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