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