block/blk-mq-debugfs.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2017 Facebook
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/blkdev.h>
   8 #include <linux/debugfs.h>
   9
  10 #include <linux/blk-mq.h>
  11 #include "blk.h"
  12 #include "blk-mq.h"
  13 #include "blk-mq-debugfs.h"
  14 #include "blk-mq-sched.h"
  15 #include "blk-mq-tag.h"
  16 #include "blk-rq-qos.h"
  17
  18 static void print_stat(struct seq_file *m, struct blk_rq_stat *stat)
  19 {
  20         if (stat->nr_samples) {
  21                 seq_printf(m, "samples=%d, mean=%llu, min=%llu, max=%llu",
  22                            stat->nr_samples, stat->mean, stat->min, stat->max);
  23         } else {
  24                 seq_puts(m, "samples=0");
  25         }
  26 }
  27
  28 static int queue_poll_stat_show(void *data, struct seq_file *m)
  29 {
  30         struct request_queue *q = data;
  31         int bucket;
  32
  33         if (!q->poll_stat)
  34                 return 0;
  35
  36         for (bucket = 0; bucket < (BLK_MQ_POLL_STATS_BKTS / 2); bucket++) {
  37                 seq_printf(m, "read  (%d Bytes): ", 1 << (9 + bucket));
  38                 print_stat(m, &q->poll_stat[2 * bucket]);
  39                 seq_puts(m, "\n");
  40
  41                 seq_printf(m, "write (%d Bytes): ",  1 << (9 + bucket));
  42                 print_stat(m, &q->poll_stat[2 * bucket + 1]);
  43                 seq_puts(m, "\n");
  44         }
  45         return 0;
  46 }
  47
  48 static void *queue_requeue_list_start(struct seq_file *m, loff_t *pos)
  49         __acquires(&q->requeue_lock)
  50 {
  51         struct request_queue *q = m->private;
  52
  53         spin_lock_irq(&q->requeue_lock);
  54         return seq_list_start(&q->requeue_list, *pos);
  55 }
  56
  57 static void *queue_requeue_list_next(struct seq_file *m, void *v, loff_t *pos)
  58 {
  59         struct request_queue *q = m->private;
  60
  61         return seq_list_next(v, &q->requeue_list, pos);
  62 }
  63
  64 static void queue_requeue_list_stop(struct seq_file *m, void *v)
  65         __releases(&q->requeue_lock)
  66 {
  67         struct request_queue *q = m->private;
  68
  69         spin_unlock_irq(&q->requeue_lock);
  70 }
  71
  72 static const struct seq_operations queue_requeue_list_seq_ops = {
  73         .start  = queue_requeue_list_start,
  74         .next   = queue_requeue_list_next,
  75         .stop   = queue_requeue_list_stop,
  76         .show   = blk_mq_debugfs_rq_show,
  77 };
  78
  79 static int blk_flags_show(struct seq_file *m, const unsigned long flags,
  80                           const char *const *flag_name, int flag_name_count)
  81 {
  82         bool sep = false;
  83         int i;
  84
  85         for (i = 0; i < sizeof(flags) * BITS_PER_BYTE; i++) {
  86                 if (!(flags & BIT(i)))
  87                         continue;
  88                 if (sep)
  89                         seq_puts(m, "|");
  90                 sep = true;
  91                 if (i < flag_name_count && flag_name[i])
  92                         seq_puts(m, flag_name[i]);
  93                 else
  94                         seq_printf(m, "%d", i);
  95         }
  96         return 0;
  97 }
  98
  99 static int queue_pm_only_show(void *data, struct seq_file *m)
 100 {
 101         struct request_queue *q = data;
 102
 103         seq_printf(m, "%d\n", atomic_read(&q->pm_only));
