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(NOXMERGES),
 117         QUEUE_FLAG_NAME(ADD_RANDOM),
 118         QUEUE_FLAG_NAME(SAME_FORCE),
 119         QUEUE_FLAG_NAME(DEAD),
 120         QUEUE_FLAG_NAME(INIT_DONE),
 121         QUEUE_FLAG_NAME(STABLE_WRITES),
 122         QUEUE_FLAG_NAME(POLL),
 123         QUEUE_FLAG_NAME(WC),
 124         QUEUE_FLAG_NAME(FUA),
 125         QUEUE_FLAG_NAME(DAX),
 126         QUEUE_FLAG_NAME(STATS),
 127         QUEUE_FLAG_NAME(REGISTERED),
 128         QUEUE_FLAG_NAME(QUIESCED),
 129         QUEUE_FLAG_NAME(PCI_P2PDMA),
 130         QUEUE_FLAG_NAME(ZONE_RESETALL),
 131         QUEUE_FLAG_NAME(RQ_ALLOC_TIME),
 132         QUEUE_FLAG_NAME(HCTX_ACTIVE),
 133         QUEUE_FLAG_NAME(NOWAIT),
 134 };
 135 #undef QUEUE_FLAG_NAME
 136
 137 static int queue_state_show(void *data, struct seq_file *m)
 138 {
 139         struct request_queue *q = data;
 140
 141         blk_flags_show(m, q->queue_flags, blk_queue_flag_name,
 142                        ARRAY_SIZE(blk_queue_flag_name));
 143         seq_puts(m, "\n");
 144         return 0;
 145 }
 146
 147 static ssize_t queue_state_write(void *data, const char __user *buf,
 148                                  size_t count, loff_t *ppos)
 149 {
 150         struct request_queue *q = data;
 151         char opbuf[16] = { }, *op;
 152
 153         /*
 154          * The "state" attribute is removed after blk_cleanup_queue() has called
 155          * blk_mq_free_queue(). Return if QUEUE_FLAG_DEAD has been set to avoid
 156          * triggering a use-after-free.
 157          */
 158         if (blk_queue_dead(q))
 159                 return -ENOENT;
 160
 161         if (count >= sizeof(opbuf)) {
 162                 pr_err("%s: operation too long\n", __func__);
 163                 goto inval;
 164         }
 165
 166         if (copy_from_user(opbuf, buf, count))
 167                 return -EFAULT;
 168         op = strstrip(opbuf);
 169         if (strcmp(op, "run") == 0) {
 170                 blk_mq_run_hw_queues(q, true);
 171         } else if (strcmp(op, "start") == 0) {
 172                 blk_mq_start_stopped_hw_queues(q, true);
 173         } else if (strcmp(op, "kick") == 0) {
 174                 blk_mq_kick_requeue_list(q);
 175         } else {
 176                 pr_err("%s: unsupported operation '%s'\n", __func__, op);
 177 inval:
 178                 pr_err("%s: use 'run', 'start' or 'kick'\n", __func__);
 179                 return -EINVAL;
 180         }
 181         return count;
 182 }
 183
 184 static const struct blk_mq_debugfs_attr blk_mq_debugfs_queue_attrs[] = {
 185         { "poll_stat", 0400, queue_poll_stat_show },
 186         { "requeue_list", 0400, .seq_ops = &queue_requeue_list_seq_ops },
 187         { "pm_only", 0600, queue_pm_only_show, NULL },
 188         { "state", 0600, queue_state_show, queue_state_write },
 189         { "zone_wlock", 0400, queue_zone_wlock_show, NULL },
 190         { },
 191 };
 192
 193 #define HCTX_STATE_NAME(name) [BLK_MQ_S_##name] = #name
 194 static const char *const hctx_state_name[] = {
 195         HCTX_STATE_NAME(STOPPED),
 196         HCTX_STATE_NAME(TAG_ACTIVE),
 197         HCTX_STATE_NAME(SCHED_RESTART),
 198         HCTX_STATE_NAME(INACTIVE),
