block/blk-mq-debugfs.c

   1 /*
   2  * Copyright (C) 2017 Facebook
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/blkdev.h>
  19 #include <linux/debugfs.h>
  20
  21 #include <linux/blk-mq.h>
  22 #include "blk.h"
  23 #include "blk-mq.h"
  24 #include "blk-mq-debugfs.h"
  25 #include "blk-mq-tag.h"
  26
  27 static void print_stat(struct seq_file *m, struct blk_rq_stat *stat)
  28 {
  29         if (stat->nr_samples) {
  30                 seq_printf(m, "samples=%d, mean=%lld, min=%llu, max=%llu",
  31                            stat->nr_samples, stat->mean, stat->min, stat->max);
  32         } else {
  33                 seq_puts(m, "samples=0");
  34         }
  35 }
  36
  37 static int queue_poll_stat_show(void *data, struct seq_file *m)
  38 {
  39         struct request_queue *q = data;
  40         int bucket;
  41
  42         for (bucket = 0; bucket < BLK_MQ_POLL_STATS_BKTS/2; bucket++) {
  43                 seq_printf(m, "read  (%d Bytes): ", 1 << (9+bucket));
  44                 print_stat(m, &q->poll_stat[2*bucket]);
  45                 seq_puts(m, "\n");
  46
  47                 seq_printf(m, "write (%d Bytes): ",  1 << (9+bucket));
  48                 print_stat(m, &q->poll_stat[2*bucket+1]);
  49                 seq_puts(m, "\n");
  50         }
  51         return 0;
  52 }
  53
  54 static void *queue_requeue_list_start(struct seq_file *m, loff_t *pos)
  55         __acquires(&q->requeue_lock)
  56 {
  57         struct request_queue *q = m->private;
  58
  59         spin_lock_irq(&q->requeue_lock);
  60         return seq_list_start(&q->requeue_list, *pos);
  61 }
  62
  63 static void *queue_requeue_list_next(struct seq_file *m, void *v, loff_t *pos)
  64 {
  65         struct request_queue *q = m->private;
  66
  67         return seq_list_next(v, &q->requeue_list, pos);
  68 }
  69
  70 static void queue_requeue_list_stop(struct seq_file *m, void *v)
  71         __releases(&q->requeue_lock)
  72 {
  73         struct request_queue *q = m->private;
  74
  75         spin_unlock_irq(&q->requeue_lock);
  76 }
  77
  78 static const struct seq_operations queue_requeue_list_seq_ops = {
  79         .start  = queue_requeue_list_start,
  80         .next   = queue_requeue_list_next,
  81         .stop   = queue_requeue_list_stop,
  82         .show   = blk_mq_debugfs_rq_show,
  83 };
  84
  85 static int blk_flags_show(struct seq_file *m, const unsigned long flags,
  86                           const char *const *flag_name, int flag_name_count)
  87 {
  88         bool sep = false;
  89         int i;
  90
  91         for (i = 0; i < sizeof(flags) * BITS_PER_BYTE; i++) {
  92                 if (!(flags & BIT(i)))
  93                         continue;
  94                 if (sep)
  95                         seq_puts(m, "|");
  96                 sep = true;
  97                 if (i < flag_name_count && flag_name[i])
  98                         seq_puts(m, flag_name[i]);
  99                 else
 100                         seq_printf(m, "%d", i);
 101         }
 102         return 0;
 103 }
 104
 105 #define QUEUE_FLAG_NAME(name) [QUEUE_FLAG_##name] = #name
 106 static const char *const blk_queue_flag_name[] = {
 107         QUEUE_FLAG_NAME(QUEUED),
 108         QUEUE_FLAG_NAME(STOPPED),
 109         QUEUE_FLAG_NAME(DYING),
 110         QUEUE_FLAG_NAME(BYPASS),
 111         QUEUE_FLAG_NAME(BIDI),
 112         QUEUE_FLAG_NAME(NOMERGES),
 113         QUEUE_FLAG_NAME(SAME_COMP),
 114         QUEUE_FLAG_NAME(FAIL_IO),
 115         QUEUE_FLAG_NAME(NONROT),
 116         QUEUE_FLAG_NAME(IO_STAT),
 117         QUEUE_FLAG_NAME(DISCARD),
 118         QUEUE_FLAG_NAME(NOXMERGES),
