lib/sbitmap.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2016 Facebook
   4  * Copyright (C) 2013-2014 Jens Axboe
   5  */
   6
   7 #include <linux/sched.h>
   8 #include <linux/random.h>
   9 #include <linux/sbitmap.h>
  10 #include <linux/seq_file.h>
  11
  12 static int init_alloc_hint(struct sbitmap *sb, gfp_t flags)
  13 {
  14         unsigned depth = sb->depth;
  15
  16         sb->alloc_hint = alloc_percpu_gfp(unsigned int, flags);
  17         if (!sb->alloc_hint)
  18                 return -ENOMEM;
  19
  20         if (depth && !sb->round_robin) {
  21                 int i;
  22
  23                 for_each_possible_cpu(i)
  24                         *per_cpu_ptr(sb->alloc_hint, i) = get_random_u32_below(depth);
  25         }
  26         return 0;
  27 }
  28
  29 static inline unsigned update_alloc_hint_before_get(struct sbitmap *sb,
  30                                                     unsigned int depth)
  31 {
  32         unsigned hint;
  33
  34         hint = this_cpu_read(*sb->alloc_hint);
  35         if (unlikely(hint >= depth)) {
  36                 hint = depth ? get_random_u32_below(depth) : 0;
  37                 this_cpu_write(*sb->alloc_hint, hint);
  38         }
  39
  40         return hint;
  41 }
  42
  43 static inline void update_alloc_hint_after_get(struct sbitmap *sb,
  44                                                unsigned int depth,
  45                                                unsigned int hint,
  46                                                unsigned int nr)
  47 {
  48         if (nr == -1) {
  49                 /* If the map is full, a hint won't do us much good. */
  50                 this_cpu_write(*sb->alloc_hint, 0);
  51         } else if (nr == hint || unlikely(sb->round_robin)) {
  52                 /* Only update the hint if we used it. */
  53                 hint = nr + 1;
  54                 if (hint >= depth - 1)
  55                         hint = 0;
  56                 this_cpu_write(*sb->alloc_hint, hint);
  57         }
  58 }
  59
  60 /*
  61  * See if we have deferred clears that we can batch move
  62  */
  63 static inline bool sbitmap_deferred_clear(struct sbitmap_word *map)
  64 {
  65         unsigned long mask;
  66
  67         if (!READ_ONCE(map->cleared))
  68                 return false;
  69
  70         /*
  71          * First get a stable cleared mask, setting the old mask to 0.
  72          */
  73         mask = xchg(&map->cleared, 0);
  74
  75         /*
  76          * Now clear the masked bits in our free word
  77          */
  78         atomic_long_andnot(mask, (atomic_long_t *)&map->word);
  79         BUILD_BUG_ON(sizeof(atomic_long_t) != sizeof(map->word));
  80         return true;
  81 }
  82
  83 int sbitmap_init_node(struct sbitmap *sb, unsigned int depth, int shift,
  84                       gfp_t flags, int node, bool round_robin,
  85                       bool alloc_hint)
  86 {
  87         unsigned int bits_per_word;
  88
  89         if (shift < 0)
  90                 shift = sbitmap_calculate_shift(depth);
  91
  92         bits_per_word = 1U << shift;
  93         if (bits_per_word > BITS_PER_LONG)
  94                 return -EINVAL;
  95
  96         sb->shift = shift;
  97         sb->depth = depth;
  98         sb->map_nr = DIV_ROUND_UP(sb->depth, bits_per_word);
  99         sb->round_robin = round_robin;
 100
 101         if (depth == 0) {
 102                 sb->map = NULL;
 103                 return 0;
 104         }
 105
 106         if (alloc_hint) {
 107                 if (init_alloc_hint(sb, flags))
 108                         return -ENOMEM;
 109         } else {
 110                 sb->alloc_hint = NULL;
 111         }
 112
 113         sb->map = kvzalloc_node(sb->map_nr * sizeof(*sb->map), flags, node);
 114         if (!sb->map) {
 115                 free_percpu(sb->alloc_hint);
 116                 return -ENOMEM;
 117         }
 118
 119         return 0;
 120 }
 121 EXPORT_SYMBOL_GPL(sbitmap_init_node);
 122
 123 void sbitmap_resize(struct sbitmap *sb, unsigned int depth)
 124 {
 125         unsigned int bits_per_word = 1U << sb->shift;
 126         unsigned int i;
 127
 128         for (i = 0; i < sb->map_nr; i++)
 129                 sbitmap_deferred_clear(&sb->map[i]);
 130
 131         sb->depth = depth;
 132         sb->map_nr = DIV_ROUND_UP(sb->depth, bits_per_word);
 133 }
 134 EXPORT_SYMBOL_GPL(sbitmap_resize);
 135
 136 static int __sbitmap_get_word(unsigned long *word, unsigned long depth,
 137                               unsigned int hint, bool wrap)
 138 {
 139         int nr;
 140
 141         /* don't wrap if starting from 0 */
 142         wrap = wrap && hint;
 143
 144         while (1) {
 145                 nr = find_next_zero_bit(word, depth, hint);
 146                 if (unlikely(nr >= depth)) {
 147                         /*
 148                          * We started with an offset, and we didn't reset the
 149                          * offset to 0 in a failure case, so start from 0 to
 150                          * exhaust the map.