 104         return 0;
 105 }
 106
 107 #define QUEUE_FLAG_NAME(name) [QUEUE_FLAG_##name] = #name
 108 static const char *const blk_queue_flag_name[] = {
 109         QUEUE_FLAG_NAME(STOPPED),
 110         QUEUE_FLAG_NAME(DYING),
 111         QUEUE_FLAG_NAME(NOMERGES),
 112         QUEUE_FLAG_NAME(SAME_COMP),
 113         QUEUE_FLAG_NAME(FAIL_IO),
 114         QUEUE_FLAG_NAME(NONROT),
 115         QUEUE_FLAG_NAME(IO_STAT),
 116         QUEUE_FLAG_NAME(DISCARD),
 117         QUEUE_FLAG_NAME(NOXMERGES),
 118         QUEUE_FLAG_NAME(ADD_RANDOM),
 119         QUEUE_FLAG_NAME(SECERASE),
 120         QUEUE_FLAG_NAME(SAME_FORCE),
 121         QUEUE_FLAG_NAME(DEAD),
 122         QUEUE_FLAG_NAME(INIT_DONE),
 123         QUEUE_FLAG_NAME(STABLE_WRITES),
 124         QUEUE_FLAG_NAME(POLL),
 125         QUEUE_FLAG_NAME(WC),
 126         QUEUE_FLAG_NAME(FUA),
 127         QUEUE_FLAG_NAME(DAX),
 128         QUEUE_FLAG_NAME(STATS),
 129         QUEUE_FLAG_NAME(REGISTERED),
 130         QUEUE_FLAG_NAME(QUIESCED),
 131         QUEUE_FLAG_NAME(PCI_P2PDMA),
 132         QUEUE_FLAG_NAME(ZONE_RESETALL),
 133         QUEUE_FLAG_NAME(RQ_ALLOC_TIME),
 134         QUEUE_FLAG_NAME(HCTX_ACTIVE),
 135         QUEUE_FLAG_NAME(NOWAIT),
 136 };
 137 #undef QUEUE_FLAG_NAME
 138
 139 static int queue_state_show(void *data, struct seq_file *m)
 140 {
 141         struct request_queue *q = data;
 142
 143         blk_flags_show(m, q->queue_flags, blk_queue_flag_name,
 144                        ARRAY_SIZE(blk_queue_flag_name));
 145         seq_puts(m, "\n");
 146         return 0;
 147 }
 148
 149 static ssize_t queue_state_write(void *data, const char __user *buf,
 150                                  size_t count, loff_t *ppos)
 151 {
 152         struct request_queue *q = data;
 153         char opbuf[16] = { }, *op;
 154
 155         /*
 156          * The "state" attribute is removed after blk_cleanup_queue() has called
 157          * blk_mq_free_queue(). Return if QUEUE_FLAG_DEAD has been set to avoid
 158          * triggering a use-after-free.
 159          */
 160         if (blk_queue_dead(q))
 161                 return -ENOENT;
 162
 163         if (count >= sizeof(opbuf)) {
 164                 pr_err("%s: operation too long\n", __func__);
 165                 goto inval;
 166         }
 167
 168         if (copy_from_user(opbuf, buf, count))
 169                 return -EFAULT;
 170         op = strstrip(opbuf);
 171         if (strcmp(op, "run") == 0) {
 172                 blk_mq_run_hw_queues(q, true);
 173         } else if (strcmp(op, "start") == 0) {
 174                 blk_mq_start_stopped_hw_queues(q, true);
 175         } else if (strcmp(op, "kick") == 0) {
 176                 blk_mq_kick_requeue_list(q);
 177         } else {
 178                 pr_err("%s: unsupported operation '%s'\n", __func__, op);
 179 inval:
 180                 pr_err("%s: use 'run', 'start' or 'kick'\n", __func__);
 181                 return -EINVAL;
 182         }
 183         return count;
 184 }
 185
 186 static const struct blk_mq_debugfs_attr blk_mq_debugfs_queue_attrs[] = {
 187         { "poll_stat", 0400, queue_poll_stat_show },
 188         { "requeue_list", 0400, .seq_ops = &queue_requeue_list_seq_ops },
 189         { "pm_only", 0600, queue_pm_only_show, NULL },
 190         { "state", 0600, queue_state_show, queue_state_write },