 199 };
 200 #undef HCTX_STATE_NAME
 201
 202 static int hctx_state_show(void *data, struct seq_file *m)
 203 {
 204         struct blk_mq_hw_ctx *hctx = data;
 205
 206         blk_flags_show(m, hctx->state, hctx_state_name,
 207                        ARRAY_SIZE(hctx_state_name));
 208         seq_puts(m, "\n");
 209         return 0;
 210 }
 211
 212 #define BLK_TAG_ALLOC_NAME(name) [BLK_TAG_ALLOC_##name] = #name
 213 static const char *const alloc_policy_name[] = {
 214         BLK_TAG_ALLOC_NAME(FIFO),
 215         BLK_TAG_ALLOC_NAME(RR),
 216 };
 217 #undef BLK_TAG_ALLOC_NAME
 218
 219 #define HCTX_FLAG_NAME(name) [ilog2(BLK_MQ_F_##name)] = #name
 220 static const char *const hctx_flag_name[] = {
 221         HCTX_FLAG_NAME(SHOULD_MERGE),
 222         HCTX_FLAG_NAME(TAG_QUEUE_SHARED),
 223         HCTX_FLAG_NAME(BLOCKING),
 224         HCTX_FLAG_NAME(NO_SCHED),
 225         HCTX_FLAG_NAME(STACKING),
 226         HCTX_FLAG_NAME(TAG_HCTX_SHARED),
 227 };
 228 #undef HCTX_FLAG_NAME
 229
 230 static int hctx_flags_show(void *data, struct seq_file *m)
 231 {
 232         struct blk_mq_hw_ctx *hctx = data;
 233         const int alloc_policy = BLK_MQ_FLAG_TO_ALLOC_POLICY(hctx->flags);
 234
 235         seq_puts(m, "alloc_policy=");
 236         if (alloc_policy < ARRAY_SIZE(alloc_policy_name) &&
 237             alloc_policy_name[alloc_policy])
 238                 seq_puts(m, alloc_policy_name[alloc_policy]);
 239         else
 240                 seq_printf(m, "%d", alloc_policy);
 241         seq_puts(m, " ");
 242         blk_flags_show(m,
 243                        hctx->flags ^ BLK_ALLOC_POLICY_TO_MQ_FLAG(alloc_policy),
 244                        hctx_flag_name, ARRAY_SIZE(hctx_flag_name));
 245         seq_puts(m, "\n");
 246         return 0;
 247 }
 248
 249 #define CMD_FLAG_NAME(name) [__REQ_##name] = #name
 250 static const char *const cmd_flag_name[] = {
 251         CMD_FLAG_NAME(FAILFAST_DEV),
 252         CMD_FLAG_NAME(FAILFAST_TRANSPORT),
 253         CMD_FLAG_NAME(FAILFAST_DRIVER),
 254         CMD_FLAG_NAME(SYNC),
 255         CMD_FLAG_NAME(META),
 256         CMD_FLAG_NAME(PRIO),
 257         CMD_FLAG_NAME(NOMERGE),
 258         CMD_FLAG_NAME(IDLE),
 259         CMD_FLAG_NAME(INTEGRITY),
 260         CMD_FLAG_NAME(FUA),
 261         CMD_FLAG_NAME(PREFLUSH),
 262         CMD_FLAG_NAME(RAHEAD),
 263         CMD_FLAG_NAME(BACKGROUND),
 264         CMD_FLAG_NAME(NOWAIT),
 265         CMD_FLAG_NAME(NOUNMAP),
 266         CMD_FLAG_NAME(POLLED),
 267 };
 268 #undef CMD_FLAG_NAME
 269
 270 #define RQF_NAME(name) [ilog2((__force u32)RQF_##name)] = #name
 271 static const char *const rqf_name[] = {
 272         RQF_NAME(STARTED),
 273         RQF_NAME(SOFTBARRIER),
 274         RQF_NAME(FLUSH_SEQ),
 275         RQF_NAME(MIXED_MERGE),
 276         RQF_NAME(MQ_INFLIGHT),
 277         RQF_NAME(DONTPREP),
 278         RQF_NAME(FAILED),
 279         RQF_NAME(QUIET),
 280         RQF_NAME(ELVPRIV),
 281         RQF_NAME(IO_STAT),
 282         RQF_NAME(PM),
 283         RQF_NAME(HASHED),
 284         RQF_NAME(STATS),
 285         RQF_NAME(SPECIAL_PAYLOAD),
 286         RQF_NAME(ZONE_WRITE_LOCKED),
 287         RQF_NAME(MQ_POLL_SLEPT),
 288         RQF_NAME(ELV),
 289 };
