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) = prandom_u32_max(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 ? prandom_u32_max(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_index(struct sbitmap *sb, int index, 171 unsigned int alloc_hint) 172 { 173 struct sbitmap_word *map = &sb->map[index]; 174 int nr; 175 176 do { 177 nr = __sbitmap_get_word(&map->word, __map_depth(sb, index), 178 alloc_hint, !sb->round_robin); 179 if (nr != -1) 180 break; 181 if (!sbitmap_deferred_clear(map)) 182 break; 183 } while (1); 184 185 return nr; 186 } 187 188 static int __sbitmap_get(struct sbitmap *sb, unsigned int alloc_hint) 189 { 190 unsigned int i, index; 191 int nr = -1; 192 193 index = SB_NR_TO_INDEX(sb, alloc_hint); 194 195 /* 196 * Unless we're doing round robin tag allocation, just use the 197 * alloc_hint to find the right word index. No point in looping 198 * twice in find_next_zero_bit() for that case. 199 */ 200 if (sb->round_robin) 201 alloc_hint = SB_NR_TO_BIT(sb, alloc_hint); 202 else 203 alloc_hint = 0; 204 205 for (i = 0; i < sb->map_nr; i++) { 206 nr = sbitmap_find_bit_in_index(sb, index, alloc_hint); 207 if (nr != -1) { 208 nr += index << sb->shift; 209 break; 210 } 211 212 /* Jump to next index. */ 213 alloc_hint = 0; 214 if (++index >= sb->map_nr) 215 index = 0; 216 } 217 218 return nr; 219 } 220 221 int sbitmap_get(struct sbitmap *sb) 222 { 223 int nr; 224 unsigned int hint, depth; 225 226 if (WARN_ON_ONCE(unlikely(!sb->alloc_hint))) 227 return -1; 228 229 depth = READ_ONCE(sb->depth); 230 hint = update_alloc_hint_before_get(sb, depth); 231 nr = __sbitmap_get(sb, hint); 232 update_alloc_hint_after_get(sb, depth, hint, nr); 233 234 return nr; 235 } 236 EXPORT_SYMBOL_GPL(sbitmap_get); 237 238 static int __sbitmap_get_shallow(struct sbitmap *sb, 239 unsigned int alloc_hint, 240 unsigned long shallow_depth) 241 { 242 unsigned int i, index; 243 int nr = -1; 244 245 index = SB_NR_TO_INDEX(sb, alloc_hint); 246 247 for (i = 0; i < sb->map_nr; i++) { 248 again: 249 nr = __sbitmap_get_word(&sb->map[index].word, 250 min_t(unsigned int, 251 __map_depth(sb, index), 252 shallow_depth), 253 SB_NR_TO_BIT(sb, alloc_hint), true); 254 if (nr != -1) { 255 nr += index << sb->shift; 256 break; 257 } 258 259 if (sbitmap_deferred_clear(&sb->map[index])) 260 goto again; 261 262 /* Jump to next index. */ 263 index++; 264 alloc_hint = index << sb->shift; 265 266 if (index >= sb->map_nr) { 267 index = 0; 268 alloc_hint = 0; 269 } 270 } 271 272 return nr; 273 } 274 275 int sbitmap_get_shallow(struct sbitmap *sb, unsigned long shallow_depth) 276 { 277 int nr; 278 unsigned int hint, depth; 279 280 if (WARN_ON_ONCE(unlikely(!sb->alloc_hint))) 281 return -1; 282 283 depth = READ_ONCE(sb->depth); 284 hint = update_alloc_hint_before_get(sb, depth); 285 nr = __sbitmap_get_shallow(sb, hint, shallow_depth); 