 191         { "zone_wlock", 0400, queue_zone_wlock_show, NULL },
 192         { },
 193 };
 194
 195 #define HCTX_STATE_NAME(name) [BLK_MQ_S_##name] = #name
 196 static const char *const hctx_state_name[] = {
 197         HCTX_STATE_NAME(STOPPED),
 198         HCTX_STATE_NAME(TAG_ACTIVE),
 199         HCTX_STATE_NAME(SCHED_RESTART),
 200         HCTX_STATE_NAME(INACTIVE),
 201 };
 202 #undef HCTX_STATE_NAME
 203
 204 static int hctx_state_show(void *data, struct seq_file *m)
 205 {
 206         struct blk_mq_hw_ctx *hctx = data;
 207
 208         blk_flags_show(m, hctx->state, hctx_state_name,
 209                        ARRAY_SIZE(hctx_state_name));
 210         seq_puts(m, "\n");
 211         return 0;
 212 }
 213
 214 #define BLK_TAG_ALLOC_NAME(name) [BLK_TAG_ALLOC_##name] = #name
 215 static const char *const alloc_policy_name[] = {
 216         BLK_TAG_ALLOC_NAME(FIFO),
 217         BLK_TAG_ALLOC_NAME(RR),
 218 };
 219 #undef BLK_TAG_ALLOC_NAME
 220
 221 #define HCTX_FLAG_NAME(name) [ilog2(BLK_MQ_F_##name)] = #name
 222 static const char *const hctx_flag_name[] = {
 223         HCTX_FLAG_NAME(SHOULD_MERGE),
 224         HCTX_FLAG_NAME(TAG_QUEUE_SHARED),
 225         HCTX_FLAG_NAME(BLOCKING),
 226         HCTX_FLAG_NAME(NO_SCHED),
 227         HCTX_FLAG_NAME(STACKING),
 228         HCTX_FLAG_NAME(TAG_HCTX_SHARED),
 229 };
 230 #undef HCTX_FLAG_NAME
 231
 232 static int hctx_flags_show(void *data, struct seq_file *m)
 233 {
 234         struct blk_mq_hw_ctx *hctx = data;
 235         const int alloc_policy = BLK_MQ_FLAG_TO_ALLOC_POLICY(hctx->flags);
 236
 237         seq_puts(m, "alloc_policy=");
 238         if (alloc_policy < ARRAY_SIZE(alloc_policy_name) &&
 239             alloc_policy_name[alloc_policy])
 240                 seq_puts(m, alloc_policy_name[alloc_policy]);
 241         else
 242                 seq_printf(m, "%d", alloc_policy);
 243         seq_puts(m, " ");
 244         blk_flags_show(m,
 245                        hctx->flags ^ BLK_ALLOC_POLICY_TO_MQ_FLAG(alloc_policy),
 246                        hctx_flag_name, ARRAY_SIZE(hctx_flag_name));
 247         seq_puts(m, "\n");
 248         return 0;
 249 }
 250
 251 #define CMD_FLAG_NAME(name) [__REQ_##name] = #name
 252 static const char *const cmd_flag_name[] = {
 253         CMD_FLAG_NAME(FAILFAST_DEV),
 254         CMD_FLAG_NAME(FAILFAST_TRANSPORT),
 255         CMD_FLAG_NAME(FAILFAST_DRIVER),
 256         CMD_FLAG_NAME(SYNC),
 257         CMD_FLAG_NAME(META),
 258         CMD_FLAG_NAME(PRIO),
 259         CMD_FLAG_NAME(NOMERGE),
 260         CMD_FLAG_NAME(IDLE),
 261         CMD_FLAG_NAME(INTEGRITY),
 262         CMD_FLAG_NAME(FUA),
 263         CMD_FLAG_NAME(PREFLUSH),
 264         CMD_FLAG_NAME(RAHEAD),
 265         CMD_FLAG_NAME(BACKGROUND),
 266         CMD_FLAG_NAME(NOWAIT),
 267         CMD_FLAG_NAME(NOUNMAP),
 268         CMD_FLAG_NAME(POLLED),
 269 };
 270 #undef CMD_FLAG_NAME
 271
 272 #define RQF_NAME(name) [ilog2((__force u32)RQF_##name)] = #name
 273 static const char *const rqf_name[] = {
 274         RQF_NAME(STARTED),
 275         RQF_NAME(SOFTBARRIER),
 276         RQF_NAME(FLUSH_SEQ),
 277         RQF_NAME(MIXED_MERGE),
 278         RQF_NAME(MQ_INFLIGHT),
 279         RQF_NAME(DONTPREP),
 280         RQF_NAME(FAILED),
 281         RQF_NAME(QUIET),
 282         RQF_NAME(ELVPRIV),
 283         RQF_NAME(IO_STAT),
 284         RQF_NAME(PM),
 285         RQF_NAME(HASHED),
 286         RQF_NAME(STATS),