 290 #undef RQF_NAME
 291
 292 static const char *const blk_mq_rq_state_name_array[] = {
 293         [MQ_RQ_IDLE]            = "idle",
 294         [MQ_RQ_IN_FLIGHT]       = "in_flight",
 295         [MQ_RQ_COMPLETE]        = "complete",
 296 };
 297
 298 static const char *blk_mq_rq_state_name(enum mq_rq_state rq_state)
 299 {
 300         if (WARN_ON_ONCE((unsigned int)rq_state >=
 301                          ARRAY_SIZE(blk_mq_rq_state_name_array)))
 302                 return "(?)";
 303         return blk_mq_rq_state_name_array[rq_state];
 304 }
 305
 306 int __blk_mq_debugfs_rq_show(struct seq_file *m, struct request *rq)
 307 {
 308         const struct blk_mq_ops *const mq_ops = rq->q->mq_ops;
 309         const unsigned int op = req_op(rq);
 310         const char *op_str = blk_op_str(op);
 311
 312         seq_printf(m, "%p {.op=", rq);
 313         if (strcmp(op_str, "UNKNOWN") == 0)
 314                 seq_printf(m, "%u", op);
 315         else
 316                 seq_printf(m, "%s", op_str);
 317         seq_puts(m, ", .cmd_flags=");
 318         blk_flags_show(m, rq->cmd_flags & ~REQ_OP_MASK, cmd_flag_name,
 319                        ARRAY_SIZE(cmd_flag_name));
 320         seq_puts(m, ", .rq_flags=");
 321         blk_flags_show(m, (__force unsigned int)rq->rq_flags, rqf_name,
 322                        ARRAY_SIZE(rqf_name));
 323         seq_printf(m, ", .state=%s", blk_mq_rq_state_name(blk_mq_rq_state(rq)));
 324         seq_printf(m, ", .tag=%d, .internal_tag=%d", rq->tag,
 325                    rq->internal_tag);
 326         if (mq_ops->show_rq)
 327                 mq_ops->show_rq(m, rq);
 328         seq_puts(m, "}\n");
 329         return 0;
 330 }
 331 EXPORT_SYMBOL_GPL(__blk_mq_debugfs_rq_show);
 332
 333 int blk_mq_debugfs_rq_show(struct seq_file *m, void *v)
 334 {
 335         return __blk_mq_debugfs_rq_show(m, list_entry_rq(v));
 336 }
 337 EXPORT_SYMBOL_GPL(blk_mq_debugfs_rq_show);
 338
 339 static void *hctx_dispatch_start(struct seq_file *m, loff_t *pos)
 340         __acquires(&hctx->lock)
 341 {
 342         struct blk_mq_hw_ctx *hctx = m->private;
 343
 344         spin_lock(&hctx->lock);
 345         return seq_list_start(&hctx->dispatch, *pos);
 346 }
 347
 348 static void *hctx_dispatch_next(struct seq_file *m, void *v, loff_t *pos)
 349 {
 350         struct blk_mq_hw_ctx *hctx = m->private;
 351
 352         return seq_list_next(v, &hctx->dispatch, pos);
 353 }
 354
 355 static void hctx_dispatch_stop(struct seq_file *m, void *v)
 356         __releases(&hctx->lock)
 357 {
 358         struct blk_mq_hw_ctx *hctx = m->private;
 359
 360         spin_unlock(&hctx->lock);
 361 }
 362
 363 static const struct seq_operations hctx_dispatch_seq_ops = {
 364         .start  = hctx_dispatch_start,
 365         .next   = hctx_dispatch_next,
 366         .stop   = hctx_dispatch_stop,
 367         .show   = blk_mq_debugfs_rq_show,
 368 };
 369
 370 struct show_busy_params {
 371         struct seq_file         *m;
 372         struct blk_mq_hw_ctx    *hctx;
 373 };
 374
 375 /*
 376  * Note: the state of a request may change while this function is in progress,
 377  * e.g. due to a concurrent blk_mq_finish_request() call. Returns true to
 378  * keep iterating requests.