 119         QUEUE_FLAG_NAME(ADD_RANDOM),
 120         QUEUE_FLAG_NAME(SECERASE),
 121         QUEUE_FLAG_NAME(SAME_FORCE),
 122         QUEUE_FLAG_NAME(DEAD),
 123         QUEUE_FLAG_NAME(INIT_DONE),
 124         QUEUE_FLAG_NAME(NO_SG_MERGE),
 125         QUEUE_FLAG_NAME(POLL),
 126         QUEUE_FLAG_NAME(WC),
 127         QUEUE_FLAG_NAME(FUA),
 128         QUEUE_FLAG_NAME(FLUSH_NQ),
 129         QUEUE_FLAG_NAME(DAX),
 130         QUEUE_FLAG_NAME(STATS),
 131         QUEUE_FLAG_NAME(POLL_STATS),
 132         QUEUE_FLAG_NAME(REGISTERED),
 133         QUEUE_FLAG_NAME(SCSI_PASSTHROUGH),
 134         QUEUE_FLAG_NAME(QUIESCED),
 135         QUEUE_FLAG_NAME(PREEMPT_ONLY),
 136 };
 137 #undef QUEUE_FLAG_NAME
 138
 139 static int queue_state_show(void *data, struct seq_file *m)
 140 {
 141         struct request_queue *q = data;
 142
 143         blk_flags_show(m, q->queue_flags, blk_queue_flag_name,
 144                        ARRAY_SIZE(blk_queue_flag_name));
 145         seq_puts(m, "\n");
 146         return 0;
 147 }
 148
 149 static ssize_t queue_state_write(void *data, const char __user *buf,
 150                                  size_t count, loff_t *ppos)
 151 {
 152         struct request_queue *q = data;
 153         char opbuf[16] = { }, *op;
 154
 155         /*
 156          * The "state" attribute is removed after blk_cleanup_queue() has called
 157          * blk_mq_free_queue(). Return if QUEUE_FLAG_DEAD has been set to avoid
 158          * triggering a use-after-free.
 159          */
 160         if (blk_queue_dead(q))
 161                 return -ENOENT;
 162
 163         if (count >= sizeof(opbuf)) {
 164                 pr_err("%s: operation too long\n", __func__);
 165                 goto inval;
 166         }
 167
 168         if (copy_from_user(opbuf, buf, count))
 169                 return -EFAULT;
 170         op = strstrip(opbuf);
 171         if (strcmp(op, "run") == 0) {
 172                 blk_mq_run_hw_queues(q, true);
 173         } else if (strcmp(op, "start") == 0) {
 174                 blk_mq_start_stopped_hw_queues(q, true);
 175         } else if (strcmp(op, "kick") == 0) {
 176                 blk_mq_kick_requeue_list(q);
 177         } else {
 178                 pr_err("%s: unsupported operation '%s'\n", __func__, op);
 179 inval:
 180                 pr_err("%s: use 'run', 'start' or 'kick'\n", __func__);
 181                 return -EINVAL;
 182         }
 183         return count;
 184 }
 185
 186 static int queue_write_hint_show(void *data, struct seq_file *m)
 187 {
 188         struct request_queue *q = data;
 189         int i;
 190
 191         for (i = 0; i < BLK_MAX_WRITE_HINTS; i++)
 192                 seq_printf(m, "hint%d: %llu\n", i, q->write_hints[i]);
 193
 194         return 0;
 195 }
 196
 197 static ssize_t queue_write_hint_store(void *data, const char __user *buf,
 198                                       size_t count, loff_t *ppos)
 199 {
 200         struct request_queue *q = data;
 201         int i;
 202
 203         for (i = 0; i < BLK_MAX_WRITE_HINTS; i++)
 204                 q->write_hints[i] = 0;
 205
 206         return count;
 207 }
 208
 209 static const struct blk_mq_debugfs_attr blk_mq_debugfs_queue_attrs[] = {
 210         { "poll_stat", 0400, queue_poll_stat_show },
 211         { "requeue_list", 0400, .seq_ops = &queue_requeue_list_seq_ops },
 212         { "state", 0600, queue_state_show, queue_state_write },
 213         { "write_hints", 0600, queue_write_hint_show, queue_write_hint_store },
 214         { "zone_wlock", 0400, queue_zone_wlock_show, NULL },
 215         { },
 216 };
 217