 287         RQF_NAME(SPECIAL_PAYLOAD),
 288         RQF_NAME(ZONE_WRITE_LOCKED),
 289         RQF_NAME(MQ_POLL_SLEPT),
 290         RQF_NAME(ELV),
 291 };
 292 #undef RQF_NAME
 293
 294 static const char *const blk_mq_rq_state_name_array[] = {
 295         [MQ_RQ_IDLE]            = "idle",
 296         [MQ_RQ_IN_FLIGHT]       = "in_flight",
 297         [MQ_RQ_COMPLETE]        = "complete",
 298 };
 299
 300 static const char *blk_mq_rq_state_name(enum mq_rq_state rq_state)
 301 {
 302         if (WARN_ON_ONCE((unsigned int)rq_state >=
 303                          ARRAY_SIZE(blk_mq_rq_state_name_array)))
 304                 return "(?)";
 305         return blk_mq_rq_state_name_array[rq_state];
 306 }
 307
 308 int __blk_mq_debugfs_rq_show(struct seq_file *m, struct request *rq)
 309 {
 310         const struct blk_mq_ops *const mq_ops = rq->q->mq_ops;
 311         const unsigned int op = req_op(rq);
 312         const char *op_str = blk_op_str(op);
 313
 314         seq_printf(m, "%p {.op=", rq);
 315         if (strcmp(op_str, "UNKNOWN") == 0)
 316                 seq_printf(m, "%u", op);
 317         else
 318                 seq_printf(m, "%s", op_str);
 319         seq_puts(m, ", .cmd_flags=");
 320         blk_flags_show(m, rq->cmd_flags & ~REQ_OP_MASK, cmd_flag_name,
 321                        ARRAY_SIZE(cmd_flag_name));
 322         seq_puts(m, ", .rq_flags=");
 323         blk_flags_show(m, (__force unsigned int)rq->rq_flags, rqf_name,
 324                        ARRAY_SIZE(rqf_name));
 325         seq_printf(m, ", .state=%s", blk_mq_rq_state_name(blk_mq_rq_state(rq)));
 326         seq_printf(m, ", .tag=%d, .internal_tag=%d", rq->tag,
 327                    rq->internal_tag);
 328         if (mq_ops->show_rq)
 329                 mq_ops->show_rq(m, rq);
 330         seq_puts(m, "}\n");
 331         return 0;
 332 }
 333 EXPORT_SYMBOL_GPL(__blk_mq_debugfs_rq_show);
 334
 335 int blk_mq_debugfs_rq_show(struct seq_file *m, void *v)
 336 {
 337         return __blk_mq_debugfs_rq_show(m, list_entry_rq(v));
 338 }
 339 EXPORT_SYMBOL_GPL(blk_mq_debugfs_rq_show);
 340
 341 static void *hctx_dispatch_start(struct seq_file *m, loff_t *pos)
 342         __acquires(&hctx->lock)
 343 {
 344         struct blk_mq_hw_ctx *hctx = m->private;
 345
 346         spin_lock(&hctx->lock);
 347         return seq_list_start(&hctx->dispatch, *pos);
 348 }
 349
 350 static void *hctx_dispatch_next(struct seq_file *m, void *v, loff_t *pos)
 351 {
 352         struct blk_mq_hw_ctx *hctx = m->private;
 353
 354         return seq_list_next(v, &hctx->dispatch, pos);
 355 }
 356
 357 static void hctx_dispatch_stop(struct seq_file *m, void *v)
 358         __releases(&hctx->lock)
 359 {
 360         struct blk_mq_hw_ctx *hctx = m->private;
 361
 362         spin_unlock(&hctx->lock);
 363 }
 364
 365 static const struct seq_operations hctx_dispatch_seq_ops = {
 366         .start  = hctx_dispatch_start,
 367         .next   = hctx_dispatch_next,
 368         .stop   = hctx_dispatch_stop,
 369         .show   = blk_mq_debugfs_rq_show,
 370 };
 371
 372 struct show_busy_params {
 373         struct seq_file         *m;
 374         struct blk_mq_hw_ctx    *hctx;
 375 };
 376
 377 /*
 378  * Note: the state of a request may change while this function is in progress,
 379  * e.g. due to a concurrent blk_mq_finish_request() call. Returns true to
 380  * keep iterating requests.
