drivers/lightnvm/pblk-gc.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-gc.c - pblk's garbage collector
  16  */
  17
  18 #include "pblk.h"
  19 #include <linux/delay.h>
  20
  21 static void pblk_gc_free_gc_rq(struct pblk_gc_rq *gc_rq)
  22 {
  23         if (gc_rq->data)
  24                 vfree(gc_rq->data);
  25         kfree(gc_rq);
  26 }
  27
  28 static int pblk_gc_write(struct pblk *pblk)
  29 {
  30         struct pblk_gc *gc = &pblk->gc;
  31         struct pblk_gc_rq *gc_rq, *tgc_rq;
  32         LIST_HEAD(w_list);
  33
  34         spin_lock(&gc->w_lock);
  35         if (list_empty(&gc->w_list)) {
  36                 spin_unlock(&gc->w_lock);
  37                 return 1;
  38         }
  39
  40         list_cut_position(&w_list, &gc->w_list, gc->w_list.prev);
  41         gc->w_entries = 0;
  42         spin_unlock(&gc->w_lock);
  43
  44         list_for_each_entry_safe(gc_rq, tgc_rq, &w_list, list) {
  45                 pblk_write_gc_to_cache(pblk, gc_rq);
  46                 list_del(&gc_rq->list);
  47                 kref_put(&gc_rq->line->ref, pblk_line_put);
  48                 pblk_gc_free_gc_rq(gc_rq);
  49         }
  50
  51         return 0;
  52 }
  53
  54 static void pblk_gc_writer_kick(struct pblk_gc *gc)
  55 {
  56         wake_up_process(gc->gc_writer_ts);
  57 }
  58
  59 static void pblk_put_line_back(struct pblk *pblk, struct pblk_line *line)
  60 {
  61         struct pblk_line_mgmt *l_mg = &pblk->l_mg;
  62         struct list_head *move_list;
  63
  64         spin_lock(&line->lock);
  65         WARN_ON(line->state != PBLK_LINESTATE_GC);
  66         line->state = PBLK_LINESTATE_CLOSED;
  67         move_list = pblk_line_gc_list(pblk, line);
  68         spin_unlock(&line->lock);
  69
  70         if (move_list) {
  71                 spin_lock(&l_mg->gc_lock);
  72                 list_add_tail(&line->list, move_list);
  73                 spin_unlock(&l_mg->gc_lock);
  74         }
  75 }
  76
  77 static void pblk_gc_line_ws(struct work_struct *work)
  78 {
  79         struct pblk_line_ws *gc_rq_ws = container_of(work,
  80                                                 struct pblk_line_ws, ws);
  81         struct pblk *pblk = gc_rq_ws->pblk;
  82         struct nvm_tgt_dev *dev = pblk->dev;
  83         struct nvm_geo *geo = &dev->geo;
  84         struct pblk_gc *gc = &pblk->gc;
  85         struct pblk_line *line = gc_rq_ws->line;
  86         struct pblk_gc_rq *gc_rq = gc_rq_ws->priv;
  87         int ret;
  88
  89         up(&gc->gc_sem);
  90
  91         gc_rq->data = vmalloc(gc_rq->nr_secs * geo->csecs);
  92         if (!gc_rq->data) {
  93                 pr_err("pblk: could not GC line:%d (%d/%d)\n",
  94                                         line->id, *line->vsc, gc_rq->nr_secs);
  95                 goto out;
  96         }
  97
  98         /* Read from GC victim block */
  99         ret = pblk_submit_read_gc(pblk, gc_rq);
 100         if (ret) {
 101                 pr_err("pblk: failed GC read in line:%d (err:%d)\n",
 102                                                                 line->id, ret);
 103                 goto out;
 104         }
 105
 106         if (!gc_rq->secs_to_gc)
 107                 goto out;
 108
 109 retry:
 110         spin_lock(&gc->w_lock);
 111         if (gc->w_entries >= PBLK_GC_RQ_QD) {
 112                 spin_unlock(&gc->w_lock);
 113                 pblk_gc_writer_kick(&pblk->gc);
 114                 usleep_range(128, 256);
 115                 goto retry;
 116         }
 117         gc->w_entries++;
 118         list_add_tail(&gc_rq->list, &gc->w_list);
 119         spin_unlock(&gc->w_lock);
 120
 121         pblk_gc_writer_kick(&pblk->gc);
 122
 123         kfree(gc_rq_ws);
 124         return;
 125
 126 out:
 127         pblk_gc_free_gc_rq(gc_rq);
 128         kref_put(&line->ref, pblk_line_put);
 129         kfree(gc_rq_ws);
 130 }
 131
 132 static __le64 *get_lba_list_from_emeta(struct pblk *pblk,
 133                                        struct pblk_line *line)
 134 {
 135         struct line_emeta *emeta_buf;
 136         struct pblk_line_mgmt *l_mg = &pblk->l_mg;
 137         struct pblk_line_meta *lm = &pblk->lm;
 138         unsigned int lba_list_size = lm->emeta_len[2];
 139         __le64 *lba_list;
 140         int ret;
 141
 142         emeta_buf = pblk_malloc(lm->emeta_len[0],
 143                                 l_mg->emeta_alloc_type, GFP_KERNEL);
 144         if (!emeta_buf)
 145                 return NULL;
 146
 147         ret = pblk_line_read_emeta(pblk, line, emeta_buf);
 148         if (ret) {
 149                 pr_err("pblk: line %d read emeta failed (%d)\n",
 150                                 line->id, ret);
 151                 pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
 152                 return NULL;
 153         }
 154
 155         /* If this read fails, it means that emeta is corrupted.