 218 #define HCTX_STATE_NAME(name) [BLK_MQ_S_##name] = #name
 219 static const char *const hctx_state_name[] = {
 220         HCTX_STATE_NAME(STOPPED),
 221         HCTX_STATE_NAME(TAG_ACTIVE),
 222         HCTX_STATE_NAME(SCHED_RESTART),
 223 };
 224 #undef HCTX_STATE_NAME
 225
 226 static int hctx_state_show(void *data, struct seq_file *m)
 227 {
 228         struct blk_mq_hw_ctx *hctx = data;
 229
 230         blk_flags_show(m, hctx->state, hctx_state_name,
 231                        ARRAY_SIZE(hctx_state_name));
 232         seq_puts(m, "\n");
 233         return 0;
 234 }
 235
 236 #define BLK_TAG_ALLOC_NAME(name) [BLK_TAG_ALLOC_##name] = #name
 237 static const char *const alloc_policy_name[] = {
 238         BLK_TAG_ALLOC_NAME(FIFO),
 239         BLK_TAG_ALLOC_NAME(RR),
 240 };
 241 #undef BLK_TAG_ALLOC_NAME
 242
 243 #define HCTX_FLAG_NAME(name) [ilog2(BLK_MQ_F_##name)] = #name
 244 static const char *const hctx_flag_name[] = {
 245         HCTX_FLAG_NAME(SHOULD_MERGE),
 246         HCTX_FLAG_NAME(TAG_SHARED),
 247         HCTX_FLAG_NAME(SG_MERGE),
 248         HCTX_FLAG_NAME(BLOCKING),
 249         HCTX_FLAG_NAME(NO_SCHED),
 250 };
 251 #undef HCTX_FLAG_NAME
 252
 253 static int hctx_flags_show(void *data, struct seq_file *m)
 254 {
 255         struct blk_mq_hw_ctx *hctx = data;
 256         const int alloc_policy = BLK_MQ_FLAG_TO_ALLOC_POLICY(hctx->flags);
 257
 258         seq_puts(m, "alloc_policy=");
 259         if (alloc_policy < ARRAY_SIZE(alloc_policy_name) &&
 260             alloc_policy_name[alloc_policy])
 261                 seq_puts(m, alloc_policy_name[alloc_policy]);
 262         else
 263                 seq_printf(m, "%d", alloc_policy);
 264         seq_puts(m, " ");
 265         blk_flags_show(m,
 266                        hctx->flags ^ BLK_ALLOC_POLICY_TO_MQ_FLAG(alloc_policy),
 267                        hctx_flag_name, ARRAY_SIZE(hctx_flag_name));
 268         seq_puts(m, "\n");
 269         return 0;
 270 }
 271
 272 #define REQ_OP_NAME(name) [REQ_OP_##name] = #name
 273 static const char *const op_name[] = {
 274         REQ_OP_NAME(READ),
 275         REQ_OP_NAME(WRITE),
 276         REQ_OP_NAME(FLUSH),
 277         REQ_OP_NAME(DISCARD),
 278         REQ_OP_NAME(ZONE_REPORT),
 279         REQ_OP_NAME(SECURE_ERASE),
 280         REQ_OP_NAME(ZONE_RESET),
 281         REQ_OP_NAME(WRITE_SAME),
 282         REQ_OP_NAME(WRITE_ZEROES),
 283         REQ_OP_NAME(SCSI_IN),
 284         REQ_OP_NAME(SCSI_OUT),
 285         REQ_OP_NAME(DRV_IN),
 286         REQ_OP_NAME(DRV_OUT),
 287 };
 288 #undef REQ_OP_NAME
 289
 290 #define CMD_FLAG_NAME(name) [__REQ_##name] = #name
 291 static const char *const cmd_flag_name[] = {
 292         CMD_FLAG_NAME(FAILFAST_DEV),
 293         CMD_FLAG_NAME(FAILFAST_TRANSPORT),
 294         CMD_FLAG_NAME(FAILFAST_DRIVER),
 295         CMD_FLAG_NAME(SYNC),
 296         CMD_FLAG_NAME(META),
 297         CMD_FLAG_NAME(PRIO),
 298         CMD_FLAG_NAME(NOMERGE),
 299         CMD_FLAG_NAME(IDLE),
 300         CMD_FLAG_NAME(INTEGRITY),
 301         CMD_FLAG_NAME(FUA),
 302         CMD_FLAG_NAME(PREFLUSH),
 303         CMD_FLAG_NAME(RAHEAD),
 304         CMD_FLAG_NAME(BACKGROUND),
 305         CMD_FLAG_NAME(NOUNMAP),
 306         CMD_FLAG_NAME(NOWAIT),
 307 };
 308 #undef CMD_FLAG_NAME
 309
 310 #define RQF_NAME(name) [ilog2((__force u32)RQF_##name)] = #name
 311 static const char *const rqf_name[] = {
 312         RQF_NAME(SORTED),
 313         RQF_NAME(STARTED),
 314         RQF_NAME(QUEUED),
 315         RQF_NAME(SOFTBARRIER),
 316         RQF_NAME(FLUSH_SEQ),
 317         RQF_NAME(MIXED_MERGE),
 318         RQF_NAME(MQ_INFLIGHT),
