root/drivers/lightnvm/pblk-write.c

DEFINITIONS

1. pblk_end_w_bio
2. pblk_end_queued_w_bio
3. pblk_complete_write
4. pblk_map_remaining
5. pblk_prepare_resubmit
6. pblk_queue_resubmit
7. pblk_submit_rec
8. pblk_end_w_fail
9. pblk_end_io_write
10. pblk_end_io_write_meta
11. pblk_alloc_w_rq
12. pblk_setup_w_rq
13. pblk_calc_secs_to_sync
14. pblk_submit_meta_io
15. pblk_valid_meta_ppa
16. pblk_should_submit_meta_io
17. pblk_submit_io_set
18. pblk_free_write_rqd
19. pblk_submit_write
20. pblk_write_ts

   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         pblk_write_kick(pblk);
 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         } else {
 261                 if (trace_pblk_chunk_state_enabled())
 262                         pblk_check_chunk_state_update(pblk, rqd);
 263 #ifdef CONFIG_NVM_PBLK_DEBUG
 264                 WARN_ONCE(rqd->bio->bi_status, "pblk: corrupted write error\n");
 265 #endif
 266         }
 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         struct ppa_addr *ppa_list = nvm_rq_to_ppa_list(rqd);
 279         int sync;
 280 
 281         pblk_up_chunk(pblk, ppa_list[0]);
 282 
 283         if (rqd->error) {
 284                 pblk_log_write_err(pblk, rqd);
 285                 pblk_err(pblk, "metadata I/O failed. Line %d\n", line->id);
 286                 line->w_err_gc->has_write_err = 1;
 287         } else {
 288                 if (trace_pblk_chunk_state_enabled())
 289                         pblk_check_chunk_state_update(pblk, rqd);
 290         }
 291 
 292         sync = atomic_add_return(rqd->nr_ppas, &emeta->sync);
 293         if (sync == emeta->nr_entries)
 294                 pblk_gen_run_ws(pblk, line, NULL, pblk_line_close_ws,
 295                                                 GFP_ATOMIC, pblk->close_wq);
 296 
 297         pblk_free_rqd(pblk, rqd, PBLK_WRITE_INT);
 298 
 299         atomic_dec(&pblk->inflight_io);
 300 }
 301 
 302 static int pblk_alloc_w_rq(struct pblk *pblk, struct nvm_rq *rqd,
 303                            unsigned int nr_secs, nvm_end_io_fn(*end_io))
 304 {
 305         /* Setup write request */
 306         rqd->opcode = NVM_OP_PWRITE;
 307         rqd->nr_ppas = nr_secs;
 308         rqd->is_seq = 1;
 309         rqd->private = pblk;
 310         rqd->end_io = end_io;
 311 
 312         return pblk_alloc_rqd_meta(pblk, rqd);
 313 }
 314 
 315 static int pblk_setup_w_rq(struct pblk *pblk, struct nvm_rq *rqd,
 316                            struct ppa_addr *erase_ppa)
 317 {
 318         struct pblk_line_meta *lm = &pblk->lm;
 319         struct pblk_line *e_line = pblk_line_get_erase(pblk);
 320         struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 321         unsigned int valid = c_ctx->nr_valid;
 322         unsigned int padded = c_ctx->nr_padded;
 323         unsigned int nr_secs = valid + padded;
 324         unsigned long *lun_bitmap;
 325         int ret;
 326 
 327         lun_bitmap = kzalloc(lm->lun_bitmap_len, GFP_KERNEL);
 328         if (!lun_bitmap)
 329                 return -ENOMEM;
 330         c_ctx->lun_bitmap = lun_bitmap;
 331 
 332         ret = pblk_alloc_w_rq(pblk, rqd, nr_secs, pblk_end_io_write);
 333         if (ret) {
 334                 kfree(lun_bitmap);
 335                 return ret;
 336         }
 337 
 338         if (likely(!e_line || !atomic_read(&e_line->left_eblks)))
 339                 ret = pblk_map_rq(pblk, rqd, c_ctx->sentry, lun_bitmap,
 340                                                         valid, 0);
 341         else
 342                 ret = pblk_map_erase_rq(pblk, rqd, c_ctx->sentry, lun_bitmap,
 343                                                         valid, erase_ppa);
 344 
 345         return ret;
 346 }
 347 