 156          * For now, leave the line untouched.
 157          * TODO: Implement a recovery routine that scans and moves
 158          * all sectors on the line.
 159          */
 160
 161         ret = pblk_recov_check_emeta(pblk, emeta_buf);
 162         if (ret) {
 163                 pr_err("pblk: inconsistent emeta (line %d)\n",
 164                                 line->id);
 165                 pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
 166                 return NULL;
 167         }
 168
 169         lba_list = pblk_malloc(lba_list_size,
 170                                l_mg->emeta_alloc_type, GFP_KERNEL);
 171         if (lba_list)
 172                 memcpy(lba_list, emeta_to_lbas(pblk, emeta_buf), lba_list_size);
 173
 174         pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
 175
 176         return lba_list;
 177 }
 178
 179 static void pblk_gc_line_prepare_ws(struct work_struct *work)
 180 {
 181         struct pblk_line_ws *line_ws = container_of(work, struct pblk_line_ws,
 182                                                                         ws);
 183         struct pblk *pblk = line_ws->pblk;
 184         struct pblk_line *line = line_ws->line;
 185         struct pblk_line_mgmt *l_mg = &pblk->l_mg;
 186         struct pblk_line_meta *lm = &pblk->lm;
 187         struct pblk_gc *gc = &pblk->gc;
 188         struct pblk_line_ws *gc_rq_ws;
 189         struct pblk_gc_rq *gc_rq;
 190         __le64 *lba_list;
 191         unsigned long *invalid_bitmap;
 192         int sec_left, nr_secs, bit;
 193
 194         invalid_bitmap = kmalloc(lm->sec_bitmap_len, GFP_KERNEL);
 195         if (!invalid_bitmap)
 196                 goto fail_free_ws;
 197
 198         if (line->w_err_gc->has_write_err) {
 199                 lba_list = line->w_err_gc->lba_list;
 200                 line->w_err_gc->lba_list = NULL;
 201         } else {
 202                 lba_list = get_lba_list_from_emeta(pblk, line);
 203                 if (!lba_list) {
 204                         pr_err("pblk: could not interpret emeta (line %d)\n",
 205                                         line->id);
 206                         goto fail_free_ws;
 207                 }
 208         }
 209
 210         spin_lock(&line->lock);
 211         bitmap_copy(invalid_bitmap, line->invalid_bitmap, lm->sec_per_line);
 212         sec_left = pblk_line_vsc(line);
 213         spin_unlock(&line->lock);
 214
 215         if (sec_left < 0) {
 216                 pr_err("pblk: corrupted GC line (%d)\n", line->id);
 217                 goto fail_free_lba_list;
 218         }
 219
 220         bit = -1;
 221 next_rq:
 222         gc_rq = kmalloc(sizeof(struct pblk_gc_rq), GFP_KERNEL);
 223         if (!gc_rq)
 224                 goto fail_free_lba_list;
 225
 226         nr_secs = 0;
 227         do {
 228                 bit = find_next_zero_bit(invalid_bitmap, lm->sec_per_line,
 229                                                                 bit + 1);
 230                 if (bit > line->emeta_ssec)
 231                         break;
 232
 233                 gc_rq->paddr_list[nr_secs] = bit;
 234                 gc_rq->lba_list[nr_secs++] = le64_to_cpu(lba_list[bit]);
 235         } while (nr_secs < pblk->max_write_pgs);
 236
 237         if (unlikely(!nr_secs)) {
 238                 kfree(gc_rq);
 239                 goto out;
 240         }
 241
 242         gc_rq->nr_secs = nr_secs;
 243         gc_rq->line = line;
 244
 245         gc_rq_ws = kmalloc(sizeof(struct pblk_line_ws), GFP_KERNEL);
 246         if (!gc_rq_ws)
 247                 goto fail_free_gc_rq;
 248
 249         gc_rq_ws->pblk = pblk;
 250         gc_rq_ws->line = line;
 251         gc_rq_ws->priv = gc_rq;
 252
 253         /* The write GC path can be much slower than the read GC one due to
 254          * the budget imposed by the rate-limiter. Balance in case that we get
 255          * back pressure from the write GC path.