 379  */
 380 static bool hctx_show_busy_rq(struct request *rq, void *data, bool reserved)
 381 {
 382         const struct show_busy_params *params = data;
 383
 384         if (rq->mq_hctx == params->hctx)
 385                 __blk_mq_debugfs_rq_show(params->m, rq);
 386
 387         return true;
 388 }
 389
 390 static int hctx_busy_show(void *data, struct seq_file *m)
 391 {
 392         struct blk_mq_hw_ctx *hctx = data;
 393         struct show_busy_params params = { .m = m, .hctx = hctx };
 394
 395         blk_mq_tagset_busy_iter(hctx->queue->tag_set, hctx_show_busy_rq,
 396                                 &params);
 397
 398         return 0;
 399 }
 400
 401 static const char *const hctx_types[] = {
 402         [HCTX_TYPE_DEFAULT]     = "default",
 403         [HCTX_TYPE_READ]        = "read",
 404         [HCTX_TYPE_POLL]        = "poll",
 405 };
 406
 407 static int hctx_type_show(void *data, struct seq_file *m)
 408 {
 409         struct blk_mq_hw_ctx *hctx = data;
 410
 411         BUILD_BUG_ON(ARRAY_SIZE(hctx_types) != HCTX_MAX_TYPES);
 412         seq_printf(m, "%s\n", hctx_types[hctx->type]);
 413         return 0;
 414 }
 415
 416 static int hctx_ctx_map_show(void *data, struct seq_file *m)
 417 {
 418         struct blk_mq_hw_ctx *hctx = data;
 419
 420         sbitmap_bitmap_show(&hctx->ctx_map, m);
 421         return 0;
 422 }
 423
 424 static void blk_mq_debugfs_tags_show(struct seq_file *m,
 425                                      struct blk_mq_tags *tags)
 426 {
 427         seq_printf(m, "nr_tags=%u\n", tags->nr_tags);
 428         seq_printf(m, "nr_reserved_tags=%u\n", tags->nr_reserved_tags);
 429         seq_printf(m, "active_queues=%d\n",
 430                    atomic_read(&tags->active_queues));
 431
 432         seq_puts(m, "\nbitmap_tags:\n");
 433         sbitmap_queue_show(&tags->bitmap_tags, m);
 434
 435         if (tags->nr_reserved_tags) {
 436                 seq_puts(m, "\nbreserved_tags:\n");
 437                 sbitmap_queue_show(&tags->breserved_tags, m);
 438         }
 439 }
 440
 441 static int hctx_tags_show(void *data, struct seq_file *m)
 442 {
 443         struct blk_mq_hw_ctx *hctx = data;
 444         struct request_queue *q = hctx->queue;
 445         int res;
 446
 447         res = mutex_lock_interruptible(&q->sysfs_lock);
 448         if (res)
 449                 goto out;
 450         if (hctx->tags)
 451                 blk_mq_debugfs_tags_show(m, hctx->tags);
 452         mutex_unlock(&q->sysfs_lock);
 453
 454 out:
 455         return res;
 456 }
 457
 458 static int hctx_tags_bitmap_show(void *data, struct seq_file *m)
 459 {
 460         struct blk_mq_hw_ctx *hctx = data;
 461         struct request_queue *q = hctx->queue;
 462         int res;
 463
 464         res = mutex_lock_interruptible(&q->sysfs_lock);
 465         if (res)
 466                 goto out;
 467         if (hctx->tags)
 468                 sbitmap_bitmap_show(&hctx->tags->bitmap_tags.sb, m);
 469         mutex_unlock(&q->sysfs_lock);
 470
 471 out:
 472         return res;
 473 }
 474
 475 static int hctx_sched_tags_show(void *data, struct seq_file *m)
 476 {
 477         struct blk_mq_hw_ctx *hctx = data;
 478         struct request_queue *q = hctx->queue;
 479         int res;
 480
 481         res = mutex_lock_interruptible(&q->sysfs_lock);
 482         if (res)
 483                 goto out;
 484         if (hctx->sched_tags)
 485                 blk_mq_debugfs_tags_show(m, hctx->sched_tags);
 486         mutex_unlock(&q->sysfs_lock);
 487
 488 out:
 489         return res;
 490 }
 491
 492 static int hctx_sched_tags_bitmap_show(void *data, struct seq_file *m)
 493 {
 494         struct blk_mq_hw_ctx *hctx = data;
 495         struct request_queue *q = hctx->queue;
 496         int res;
 497
 498         res = mutex_lock_interruptible(&q->sysfs_lock);
 499         if (res)
 500                 goto out;
 501         if (hctx->sched_tags)
 502                 sbitmap_bitmap_show(&hctx->sched_tags->bitmap_tags.sb, m);
 503         mutex_unlock(&q->sysfs_lock);
 504
 505 out:
 506         return res;
 507 }
 508
 509 static int hctx_run_show(void *data, struct seq_file *m)
 510 {