286 update_alloc_hint_after_get(sb, depth, hint, nr); 287 288 return nr; 289 } 290 EXPORT_SYMBOL_GPL(sbitmap_get_shallow); 291 292 bool sbitmap_any_bit_set(const struct sbitmap *sb) 293 { 294 unsigned int i; 295 296 for (i = 0; i < sb->map_nr; i++) { 297 if (sb->map[i].word & ~sb->map[i].cleared) 298 return true; 299 } 300 return false; 301 } 302 EXPORT_SYMBOL_GPL(sbitmap_any_bit_set); 303 304 static unsigned int __sbitmap_weight(const struct sbitmap *sb, bool set) 305 { 306 unsigned int i, weight = 0; 307 308 for (i = 0; i < sb->map_nr; i++) { 309 const struct sbitmap_word *word = &sb->map[i]; 310 unsigned int word_depth = __map_depth(sb, i); 311 312 if (set) 313 weight += bitmap_weight(&word->word, word_depth); 314 else 315 weight += bitmap_weight(&word->cleared, word_depth); 316 } 317 return weight; 318 } 319 320 static unsigned int sbitmap_cleared(const struct sbitmap *sb) 321 { 322 return __sbitmap_weight(sb, false); 323 } 324 325 unsigned int sbitmap_weight(const struct sbitmap *sb) 326 { 327 return __sbitmap_weight(sb, true) - sbitmap_cleared(sb); 328 } 329 EXPORT_SYMBOL_GPL(sbitmap_weight); 330 331 void sbitmap_show(struct sbitmap *sb, struct seq_file *m) 332 { 333 seq_printf(m, "depth=%u\n", sb->depth); 334 seq_printf(m, "busy=%u\n", sbitmap_weight(sb)); 335 seq_printf(m, "cleared=%u\n", sbitmap_cleared(sb)); 336 seq_printf(m, "bits_per_word=%u\n", 1U << sb->shift); 337 seq_printf(m, "map_nr=%u\n", sb->map_nr); 338 } 339 EXPORT_SYMBOL_GPL(sbitmap_show); 340 341 static inline void emit_byte(struct seq_file *m, unsigned int offset, u8 byte) 342 { 343 if ((offset & 0xf) == 0) { 344 if (offset != 0) 345 seq_putc(m, '\n'); 346 seq_printf(m, "%08x:", offset); 347 } 348 if ((offset & 0x1) == 0) 349 seq_putc(m, ' '); 350 seq_printf(m, "%02x", byte); 351 } 352 353 void sbitmap_bitmap_show(struct sbitmap *sb, struct seq_file *m) 354 { 355 u8 byte = 0; 356 unsigned int byte_bits = 0; 357 unsigned int offset = 0; 358 int i; 359 360 for (i = 0; i < sb->map_nr; i++) { 361 unsigned long word = READ_ONCE(sb->map[i].word); 362 unsigned long cleared = READ_ONCE(sb->map[i].cleared); 363 unsigned int word_bits = __map_depth(sb, i); 364 365 word &= ~cleared; 366 367 while (word_bits > 0) { 368 unsigned int bits = min(8 - byte_bits, word_bits); 369 370 byte |= (word & (BIT(bits) - 1)) << byte_bits; 371 byte_bits += bits; 372 if (byte_bits == 8) { 373 emit_byte(m, offset, byte); 374 byte = 0; 375 byte_bits = 0; 376 offset++; 377 } 378 word >>= bits; 379 word_bits -= bits; 380 } 381 } 382 if (byte_bits) { 383 emit_byte(m, offset, byte); 384 offset++; 385 } 386 if (offset) 387 seq_putc(m, '\n'); 388 } 389 EXPORT_SYMBOL_GPL(sbitmap_bitmap_show); 390 391 static unsigned int sbq_calc_wake_batch(struct sbitmap_queue *sbq, 392 unsigned int depth) 393 { 394 unsigned int wake_batch; 395 unsigned int shallow_depth; 396 397 /* 398 * For each batch, we wake up one queue. We need to make sure that our 399 * batch size is small enough that the full depth of the bitmap, 400 * potentially limited by a shallow depth, is enough to wake up all of 401 * the queues. 