 381  */
 382 static bool hctx_show_busy_rq(struct request *rq, void *data, bool reserved)
 383 {
 384         const struct show_busy_params *params = data;
 385
 386         if (rq->mq_hctx == params->hctx)
 387                 __blk_mq_debugfs_rq_show(params->m, rq);
 388
 389         return true;
 390 }
 391
 392 static int hctx_busy_show(void *data, struct seq_file *m)
 393 {
 394         struct blk_mq_hw_ctx *hctx = data;
 395         struct show_busy_params params = { .m = m, .hctx = hctx };
 396
 397         blk_mq_tagset_busy_iter(hctx->queue->tag_set, hctx_show_busy_rq,
 398                                 &params);
 399
 400         return 0;
 401 }
 402
 403 static const char *const hctx_types[] = {
 404         [HCTX_TYPE_DEFAULT]     = "default",
 405         [HCTX_TYPE_READ]        = "read",
 406         [HCTX_TYPE_POLL]        = "poll",
 407 };
 408
 409 static int hctx_type_show(void *data, struct seq_file *m)
 410 {
 411         struct blk_mq_hw_ctx *hctx = data;
 412
 413         BUILD_BUG_ON(ARRAY_SIZE(hctx_types) != HCTX_MAX_TYPES);
 414         seq_printf(m, "%s\n", hctx_types[hctx->type]);
 415         return 0;
 416 }
 417
 418 static int hctx_ctx_map_show(void *data, struct seq_file *m)
 419 {
 420         struct blk_mq_hw_ctx *hctx = data;
 421
 422         sbitmap_bitmap_show(&hctx->ctx_map, m);
 423         return 0;
 424 }
 425
 426 static void blk_mq_debugfs_tags_show(struct seq_file *m,
 427                                      struct blk_mq_tags *tags)
 428 {
 429         seq_printf(m, "nr_tags=%u\n", tags->nr_tags);
 430         seq_printf(m, "nr_reserved_tags=%u\n", tags->nr_reserved_tags);
 431         seq_printf(m, "active_queues=%d\n",
 432                    atomic_read(&tags->active_queues));
 433
 434         seq_puts(m, "\nbitmap_tags:\n");
 435         sbitmap_queue_show(&tags->bitmap_tags, m);
 436
 437         if (tags->nr_reserved_tags) {
 438                 seq_puts(m, "\nbreserved_tags:\n");
 439                 sbitmap_queue_show(&tags->breserved_tags, m);
 440         }
 441 }
 442
 443 static int hctx_tags_show(void *data, struct seq_file *m)
 444 {
 445         struct blk_mq_hw_ctx *hctx = data;
 446         struct request_queue *q = hctx->queue;
 447         int res;
 448
 449         res = mutex_lock_interruptible(&q->sysfs_lock);
 450         if (res)
 451                 goto out;
 452         if (hctx->tags)
 453                 blk_mq_debugfs_tags_show(m, hctx->tags);
 454         mutex_unlock(&q->sysfs_lock);
 455
 456 out:
 457         return res;
 458 }
 459
 460 static int hctx_tags_bitmap_show(void *data, struct seq_file *m)
 461 {
 462         struct blk_mq_hw_ctx *hctx = data;
 463         struct request_queue *q = hctx->queue;
 464         int res;
 465
 466         res = mutex_lock_interruptible(&q->sysfs_lock);
 467         if (res)
 468                 goto out;
 469         if (hctx->tags)
 470                 sbitmap_bitmap_show(&hctx->tags->bitmap_tags.sb, m);
 471         mutex_unlock(&q->sysfs_lock);
 472
 473 out:
 474         return res;
 475 }
 476
 477 static int hctx_sched_tags_show(void *data, struct seq_file *m)
 478 {
 479         struct blk_mq_hw_ctx *hctx = data;
 480         struct request_queue *q = hctx->queue;
 481         int res;
 482
 483         res = mutex_lock_interruptible(&q->sysfs_lock);
 484         if (res)
 485                 goto out;
 486         if (hctx->sched_tags)
 487                 blk_mq_debugfs_tags_show(m, hctx->sched_tags);
 488         mutex_unlock(&q->sysfs_lock);
 489
 490 out:
 491         return res;
 492 }
 493
 494 static int hctx_sched_tags_bitmap_show(void *data, struct seq_file *m)
 495 {
 496         struct blk_mq_hw_ctx *hctx = data;
 497         struct request_queue *q = hctx->queue;
 498         int res;
 499
 500         res = mutex_lock_interruptible(&q->sysfs_lock);
 501         if (res)
 502                 goto out;
 503         if (hctx->sched_tags)
 504                 sbitmap_bitmap_show(&hctx->sched_tags->bitmap_tags.sb, m);
 505         mutex_unlock(&q->sysfs_lock);
 506
 507 out:
 508         return res;
 509 }
 510
 511 static int hctx_run_show(void *data, struct seq_file *m)
 512 {
 513         struct blk_mq_hw_ctx *hctx = data;
 514
 515         seq_printf(m, "%lu\n", hctx->run);
 516         return 0;
 517 }
 518
 519 static ssize_t hctx_run_write(void *data, const char __user *buf, size_t count,
 520                               loff_t *ppos)
 521 {
 522         struct blk_mq_hw_ctx *hctx = data;
 523
 524         hctx->run = 0;
 525         return count;
 526 }
 527
 528 static int hctx_active_show(void *data, struct seq_file *m)
 529 {
 530         struct blk_mq_hw_ctx *hctx = data;
 531
 532         seq_printf(m, "%d\n", __blk_mq_active_requests(hctx));
 533         return 0;
 534 }
 535
 536 static int hctx_dispatch_busy_show(void *data, struct seq_file *m)
 537 {
 538         struct blk_mq_hw_ctx *hctx = data;
 539
 540         seq_printf(m, "%u\n", hctx->dispatch_busy);
 541         return 0;
 542 }
 543