 511         struct blk_mq_hw_ctx *hctx = data;
 512
 513         seq_printf(m, "%lu\n", hctx->run);
 514         return 0;
 515 }
 516
 517 static ssize_t hctx_run_write(void *data, const char __user *buf, size_t count,
 518                               loff_t *ppos)
 519 {
 520         struct blk_mq_hw_ctx *hctx = data;
 521
 522         hctx->run = 0;
 523         return count;
 524 }
 525
 526 static int hctx_active_show(void *data, struct seq_file *m)
 527 {
 528         struct blk_mq_hw_ctx *hctx = data;
 529
 530         seq_printf(m, "%d\n", __blk_mq_active_requests(hctx));
 531         return 0;
 532 }
 533
 534 static int hctx_dispatch_busy_show(void *data, struct seq_file *m)
 535 {
 536         struct blk_mq_hw_ctx *hctx = data;
 537
 538         seq_printf(m, "%u\n", hctx->dispatch_busy);
 539         return 0;
 540 }
 541
 542 #define CTX_RQ_SEQ_OPS(name, type)                                      \
 543 static void *ctx_##name##_rq_list_start(struct seq_file *m, loff_t *pos) \
 544         __acquires(&ctx->lock)                                          \
 545 {                                                                       \
 546         struct blk_mq_ctx *ctx = m->private;                            \
 547                                                                         \
 548         spin_lock(&ctx->lock);                                          \
 549         return seq_list_start(&ctx->rq_lists[type], *pos);              \
 550 }                                                                       \
 551                                                                         \
 552 static void *ctx_##name##_rq_list_next(struct seq_file *m, void *v,     \
 553                                      loff_t *pos)                       \
 554 {                                                                       \
 555         struct blk_mq_ctx *ctx = m->private;                            \
 556                                                                         \
 557         return seq_list_next(v, &ctx->rq_lists[type], pos);             \
 558 }                                                                       \
 559                                                                         \
 560 static void ctx_##name##_rq_list_stop(struct seq_file *m, void *v)      \
 561         __releases(&ctx->lock)                                          \
 562 {                                                                       \
 563         struct blk_mq_ctx *ctx = m->private;                            \
 564                                                                         \
 565         spin_unlock(&ctx->lock);                                        \
 566 }                                                                       \
 567                                                                         \
 568 static const struct seq_operations ctx_##name##_rq_list_seq_ops = {     \
 569         .start  = ctx_##name##_rq_list_start,                           \
 570         .next   = ctx_##name##_rq_list_next,                            \
 571         .stop   = ctx_##name##_rq_list_stop,                            \
 572         .show   = blk_mq_debugfs_rq_show,                               \
 573 }
 574
 575 CTX_RQ_SEQ_OPS(default, HCTX_TYPE_DEFAULT);
 576 CTX_RQ_SEQ_OPS(read, HCTX_TYPE_READ);
 577 CTX_RQ_SEQ_OPS(poll, HCTX_TYPE_POLL);
 578
 579 static int blk_mq_debugfs_show(struct seq_file *m, void *v)
 580 {
 581         const struct blk_mq_debugfs_attr *attr = m->private;
 582         void *data = d_inode(m->file->f_path.dentry->d_parent)->i_private;
 583
 584         return attr->show(data, m);
 585 }
 586
 587 static ssize_t blk_mq_debugfs_write(struct file *file, const char __user *buf,
 588                                     size_t count, loff_t *ppos)
 589 {
 590         struct seq_file *m = file->private_data;
 591         const struct blk_mq_debugfs_attr *attr = m->private;
 592         void *data = d_inode(file->f_path.dentry->d_parent)->i_private;
 593
 594         /*
 595          * Attributes that only implement .seq_ops are read-only and 'attr' is
 596          * the same with 'data' in this case.