 319         RQF_NAME(DONTPREP),
 320         RQF_NAME(PREEMPT),
 321         RQF_NAME(COPY_USER),
 322         RQF_NAME(FAILED),
 323         RQF_NAME(QUIET),
 324         RQF_NAME(ELVPRIV),
 325         RQF_NAME(IO_STAT),
 326         RQF_NAME(ALLOCED),
 327         RQF_NAME(PM),
 328         RQF_NAME(HASHED),
 329         RQF_NAME(STATS),
 330         RQF_NAME(SPECIAL_PAYLOAD),
 331         RQF_NAME(ZONE_WRITE_LOCKED),
 332         RQF_NAME(MQ_POLL_SLEPT),
 333 };
 334 #undef RQF_NAME
 335
 336 static const char *const blk_mq_rq_state_name_array[] = {
 337         [MQ_RQ_IDLE]            = "idle",
 338         [MQ_RQ_IN_FLIGHT]       = "in_flight",
 339         [MQ_RQ_COMPLETE]        = "complete",
 340 };
 341
 342 static const char *blk_mq_rq_state_name(enum mq_rq_state rq_state)
 343 {
 344         if (WARN_ON_ONCE((unsigned int)rq_state >=
 345                          ARRAY_SIZE(blk_mq_rq_state_name_array)))
 346                 return "(?)";
 347         return blk_mq_rq_state_name_array[rq_state];
 348 }
 349
 350 int __blk_mq_debugfs_rq_show(struct seq_file *m, struct request *rq)
 351 {
 352         const struct blk_mq_ops *const mq_ops = rq->q->mq_ops;
 353         const unsigned int op = rq->cmd_flags & REQ_OP_MASK;
 354
 355         seq_printf(m, "%p {.op=", rq);
 356         if (op < ARRAY_SIZE(op_name) && op_name[op])
 357                 seq_printf(m, "%s", op_name[op]);
 358         else
 359                 seq_printf(m, "%d", op);
 360         seq_puts(m, ", .cmd_flags=");
 361         blk_flags_show(m, rq->cmd_flags & ~REQ_OP_MASK, cmd_flag_name,
 362                        ARRAY_SIZE(cmd_flag_name));
 363         seq_puts(m, ", .rq_flags=");
 364         blk_flags_show(m, (__force unsigned int)rq->rq_flags, rqf_name,
 365                        ARRAY_SIZE(rqf_name));
 366         seq_printf(m, ", .state=%s", blk_mq_rq_state_name(blk_mq_rq_state(rq)));
 367         seq_printf(m, ", .tag=%d, .internal_tag=%d", rq->tag,
 368                    rq->internal_tag);
 369         if (mq_ops->show_rq)
 370                 mq_ops->show_rq(m, rq);
 371         seq_puts(m, "}\n");
 372         return 0;
 373 }
 374 EXPORT_SYMBOL_GPL(__blk_mq_debugfs_rq_show);
 375
 376 int blk_mq_debugfs_rq_show(struct seq_file *m, void *v)
 377 {
 378         return __blk_mq_debugfs_rq_show(m, list_entry_rq(v));
 379 }
 380 EXPORT_SYMBOL_GPL(blk_mq_debugfs_rq_show);
 381
 382 static void *hctx_dispatch_start(struct seq_file *m, loff_t *pos)
 383         __acquires(&hctx->lock)
 384 {
 385         struct blk_mq_hw_ctx *hctx = m->private;
 386
 387         spin_lock(&hctx->lock);
 388         return seq_list_start(&hctx->dispatch, *pos);
 389 }
 390
 391 static void *hctx_dispatch_next(struct seq_file *m, void *v, loff_t *pos)
 392 {
 393         struct blk_mq_hw_ctx *hctx = m->private;
 394
 395         return seq_list_next(v, &hctx->dispatch, pos);
 396 }
 397
 398 static void hctx_dispatch_stop(struct seq_file *m, void *v)
 399         __releases(&hctx->lock)
 400 {
 401         struct blk_mq_hw_ctx *hctx = m->private;
 402
 403         spin_unlock(&hctx->lock);
 404 }
 405
 406 static const struct seq_operations hctx_dispatch_seq_ops = {
 407         .start  = hctx_dispatch_start,
 408         .next   = hctx_dispatch_next,
 409         .stop   = hctx_dispatch_stop,
 410         .show   = blk_mq_debugfs_rq_show,
 411 };
 412
 413 struct show_busy_params {
 414         struct seq_file         *m;
 415         struct blk_mq_hw_ctx    *hctx;
 416 };
 417
 418 /*
 419  * Note: the state of a request may change while this function is in progress,
 420  * e.g. due to a concurrent blk_mq_finish_request() call.