 151                          */
 152                         if (hint && wrap) {
 153                                 hint = 0;
 154                                 continue;
 155                         }
 156                         return -1;
 157                 }
 158
 159                 if (!test_and_set_bit_lock(nr, word))
 160                         break;
 161
 162                 hint = nr + 1;
 163                 if (hint >= depth - 1)
 164                         hint = 0;
 165         }
 166
 167         return nr;
 168 }
 169
 170 static int sbitmap_find_bit_in_word(struct sbitmap_word *map,
 171                                     unsigned int depth,
 172                                     unsigned int alloc_hint,
 173                                     bool wrap)
 174 {
 175         int nr;
 176
 177         do {
 178                 nr = __sbitmap_get_word(&map->word, depth,
 179                                         alloc_hint, wrap);
 180                 if (nr != -1)
 181                         break;
 182                 if (!sbitmap_deferred_clear(map))
 183                         break;
 184         } while (1);
 185
 186         return nr;
 187 }
 188
 189 static int sbitmap_find_bit(struct sbitmap *sb,
 190                             unsigned int depth,
 191                             unsigned int index,
 192                             unsigned int alloc_hint,
 193                             bool wrap)
 194 {
 195         unsigned int i;
 196         int nr = -1;
 197
 198         for (i = 0; i < sb->map_nr; i++) {
 199                 nr = sbitmap_find_bit_in_word(&sb->map[index],
 200                                               min_t(unsigned int,
 201                                                     __map_depth(sb, index),
 202                                                     depth),
 203                                               alloc_hint, wrap);
 204
 205                 if (nr != -1) {
 206                         nr += index << sb->shift;
 207                         break;
 208                 }
 209
 210                 /* Jump to next index. */
 211                 alloc_hint = 0;
 212                 if (++index >= sb->map_nr)
 213                         index = 0;
 214         }
 215
 216         return nr;
 217 }
 218
 219 static int __sbitmap_get(struct sbitmap *sb, unsigned int alloc_hint)
 220 {
 221         unsigned int index;
 222
 223         index = SB_NR_TO_INDEX(sb, alloc_hint);
 224
 225         /*
 226          * Unless we're doing round robin tag allocation, just use the
 227          * alloc_hint to find the right word index. No point in looping
 228          * twice in find_next_zero_bit() for that case.