 256          */
 257         while (down_timeout(&gc->gc_sem, msecs_to_jiffies(30000)))
 258                 io_schedule();
 259
 260         kref_get(&line->ref);
 261
 262         INIT_WORK(&gc_rq_ws->ws, pblk_gc_line_ws);
 263         queue_work(gc->gc_line_reader_wq, &gc_rq_ws->ws);
 264
 265         sec_left -= nr_secs;
 266         if (sec_left > 0)
 267                 goto next_rq;
 268
 269 out:
 270         pblk_mfree(lba_list, l_mg->emeta_alloc_type);
 271         kfree(line_ws);
 272         kfree(invalid_bitmap);
 273
 274         kref_put(&line->ref, pblk_line_put);
 275         atomic_dec(&gc->read_inflight_gc);
 276
 277         return;
 278
 279 fail_free_gc_rq:
 280         kfree(gc_rq);
 281 fail_free_lba_list:
 282         pblk_mfree(lba_list, l_mg->emeta_alloc_type);
 283         kfree(invalid_bitmap);
 284 fail_free_ws:
 285         kfree(line_ws);
 286
 287         pblk_put_line_back(pblk, line);
 288         kref_put(&line->ref, pblk_line_put);
 289         atomic_dec(&gc->read_inflight_gc);
 290
 291         pr_err("pblk: Failed to GC line %d\n", line->id);
 292 }
 293
 294 static int pblk_gc_line(struct pblk *pblk, struct pblk_line *line)
 295 {
 296         struct pblk_gc *gc = &pblk->gc;
 297         struct pblk_line_ws *line_ws;
 298
 299         pr_debug("pblk: line '%d' being reclaimed for GC\n", line->id);
 300
 301         line_ws = kmalloc(sizeof(struct pblk_line_ws), GFP_KERNEL);
 302         if (!line_ws)
 303                 return -ENOMEM;
 304
 305         line_ws->pblk = pblk;
 306         line_ws->line = line;
 307
 308         atomic_inc(&gc->pipeline_gc);
 309         INIT_WORK(&line_ws->ws, pblk_gc_line_prepare_ws);
 310         queue_work(gc->gc_reader_wq, &line_ws->ws);
 311
 312         return 0;
 313 }
 314
 315 static void pblk_gc_reader_kick(struct pblk_gc *gc)
 316 {
 317         wake_up_process(gc->gc_reader_ts);
 318 }
 319
 320 static void pblk_gc_kick(struct pblk *pblk)
 321 {
 322         struct pblk_gc *gc = &pblk->gc;
 323
 324         pblk_gc_writer_kick(gc);
 325         pblk_gc_reader_kick(gc);
 326
 327         /* If we're shutting down GC, let's not start it up again */
 328         if (gc->gc_enabled) {
 329                 wake_up_process(gc->gc_ts);
 330                 mod_timer(&gc->gc_timer,
 331                           jiffies + msecs_to_jiffies(GC_TIME_MSECS));
 332         }
 333 }
 334
 335 static int pblk_gc_read(struct pblk *pblk)
 336 {
 337         struct pblk_gc *gc = &pblk->gc;
 338         struct pblk_line *line;
 339
 340         spin_lock(&gc->r_lock);
 341         if (list_empty(&gc->r_list)) {
 342                 spin_unlock(&gc->r_lock);
 343                 return 1;
 344         }
 345
 346         line = list_first_entry(&gc->r_list, struct pblk_line, list);
 347         list_del(&line->list);
 348         spin_unlock(&gc->r_lock);
 349
 350         pblk_gc_kick(pblk);
 351
 352         if (pblk_gc_line(pblk, line))
 353                 pr_err("pblk: failed to GC line %d\n", line->id);
 354
 355         return 0;
 356 }
 357
 358 static struct pblk_line *pblk_gc_get_victim_line(struct pblk *pblk,
 359                                                  struct list_head *group_list)
 360 {
 361         struct pblk_line *line, *victim;
 362         int line_vsc, victim_vsc;
 363
 364         victim = list_first_entry(group_list, struct pblk_line, list);
 365         list_for_each_entry(line, group_list, list) {
 366                 line_vsc = le32_to_cpu(*line->vsc);
 367                 victim_vsc = le32_to_cpu(*victim->vsc);
 368                 if (line_vsc < victim_vsc)
 369                         victim = line;
 370         }
 371
 372         return victim;
 373 }
 374