 421  */
 422 static void hctx_show_busy_rq(struct request *rq, void *data, bool reserved)
 423 {
 424         const struct show_busy_params *params = data;
 425
 426         if (blk_mq_map_queue(rq->q, rq->mq_ctx->cpu) == params->hctx &&
 427             blk_mq_rq_state(rq) != MQ_RQ_IDLE)
 428                 __blk_mq_debugfs_rq_show(params->m,
 429                                          list_entry_rq(&rq->queuelist));
 430 }
 431
 432 static int hctx_busy_show(void *data, struct seq_file *m)
 433 {
 434         struct blk_mq_hw_ctx *hctx = data;
 435         struct show_busy_params params = { .m = m, .hctx = hctx };
 436
 437         blk_mq_tagset_busy_iter(hctx->queue->tag_set, hctx_show_busy_rq,
 438                                 &params);
 439
 440         return 0;
 441 }
 442
 443 static int hctx_ctx_map_show(void *data, struct seq_file *m)
 444 {
 445         struct blk_mq_hw_ctx *hctx = data;
 446
 447         sbitmap_bitmap_show(&hctx->ctx_map, m);
 448         return 0;
 449 }
 450
 451 static void blk_mq_debugfs_tags_show(struct seq_file *m,
 452                                      struct blk_mq_tags *tags)
 453 {
 454         seq_printf(m, "nr_tags=%u\n", tags->nr_tags);
 455         seq_printf(m, "nr_reserved_tags=%u\n", tags->nr_reserved_tags);
 456         seq_printf(m, "active_queues=%d\n",
 457                    atomic_read(&tags->active_queues));
 458
 459         seq_puts(m, "\nbitmap_tags:\n");
 460         sbitmap_queue_show(&tags->bitmap_tags, m);
 461
 462         if (tags->nr_reserved_tags) {
 463                 seq_puts(m, "\nbreserved_tags:\n");
 464                 sbitmap_queue_show(&tags->breserved_tags, m);
 465         }
 466 }
 467
 468 static int hctx_tags_show(void *data, struct seq_file *m)
 469 {
 470         struct blk_mq_hw_ctx *hctx = data;
 471         struct request_queue *q = hctx->queue;
 472         int res;
 473
 474         res = mutex_lock_interruptible(&q->sysfs_lock);
 475         if (res)
 476                 goto out;
 477         if (hctx->tags)
 478                 blk_mq_debugfs_tags_show(m, hctx->tags);
 479         mutex_unlock(&q->sysfs_lock);
 480
 481 out:
 482         return res;
 483 }
 484
 485 static int hctx_tags_bitmap_show(void *data, struct seq_file *m)
 486 {
 487         struct blk_mq_hw_ctx *hctx = data;
 488         struct request_queue *q = hctx->queue;
 489         int res;
 490
 491         res = mutex_lock_interruptible(&q->sysfs_lock);
 492         if (res)
 493                 goto out;
 494         if (hctx->tags)
 495                 sbitmap_bitmap_show(&hctx->tags->bitmap_tags.sb, m);
 496         mutex_unlock(&q->sysfs_lock);
 497
 498 out:
 499         return res;
 500 }
 501
 502 static int hctx_sched_tags_show(void *data, struct seq_file *m)
 503 {
 504         struct blk_mq_hw_ctx *hctx = data;
 505         struct request_queue *q = hctx->queue;
 506         int res;
 507
 508         res = mutex_lock_interruptible(&q->sysfs_lock);
 509         if (res)
 510                 goto out;
 511         if (hctx->sched_tags)
 512                 blk_mq_debugfs_tags_show(m, hctx->sched_tags);
 513         mutex_unlock(&q->sysfs_lock);
 514
 515 out:
 516         return res;
 517 }
 518
 519 static int hctx_sched_tags_bitmap_show(void *data, struct seq_file *m)
 520 {
 521         struct blk_mq_hw_ctx *hctx = data;
 522         struct request_queue *q = hctx->queue;
 523         int res;
 524
 525         res = mutex_lock_interruptible(&q->sysfs_lock);
 526         if (res)
 527                 goto out;
 528         if (hctx->sched_tags)
 529                 sbitmap_bitmap_show(&hctx->sched_tags->bitmap_tags.sb, m);
 530         mutex_unlock(&q->sysfs_lock);
 531
 532 out:
 533         return res;
 534 }
 535
 536 static int hctx_io_poll_show(void *data, struct seq_file *m)
 537 {
 538         struct blk_mq_hw_ctx *hctx = data;
 539
 540         seq_printf(m, "considered=%lu\n", hctx->poll_considered);
 541         seq_printf(m, "invoked=%lu\n", hctx->poll_invoked);
 542         seq_printf(m, "success=%lu\n", hctx->poll_success);
 543         return 0;
 544 }
 545
 546 static ssize_t hctx_io_poll_write(void *data, const char __user *buf,
 547                                   size_t count, loff_t *ppos)
 548 {
 549         struct blk_mq_hw_ctx *hctx = data;
 550
 551         hctx->poll_considered = hctx->poll_invoked = hctx->poll_success = 0;
 552         return count;
 553 }
 554
 555 static int hctx_dispatched_show(void *data, struct seq_file *m)
 556 {
 557         struct blk_mq_hw_ctx *hctx = data;
 558         int i;
 559
 560         seq_printf(m, "%8u\t%lu\n", 0U, hctx->dispatched[0]);
 561
 562         for (i = 1; i < BLK_MQ_MAX_DISPATCH_ORDER - 1; i++) {
 563                 unsigned int d = 1U << (i - 1);
 564
 565                 seq_printf(m, "%8u\t%lu\n", d, hctx->dispatched[i]);
 566         }
 567
 568         seq_printf(m, "%8u+\t%lu\n", 1U << (i - 1), hctx->dispatched[i]);
 569         return 0;
 570 }
 571