 229          */
 230         if (sb->round_robin)
 231                 alloc_hint = SB_NR_TO_BIT(sb, alloc_hint);
 232         else
 233                 alloc_hint = 0;
 234
 235         return sbitmap_find_bit(sb, UINT_MAX, index, alloc_hint,
 236                                 !sb->round_robin);
 237 }
 238
 239 int sbitmap_get(struct sbitmap *sb)
 240 {
 241         int nr;
 242         unsigned int hint, depth;
 243
 244         if (WARN_ON_ONCE(unlikely(!sb->alloc_hint)))
 245                 return -1;
 246
 247         depth = READ_ONCE(sb->depth);
 248         hint = update_alloc_hint_before_get(sb, depth);
 249         nr = __sbitmap_get(sb, hint);
 250         update_alloc_hint_after_get(sb, depth, hint, nr);
 251
 252         return nr;
 253 }
 254 EXPORT_SYMBOL_GPL(sbitmap_get);
 255
 256 static int __sbitmap_get_shallow(struct sbitmap *sb,
 257                                  unsigned int alloc_hint,
 258                                  unsigned long shallow_depth)
 259 {
 260         unsigned int index;
 261
 262         index = SB_NR_TO_INDEX(sb, alloc_hint);
 263         alloc_hint = SB_NR_TO_BIT(sb, alloc_hint);
 264
 265         return sbitmap_find_bit(sb, shallow_depth, index, alloc_hint, true);
 266 }
 267
 268 int sbitmap_get_shallow(struct sbitmap *sb, unsigned long shallow_depth)
 269 {
 270         int nr;
 271         unsigned int hint, depth;
 272
 273         if (WARN_ON_ONCE(unlikely(!sb->alloc_hint)))
 274                 return -1;
 275
 276         depth = READ_ONCE(sb->depth);
 277         hint = update_alloc_hint_before_get(sb, depth);
 278         nr = __sbitmap_get_shallow(sb, hint, shallow_depth);
 279         update_alloc_hint_after_get(sb, depth, hint, nr);
 280
 281         return nr;
 282 }
 283 EXPORT_SYMBOL_GPL(sbitmap_get_shallow);
 284
 285 bool sbitmap_any_bit_set(const struct sbitmap *sb)
 286 {
 287         unsigned int i;
 288
 289         for (i = 0; i < sb->map_nr; i++) {
 290                 if (sb->map[i].word & ~sb->map[i].cleared)
 291                         return true;
 292         }
 293         return false;
 294 }
 295 EXPORT_SYMBOL_GPL(sbitmap_any_bit_set);
 296
 297 static unsigned int __sbitmap_weight(const struct sbitmap *sb, bool set)
 298 {
 299         unsigned int i, weight = 0;
 300
 301         for (i = 0; i < sb->map_nr; i++) {
 302                 const struct sbitmap_word *word = &sb->map[i];
 303                 unsigned int word_depth = __map_depth(sb, i);
 304
 305                 if (set)
 306                         weight += bitmap_weight(&word->word, word_depth);
 307                 else
 308                         weight += bitmap_weight(&word->cleared, word_depth);
 309         }
 310         return weight;
 311 }
 312
 313 static unsigned int sbitmap_cleared(const struct sbitmap *sb)
 314 {
 315         return __sbitmap_weight(sb, false);
 316 }
 317
 318 unsigned int sbitmap_weight(const struct sbitmap *sb)
 319 {
 320         return __sbitmap_weight(sb, true) - sbitmap_cleared(sb);
 321 }
 322 EXPORT_SYMBOL_GPL(sbitmap_weight);
 323
 324 void sbitmap_show(struct sbitmap *sb, struct seq_file *m)
 325 {
 326         seq_printf(m, "depth=%u\n", sb->depth);
 327         seq_printf(m, "busy=%u\n", sbitmap_weight(sb));
 328         seq_printf(m, "cleared=%u\n", sbitmap_cleared(sb));
 329         seq_printf(m, "bits_per_word=%u\n", 1U << sb->shift);
 330         seq_printf(m, "map_nr=%u\n", sb->map_nr);
 331 }
 332 EXPORT_SYMBOL_GPL(sbitmap_show);
 333
 334 static inline void emit_byte(struct seq_file *m, unsigned int offset, u8 byte)
 335 {
 336         if ((offset & 0xf) == 0) {
 337                 if (offset != 0)
 338                         seq_putc(m, '\n');
 339                 seq_printf(m, "%08x:", offset);
 340         }
 341         if ((offset & 0x1) == 0)
 342                 seq_putc(m, ' ');
 343         seq_printf(m, "%02x", byte);
 344 }
 345
 346 void sbitmap_bitmap_show(struct sbitmap *sb, struct seq_file *m)
 347 {
 348         u8 byte = 0;
 349         unsigned int byte_bits = 0;
 350         unsigned int offset = 0;
 351         int i;
 352
 353         for (i = 0; i < sb->map_nr; i++) {
