlock(&pblk->trans_lock);
 182 }
 183
 184 static void pblk_queue_resubmit(struct pblk *pblk, struct pblk_c_ctx *c_ctx)
 185 {
 186         struct pblk_c_ctx *r_ctx;
 187
 188         r_ctx = kzalloc(sizeof(struct pblk_c_ctx), GFP_KERNEL);
 189         if (!r_ctx)
 190                 return;
 191
 192         r_ctx->lun_bitmap = NULL;
 193         r_ctx->sentry = c_ctx->sentry;
 194         r_ctx->nr_valid = c_ctx->nr_valid;
 195         r_ctx->nr_padded = c_ctx->nr_padded;
 196
 197         spin_lock(&pblk->resubmit_lock);
 198         list_add_tail(&r_ctx->list, &pblk->resubmit_list);
 199         spin_unlock(&pblk->resubmit_lock);
 200
 201 #ifdef CONFIG_NVM_PBLK_DEBUG
 202         atomic_long_add(c_ctx->nr_valid, &pblk->recov_writes);
 203 #endif
 204 }
 205
 206 static void pblk_submit_rec(struct work_struct *work)
 207 {
 208         struct pblk_rec_ctx *recovery =
 209                         container_of(work, struct pblk_rec_ctx, ws_rec);
 210         struct pblk *pblk = recovery->pblk;
 211         struct nvm_rq *rqd = recovery->rqd;
 212         struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 213         struct ppa_addr *ppa_list;
 214
 215         pblk_log_write_err(pblk, rqd);
 216
 217         if (rqd->nr_ppas == 1)
 218                 ppa_list = &rqd->ppa_addr;
 219         else
 220                 ppa_list = rqd->ppa_list;
 221
 222         pblk_map_remaining(pblk, ppa_list);
 223         pblk_queue_resubmit(pblk, c_ctx);
 224
 225         pblk_up_rq(pblk, rqd->ppa_list, rqd->nr_ppas, c_ctx->lun_bitmap);
 226         if (c_ctx->nr_padded)
 227                 pblk_bio_free_pages(pblk, rqd->bio, c_ctx->nr_valid,
 228                                                         c_ctx->nr_padded);
 229         bio_put(rqd->bio);
 230         pblk_free_rqd(pblk, rqd, PBLK_WRITE);
 231         mempool_free(recovery, &pblk->rec_pool);
 232
 233         atomic_dec(&pblk->inflight_io);
 234 }
 235
 236
 237 static void pblk_end_w_fail(struct pblk *pblk, struct nvm_rq *rqd)
 238 {
 239         struct pblk_rec_ctx *recovery;
 240
 241         recovery = mempool_alloc(&pblk->rec_pool, GFP_ATOMIC);
 242         if (!recovery) {
 243                 pblk_err(pblk, "could not allocate recovery work\n");
 244                 return;
 245         }
 246
 247         recovery->pblk = pblk;
 248         recovery->rqd = rqd;
 249
 250         INIT_WORK(&recovery->ws_rec, pblk_submit_rec);
 251         queue_work(pblk->close_wq, &recovery->ws_rec);
 252 }
 253
 254 static void pblk_end_io_write(struct nvm_rq *rqd)
 255 {
 256         struct pblk *pblk = rqd->private;
 257         struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 258
 259         if (rqd->error) {
 260                 pblk_end_w_fail(pblk, rqd);
 261                 return;
 262         }
 263 #ifdef CONFIG_NVM_PBLK_DEBUG
 264         else
 265                 WARN_ONCE(rqd->bio->bi_status, "pblk: corrupted write error\n");
 266 #endif
 267
 268         pblk_complete_write(pblk, rqd, c_ctx);
 269         atomic_dec(&pblk->inflight_io);
 270 }
 271
 272 static void pblk_end_io_write_meta(struct nvm_rq *rqd)
 273 {
 274         struct pblk *pblk = rqd->private;
 275         struct pblk_g_ctx *m_ctx = nvm_rq_to_pdu(rqd);
 276         struct pblk_line *line = m_ctx->private;
 277         struct pblk_emeta *emeta = line->emeta;
 278         int sync;
 279
 280         pblk_up_page(pblk, rqd->ppa_list, rqd->nr_ppas);
 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         }
 287