 348 static int pblk_calc_secs_to_sync(struct pblk *pblk, unsigned int secs_avail,
 349                                   unsigned int secs_to_flush)
 350 {
 351         int secs_to_sync;
 352 
 353         secs_to_sync = pblk_calc_secs(pblk, secs_avail, secs_to_flush, true);
 354 
 355 #ifdef CONFIG_NVM_PBLK_DEBUG
 356         if ((!secs_to_sync && secs_to_flush)
 357                         || (secs_to_sync < 0)
 358                         || (secs_to_sync > secs_avail && !secs_to_flush)) {
 359                 pblk_err(pblk, "bad sector calculation (a:%d,s:%d,f:%d)\n",
 360                                 secs_avail, secs_to_sync, secs_to_flush);
 361         }
 362 #endif
 363 
 364         return secs_to_sync;
 365 }
 366 
 367 int pblk_submit_meta_io(struct pblk *pblk, struct pblk_line *meta_line)
 368 {
 369         struct nvm_tgt_dev *dev = pblk->dev;
 370         struct nvm_geo *geo = &dev->geo;
 371         struct pblk_line_mgmt *l_mg = &pblk->l_mg;
 372         struct pblk_line_meta *lm = &pblk->lm;
 373         struct pblk_emeta *emeta = meta_line->emeta;
 374         struct ppa_addr *ppa_list;
 375         struct pblk_g_ctx *m_ctx;
 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         ret = pblk_alloc_w_rq(pblk, rqd, rq_ppas, pblk_end_io_write_meta);
 394         if (ret)
 395                 goto fail_free_rqd;
 396 
 397         ppa_list = nvm_rq_to_ppa_list(rqd);
 398         for (i = 0; i < rqd->nr_ppas; ) {
 399                 spin_lock(&meta_line->lock);
 400                 paddr = __pblk_alloc_page(pblk, meta_line, rq_ppas);
 401                 spin_unlock(&meta_line->lock);
 402                 for (j = 0; j < rq_ppas; j++, i++, paddr++)
 403                         ppa_list[i] = addr_to_gen_ppa(pblk, paddr, id);
 404         }
 405 
 406         spin_lock(&l_mg->close_lock);
 407         emeta->mem += rq_len;
 408         if (emeta->mem >= lm->emeta_len[0])
 409                 list_del(&meta_line->list);
 410         spin_unlock(&l_mg->close_lock);
 411 
 412         pblk_down_chunk(pblk, ppa_list[0]);
 413 
 414         ret = pblk_submit_io(pblk, rqd, data);
 415         if (ret) {
 416                 pblk_err(pblk, "emeta I/O submission failed: %d\n", ret);
 417                 goto fail_rollback;
 418         }
 419 
 420         return NVM_IO_OK;
 421 
 422 fail_rollback:
 423         pblk_up_chunk(pblk, ppa_list[0]);
 424         spin_lock(&l_mg->close_lock);
 425         pblk_dealloc_page(pblk, meta_line, rq_ppas);
 426         list_add(&meta_line->list, &meta_line->list);
 427         spin_unlock(&l_mg->close_lock);
 428 fail_free_rqd:
 429         pblk_free_rqd(pblk, rqd, PBLK_WRITE_INT);
 430         return ret;
 431 }
 432 
 433 static inline bool pblk_valid_meta_ppa(struct pblk *pblk,
 434                                        struct pblk_line *meta_line,
 435                                        struct nvm_rq *data_rqd)
 436 {
 437         struct nvm_tgt_dev *dev = pblk->dev;
 438         struct nvm_geo *geo = &dev->geo;
 439         struct pblk_c_ctx *data_c_ctx = nvm_rq_to_pdu(data_rqd);
 440         struct pblk_line *data_line = pblk_line_get_data(pblk);
 441         struct ppa_addr ppa, ppa_opt;
 442         u64 paddr;
 443         int pos_opt;
 444 
 445         /* Schedule a metadata I/O that is half the distance from the data I/O
 446          * with regards to the number of LUNs forming the pblk instance. This
 447          * balances LUN conflicts across every I/O.
 448          *
 449          * When the LUN configuration changes (e.g., due to GC), this distance
 450          * can align, which would result on metadata and data I/Os colliding. In
 451          * this case, modify the distance to not be optimal, but move the
 452          * optimal in the right direction.