 572 static ssize_t hctx_dispatched_write(void *data, const char __user *buf,
 573                                      size_t count, loff_t *ppos)
 574 {
 575         struct blk_mq_hw_ctx *hctx = data;
 576         int i;
 577
 578         for (i = 0; i < BLK_MQ_MAX_DISPATCH_ORDER; i++)
 579                 hctx->dispatched[i] = 0;
 580         return count;
 581 }
 582
 583 static int hctx_queued_show(void *data, struct seq_file *m)
 584 {
 585         struct blk_mq_hw_ctx *hctx = data;
 586
 587         seq_printf(m, "%lu\n", hctx->queued);
 588         return 0;
 589 }
 590
 591 static ssize_t hctx_queued_write(void *data, const char __user *buf,
 592                                  size_t count, loff_t *ppos)
 593 {
 594         struct blk_mq_hw_ctx *hctx = data;
 595
 596         hctx->queued = 0;
 597         return count;
 598 }
 599
 600 static int hctx_run_show(void *data, struct seq_file *m)
 601 {
 602         struct blk_mq_hw_ctx *hctx = data;
 603
 604         seq_printf(m, "%lu\n", hctx->run);
 605         return 0;
 606 }
 607
 608 static ssize_t hctx_run_write(void *data, const char __user *buf, size_t count,
 609                               loff_t *ppos)
 610 {
 611         struct blk_mq_hw_ctx *hctx = data;
 612
 613         hctx->run = 0;
 614         return count;
 615 }
 616
 617 static int hctx_active_show(void *data, struct seq_file *m)
 618 {
 619         struct blk_mq_hw_ctx *hctx = data;
 620
 621         seq_printf(m, "%d\n", atomic_read(&hctx->nr_active));
 622         return 0;
 623 }
 624
 625 static int hctx_dispatch_busy_show(void *data, struct seq_file *m)
 626 {
 627         struct blk_mq_hw_ctx *hctx = data;
 628
 629         seq_printf(m, "%u\n", hctx->dispatch_busy);
 630         return 0;
 631 }
 632
 633 static void *ctx_rq_list_start(struct seq_file *m, loff_t *pos)
 634         __acquires(&ctx->lock)
 635 {
 636         struct blk_mq_ctx *ctx = m->private;
 637
 638         spin_lock(&ctx->lock);
 639         return seq_list_start(&ctx->rq_list, *pos);
 640 }
 641
 642 static void *ctx_rq_list_next(struct seq_file *m, void *v, loff_t *pos)
 643 {
 644         struct blk_mq_ctx *ctx = m->private;
 645
 646         return seq_list_next(v, &ctx->rq_list, pos);
 647 }
 648
 649 static void ctx_rq_list_stop(struct seq_file *m, void *v)
 650         __releases(&ctx->lock)
 651 {
 652         struct blk_mq_ctx *ctx = m->private;
 653
 654         spin_unlock(&ctx->lock);
 655 }
 656
 657 static const struct seq_operations ctx_rq_list_seq_ops = {
 658         .start  = ctx_rq_list_start,
 659         .next   = ctx_rq_list_next,
 660         .stop   = ctx_rq_list_stop,
 661         .show   = blk_mq_debugfs_rq_show,
 662 };
 663 static int ctx_dispatched_show(void *data, struct seq_file *m)
 664 {
 665         struct blk_mq_ctx *ctx = data;
 666
 667         seq_printf(m, "%lu %lu\n", ctx->rq_dispatched[1], ctx->rq_dispatched[0]);
 668         return 0;
 669 }
 670
 671 static ssize_t ctx_dispatched_write(void *data, const char __user *buf,
 672                                     size_t count, loff_t *ppos)
 673 {
 674         struct blk_mq_ctx *ctx = data;
 675
 676         ctx->rq_dispatched[0] = ctx->rq_dispatched[1] = 0;
 677         return count;
 678 }
 679
 680 static int ctx_merged_show(void *data, struct seq_file *m)
 681 {
 682         struct blk_mq_ctx *ctx = data;
 683
 684         seq_printf(m, "%lu\n", ctx->rq_merged);
 685         return 0;
 686 }
 687
 688 static ssize_t ctx_merged_write(void *data, const char __user *buf,
 689                                 size_t count, loff_t *ppos)
 690 {
 691         struct blk_mq_ctx *ctx = data;
 692
 693         ctx->rq_merged = 0;
 694         return count;
 695 }
 696
 697 static int ctx_completed_show(void *data, struct seq_file *m)
 698 {
 699         struct blk_mq_ctx *ctx = data;
 700
 701         seq_printf(m, "%lu %lu\n", ctx->rq_completed[1], ctx->rq_completed[0]);
 702         return 0;
 703 }
 704
 705 static ssize_t ctx_completed_write(void *data, const char __user *buf,
 706                                    size_t count, loff_t *ppos)
 707 {
 708         struct blk_mq_ctx *ctx = data;
 709
 710         ctx->rq_completed[0] = ctx->rq_completed[1] = 0;
 711         return count;
 712 }
 713
 714 static int blk_mq_debugfs_show(struct seq_file *m, void *v)
 715 {
 716         const struct blk_mq_debugfs_attr *attr = m->private;
 717         void *data = d_inode(m->file->f_path.dentry->d_parent)->i_private;
 718
 719         return attr->show(data, m);
 720 }
 721
 722 static ssize_t blk_mq_debugfs_write(struct file *file, const char __user *buf,
 723                                     size_t count, loff_t *ppos)
 724 {
 725         struct seq_file *m = file->private_data;
 726         const struct blk_mq_debugfs_attr *attr = m->private;
 727         void *data = d_inode(file->f_path.dentry->d_parent)->i_private;
 728
 729         /*
 730          * Attributes that only implement .seq_ops are read-only and 'attr' is
 731          * the same with 'data' in this case.