402 * 403 * Each full word of the bitmap has bits_per_word bits, and there might 404 * be a partial word. There are depth / bits_per_word full words and 405 * depth % bits_per_word bits left over. In bitwise arithmetic: 406 * 407 * bits_per_word = 1 << shift 408 * depth / bits_per_word = depth >> shift 409 * depth % bits_per_word = depth & ((1 << shift) - 1) 410 * 411 * Each word can be limited to sbq->min_shallow_depth bits. 412 */ 413 shallow_depth = min(1U << sbq->sb.shift, sbq->min_shallow_depth); 414 depth = ((depth >> sbq->sb.shift) * shallow_depth + 415 min(depth & ((1U << sbq->sb.shift) - 1), shallow_depth)); 416 wake_batch = clamp_t(unsigned int, depth / SBQ_WAIT_QUEUES, 1, 417 SBQ_WAKE_BATCH); 418 419 return wake_batch; 420 } 421 422 int sbitmap_queue_init_node(struct sbitmap_queue *sbq, unsigned int depth, 423 int shift, bool round_robin, gfp_t flags, int node) 424 { 425 int ret; 426 int i; 427 428 ret = sbitmap_init_node(&sbq->sb, depth, shift, flags, node, 429 round_robin, true); 430 if (ret) 431 return ret; 432 433 sbq->min_shallow_depth = UINT_MAX; 434 sbq->wake_batch = sbq_calc_wake_batch(sbq, depth); 435 atomic_set(&sbq->wake_index, 0); 436 atomic_set(&sbq->ws_active, 0); 437 atomic_set(&sbq->completion_cnt, 0); 438 atomic_set(&sbq->wakeup_cnt, 0); 439 440 sbq->ws = kzalloc_node(SBQ_WAIT_QUEUES * sizeof(*sbq->ws), flags, node); 441 if (!sbq->ws) { 442 sbitmap_free(&sbq->sb); 443 return -ENOMEM; 444 } 445 446 for (i = 0; i < SBQ_WAIT_QUEUES; i++) 447 init_waitqueue_head(&sbq->ws[i].wait); 448 449 return 0; 450 } 451 EXPORT_SYMBOL_GPL(sbitmap_queue_init_node); 452 453 static void sbitmap_queue_update_wake_batch(struct sbitmap_queue *sbq, 454 unsigned int depth) 455 { 456 unsigned int wake_batch; 457 458 wake_batch = sbq_calc_wake_batch(sbq, depth); 459 if (sbq->wake_batch != wake_batch) 460 WRITE_ONCE(sbq->wake_batch, wake_batch); 461 } 462 463 void sbitmap_queue_recalculate_wake_batch(struct sbitmap_queue *sbq, 464 unsigned int users) 465 { 466 unsigned int wake_batch; 467 unsigned int min_batch; 468 unsigned int depth = (sbq->sb.depth + users - 1) / users; 469 470 min_batch = sbq->sb.depth >= (4 * SBQ_WAIT_QUEUES) ? 4 : 1; 471 472 wake_batch = clamp_val(depth / SBQ_WAIT_QUEUES, 473 min_batch, SBQ_WAKE_BATCH); 474 475 WRITE_ONCE(sbq->wake_batch, wake_batch); 476 } 477 EXPORT_SYMBOL_GPL(sbitmap_queue_recalculate_wake_batch); 478 479 void sbitmap_queue_resize(struct sbitmap_queue *sbq, unsigned int depth) 480 { 481 sbitmap_queue_update_wake_batch(sbq, depth); 482 sbitmap_resize(&sbq->sb, depth); 483 } 484 EXPORT_SYMBOL_GPL(sbitmap_queue_resize); 