 597          */
 598         if (attr == data || !attr->write)
 599                 return -EPERM;
 600
 601         return attr->write(data, buf, count, ppos);
 602 }
 603
 604 static int blk_mq_debugfs_open(struct inode *inode, struct file *file)
 605 {
 606         const struct blk_mq_debugfs_attr *attr = inode->i_private;
 607         void *data = d_inode(file->f_path.dentry->d_parent)->i_private;
 608         struct seq_file *m;
 609         int ret;
 610
 611         if (attr->seq_ops) {
 612                 ret = seq_open(file, attr->seq_ops);
 613                 if (!ret) {
 614                         m = file->private_data;
 615                         m->private = data;
 616                 }
 617                 return ret;
 618         }
 619
 620         if (WARN_ON_ONCE(!attr->show))
 621                 return -EPERM;
 622
 623         return single_open(file, blk_mq_debugfs_show, inode->i_private);
 624 }
 625
 626 static int blk_mq_debugfs_release(struct inode *inode, struct file *file)
 627 {
 628         const struct blk_mq_debugfs_attr *attr = inode->i_private;
 629
 630         if (attr->show)
 631                 return single_release(inode, file);
 632
 633         return seq_release(inode, file);
 634 }
 635
 636 static const struct file_operations blk_mq_debugfs_fops = {
 637         .open           = blk_mq_debugfs_open,
 638         .read           = seq_read,
 639         .write          = blk_mq_debugfs_write,
 640         .llseek         = seq_lseek,
 641         .release        = blk_mq_debugfs_release,
 642 };
 643
 644 static const struct blk_mq_debugfs_attr blk_mq_debugfs_hctx_attrs[] = {
 645         {"state", 0400, hctx_state_show},
 646         {"flags", 0400, hctx_flags_show},
 647         {"dispatch", 0400, .seq_ops = &hctx_dispatch_seq_ops},
 648         {"busy", 0400, hctx_busy_show},
 649         {"ctx_map", 0400, hctx_ctx_map_show},
 650         {"tags", 0400, hctx_tags_show},
 651         {"tags_bitmap", 0400, hctx_tags_bitmap_show},
 652         {"sched_tags", 0400, hctx_sched_tags_show},
 653         {"sched_tags_bitmap", 0400, hctx_sched_tags_bitmap_show},
 654         {"run", 0600, hctx_run_show, hctx_run_write},
 655         {"active", 0400, hctx_active_show},
 656         {"dispatch_busy", 0400, hctx_dispatch_busy_show},
 657         {"type", 0400, hctx_type_show},
 658         {},
 659 };
 660
 661 static const struct blk_mq_debugfs_attr blk_mq_debugfs_ctx_attrs[] = {
 662         {"default_rq_list", 0400, .seq_ops = &ctx_default_rq_list_seq_ops},
 663         {"read_rq_list", 0400, .seq_ops = &ctx_read_rq_list_seq_ops},
 664         {"poll_rq_list", 0400, .seq_ops = &ctx_poll_rq_list_seq_ops},
 665         {},
 666 };
 667
 668 static void debugfs_create_files(struct dentry *parent, void *data,
 669                                  const struct blk_mq_debugfs_attr *attr)
 670 {
 671         if (IS_ERR_OR_NULL(parent))
 672                 return;
 673
 674         d_inode(parent)->i_private = data;
 675
 676         for (; attr->name; attr++)
 677                 debugfs_create_file(attr->name, attr->mode, parent,
 678                                     (void *)attr, &blk_mq_debugfs_fops);
 679 }
 680
 681 void blk_mq_debugfs_register(struct request_queue *q)
 682 {
 683         struct blk_mq_hw_ctx *hctx;
 684         unsigned long i;
 685
 686         debugfs_create_files(q->debugfs_dir, q, blk_mq_debugfs_queue_attrs);
 687
 688         /*
 689          * blk_mq_init_sched() attempted to do this already, but q->debugfs_dir
 690          * didn't exist yet (because we don't know what to name the directory
 691          * until the queue is registered to a gendisk).