 732          */
 733         if (attr == data || !attr->write)
 734                 return -EPERM;
 735
 736         return attr->write(data, buf, count, ppos);
 737 }
 738
 739 static int blk_mq_debugfs_open(struct inode *inode, struct file *file)
 740 {
 741         const struct blk_mq_debugfs_attr *attr = inode->i_private;
 742         void *data = d_inode(file->f_path.dentry->d_parent)->i_private;
 743         struct seq_file *m;
 744         int ret;
 745
 746         if (attr->seq_ops) {
 747                 ret = seq_open(file, attr->seq_ops);
 748                 if (!ret) {
 749                         m = file->private_data;
 750                         m->private = data;
 751                 }
 752                 return ret;
 753         }
 754
 755         if (WARN_ON_ONCE(!attr->show))
 756                 return -EPERM;
 757
 758         return single_open(file, blk_mq_debugfs_show, inode->i_private);
 759 }
 760
 761 static int blk_mq_debugfs_release(struct inode *inode, struct file *file)
 762 {
 763         const struct blk_mq_debugfs_attr *attr = inode->i_private;
 764
 765         if (attr->show)
 766                 return single_release(inode, file);
 767         else
 768                 return seq_release(inode, file);
 769 }
 770
 771 static const struct file_operations blk_mq_debugfs_fops = {
 772         .open           = blk_mq_debugfs_open,
 773         .read           = seq_read,
 774         .write          = blk_mq_debugfs_write,
 775         .llseek         = seq_lseek,
 776         .release        = blk_mq_debugfs_release,
 777 };
 778
 779 static const struct blk_mq_debugfs_attr blk_mq_debugfs_hctx_attrs[] = {
 780         {"state", 0400, hctx_state_show},
 781         {"flags", 0400, hctx_flags_show},
 782         {"dispatch", 0400, .seq_ops = &hctx_dispatch_seq_ops},
 783         {"busy", 0400, hctx_busy_show},
 784         {"ctx_map", 0400, hctx_ctx_map_show},
 785         {"tags", 0400, hctx_tags_show},
 786         {"tags_bitmap", 0400, hctx_tags_bitmap_show},
 787         {"sched_tags", 0400, hctx_sched_tags_show},
 788         {"sched_tags_bitmap", 0400, hctx_sched_tags_bitmap_show},
 789         {"io_poll", 0600, hctx_io_poll_show, hctx_io_poll_write},
 790         {"dispatched", 0600, hctx_dispatched_show, hctx_dispatched_write},
 791         {"queued", 0600, hctx_queued_show, hctx_queued_write},
 792         {"run", 0600, hctx_run_show, hctx_run_write},
 793         {"active", 0400, hctx_active_show},
 794         {"dispatch_busy", 0400, hctx_dispatch_busy_show},
 795         {},
 796 };
 797
 798 static const struct blk_mq_debugfs_attr blk_mq_debugfs_ctx_attrs[] = {
 799         {"rq_list", 0400, .seq_ops = &ctx_rq_list_seq_ops},
 800         {"dispatched", 0600, ctx_dispatched_show, ctx_dispatched_write},
 801         {"merged", 0600, ctx_merged_show, ctx_merged_write},
 802         {"completed", 0600, ctx_completed_show, ctx_completed_write},
 803         {},
 804 };
 805
 806 static bool debugfs_create_files(struct dentry *parent, void *data,
 807                                  const struct blk_mq_debugfs_attr *attr)
 808 {
 809         d_inode(parent)->i_private = data;
 810
 811         for (; attr->name; attr++) {
 812                 if (!debugfs_create_file(attr->name, attr->mode, parent,
 813                                          (void *)attr, &blk_mq_debugfs_fops))
 814                         return false;
 815         }
 816         return true;
 817 }
 818
 819 int blk_mq_debugfs_register(struct request_queue *q)
 820 {
 821         struct blk_mq_hw_ctx *hctx;
 822         int i;
 823
 824         if (!blk_debugfs_root)
 825                 return -ENOENT;
 826
 827         q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
 828                                             blk_debugfs_root);
 829         if (!q->debugfs_dir)
 830                 return -ENOMEM;
 831
 832         if (!debugfs_create_files(q->debugfs_dir, q,
 833                                   blk_mq_debugfs_queue_attrs))
 834                 goto err;
 835
 836         /*
 837          * blk_mq_init_sched() attempted to do this already, but q->debugfs_dir
 838          * didn't exist yet (because we don't know what to name the directory
 839          * until the queue is registered to a gendisk).