485 486 int __sbitmap_queue_get(struct sbitmap_queue *sbq) 487 { 488 return sbitmap_get(&sbq->sb); 489 } 490 EXPORT_SYMBOL_GPL(__sbitmap_queue_get); 491 492 unsigned long __sbitmap_queue_get_batch(struct sbitmap_queue *sbq, int nr_tags, 493 unsigned int *offset) 494 { 495 struct sbitmap *sb = &sbq->sb; 496 unsigned int hint, depth; 497 unsigned long index, nr; 498 int i; 499 500 if (unlikely(sb->round_robin)) 501 return 0; 502 503 depth = READ_ONCE(sb->depth); 504 hint = update_alloc_hint_before_get(sb, depth); 505 506 index = SB_NR_TO_INDEX(sb, hint); 507 508 for (i = 0; i < sb->map_nr; i++) { 509 struct sbitmap_word *map = &sb->map[index]; 510 unsigned long get_mask; 511 unsigned int map_depth = __map_depth(sb, index); 512 513 sbitmap_deferred_clear(map); 514 if (map->word == (1UL << (map_depth - 1)) - 1) 515 goto next; 516 517 nr = find_first_zero_bit(&map->word, map_depth); 518 if (nr + nr_tags <= map_depth) { 519 atomic_long_t *ptr = (atomic_long_t *) &map->word; 520 unsigned long val; 521 522 get_mask = ((1UL << nr_tags) - 1) << nr; 523 val = READ_ONCE(map->word); 524 do { 525 if ((val & ~get_mask) != val) 526 goto next; 527 } while (!atomic_long_try_cmpxchg(ptr, &val, 528 get_mask | val)); 529 get_mask = (get_mask & ~val) >> nr; 530 if (get_mask) { 531 *offset = nr + (index << sb->shift); 532 update_alloc_hint_after_get(sb, depth, hint, 533 *offset + nr_tags - 1); 534 return get_mask; 535 } 536 } 537 next: 538 /* Jump to next index. */ 539 if (++index >= sb->map_nr) 540 index = 0; 541 } 542 543 return 0; 544 } 545 546 int sbitmap_queue_get_shallow(struct sbitmap_queue *sbq, 547 unsigned int shallow_depth) 548 { 549 WARN_ON_ONCE(shallow_depth < sbq->min_shallow_depth); 550 551 return sbitmap_get_shallow(&sbq->sb, shallow_depth); 552 } 553 EXPORT_SYMBOL_GPL(sbitmap_queue_get_shallow); 554 555 void sbitmap_queue_min_shallow_depth(struct sbitmap_queue *sbq, 556 unsigned int min_shallow_depth) 557 { 558 sbq->min_shallow_depth = min_shallow_depth; 559 sbitmap_queue_update_wake_batch(sbq, sbq->sb.depth); 560 } 561 EXPORT_SYMBOL_GPL(sbitmap_queue_min_shallow_depth); 562 563 static struct sbq_wait_state *sbq_wake_ptr(struct sbitmap_queue *sbq) 564 { 565 int i, wake_index; 566 567 if (!atomic_read(&sbq->ws_active)) 568 return NULL; 569 570 wake_index = atomic_read(&sbq->wake_index); 571 for (i = 0; i < SBQ_WAIT_QUEUES; i++) { 572 struct sbq_wait_state *ws = &sbq->ws[wake_index]; 573 574 /* 575 * Advance the index before checking the current queue. 