 354                 unsigned long word = READ_ONCE(sb->map[i].word);
 355                 unsigned long cleared = READ_ONCE(sb->map[i].cleared);
 356                 unsigned int word_bits = __map_depth(sb, i);
 357
 358                 word &= ~cleared;
 359
 360                 while (word_bits > 0) {
 361                         unsigned int bits = min(8 - byte_bits, word_bits);
 362
 363                         byte |= (word & (BIT(bits) - 1)) << byte_bits;
 364                         byte_bits += bits;
 365                         if (byte_bits == 8) {
 366                                 emit_byte(m, offset, byte);
 367                                 byte = 0;
 368                                 byte_bits = 0;
 369                                 offset++;
 370                         }
 371                         word >>= bits;
 372                         word_bits -= bits;
 373                 }
 374         }
 375         if (byte_bits) {
 376                 emit_byte(m, offset, byte);
 377                 offset++;
 378         }
 379         if (offset)
 380                 seq_putc(m, '\n');
 381 }
 382 EXPORT_SYMBOL_GPL(sbitmap_bitmap_show);
 383
 384 static unsigned int sbq_calc_wake_batch(struct sbitmap_queue *sbq,
 385                                         unsigned int depth)
 386 {
 387         unsigned int wake_batch;
 388         unsigned int shallow_depth;
 389
 390         /*
 391          * Each full word of the bitmap has bits_per_word bits, and there might
 392          * be a partial word. There are depth / bits_per_word full words and
 393          * depth % bits_per_word bits left over. In bitwise arithmetic:
 394          *
 395          * bits_per_word = 1 << shift
 396          * depth / bits_per_word = depth >> shift
 397          * depth % bits_per_word = depth & ((1 << shift) - 1)
 398          *
 399          * Each word can be limited to sbq->min_shallow_depth bits.
 400          */
 401         shallow_depth = min(1U << sbq->sb.shift, sbq->min_shallow_depth);
 402         depth = ((depth >> sbq->sb.shift) * shallow_depth +
 403                  min(depth & ((1U << sbq->sb.shift) - 1), shallow_depth));
 404         wake_batch = clamp_t(unsigned int, depth / SBQ_WAIT_QUEUES, 1,
 405                              SBQ_WAKE_BATCH);
 406
 407         return wake_batch;
 408 }
 409
 410 int sbitmap_queue_init_node(struct sbitmap_queue *sbq, unsigned int depth,
 411                             int shift, bool round_robin, gfp_t flags, int node)
 412 {
 413         int ret;
 414         int i;
 415
 416         ret = sbitmap_init_node(&sbq->sb, depth, shift, flags, node,
 417                                 round_robin, true);
 418         if (ret)
 419                 return ret;
 420
 421         sbq->min_shallow_depth = UINT_MAX;
 422         sbq->wake_batch = sbq_calc_wake_batch(sbq, depth);
 423         atomic_set(&sbq->wake_index, 0);
 424         atomic_set(&sbq->ws_active, 0);
 425         atomic_set(&sbq->completion_cnt, 0);
 426         atomic_set(&sbq->wakeup_cnt, 0);
 427
 428         sbq->ws = kzalloc_node(SBQ_WAIT_QUEUES * sizeof(*sbq->ws), flags, node);
 429         if (!sbq->ws) {
 430                 sbitmap_free(&sbq->sb);
 431                 return -ENOMEM;
 432         }
 433
 434         for (i = 0; i < SBQ_WAIT_QUEUES; i++)
 435                 init_waitqueue_head(&sbq->ws[i].wait);
 436
 437         return 0;
 438 }
 439 EXPORT_SYMBOL_GPL(sbitmap_queue_init_node);
 440
 441 static void sbitmap_queue_update_wake_batch(struct sbitmap_queue *sbq,
 442                                             unsigned int depth)
 443 {
 444         unsigned int wake_batch;
 445
 446         wake_batch = sbq_calc_wake_batch(sbq, depth);
 447         if (sbq->wake_batch != wake_batch)
 448                 WRITE_ONCE(sbq->wake_batch, wake_batch);
 449 }
 450
 451 void sbitmap_queue_recalculate_wake_batch(struct sbitmap_queue *sbq,
 452                                             unsigned int users)
 453 {
 454         unsigned int wake_batch;
 455         unsigned int depth = (sbq->sb.depth + users - 1) / users;
 456
 457         wake_batch = clamp_val(depth / SBQ_WAIT_QUEUES,