 692          */
 693         if (q->elevator && !q->sched_debugfs_dir)
 694                 blk_mq_debugfs_register_sched(q);
 695
 696         /* Similarly, blk_mq_init_hctx() couldn't do this previously. */
 697         queue_for_each_hw_ctx(q, hctx, i) {
 698                 if (!hctx->debugfs_dir)
 699                         blk_mq_debugfs_register_hctx(q, hctx);
 700                 if (q->elevator && !hctx->sched_debugfs_dir)
 701                         blk_mq_debugfs_register_sched_hctx(q, hctx);
 702         }
 703
 704         if (q->rq_qos) {
 705                 struct rq_qos *rqos = q->rq_qos;
 706
 707                 while (rqos) {
 708                         blk_mq_debugfs_register_rqos(rqos);
 709                         rqos = rqos->next;
 710                 }
 711         }
 712 }
 713
 714 static void blk_mq_debugfs_register_ctx(struct blk_mq_hw_ctx *hctx,
 715                                         struct blk_mq_ctx *ctx)
 716 {
 717         struct dentry *ctx_dir;
 718         char name[20];
 719
 720         snprintf(name, sizeof(name), "cpu%u", ctx->cpu);
 721         ctx_dir = debugfs_create_dir(name, hctx->debugfs_dir);
 722
 723         debugfs_create_files(ctx_dir, ctx, blk_mq_debugfs_ctx_attrs);
 724 }
 725
 726 void blk_mq_debugfs_register_hctx(struct request_queue *q,
 727                                   struct blk_mq_hw_ctx *hctx)
 728 {
 729         struct blk_mq_ctx *ctx;
 730         char name[20];
 731         int i;
 732
 733         snprintf(name, sizeof(name), "hctx%u", hctx->queue_num);
 734         hctx->debugfs_dir = debugfs_create_dir(name, q->debugfs_dir);
 735
 736         debugfs_create_files(hctx->debugfs_dir, hctx, blk_mq_debugfs_hctx_attrs);
 737
 738         hctx_for_each_ctx(hctx, ctx, i)
 739                 blk_mq_debugfs_register_ctx(hctx, ctx);
 740 }
 741
 742 void blk_mq_debugfs_unregister_hctx(struct blk_mq_hw_ctx *hctx)
 743 {
 744         if (!hctx->queue->debugfs_dir)
 745                 return;
 746         debugfs_remove_recursive(hctx->debugfs_dir);
 747         hctx->sched_debugfs_dir = NULL;
 748         hctx->debugfs_dir = NULL;
 749 }
 750
 751 void blk_mq_debugfs_register_hctxs(struct request_queue *q)
 752 {
 753         struct blk_mq_hw_ctx *hctx;
 754         unsigned long i;
 755
 756         queue_for_each_hw_ctx(q, hctx, i)
 757                 blk_mq_debugfs_register_hctx(q, hctx);
 758 }
 759
 760 void blk_mq_debugfs_unregister_hctxs(struct request_queue *q)
 761 {
 762         struct blk_mq_hw_ctx *hctx;
 763         unsigned long i;
 764
 765         queue_for_each_hw_ctx(q, hctx, i)
 766                 blk_mq_debugfs_unregister_hctx(hctx);
 767 }
 768
 769 void blk_mq_debugfs_register_sched(struct request_queue *q)
 770 {
 771         struct elevator_type *e = q->elevator->type;
 772
 773         lockdep_assert_held(&q->debugfs_mutex);
 774
 775         /*
 776          * If the parent directory has not been created yet, return, we will be
 777          * called again later on and the directory/files will be created then.