576 * It improves fairness, by ensuring the queue doesn't 577 * need to be fully emptied before trying to wake up 578 * from the next one. 579 */ 580 wake_index = sbq_index_inc(wake_index); 581 582 if (waitqueue_active(&ws->wait)) { 583 if (wake_index != atomic_read(&sbq->wake_index)) 584 atomic_set(&sbq->wake_index, wake_index); 585 return ws; 586 } 587 } 588 589 return NULL; 590 } 591 592 void sbitmap_queue_wake_up(struct sbitmap_queue *sbq, int nr) 593 { 594 unsigned int wake_batch = READ_ONCE(sbq->wake_batch); 595 struct sbq_wait_state *ws = NULL; 596 unsigned int wakeups; 597 598 if (!atomic_read(&sbq->ws_active)) 599 return; 600 601 atomic_add(nr, &sbq->completion_cnt); 602 wakeups = atomic_read(&sbq->wakeup_cnt); 603 604 do { 605 if (atomic_read(&sbq->completion_cnt) - wakeups < wake_batch) 606 return; 607 608 if (!ws) { 609 ws = sbq_wake_ptr(sbq); 610 if (!ws) 611 return; 612 } 613 } while (!atomic_try_cmpxchg(&sbq->wakeup_cnt, 614 &wakeups, wakeups + wake_batch)); 615 616 wake_up_nr(&ws->wait, wake_batch); 617 } 618 EXPORT_SYMBOL_GPL(sbitmap_queue_wake_up); 619 620 static inline void sbitmap_update_cpu_hint(struct sbitmap *sb, int cpu, int tag) 621 { 622 if (likely(!sb->round_robin && tag < sb->depth)) 623 data_race(*per_cpu_ptr(sb->alloc_hint, cpu) = tag); 624 } 625 626 void sbitmap_queue_clear_batch(struct sbitmap_queue *sbq, int offset, 627 int *tags, int nr_tags) 628 { 629 struct sbitmap *sb = &sbq->sb; 630 unsigned long *addr = NULL; 631 unsigned long mask = 0; 632 int i; 633 634 smp_mb__before_atomic(); 635 for (i = 0; i < nr_tags; i++) { 636 const int tag = tags[i] - offset; 637 unsigned long *this_addr; 638 639 /* since we're clearing a batch, skip the deferred map */ 640 this_addr = &sb->map[SB_NR_TO_INDEX(sb, tag)].word; 641 if (!addr) { 642 addr = this_addr; 643 } else if (addr != this_addr) { 644 atomic_long_andnot(mask, (atomic_long_t *) addr); 645 mask = 0; 646 addr = this_addr; 647 } 648 mask |= (1UL << SB_NR_TO_BIT(sb, tag)); 649 } 650 651 if (mask) 652 atomic_long_andnot(mask, (atomic_long_t *) addr); 653 654 smp_mb__after_atomic(); 655 sbitmap_queue_wake_up(sbq, nr_tags); 656 sbitmap_update_cpu_hint(&sbq->sb, raw_smp_processor_id(), 657 tags[nr_tags - 1] - offset); 658 } 659 660 void sbitmap_queue_clear(struct sbitmap_queue *sbq, unsigned int nr, 661 unsigned int cpu) 662 { 663 /* 664 * Once the clear bit is set, the bit may be allocated out. 665 * 666 * Orders READ/WRITE on the associated instance(such as request 667 * of blk_mq) by this bit for avoiding race with re-allocation, 668 * and its pair is the memory barrier implied in __sbitmap_get_word. 669 * 670 * One invariant is that the clear bit has to be zero when the bit 671 * is in use. 672 */ 673 smp_mb__before_atomic(); 674 sbitmap_deferred_clear_bit(&sbq->sb, nr); 675 676 /* 677 * Pairs with the memory barrier in set_current_state() to ensure the 678 * proper ordering of clear_bit_unlock()/waitqueue_active() in the waker 679 * and test_and_set_bit_lock()/prepare_to_wait()/finish_wait() in the 680 * waiter. See the comment on waitqueue_active(). 