 458                         1, SBQ_WAKE_BATCH);
 459
 460         WRITE_ONCE(sbq->wake_batch, wake_batch);
 461 }
 462 EXPORT_SYMBOL_GPL(sbitmap_queue_recalculate_wake_batch);
 463
 464 void sbitmap_queue_resize(struct sbitmap_queue *sbq, unsigned int depth)
 465 {
 466         sbitmap_queue_update_wake_batch(sbq, depth);
 467         sbitmap_resize(&sbq->sb, depth);
 468 }
 469 EXPORT_SYMBOL_GPL(sbitmap_queue_resize);
 470
 471 int __sbitmap_queue_get(struct sbitmap_queue *sbq)
 472 {
 473         return sbitmap_get(&sbq->sb);
 474 }
 475 EXPORT_SYMBOL_GPL(__sbitmap_queue_get);
 476
 477 unsigned long __sbitmap_queue_get_batch(struct sbitmap_queue *sbq, int nr_tags,
 478                                         unsigned int *offset)
 479 {
 480         struct sbitmap *sb = &sbq->sb;
 481         unsigned int hint, depth;
 482         unsigned long index, nr;
 483         int i;
 484
 485         if (unlikely(sb->round_robin))
 486                 return 0;
 487
 488         depth = READ_ONCE(sb->depth);
 489         hint = update_alloc_hint_before_get(sb, depth);
 490
 491         index = SB_NR_TO_INDEX(sb, hint);
 492
 493         for (i = 0; i < sb->map_nr; i++) {
 494                 struct sbitmap_word *map = &sb->map[index];
 495                 unsigned long get_mask;
 496                 unsigned int map_depth = __map_depth(sb, index);
 497
 498                 sbitmap_deferred_clear(map);
 499                 if (map->word == (1UL << (map_depth - 1)) - 1)
 500                         goto next;
 501
 502                 nr = find_first_zero_bit(&map->word, map_depth);
 503                 if (nr + nr_tags <= map_depth) {
 504                         atomic_long_t *ptr = (atomic_long_t *) &map->word;
 505                         unsigned long val;
 506
 507                         get_mask = ((1UL << nr_tags) - 1) << nr;
 508                         val = READ_ONCE(map->word);
 509                         while (!atomic_long_try_cmpxchg(ptr, &val,
 510                                                           get_mask | val))
 511                                 ;
 512                         get_mask = (get_mask & ~val) >> nr;
 513                         if (get_mask) {
 514                                 *offset = nr + (index << sb->shift);
 515                                 update_alloc_hint_after_get(sb, depth, hint,
 516                                                         *offset + nr_tags - 1);
 517                                 return get_mask;
 518                         }
 519                 }
 520 next:
 521                 /* Jump to next index. */
 522                 if (++index >= sb->map_nr)
 523                         index = 0;
 524         }
 525
 526         return 0;
 527 }
 528
 529 int sbitmap_queue_get_shallow(struct sbitmap_queue *sbq,
 530                               unsigned int shallow_depth)
 531 {
 532         WARN_ON_ONCE(shallow_depth < sbq->min_shallow_depth);
 533
 534         return sbitmap_get_shallow(&sbq->sb, shallow_depth);
 535 }
 536 EXPORT_SYMBOL_GPL(sbitmap_queue_get_shallow);
 537
 538 void sbitmap_queue_min_shallow_depth(struct sbitmap_queue *sbq,
 539                                      unsigned int min_shallow_depth)
 540 {
 541         sbq->min_shallow_depth = min_shallow_depth;
 542         sbitmap_queue_update_wake_batch(sbq, sbq->sb.depth);
 543 }
 544 EXPORT_SYMBOL_GPL(sbitmap_queue_min_shallow_depth);
 545
 546 static void __sbitmap_queue_wake_up(struct sbitmap_queue *sbq, int nr)
 547 {
 548         int i, wake_index, woken;
 549
 550         if (!atomic_read(&sbq->ws_active))
 551                 return;
 552
 553         wake_index = atomic_read(&sbq->wake_index);
 554         for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
 555                 struct sbq_wait_state *ws = &sbq->ws[wake_index];
 556
 557                 /*
 558                  * Advance the index before checking the current queue.
 559                  * It improves fairness, by ensuring the queue doesn't
 560                  * need to be fully emptied before trying to wake up
 561                  * from the next one.