 375 static bool pblk_gc_should_run(struct pblk_gc *gc, struct pblk_rl *rl)
 376 {
 377         unsigned int nr_blocks_free, nr_blocks_need;
 378         unsigned int werr_lines = atomic_read(&rl->werr_lines);
 379
 380         nr_blocks_need = pblk_rl_high_thrs(rl);
 381         nr_blocks_free = pblk_rl_nr_free_blks(rl);
 382
 383         /* This is not critical, no need to take lock here */
 384         return ((werr_lines > 0) ||
 385                 ((gc->gc_active) && (nr_blocks_need > nr_blocks_free)));
 386 }
 387
 388 void pblk_gc_free_full_lines(struct pblk *pblk)
 389 {
 390         struct pblk_line_mgmt *l_mg = &pblk->l_mg;
 391         struct pblk_gc *gc = &pblk->gc;
 392         struct pblk_line *line;
 393
 394         do {
 395                 spin_lock(&l_mg->gc_lock);
 396                 if (list_empty(&l_mg->gc_full_list)) {
 397                         spin_unlock(&l_mg->gc_lock);
 398                         return;
 399                 }
 400
 401                 line = list_first_entry(&l_mg->gc_full_list,
 402                                                         struct pblk_line, list);
 403
 404                 spin_lock(&line->lock);
 405                 WARN_ON(line->state != PBLK_LINESTATE_CLOSED);
 406                 line->state = PBLK_LINESTATE_GC;
 407                 spin_unlock(&line->lock);
 408
 409                 list_del(&line->list);
 410                 spin_unlock(&l_mg->gc_lock);
 411
 412                 atomic_inc(&gc->pipeline_gc);
 413                 kref_put(&line->ref, pblk_line_put);
 414         } while (1);
 415 }
 416
 417 /*
 418  * Lines with no valid sectors will be returned to the free list immediately. If
 419  * GC is activated - either because the free block count is under the determined
 420  * threshold, or because it is being forced from user space - only lines with a
 421  * high count of invalid sectors will be recycled.
 422  */
 423 static void pblk_gc_run(struct pblk *pblk)
 424 {
 425         struct pblk_line_mgmt *l_mg = &pblk->l_mg;
 426         struct pblk_gc *gc = &pblk->gc;
 427         struct pblk_line *line;
 428         struct list_head *group_list;
 429         bool run_gc;
 430         int read_inflight_gc, gc_group = 0, prev_group = 0;
 431
 432         pblk_gc_free_full_lines(pblk);
 433
 434         run_gc = pblk_gc_should_run(&pblk->gc, &pblk->rl);
 435         if (!run_gc || (atomic_read(&gc->read_inflight_gc) >= PBLK_GC_L_QD))
 436                 return;
 437
 438 next_gc_group:
 439         group_list = l_mg->gc_lists[gc_group++];
 440
 441         do {
 442                 spin_lock(&l_mg->gc_lock);
 443                 if (list_empty(group_list)) {
 444                         spin_unlock(&l_mg->gc_lock);
 445                         break;
 446                 }
 447
 448                 line = pblk_gc_get_victim_line(pblk, group_list);
 449
 450                 spin_lock(&line->lock);
 451                 WARN_ON(line->state != PBLK_LINESTATE_CLOSED);
 452                 line->state = PBLK_LINESTATE_GC;
 453                 spin_unlock(&line->lock);
 454
 455                 list_del(&line->list);
 456                 spin_unlock(&l_mg->gc_lock);
 457
 458                 spin_lock(&gc->r_lock);
 459                 list_add_tail(&line->list, &gc->r_list);
 460                 spin_unlock(&gc->r_lock);
 461
 462                 read_inflight_gc = atomic_inc_return(&gc->read_inflight_gc);
 463                 pblk_gc_reader_kick(gc);
 464
 465                 prev_group = 1;
 466
 467                 /* No need to queue up more GC lines than we can handle */
 468                 run_gc = pblk_gc_should_run(&pblk->gc, &pblk->rl);
 469                 if (!run_gc || read_inflight_gc >= PBLK_GC_L_QD)