681 */ 682 smp_mb__after_atomic(); 683 sbitmap_queue_wake_up(sbq, 1); 684 sbitmap_update_cpu_hint(&sbq->sb, cpu, nr); 685 } 686 EXPORT_SYMBOL_GPL(sbitmap_queue_clear); 687 688 void sbitmap_queue_wake_all(struct sbitmap_queue *sbq) 689 { 690 int i, wake_index; 691 692 /* 693 * Pairs with the memory barrier in set_current_state() like in 694 * sbitmap_queue_wake_up(). 695 */ 696 smp_mb(); 697 wake_index = atomic_read(&sbq->wake_index); 698 for (i = 0; i < SBQ_WAIT_QUEUES; i++) { 699 struct sbq_wait_state *ws = &sbq->ws[wake_index]; 700 701 if (waitqueue_active(&ws->wait)) 702 wake_up(&ws->wait); 703 704 wake_index = sbq_index_inc(wake_index); 705 } 706 } 707 EXPORT_SYMBOL_GPL(sbitmap_queue_wake_all); 708 709 void sbitmap_queue_show(struct sbitmap_queue *sbq, struct seq_file *m) 710 { 711 bool first; 712 int i; 713 714 sbitmap_show(&sbq->sb, m); 715 716 seq_puts(m, "alloc_hint={"); 717 first = true; 718 for_each_possible_cpu(i) { 719 if (!first) 720 seq_puts(m, ", "); 721 first = false; 722 seq_printf(m, "%u", *per_cpu_ptr(sbq->sb.alloc_hint, i)); 723 } 724 seq_puts(m, "}\n"); 725 726 seq_printf(m, "wake_batch=%u\n", sbq->wake_batch); 727 seq_printf(m, "wake_index=%d\n", atomic_read(&sbq->wake_index)); 728 seq_printf(m, "ws_active=%d\n", atomic_read(&sbq->ws_active)); 729 730 seq_puts(m, "ws={\n"); 731 for (i = 0; i < SBQ_WAIT_QUEUES; i++) { 732 struct sbq_wait_state *ws = &sbq->ws[i]; 733 seq_printf(m, "\t{.wait=%s},\n", 734 waitqueue_active(&ws->wait) ? "active" : "inactive"); 735 } 736 seq_puts(m, "}\n"); 737 738 seq_printf(m, "round_robin=%d\n", sbq->sb.round_robin); 739 seq_printf(m, "min_shallow_depth=%u\n", sbq->min_shallow_depth); 740 } 741 EXPORT_SYMBOL_GPL(sbitmap_queue_show); 742 743 void sbitmap_add_wait_queue(struct sbitmap_queue *sbq, 744 struct sbq_wait_state *ws, 745 struct sbq_wait *sbq_wait) 746 { 747 if (!sbq_wait->sbq) { 748 sbq_wait->sbq = sbq; 749 atomic_inc(&sbq->ws_active); 750 add_wait_queue(&ws->wait, &sbq_wait->wait); 751 } 752 } 753 EXPORT_SYMBOL_GPL(sbitmap_add_wait_queue); 754 755 void sbitmap_del_wait_queue(struct sbq_wait *sbq_wait) 756 { 757 list_del_init(&sbq_wait->wait.entry); 758 if (sbq_wait->sbq) { 759 atomic_dec(&sbq_wait->sbq->ws_active); 760 sbq_wait->sbq = NULL; 761 } 762 } 763 EXPORT_SYMBOL_GPL(sbitmap_del_wait_queue); 764 765 void sbitmap_prepare_to_wait(struct sbitmap_queue *sbq, 766 struct sbq_wait_state *ws, 767 struct sbq_wait *sbq_wait, int state) 768 { 769 if (!sbq_wait->sbq) { 770 atomic_inc(&sbq->ws_active); 771 sbq_wait->sbq = sbq; 772 } 773 prepare_to_wait_exclusive(&ws->wait, &sbq_wait->wait, state); 774 } 775 EXPORT_SYMBOL_GPL(sbitmap_prepare_to_wait); 776 777 void sbitmap_finish_wait(struct sbitmap_queue *sbq, struct sbq_wait_state *ws, 778 struct sbq_wait *sbq_wait) 779 { 780 finish_wait(&ws->wait, &sbq_wait->wait); 781 if (sbq_wait->sbq) { 782 atomic_dec(&sbq->ws_active); 783 sbq_wait->sbq = NULL; 784 } 785 } 786 EXPORT_SYMBOL_GPL(sbitmap_finish_wait); 787