 778          */
 779         if (!q->debugfs_dir)
 780                 return;
 781
 782         if (!e->queue_debugfs_attrs)
 783                 return;
 784
 785         q->sched_debugfs_dir = debugfs_create_dir("sched", q->debugfs_dir);
 786
 787         debugfs_create_files(q->sched_debugfs_dir, q, e->queue_debugfs_attrs);
 788 }
 789
 790 void blk_mq_debugfs_unregister_sched(struct request_queue *q)
 791 {
 792         lockdep_assert_held(&q->debugfs_mutex);
 793
 794         debugfs_remove_recursive(q->sched_debugfs_dir);
 795         q->sched_debugfs_dir = NULL;
 796 }
 797
 798 static const char *rq_qos_id_to_name(enum rq_qos_id id)
 799 {
 800         switch (id) {
 801         case RQ_QOS_WBT:
 802                 return "wbt";
 803         case RQ_QOS_LATENCY:
 804                 return "latency";
 805         case RQ_QOS_COST:
 806                 return "cost";
 807         case RQ_QOS_IOPRIO:
 808                 return "ioprio";
 809         }
 810         return "unknown";
 811 }
 812
 813 void blk_mq_debugfs_unregister_rqos(struct rq_qos *rqos)
 814 {
 815         lockdep_assert_held(&rqos->q->debugfs_mutex);
 816
 817         if (!rqos->q->debugfs_dir)
 818                 return;
 819         debugfs_remove_recursive(rqos->debugfs_dir);
 820         rqos->debugfs_dir = NULL;
 821 }
 822
 823 void blk_mq_debugfs_register_rqos(struct rq_qos *rqos)
 824 {
 825         struct request_queue *q = rqos->q;
 826         const char *dir_name = rq_qos_id_to_name(rqos->id);
 827
 828         lockdep_assert_held(&q->debugfs_mutex);
 829
 830         if (rqos->debugfs_dir || !rqos->ops->debugfs_attrs)
 831                 return;
 832
 833         if (!q->rqos_debugfs_dir)
 834                 q->rqos_debugfs_dir = debugfs_create_dir("rqos",
 835                                                          q->debugfs_dir);
 836
 837         rqos->debugfs_dir = debugfs_create_dir(dir_name,
 838                                                rqos->q->rqos_debugfs_dir);
 839
 840         debugfs_create_files(rqos->debugfs_dir, rqos, rqos->ops->debugfs_attrs);
 841 }
 842
 843 void blk_mq_debugfs_register_sched_hctx(struct request_queue *q,
 844                                         struct blk_mq_hw_ctx *hctx)
 845 {
 846         struct elevator_type *e = q->elevator->type;
 847
 848         lockdep_assert_held(&q->debugfs_mutex);
 849
 850         /*
 851          * If the parent debugfs directory has not been created yet, return;
 852          * We will be called again later on with appropriate parent debugfs
 853          * directory from blk_register_queue()
 854          */
 855         if (!hctx->debugfs_dir)
 856                 return;
 857
 858         if (!e->hctx_debugfs_attrs)
 859                 return;
 860
 861         hctx->sched_debugfs_dir = debugfs_create_dir("sched",
 862                                                      hctx->debugfs_dir);
 863         debugfs_create_files(hctx->sched_debugfs_dir, hctx,
 864                              e->hctx_debugfs_attrs);
 865 }
 866
 867 void blk_mq_debugfs_unregister_sched_hctx(struct blk_mq_hw_ctx *hctx)
 868 {
 869         lockdep_assert_held(&hctx->queue->debugfs_mutex);
 870
 871         if (!hctx->queue->debugfs_dir)
 872                 return;
 873         debugfs_remove_recursive(hctx->sched_debugfs_dir);
 874         hctx->sched_debugfs_dir = NULL;
 875 }