 562                  */
 563                 wake_index = sbq_index_inc(wake_index);
 564
 565                 if (waitqueue_active(&ws->wait)) {
 566                         woken = wake_up_nr(&ws->wait, nr);
 567                         if (woken == nr)
 568                                 break;
 569                         nr -= woken;
 570                 }
 571         }
 572
 573         if (wake_index != atomic_read(&sbq->wake_index))
 574                 atomic_set(&sbq->wake_index, wake_index);
 575 }
 576
 577 void sbitmap_queue_wake_up(struct sbitmap_queue *sbq, int nr)
 578 {
 579         unsigned int wake_batch = READ_ONCE(sbq->wake_batch);
 580         unsigned int wakeups;
 581
 582         if (!atomic_read(&sbq->ws_active))
 583                 return;
 584
 585         atomic_add(nr, &sbq->completion_cnt);
 586         wakeups = atomic_read(&sbq->wakeup_cnt);
 587
 588         do {
 589                 if (atomic_read(&sbq->completion_cnt) - wakeups < wake_batch)
 590                         return;
 591         } while (!atomic_try_cmpxchg(&sbq->wakeup_cnt,
 592                                      &wakeups, wakeups + wake_batch));
 593
 594         __sbitmap_queue_wake_up(sbq, wake_batch);
 595 }
 596 EXPORT_SYMBOL_GPL(sbitmap_queue_wake_up);
 597
 598 static inline void sbitmap_update_cpu_hint(struct sbitmap *sb, int cpu, int tag)
 599 {
 600         if (likely(!sb->round_robin && tag < sb->depth))
 601                 data_race(*per_cpu_ptr(sb->alloc_hint, cpu) = tag);
 602 }
 603
 604 void sbitmap_queue_clear_batch(struct sbitmap_queue *sbq, int offset,
 605                                 int *tags, int nr_tags)
 606 {
 607         struct sbitmap *sb = &sbq->sb;
 608         unsigned long *addr = NULL;
 609         unsigned long mask = 0;
 610         int i;
 611
 612         smp_mb__before_atomic();
 613         for (i = 0; i < nr_tags; i++) {
 614                 const int tag = tags[i] - offset;
 615                 unsigned long *this_addr;
 616
 617                 /* since we're clearing a batch, skip the deferred map */
 618                 this_addr = &sb->map[SB_NR_TO_INDEX(sb, tag)].word;
 619                 if (!addr) {
 620                         addr = this_addr;
 621                 } else if (addr != this_addr) {
 622                         atomic_long_andnot(mask, (atomic_long_t *) addr);
 623                         mask = 0;
 624                         addr = this_addr;
 625                 }
 626                 mask |= (1UL << SB_NR_TO_BIT(sb, tag));
 627         }
 628
 629         if (mask)
 630                 atomic_long_andnot(mask, (atomic_long_t *) addr);
 631
 632         smp_mb__after_atomic();
 633         sbitmap_queue_wake_up(sbq, nr_tags);
 634         sbitmap_update_cpu_hint(&sbq->sb, raw_smp_processor_id(),
 635                                         tags[nr_tags - 1] - offset);
 636 }
 637
 638 void sbitmap_queue_clear(struct sbitmap_queue *sbq, unsigned int nr,
 639                          unsigned int cpu)
 640 {
 641         /*
 642          * Once the clear bit is set, the bit may be allocated out.
 643          *
 644          * Orders READ/WRITE on the associated instance(such as request
 645          * of blk_mq) by this bit for avoiding race with re-allocation,
 646          * and its pair is the memory barrier implied in __sbitmap_get_word.
 647          *
 648          * One invariant is that the clear bit has to be zero when the bit
 649          * is in use.
 650          */
 651         smp_mb__before_atomic();
 652         sbitmap_deferred_clear_bit(&sbq->sb, nr);
 653
 654         /*
 655          * Pairs with the memory barrier in set_current_state() to ensure the
 656          * proper ordering of clear_bit_unlock()/waitqueue_active() in the waker
 657          * and test_and_set_bit_lock()/prepare_to_wait()/finish_wait() in the
 658          * waiter. See the comment on waitqueue_active().
 659          */
 660         smp_mb__after_atomic();
 661         sbitmap_queue_wake_up(sbq, 1);
 662         sbitmap_update_cpu_hint(&sbq->sb, cpu, nr);
 663 }
 664 EXPORT_SYMBOL_GPL(sbitmap_queue_clear);
 665
 666 void sbitmap_queue_wake_all(struct sbitmap_queue *sbq)
 667 {
 668         int i, wake_index;
 669
 670         /*
 671          * Pairs with the memory barrier in set_current_state() like in
 672          * sbitmap_queue_wake_up().