 453          */
 454         paddr = pblk_lookup_page(pblk, meta_line);
 455         ppa = addr_to_gen_ppa(pblk, paddr, 0);
 456         ppa_opt = addr_to_gen_ppa(pblk, paddr + data_line->meta_distance, 0);
 457         pos_opt = pblk_ppa_to_pos(geo, ppa_opt);
 458 
 459         if (test_bit(pos_opt, data_c_ctx->lun_bitmap) ||
 460                                 test_bit(pos_opt, data_line->blk_bitmap))
 461                 return true;
 462 
 463         if (unlikely(pblk_ppa_comp(ppa_opt, ppa)))
 464                 data_line->meta_distance--;
 465 
 466         return false;
 467 }
 468 
 469 static struct pblk_line *pblk_should_submit_meta_io(struct pblk *pblk,
 470                                                     struct nvm_rq *data_rqd)
 471 {
 472         struct pblk_line_meta *lm = &pblk->lm;
 473         struct pblk_line_mgmt *l_mg = &pblk->l_mg;
 474         struct pblk_line *meta_line;
 475 
 476         spin_lock(&l_mg->close_lock);
 477         if (list_empty(&l_mg->emeta_list)) {
 478                 spin_unlock(&l_mg->close_lock);
 479                 return NULL;
 480         }
 481         meta_line = list_first_entry(&l_mg->emeta_list, struct pblk_line, list);
 482         if (meta_line->emeta->mem >= lm->emeta_len[0]) {
 483                 spin_unlock(&l_mg->close_lock);
 484                 return NULL;
 485         }
 486         spin_unlock(&l_mg->close_lock);
 487 
 488         if (!pblk_valid_meta_ppa(pblk, meta_line, data_rqd))
 489                 return NULL;
 490 
 491         return meta_line;
 492 }
 493 
 494 static int pblk_submit_io_set(struct pblk *pblk, struct nvm_rq *rqd)
 495 {
 496         struct ppa_addr erase_ppa;
 497         struct pblk_line *meta_line;
 498         int err;
 499 
 500         pblk_ppa_set_empty(&erase_ppa);
 501 
 502         /* Assign lbas to ppas and populate request structure */
 503         err = pblk_setup_w_rq(pblk, rqd, &erase_ppa);
 504         if (err) {
 505                 pblk_err(pblk, "could not setup write request: %d\n", err);
 506                 return NVM_IO_ERR;
 507         }
 508 
 509         meta_line = pblk_should_submit_meta_io(pblk, rqd);
 510 
 511         /* Submit data write for current data line */
 512         err = pblk_submit_io(pblk, rqd, NULL);
 513         if (err) {
 514                 pblk_err(pblk, "data I/O submission failed: %d\n", err);
 515                 return NVM_IO_ERR;
 516         }
 517 
 518         if (!pblk_ppa_empty(erase_ppa)) {
 519                 /* Submit erase for next data line */
 520                 if (pblk_blk_erase_async(pblk, erase_ppa)) {
 521                         struct pblk_line *e_line = pblk_line_get_erase(pblk);
 522                         struct nvm_tgt_dev *dev = pblk->dev;
 523                         struct nvm_geo *geo = &dev->geo;
 524                         int bit;
 525 
 526                         atomic_inc(&e_line->left_eblks);
 527                         bit = pblk_ppa_to_pos(geo, erase_ppa);
 528                         WARN_ON(!test_and_clear_bit(bit, e_line->erase_bitmap));
 529                 }
 530         }
 531 
 532         if (meta_line) {
 533                 /* Submit metadata write for previous data line */
 534                 err = pblk_submit_meta_io(pblk, meta_line);
 535                 if (err) {
 536                         pblk_err(pblk, "metadata I/O submission failed: %d",
 537                                         err);
 538                         return NVM_IO_ERR;
 539                 }
 540         }
 541 
 542         return NVM_IO_OK;
 543 }
 544 
 545 static void pblk_free_write_rqd(struct pblk *pblk, struct nvm_rq *rqd)
 546 {
 547         struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 548         struct bio *bio = rqd->bio;
 549 
 550         if (c_ctx->nr_padded)
 551                 pblk_bio_free_pages(pblk, bio, c_ctx->nr_valid,
 552                                                         c_ctx->nr_padded);
 553 }
 554 
 555 static int pblk_submit_write(struct pblk *pblk, int *secs_left)
 556 {