 288         sync = atomic_add_return(rqd->nr_ppas, &emeta->sync);
 289         if (sync == emeta->nr_entries)
 290                 pblk_gen_run_ws(pblk, line, NULL, pblk_line_close_ws,
 291                                                 GFP_ATOMIC, pblk->close_wq);
 292
 293         pblk_free_rqd(pblk, rqd, PBLK_WRITE_INT);
 294
 295         atomic_dec(&pblk->inflight_io);
 296 }
 297
 298 static int pblk_alloc_w_rq(struct pblk *pblk, struct nvm_rq *rqd,
 299                            unsigned int nr_secs,
 300                            nvm_end_io_fn(*end_io))
 301 {
 302         struct nvm_tgt_dev *dev = pblk->dev;
 303
 304         /* Setup write request */
 305         rqd->opcode = NVM_OP_PWRITE;
 306         rqd->nr_ppas = nr_secs;
 307         rqd->flags = pblk_set_progr_mode(pblk, PBLK_WRITE);
 308         rqd->private = pblk;
 309         rqd->end_io = end_io;
 310
 311         rqd->meta_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
 312                                                         &rqd->dma_meta_list);
 313         if (!rqd->meta_list)
 314                 return -ENOMEM;
 315
 316         rqd->ppa_list = rqd->meta_list + pblk_dma_meta_size;
 317         rqd->dma_ppa_list = rqd->dma_meta_list + pblk_dma_meta_size;
 318
 319         return 0;
 320 }
 321
 322 static int pblk_setup_w_rq(struct pblk *pblk, struct nvm_rq *rqd,
 323                            struct ppa_addr *erase_ppa)
 324 {
 325         struct pblk_line_meta *lm = &pblk->lm;
 326         struct pblk_line *e_line = pblk_line_get_erase(pblk);
 327         struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 328         unsigned int valid = c_ctx->nr_valid;
 329         unsigned int padded = c_ctx->nr_padded;
 330         unsigned int nr_secs = valid + padded;
 331         unsigned long *lun_bitmap;
 332         int ret;
 333
 334         lun_bitmap = kzalloc(lm->lun_bitmap_len, GFP_KERNEL);
 335         if (!lun_bitmap)
 336                 return -ENOMEM;
 337         c_ctx->lun_bitmap = lun_bitmap;
 338
 339         ret = pblk_alloc_w_rq(pblk, rqd, nr_secs, pblk_end_io_write);
 340         if (ret) {
 341                 kfree(lun_bitmap);
 342                 return ret;
 343         }
 344
 345         if (likely(!e_line || !atomic_read(&e_line->left_eblks)))
 346                 pblk_map_rq(pblk, rqd, c_ctx->sentry, lun_bitmap, valid, 0);
 347         else
 348                 pblk_map_erase_rq(pblk, rqd, c_ctx->sentry, lun_bitmap,
 349                                                         valid, erase_ppa);
 350
 351         return 0;
 352 }
 353
 354 static int pblk_calc_secs_to_sync(struct pblk *pblk, unsigned int secs_avail,
 355                                   unsigned int secs_to_flush)
 356 {
 357         int secs_to_sync;
 358
 359         secs_to_sync = pblk_calc_secs(pblk, secs_avail, secs_to_flush);
 360
 361 #ifdef CONFIG_NVM_PBLK_DEBUG
 362         if ((!secs_to_sync && secs_to_flush)
 363                         || (secs_to_sync < 0)
 364                         || (secs_to_sync > secs_avail && !secs_to_flush)) {
 365                 pblk_err(pblk, "bad sector calculation (a:%d,s:%d,f:%d)\n",
 366                                 secs_avail, secs_to_sync, secs_to_flush);
 367         }
 368 #endif
 369
 370         return secs_to_sync;
 371 }
 372
 373 int pblk_submit_meta_io(struct pblk *pblk, struct pblk_line *meta_line)
 374 {
 375         struct nvm_tgt_dev *dev = pblk->dev;
 376         struct nvm_geo *geo = &dev->geo;