 544 #define CTX_RQ_SEQ_OPS(name, type)                                      \
 545 static void *ctx_##name##_rq_list_start(struct seq_file *m, loff_t *pos) \
 546         __acquires(&ctx->lock)                                          \
 547 {                                                                       \
 548         struct blk_mq_ctx *ctx = m->private;                            \
 549                                                                         \
 550         spin_lock(&ctx->lock);                                          \
 551         return seq_list_start(&ctx->rq_lists[type], *pos);              \
 552 }                                                                       \
 553                                                                         \
 554 static void *ctx_##name##_rq_list_next(struct seq_file *m, void *v,     \
 555                                      loff_t *pos)                       \
 556 {                                                                       \
 557         struct blk_mq_ctx *ctx = m->private;                            \
 558                                                                         \
 559         return seq_list_next(v, &ctx->rq_lists[type], pos);             \
 560 }                                                                       \
 561                                                                         \
 562 static void ctx_##name##_rq_list_stop(struct seq_file *m, void *v)      \
 563         __releases(&ctx->lock)                                          \
 564 {                                                                       \
 565         struct blk_mq_ctx *ctx = m->private;                            \
 566                                                                         \
 567         spin_unlock(&ctx->lock);                                        \
 568 }                                                                       \
 569                                                                         \
 570 static const struct seq_operations ctx_##name##_rq_list_seq_ops = {     \
 571         .start  = ctx_##name##_rq_list_start,                           \
 572         .next   = ctx_##name##_rq_list_next,                            \
 573         .stop   = ctx_##name##_rq_list_stop,                            \
 574         .show   = blk_mq_debugfs_rq_show,                               \
 575 }
 576
 577 CTX_RQ_SEQ_OPS(default, HCTX_TYPE_DEFAULT);
 578 CTX_RQ_SEQ_OPS(read, HCTX_TYPE_READ);
 579 CTX_RQ_SEQ_OPS(poll, HCTX_TYPE_POLL);
 580
 581 static int blk_mq_debugfs_show(struct seq_file *m, void *v)
 582 {
 583         const struct blk_mq_debugfs_attr *attr = m->private;
 584         void *data = d_inode(m->file->f_path.dentry->d_parent)->i_private;
 585
 586         return attr->show(data, m);
 587 }
 588
 589 static ssize_t blk_mq_debugfs_write(struct file *file, const char __user *buf,
 590                                     size_t count, loff_t *ppos)
 591 {
 592         struct seq_file *m = file->private_data;
 593         const struct blk_mq_debugfs_attr *attr = m->private;
 594         void *data = d_inode(file->f_path.dentry->d_parent)->i_private;
 595
 596         /*
 597          * Attributes that only implement .seq_ops are read-only and 'attr' is
 598          * the same with 'data' in this case.
 599          */
 600         if (attr == data || !attr->write)
 601                 return -EPERM;
 602
 603         return attr->write(data, buf, count, ppos);
 604 }
 605
 606 static int blk_mq_debugfs_open(struct inode *inode, struct file *file)
 607 {
 608         const struct blk_mq_debugfs_attr *attr = inode->i_private;
 609         void *data = d_inode(file->f_path.dentry->d_parent)->i_private;
 610         struct seq_file *m;
 611         int ret;
 612
 613         if (attr->seq_ops) {
 614                 ret = seq_open(file, attr->seq_ops);
 615                 if (!ret) {
 616                         m = file->private_data;
 617                         m->private = data;
 618                 }
 619                 return ret;
 620         }
 621
 622         if (WARN_ON_ONCE(!attr->show))
 623                 return -EPERM;
 624
 625         return single_open(file, blk_mq_debugfs_show, inode->i_private);
 626 }
 627
 628 static int blk_mq_debugfs_release(struct inode *inode, struct file *file)
 629 {
 630         const struct blk_mq_debugfs_attr *attr = inode->i_private;
 631
 632         if (attr->show)
 633                 return single_release(inode, file);
 634
 635         return seq_release(inode, file);
 636 }
 637
 638 static const struct file_operations blk_mq_debugfs_fops = {
 639         .open           = blk_mq_debugfs_open,
 640         .read           = seq_read,
 641         .write          = blk_mq_debugfs_write,
 642         .llseek         = seq_lseek,
 643         .release        = blk_mq_debugfs_release,
 644 };
 645
 646 static const struct blk_mq_debugfs_attr blk_mq_debugfs_hctx_attrs[] = {
 647         {"state", 0400, hctx_state_show},