 470                         break;
 471         } while (1);
 472
 473         if (!prev_group && pblk->rl.rb_state > gc_group &&
 474                                                 gc_group < PBLK_GC_NR_LISTS)
 475                 goto next_gc_group;
 476 }
 477
 478 static void pblk_gc_timer(struct timer_list *t)
 479 {
 480         struct pblk *pblk = from_timer(pblk, t, gc.gc_timer);
 481
 482         pblk_gc_kick(pblk);
 483 }
 484
 485 static int pblk_gc_ts(void *data)
 486 {
 487         struct pblk *pblk = data;
 488
 489         while (!kthread_should_stop()) {
 490                 pblk_gc_run(pblk);
 491                 set_current_state(TASK_INTERRUPTIBLE);
 492                 io_schedule();
 493         }
 494
 495         return 0;
 496 }
 497
 498 static int pblk_gc_writer_ts(void *data)
 499 {
 500         struct pblk *pblk = data;
 501
 502         while (!kthread_should_stop()) {
 503                 if (!pblk_gc_write(pblk))
 504                         continue;
 505                 set_current_state(TASK_INTERRUPTIBLE);
 506                 io_schedule();
 507         }
 508
 509         return 0;
 510 }
 511
 512 static int pblk_gc_reader_ts(void *data)
 513 {
 514         struct pblk *pblk = data;
 515         struct pblk_gc *gc = &pblk->gc;
 516
 517         while (!kthread_should_stop()) {
 518                 if (!pblk_gc_read(pblk))
 519                         continue;
 520                 set_current_state(TASK_INTERRUPTIBLE);
 521                 io_schedule();
 522         }
 523
 524 #ifdef CONFIG_NVM_DEBUG
 525         pr_info("pblk: flushing gc pipeline, %d lines left\n",
 526                 atomic_read(&gc->pipeline_gc));
 527 #endif
 528
 529         do {
 530                 if (!atomic_read(&gc->pipeline_gc))
 531                         break;
 532
 533                 schedule();
 534         } while (1);
 535
 536         return 0;
 537 }
 538
 539 static void pblk_gc_start(struct pblk *pblk)
 540 {
 541         pblk->gc.gc_active = 1;
 542         pr_debug("pblk: gc start\n");
 543 }
 544
 545 void pblk_gc_should_start(struct pblk *pblk)
 546 {
 547         struct pblk_gc *gc = &pblk->gc;
 548
 549         if (gc->gc_enabled && !gc->gc_active) {
 550                 pblk_gc_start(pblk);
 551                 pblk_gc_kick(pblk);
 552         }
 553 }
 554
 555 void pblk_gc_should_stop(struct pblk *pblk)
 556 {
 557         struct pblk_gc *gc = &pblk->gc;
 558
 559         if (gc->gc_active && !gc->gc_forced)
 560                 gc->gc_active = 0;
 561 }
 562
 563 void pblk_gc_should_kick(struct pblk *pblk)
 564 {
 565         pblk_rl_update_rates(&pblk->rl);
 566 }
 567
 568 void pblk_gc_sysfs_state_show(struct pblk *pblk, int *gc_enabled,
 569                               int *gc_active)
 570 {
 571         struct pblk_gc *gc = &pblk->gc;
 572
 573         spin_lock(&gc->lock);
 574         *gc_enabled = gc->gc_enabled;
 575         *gc_active = gc->gc_active;
 576         spin_unlock(&gc->lock);
 577 }
 578
 579 int pblk_gc_sysfs_force(struct pblk *pblk, int force)
 580 {
 581         struct pblk_gc *gc = &pblk->gc;
 582
 583         if (force < 0 || force > 1)
 584                 return -EINVAL;
 585
 586         spin_lock(&gc->lock);
 587         gc->gc_forced = force;
 588
 589         if (force)
 590                 gc->gc_enabled = 1;
 591         else
 592                 gc->gc_enabled = 0;
 593         spin_unlock(&gc->lock);
 594
 595         pblk_gc_should_start(pblk);
 596
 597         return 0;
 598 }
 599
 600 int pblk_gc_init(struct pblk *pblk)
 601 {
 602         struct pblk_gc *gc = &pblk->gc;
 603         int ret;
 604
 605         gc->gc_ts = kthread_create(pblk_gc_ts, pblk, "pblk-gc-ts");