 377         struct pblk_line_mgmt *l_mg = &pblk->l_mg;
 378         struct pblk_line_meta *lm = &pblk->lm;
 379         struct pblk_emeta *emeta = meta_line->emeta;
 380         struct pblk_g_ctx *m_ctx;
 381         struct bio *bio;
 382         struct nvm_rq *rqd;
 383         void *data;
 384         u64 paddr;
 385         int rq_ppas = pblk->min_write_pgs;
 386         int id = meta_line->id;
 387         int rq_len;
 388         int i, j;
 389         int ret;
 390
 391         rqd = pblk_alloc_rqd(pblk, PBLK_WRITE_INT);
 392
 393         m_ctx = nvm_rq_to_pdu(rqd);
 394         m_ctx->private = meta_line;
 395
 396         rq_len = rq_ppas * geo->csecs;
 397         data = ((void *)emeta->buf) + emeta->mem;
 398
 399         bio = pblk_bio_map_addr(pblk, data, rq_ppas, rq_len,
 400                                         l_mg->emeta_alloc_type, GFP_KERNEL);
 401         if (IS_ERR(bio)) {
 402                 pblk_err(pblk, "failed to map emeta io");
 403                 ret = PTR_ERR(bio);
 404                 goto fail_free_rqd;
 405         }
 406         bio->bi_iter.bi_sector = 0; /* internal bio */
 407         bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
 408         rqd->bio = bio;
 409
 410         ret = pblk_alloc_w_rq(pblk, rqd, rq_ppas, pblk_end_io_write_meta);
 411         if (ret)
 412                 goto fail_free_bio;
 413
 414         for (i = 0; i < rqd->nr_ppas; ) {
 415                 spin_lock(&meta_line->lock);
 416                 paddr = __pblk_alloc_page(pblk, meta_line, rq_ppas);
 417                 spin_unlock(&meta_line->lock);
 418                 for (j = 0; j < rq_ppas; j++, i++, paddr++)
 419                         rqd->ppa_list[i] = addr_to_gen_ppa(pblk, paddr, id);
 420         }
 421
 422         spin_lock(&l_mg->close_lock);
 423         emeta->mem += rq_len;
 424         if (emeta->mem >= lm->emeta_len[0])
 425                 list_del(&meta_line->list);
 426         spin_unlock(&l_mg->close_lock);
 427
 428         pblk_down_page(pblk, rqd->ppa_list, rqd->nr_ppas);
 429
 430         ret = pblk_submit_io(pblk, rqd);
 431         if (ret) {
 432                 pblk_err(pblk, "emeta I/O submission failed: %d\n", ret);
 433                 goto fail_rollback;
 434         }
 435
 436         return NVM_IO_OK;
 437
 438 fail_rollback:
 439         pblk_up_page(pblk, rqd->ppa_list, rqd->nr_ppas);
 440         spin_lock(&l_mg->close_lock);
 441         pblk_dealloc_page(pblk, meta_line, rq_ppas);
 442         list_add(&meta_line->list, &meta_line->list);
 443         spin_unlock(&l_mg->close_lock);
 444 fail_free_bio:
 445         bio_put(bio);
 446 fail_free_rqd:
 447         pblk_free_rqd(pblk, rqd, PBLK_WRITE_INT);
 448         return ret;
 449 }
 450
 451 static inline bool pblk_valid_meta_ppa(struct pblk *pblk,
 452                                        struct pblk_line *meta_line,
 453                                        struct nvm_rq *data_rqd)
 454 {
 455         struct nvm_tgt_dev *dev = pblk->dev;
 456         struct nvm_geo *geo = &dev->geo;
 457         struct pblk_c_ctx *data_c_ctx = nvm_rq_to_pdu(data_rqd);
 458         struct pblk_line *data_line = pblk_line_get_data(pblk);
 459         struct ppa_addr ppa, ppa_opt;
 460         u64 paddr;
 461         int pos_opt;
 462
 463         /* Schedule a metadata I/O that is half the distance from the data I/O
 464          * with regards to the number of LUNs forming the pblk instance. This
 465          * balances LUN conflicts across every I/O.