 557         struct bio *bio;
 558         struct nvm_rq *rqd;
 559         unsigned int secs_avail, secs_to_sync, secs_to_com;
 560         unsigned int secs_to_flush, packed_meta_pgs;
 561         unsigned long pos;
 562         unsigned int resubmit;
 563 
 564         *secs_left = 0;
 565 
 566         spin_lock(&pblk->resubmit_lock);
 567         resubmit = !list_empty(&pblk->resubmit_list);
 568         spin_unlock(&pblk->resubmit_lock);
 569 
 570         /* Resubmit failed writes first */
 571         if (resubmit) {
 572                 struct pblk_c_ctx *r_ctx;
 573 
 574                 spin_lock(&pblk->resubmit_lock);
 575                 r_ctx = list_first_entry(&pblk->resubmit_list,
 576                                         struct pblk_c_ctx, list);
 577                 list_del(&r_ctx->list);
 578                 spin_unlock(&pblk->resubmit_lock);
 579 
 580                 secs_avail = r_ctx->nr_valid;
 581                 pos = r_ctx->sentry;
 582 
 583                 pblk_prepare_resubmit(pblk, pos, secs_avail);
 584                 secs_to_sync = pblk_calc_secs_to_sync(pblk, secs_avail,
 585                                 secs_avail);
 586 
 587                 kfree(r_ctx);
 588         } else {
 589                 /* If there are no sectors in the cache,
 590                  * flushes (bios without data) will be cleared on
 591                  * the cache threads
 592                  */
 593                 secs_avail = pblk_rb_read_count(&pblk->rwb);
 594                 if (!secs_avail)
 595                         return 0;
 596 
 597                 secs_to_flush = pblk_rb_flush_point_count(&pblk->rwb);
 598                 if (!secs_to_flush && secs_avail < pblk->min_write_pgs_data)
 599                         return 0;
 600 
 601                 secs_to_sync = pblk_calc_secs_to_sync(pblk, secs_avail,
 602                                         secs_to_flush);
 603                 if (secs_to_sync > pblk->max_write_pgs) {
 604                         pblk_err(pblk, "bad buffer sync calculation\n");
 605                         return 0;
 606                 }
 607 
 608                 secs_to_com = (secs_to_sync > secs_avail) ?
 609                         secs_avail : secs_to_sync;
 610                 pos = pblk_rb_read_commit(&pblk->rwb, secs_to_com);
 611         }
 612 
 613         packed_meta_pgs = (pblk->min_write_pgs - pblk->min_write_pgs_data);
 614         bio = bio_alloc(GFP_KERNEL, secs_to_sync + packed_meta_pgs);
 615 
 616         bio->bi_iter.bi_sector = 0; /* internal bio */
 617         bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
 618 
 619         rqd = pblk_alloc_rqd(pblk, PBLK_WRITE);
 620         rqd->bio = bio;
 621 
 622         if (pblk_rb_read_to_bio(&pblk->rwb, rqd, pos, secs_to_sync,
 623                                                                 secs_avail)) {
 624                 pblk_err(pblk, "corrupted write bio\n");
 625                 goto fail_put_bio;
 626         }
 627 
 628         if (pblk_submit_io_set(pblk, rqd))
 629                 goto fail_free_bio;
 630 
 631 #ifdef CONFIG_NVM_PBLK_DEBUG
 632         atomic_long_add(secs_to_sync, &pblk->sub_writes);
 633 #endif
 634 
 635         *secs_left = 1;
 636         return 0;
 637 
 638 fail_free_bio:
 639         pblk_free_write_rqd(pblk, rqd);
 640 fail_put_bio:
 641         bio_put(bio);
 642         pblk_free_rqd(pblk, rqd, PBLK_WRITE);
 643 
 644         return -EINTR;
 645 }
 646 
 647 int pblk_write_ts(void *data)
 648 {
 649         struct pblk *pblk = data;
 650         int secs_left;
 651         int write_failure = 0;
 652 
 653         while (!kthread_should_stop()) {
 654                 if (!write_failure) {
 655                         write_failure = pblk_submit_write(pblk, &secs_left);
 656 
 657                         if (secs_left)
 658                                 continue;
 659                 }
 660                 set_current_state(TASK_INTERRUPTIBLE);
 661                 io_schedule();
 662         }
 663 
 664         return 0;
 665 }