 606         if (IS_ERR(gc->gc_ts)) {
 607                 pr_err("pblk: could not allocate GC main kthread\n");
 608                 return PTR_ERR(gc->gc_ts);
 609         }
 610
 611         gc->gc_writer_ts = kthread_create(pblk_gc_writer_ts, pblk,
 612                                                         "pblk-gc-writer-ts");
 613         if (IS_ERR(gc->gc_writer_ts)) {
 614                 pr_err("pblk: could not allocate GC writer kthread\n");
 615                 ret = PTR_ERR(gc->gc_writer_ts);
 616                 goto fail_free_main_kthread;
 617         }
 618
 619         gc->gc_reader_ts = kthread_create(pblk_gc_reader_ts, pblk,
 620                                                         "pblk-gc-reader-ts");
 621         if (IS_ERR(gc->gc_reader_ts)) {
 622                 pr_err("pblk: could not allocate GC reader kthread\n");
 623                 ret = PTR_ERR(gc->gc_reader_ts);
 624                 goto fail_free_writer_kthread;
 625         }
 626
 627         timer_setup(&gc->gc_timer, pblk_gc_timer, 0);
 628         mod_timer(&gc->gc_timer, jiffies + msecs_to_jiffies(GC_TIME_MSECS));
 629
 630         gc->gc_active = 0;
 631         gc->gc_forced = 0;
 632         gc->gc_enabled = 1;
 633         gc->w_entries = 0;
 634         atomic_set(&gc->read_inflight_gc, 0);
 635         atomic_set(&gc->pipeline_gc, 0);
 636
 637         /* Workqueue that reads valid sectors from a line and submit them to the
 638          * GC writer to be recycled.
 639          */
 640         gc->gc_line_reader_wq = alloc_workqueue("pblk-gc-line-reader-wq",
 641                         WQ_MEM_RECLAIM | WQ_UNBOUND, PBLK_GC_MAX_READERS);
 642         if (!gc->gc_line_reader_wq) {
 643                 pr_err("pblk: could not allocate GC line reader workqueue\n");
 644                 ret = -ENOMEM;
 645                 goto fail_free_reader_kthread;
 646         }
 647
 648         /* Workqueue that prepare lines for GC */
 649         gc->gc_reader_wq = alloc_workqueue("pblk-gc-line_wq",
 650                                         WQ_MEM_RECLAIM | WQ_UNBOUND, 1);
 651         if (!gc->gc_reader_wq) {
 652                 pr_err("pblk: could not allocate GC reader workqueue\n");
 653                 ret = -ENOMEM;
 654                 goto fail_free_reader_line_wq;
 655         }
 656
 657         spin_lock_init(&gc->lock);
 658         spin_lock_init(&gc->w_lock);
 659         spin_lock_init(&gc->r_lock);
 660
 661         sema_init(&gc->gc_sem, PBLK_GC_RQ_QD);
 662
 663         INIT_LIST_HEAD(&gc->w_list);
 664         INIT_LIST_HEAD(&gc->r_list);
 665
 666         return 0;
 667
 668 fail_free_reader_line_wq:
 669         destroy_workqueue(gc->gc_line_reader_wq);
 670 fail_free_reader_kthread:
 671         kthread_stop(gc->gc_reader_ts);
 672 fail_free_writer_kthread:
 673         kthread_stop(gc->gc_writer_ts);
 674 fail_free_main_kthread:
 675         kthread_stop(gc->gc_ts);
 676
 677         return ret;
 678 }
 679
 680 void pblk_gc_exit(struct pblk *pblk, bool graceful)
 681 {
 682         struct pblk_gc *gc = &pblk->gc;
 683
 684         gc->gc_enabled = 0;
 685         del_timer_sync(&gc->gc_timer);
 686         gc->gc_active = 0;
 687
 688         if (gc->gc_ts)
 689                 kthread_stop(gc->gc_ts);
 690
 691         if (gc->gc_reader_ts)
 692                 kthread_stop(gc->gc_reader_ts);
 693
 694         if (graceful) {
 695                 flush_workqueue(gc->gc_reader_wq);
 696                 flush_workqueue(gc->gc_line_reader_wq);
 697         }
 698
 699         destroy_workqueue(gc->gc_reader_wq);
 700         destroy_workqueue(gc->gc_line_reader_wq);
 701
 702         if (gc->gc_writer_ts)
 703                 kthread_stop(gc->gc_writer_ts);
 704 }