 466          *
 467          * When the LUN configuration changes (e.g., due to GC), this distance
 468          * can align, which would result on metadata and data I/Os colliding. In
 469          * this case, modify the distance to not be optimal, but move the
 470          * optimal in the right direction.
 471          */
 472         paddr = pblk_lookup_page(pblk, meta_line);
 473         ppa = addr_to_gen_ppa(pblk, paddr, 0);
 474         ppa_opt = addr_to_gen_ppa(pblk, paddr + data_line->meta_distance, 0);
 475         pos_opt = pblk_ppa_to_pos(geo, ppa_opt);
 476
 477         if (test_bit(pos_opt, data_c_ctx->lun_bitmap) ||
 478                                 test_bit(pos_opt, data_line->blk_bitmap))
 479                 return true;
 480
 481         if (unlikely(pblk_ppa_comp(ppa_opt, ppa)))
 482                 data_line->meta_distance--;
 483
 484         return false;
 485 }
 486
 487 static struct pblk_line *pblk_should_submit_meta_io(struct pblk *pblk,
 488                                                     struct nvm_rq *data_rqd)
 489 {
 490         struct pblk_line_meta *lm = &pblk->lm;
 491         struct pblk_line_mgmt *l_mg = &pblk->l_mg;
 492         struct pblk_line *meta_line;
 493
 494         spin_lock(&l_mg->close_lock);
 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                 spin_unlock(&l_mg->close_lock);
 502                 return NULL;
 503         }
 504         spin_unlock(&l_mg->close_lock);
 505
 506         if (!pblk_valid_meta_ppa(pblk, meta_line, data_rqd))
 507                 return NULL;
 508
 509         return meta_line;
 510 }
 511
 512 static int pblk_submit_io_set(struct pblk *pblk, struct nvm_rq *rqd)
 513 {
 514         struct ppa_addr erase_ppa;
 515         struct pblk_line *meta_line;
 516         int err;
 517
 518         pblk_ppa_set_empty(&erase_ppa);
 519
 520         /* Assign lbas to ppas and populate request structure */
 521         err = pblk_setup_w_rq(pblk, rqd, &erase_ppa);
 522         if (err) {
 523                 pblk_err(pblk, "could not setup write request: %d\n", err);
 524                 return NVM_IO_ERR;
 525         }
 526
 527         meta_line = pblk_should_submit_meta_io(pblk, rqd);
 528
 529         /* Submit data write for current data line */
 530         err = pblk_submit_io(pblk, rqd);
 531         if (err) {
 532                 pblk_err(pblk, "data I/O submission failed: %d\n", err);
 533                 return NVM_IO_ERR;
 534         }
 535
 536         if (!pblk_ppa_empty(erase_ppa)) {
 537                 /* Submit erase for next data line */
 538                 if (pblk_blk_erase_async(pblk, erase_ppa)) {
 539                         struct pblk_line *e_line = pblk_line_get_erase(pblk);
 540                         struct nvm_tgt_dev *dev = pblk->dev;
 541                         struct nvm_geo *geo = &dev->geo;
 542                         int bit;
 543
 544                         atomic_inc(&e_line->left_eblks);
 545                         bit = pblk_ppa_to_pos(geo, erase_ppa);
 546                         WARN_ON(!test_and_clear_bit(bit, e_line->erase_bitmap));
 547                 }
 548         }
 549
 550         if (meta_line) {
 551                 /* Submit metadata write for previous data line */
 552                 err = pblk_submit_meta_io(pblk, meta_line);
 553                 if (err) {
 554                         pblk_err(pblk, "metadata I/O submission failed: %d",
 555                                         err);
 556                         return NVM_IO_ERR;
 557                 }
 558         }
 559
 560         return NVM_IO_OK;
 561 }
 562
 563 static void pblk_free_write_rqd(struct pblk *pblk, struct nvm_rq *rqd)
 564 {
 565         struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 566         struct bio *bio = rqd->bio;
 567
 568         if (c_ctx->nr_padded)
