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