 673          */
 674         smp_mb();
 675         wake_index = atomic_read(&sbq->wake_index);
 676         for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
 677                 struct sbq_wait_state *ws = &sbq->ws[wake_index];
 678
 679                 if (waitqueue_active(&ws->wait))
 680                         wake_up(&ws->wait);
 681
 682                 wake_index = sbq_index_inc(wake_index);
 683         }
 684 }
 685 EXPORT_SYMBOL_GPL(sbitmap_queue_wake_all);
 686
 687 void sbitmap_queue_show(struct sbitmap_queue *sbq, struct seq_file *m)
 688 {
 689         bool first;
 690         int i;
 691
 692         sbitmap_show(&sbq->sb, m);
 693
 694         seq_puts(m, "alloc_hint={");
 695         first = true;
 696         for_each_possible_cpu(i) {
 697                 if (!first)
 698                         seq_puts(m, ", ");
 699                 first = false;
 700                 seq_printf(m, "%u", *per_cpu_ptr(sbq->sb.alloc_hint, i));
 701         }
 702         seq_puts(m, "}\n");
 703
 704         seq_printf(m, "wake_batch=%u\n", sbq->wake_batch);
 705         seq_printf(m, "wake_index=%d\n", atomic_read(&sbq->wake_index));
 706         seq_printf(m, "ws_active=%d\n", atomic_read(&sbq->ws_active));
 707
 708         seq_puts(m, "ws={\n");
 709         for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
 710                 struct sbq_wait_state *ws = &sbq->ws[i];
 711                 seq_printf(m, "\t{.wait=%s},\n",
 712                            waitqueue_active(&ws->wait) ? "active" : "inactive");
 713         }
 714         seq_puts(m, "}\n");
 715
 716         seq_printf(m, "round_robin=%d\n", sbq->sb.round_robin);
 717         seq_printf(m, "min_shallow_depth=%u\n", sbq->min_shallow_depth);
 718 }
 719 EXPORT_SYMBOL_GPL(sbitmap_queue_show);
 720
 721 void sbitmap_add_wait_queue(struct sbitmap_queue *sbq,
 722                             struct sbq_wait_state *ws,
 723                             struct sbq_wait *sbq_wait)
 724 {
 725         if (!sbq_wait->sbq) {
 726                 sbq_wait->sbq = sbq;
 727                 atomic_inc(&sbq->ws_active);
 728                 add_wait_queue(&ws->wait, &sbq_wait->wait);
 729         }
 730 }
 731 EXPORT_SYMBOL_GPL(sbitmap_add_wait_queue);
 732
 733 void sbitmap_del_wait_queue(struct sbq_wait *sbq_wait)
 734 {
 735         list_del_init(&sbq_wait->wait.entry);
 736         if (sbq_wait->sbq) {
 737                 atomic_dec(&sbq_wait->sbq->ws_active);
 738                 sbq_wait->sbq = NULL;
 739         }
 740 }
 741 EXPORT_SYMBOL_GPL(sbitmap_del_wait_queue);
 742
 743 void sbitmap_prepare_to_wait(struct sbitmap_queue *sbq,
 744                              struct sbq_wait_state *ws,
 745                              struct sbq_wait *sbq_wait, int state)
 746 {
 747         if (!sbq_wait->sbq) {
 748                 atomic_inc(&sbq->ws_active);
 749                 sbq_wait->sbq = sbq;
 750         }
 751         prepare_to_wait_exclusive(&ws->wait, &sbq_wait->wait, state);
 752 }
 753 EXPORT_SYMBOL_GPL(sbitmap_prepare_to_wait);
 754
 755 void sbitmap_finish_wait(struct sbitmap_queue *sbq, struct sbq_wait_state *ws,
 756                          struct sbq_wait *sbq_wait)
 757 {
 758         finish_wait(&ws->wait, &sbq_wait->wait);
 759         if (sbq_wait->sbq) {
 760                 atomic_dec(&sbq->ws_active);
 761                 sbq_wait->sbq = NULL;
 762         }
 763 }
 764 EXPORT_SYMBOL_GPL(sbitmap_finish_wait);