 569                 pblk_bio_free_pages(pblk, bio, c_ctx->nr_valid,
 570                                                         c_ctx->nr_padded);
 571 }
 572
 573 static int pblk_submit_write(struct pblk *pblk)
 574 {
 575         struct bio *bio;
 576         struct nvm_rq *rqd;
 577         unsigned int secs_avail, secs_to_sync, secs_to_com;
 578         unsigned int secs_to_flush;
 579         unsigned long pos;
 580         unsigned int resubmit;
 581
 582         spin_lock(&pblk->resubmit_lock);
 583         resubmit = !list_empty(&pblk->resubmit_list);
 584         spin_unlock(&pblk->resubmit_lock);
 585
 586         /* Resubmit failed writes first */
 587         if (resubmit) {
 588                 struct pblk_c_ctx *r_ctx;
 589
 590                 spin_lock(&pblk->resubmit_lock);
 591                 r_ctx = list_first_entry(&pblk->resubmit_list,
 592                                         struct pblk_c_ctx, list);
 593                 list_del(&r_ctx->list);
 594                 spin_unlock(&pblk->resubmit_lock);
 595
 596                 secs_avail = r_ctx->nr_valid;
 597                 pos = r_ctx->sentry;
 598
 599                 pblk_prepare_resubmit(pblk, pos, secs_avail);
 600                 secs_to_sync = pblk_calc_secs_to_sync(pblk, secs_avail,
 601                                 secs_avail);
 602
 603                 kfree(r_ctx);
 604         } else {
 605                 /* If there are no sectors in the cache,
 606                  * flushes (bios without data) will be cleared on
 607                  * the cache threads
 608                  */
 609                 secs_avail = pblk_rb_read_count(&pblk->rwb);
 610                 if (!secs_avail)
 611                         return 1;
 612
 613                 secs_to_flush = pblk_rb_flush_point_count(&pblk->rwb);
 614                 if (!secs_to_flush && secs_avail < pblk->min_write_pgs)
 615                         return 1;
 616
 617                 secs_to_sync = pblk_calc_secs_to_sync(pblk, secs_avail,
 618                                         secs_to_flush);
 619                 if (secs_to_sync > pblk->max_write_pgs) {
 620                         pblk_err(pblk, "bad buffer sync calculation\n");
 621                         return 1;
 622                 }
 623
 624                 secs_to_com = (secs_to_sync > secs_avail) ?
 625                         secs_avail : secs_to_sync;
 626                 pos = pblk_rb_read_commit(&pblk->rwb, secs_to_com);
 627         }
 628
 629         bio = bio_alloc(GFP_KERNEL, secs_to_sync);
 630
 631         bio->bi_iter.bi_sector = 0; /* internal bio */
 632         bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
 633
 634         rqd = pblk_alloc_rqd(pblk, PBLK_WRITE);
 635         rqd->bio = bio;
 636
 637         if (pblk_rb_read_to_bio(&pblk->rwb, rqd, pos, secs_to_sync,
 638                                                                 secs_avail)) {
 639                 pblk_err(pblk, "corrupted write bio\n");
 640                 goto fail_put_bio;
 641         }
 642
 643         if (pblk_submit_io_set(pblk, rqd))
 644                 goto fail_free_bio;
 645
 646 #ifdef CONFIG_NVM_PBLK_DEBUG
 647         atomic_long_add(secs_to_sync, &pblk->sub_writes);
 648 #endif
 649
 650         return 0;
 651
 652 fail_free_bio:
 653         pblk_free_write_rqd(pblk, rqd);
 654 fail_put_bio:
 655         bio_put(bio);
 656         pblk_free_rqd(pblk, rqd, PBLK_WRITE);
 657
 658         return 1;
 659 }
 660
 661 int pblk_write_ts(void *data)
 662 {
 663         struct pblk *pblk = data;
 664
 665         while (!kthread_should_stop()) {
 666                 if (!pblk_submit_write(pblk))
 667                         continue;
 668                 set_current_state(TASK_INTERRUPTIBLE);
 669                 io_schedule();
 670         }
 671
 672         return 0;
 673 }