 648         {"flags", 0400, hctx_flags_show},
 649         {"dispatch", 0400, .seq_ops = &hctx_dispatch_seq_ops},
 650         {"busy", 0400, hctx_busy_show},
 651         {"ctx_map", 0400, hctx_ctx_map_show},
 652         {"tags", 0400, hctx_tags_show},
 653         {"tags_bitmap", 0400, hctx_tags_bitmap_show},
 654         {"sched_tags", 0400, hctx_sched_tags_show},
 655         {"sched_tags_bitmap", 0400, hctx_sched_tags_bitmap_show},
 656         {"run", 0600, hctx_run_show, hctx_run_write},
 657         {"active", 0400, hctx_active_show},
 658         {"dispatch_busy", 0400, hctx_dispatch_busy_show},
 659         {"type", 0400, hctx_type_show},
 660         {},
 661 };
 662
 663 static const struct blk_mq_debugfs_attr blk_mq_debugfs_ctx_attrs[] = {
 664         {"default_rq_list", 0400, .seq_ops = &ctx_default_rq_list_seq_ops},
 665         {"read_rq_list", 0400, .seq_ops = &ctx_read_rq_list_seq_ops},
 666         {"poll_rq_list", 0400, .seq_ops = &ctx_poll_rq_list_seq_ops},
 667         {},
 668 };
 669
 670 static void debugfs_create_files(struct dentry *parent, void *data,
 671                                  const struct blk_mq_debugfs_attr *attr)
 672 {
 673         if (IS_ERR_OR_NULL(parent))
 674                 return;
 675
 676         d_inode(parent)->i_private = data;
 677
 678         for (; attr->name; attr++)
 679                 debugfs_create_file(attr->name, attr->mode, parent,
 680                                     (void *)attr, &blk_mq_debugfs_fops);
 681 }
 682
 683 void blk_mq_debugfs_register(struct request_queue *q)
 684 {
 685         struct blk_mq_hw_ctx *hctx;
 686         unsigned long i;
 687
 688         debugfs_create_files(q->debugfs_dir, q, blk_mq_debugfs_queue_attrs);
 689
 690         /*
 691          * blk_mq_init_sched() attempted to do this already, but q->debugfs_dir
 692          * didn't exist yet (because we don't know what to name the directory
 693          * until the queue is registered to a gendisk).
 694          */
 695         if (q->elevator && !q->sched_debugfs_dir)
 696                 blk_mq_debugfs_register_sched(q);
 697
 698         /* Similarly, blk_mq_init_hctx() couldn't do this previously. */
 699         queue_for_each_hw_ctx(q, hctx, i) {
 700                 if (!hctx->debugfs_dir)
 701                         blk_mq_debugfs_register_hctx(q, hctx);
 702                 if (q->elevator && !hctx->sched_debugfs_dir)
 703                         blk_mq_debugfs_register_sched_hctx(q, hctx);
 704         }
 705
 706         if (q->rq_qos) {
 707                 struct rq_qos *rqos = q->rq_qos;
 708
 709                 while (rqos) {
 710                         blk_mq_debugfs_register_rqos(rqos);
 711                         rqos = rqos->next;
 712                 }
 713         }
 714 }
 715
 716 void blk_mq_debugfs_unregister(struct request_queue *q)
 717 {
 718         q->sched_debugfs_dir = NULL;
 719 }
 720
 721 static void blk_mq_debugfs_register_ctx(struct blk_mq_hw_ctx *hctx,
 722                                         struct blk_mq_ctx *ctx)
 723 {
 724         struct dentry *ctx_dir;
 725         char name[20];
 726
 727         snprintf(name, sizeof(name), "cpu%u", ctx->cpu);
 728         ctx_dir = debugfs_create_dir(name, hctx->debugfs_dir);
 729
 730         debugfs_create_files(ctx_dir, ctx, blk_mq_debugfs_ctx_attrs);
 731 }
 732
 733 void blk_mq_debugfs_register_hctx(struct request_queue *q,
 734                                   struct blk_mq_hw_ctx *hctx)
 735 {
 736         struct blk_mq_ctx *ctx;
 737         char name[20];
 738         int i;
 739
 740         snprintf(name, sizeof(name), "hctx%u", hctx->queue_num);
 741         hctx->debugfs_dir = debugfs_create_dir(name, q->debugfs_dir);
 742
 743         debugfs_create_files(hctx->debugfs_dir, hctx, blk_mq_debugfs_hctx_attrs);
 744
 745         hctx_for_each_ctx(hctx, ctx, i)
 746                 blk_mq_debugfs_register_ctx(hctx, ctx);
 747 }
 748
 749 void blk_mq_debugfs_unregister_hctx(struct blk_mq_hw_ctx *hctx)
 750 {
 751         debugfs_remove_recursive(hctx->debugfs_dir);
 752         hctx->sched_debugfs_dir = NULL;
 753         hctx->debugfs_dir = NULL;
 754 }
 755
 756 void blk_mq_debugfs_register_hctxs(struct request_queue *q)
 757 {
 758         struct blk_mq_hw_ctx *hctx;
 759         unsigned long i;
 760
 761         queue_for_each_hw_ctx(q, hctx, i)
 762                 blk_mq_debugfs_register_hctx(q, hctx);
 763 }
 764
 765 void blk_mq_debugfs_unregister_hctxs(struct request_queue *q)
 766 {
 767         struct blk_mq_hw_ctx *hctx;
 768         unsigned long i;
 769
 770         queue_for_each_hw_ctx(q, hctx, i)
 771                 blk_mq_debugfs_unregister_hctx(hctx);
 772 }
 773
 774 void blk_mq_debugfs_register_sched(struct request_queue *q)
 775 {
 776         struct elevator_type *e = q->elevator->type;
 777
 778         /*
 779          * If the parent directory has not been created yet, return, we will be
 780          * called again later on and the directory/files will be created then.
 781          */
 782         if (!q->debugfs_dir)
 783                 return;
 784
 785         if (!e->queue_debugfs_attrs)
 786                 return;
 787
 788         q->sched_debugfs_dir = debugfs_create_dir("sched", q->debugfs_dir);
 789
 790         debugfs_create_files(q->sched_debugfs_dir, q, e->queue_debugfs_attrs);
 791 }
 792
 793 void blk_mq_debugfs_unregister_sched(struct request_queue *q)
 794 {
 795         debugfs_remove_recursive(q->sched_debugfs_dir);
 796         q->sched_debugfs_dir = NULL;
 797 }
 798
 799 static const char *rq_qos_id_to_name(enum rq_qos_id id)
 800 {
 801         switch (id) {
 802         case RQ_QOS_WBT:
 803                 return "wbt";
 804         case RQ_QOS_LATENCY:
 805                 return "latency";
 806         case RQ_QOS_COST:
 807                 return "cost";
 808         case RQ_QOS_IOPRIO:
 809                 return "ioprio";
 810         }
 811         return "unknown";
 812 }
 813
 814 void blk_mq_debugfs_unregister_rqos(struct rq_qos *rqos)
 815 {
 816         debugfs_remove_recursive(rqos->debugfs_dir);
 817         rqos->debugfs_dir = NULL;
 818 }
 819
 820 void blk_mq_debugfs_register_rqos(struct rq_qos *rqos)
 821 {
 822         struct request_queue *q = rqos->q;
 823         const char *dir_name = rq_qos_id_to_name(rqos->id);
 824
 825         if (rqos->debugfs_dir || !rqos->ops->debugfs_attrs)
 826                 return;
 827
 828         if (!q->rqos_debugfs_dir)
 829                 q->rqos_debugfs_dir = debugfs_create_dir("rqos",
 830                                                          q->debugfs_dir);
 831
 832         rqos->debugfs_dir = debugfs_create_dir(dir_name,
 833                                                rqos->q->rqos_debugfs_dir);
 834
 835         debugfs_create_files(rqos->debugfs_dir, rqos, rqos->ops->debugfs_attrs);
 836 }
 837
 838 void blk_mq_debugfs_unregister_queue_rqos(struct request_queue *q)
 839 {
 840         debugfs_remove_recursive(q->rqos_debugfs_dir);
 841         q->rqos_debugfs_dir = NULL;
 842 }
 843
 844 void blk_mq_debugfs_register_sched_hctx(struct request_queue *q,
 845                                         struct blk_mq_hw_ctx *hctx)
 846 {
 847         struct elevator_type *e = q->elevator->type;
 848
 849         /*
 850          * If the parent debugfs directory has not been created yet, return;
 851          * We will be called again later on with appropriate parent debugfs
 852          * directory from blk_register_queue()
 853          */
 854         if (!hctx->debugfs_dir)
 855                 return;
 856
 857         if (!e->hctx_debugfs_attrs)
 858                 return;
 859
 860         hctx->sched_debugfs_dir = debugfs_create_dir("sched",
 861                                                      hctx->debugfs_dir);
 862         debugfs_create_files(hctx->sched_debugfs_dir, hctx,
 863                              e->hctx_debugfs_attrs);
 864 }
 865
 866 void blk_mq_debugfs_unregister_sched_hctx(struct blk_mq_hw_ctx *hctx)
 867 {
 868         debugfs_remove_recursive(hctx->sched_debugfs_dir);
 869         hctx->sched_debugfs_dir = NULL;
 870 }