 840          */
 841         if (q->elevator && !q->sched_debugfs_dir)
 842                 blk_mq_debugfs_register_sched(q);
 843
 844         /* Similarly, blk_mq_init_hctx() couldn't do this previously. */
 845         queue_for_each_hw_ctx(q, hctx, i) {
 846                 if (!hctx->debugfs_dir && blk_mq_debugfs_register_hctx(q, hctx))
 847                         goto err;
 848                 if (q->elevator && !hctx->sched_debugfs_dir &&
 849                     blk_mq_debugfs_register_sched_hctx(q, hctx))
 850                         goto err;
 851         }
 852
 853         return 0;
 854
 855 err:
 856         blk_mq_debugfs_unregister(q);
 857         return -ENOMEM;
 858 }
 859
 860 void blk_mq_debugfs_unregister(struct request_queue *q)
 861 {
 862         debugfs_remove_recursive(q->debugfs_dir);
 863         q->sched_debugfs_dir = NULL;
 864         q->debugfs_dir = NULL;
 865 }
 866
 867 static int blk_mq_debugfs_register_ctx(struct blk_mq_hw_ctx *hctx,
 868                                        struct blk_mq_ctx *ctx)
 869 {
 870         struct dentry *ctx_dir;
 871         char name[20];
 872
 873         snprintf(name, sizeof(name), "cpu%u", ctx->cpu);
 874         ctx_dir = debugfs_create_dir(name, hctx->debugfs_dir);
 875         if (!ctx_dir)
 876                 return -ENOMEM;
 877
 878         if (!debugfs_create_files(ctx_dir, ctx, blk_mq_debugfs_ctx_attrs))
 879                 return -ENOMEM;
 880
 881         return 0;
 882 }
 883
 884 int blk_mq_debugfs_register_hctx(struct request_queue *q,
 885                                  struct blk_mq_hw_ctx *hctx)
 886 {
 887         struct blk_mq_ctx *ctx;
 888         char name[20];
 889         int i;
 890
 891         if (!q->debugfs_dir)
 892                 return -ENOENT;
 893
 894         snprintf(name, sizeof(name), "hctx%u", hctx->queue_num);
 895         hctx->debugfs_dir = debugfs_create_dir(name, q->debugfs_dir);
 896         if (!hctx->debugfs_dir)
 897                 return -ENOMEM;
 898
 899         if (!debugfs_create_files(hctx->debugfs_dir, hctx,
 900                                   blk_mq_debugfs_hctx_attrs))
 901                 goto err;
 902
 903         hctx_for_each_ctx(hctx, ctx, i) {
 904                 if (blk_mq_debugfs_register_ctx(hctx, ctx))
 905                         goto err;
 906         }
 907
 908         return 0;
 909
 910 err:
 911         blk_mq_debugfs_unregister_hctx(hctx);
 912         return -ENOMEM;
 913 }
 914
 915 void blk_mq_debugfs_unregister_hctx(struct blk_mq_hw_ctx *hctx)
 916 {
 917         debugfs_remove_recursive(hctx->debugfs_dir);
 918         hctx->sched_debugfs_dir = NULL;
 919         hctx->debugfs_dir = NULL;
 920 }
 921
 922 int blk_mq_debugfs_register_hctxs(struct request_queue *q)
 923 {
 924         struct blk_mq_hw_ctx *hctx;
 925         int i;
 926
 927         queue_for_each_hw_ctx(q, hctx, i) {
 928                 if (blk_mq_debugfs_register_hctx(q, hctx))
 929                         return -ENOMEM;
 930         }
 931
 932         return 0;
 933 }
 934
 935 void blk_mq_debugfs_unregister_hctxs(struct request_queue *q)
 936 {
 937         struct blk_mq_hw_ctx *hctx;
 938         int i;
 939
 940         queue_for_each_hw_ctx(q, hctx, i)
 941                 blk_mq_debugfs_unregister_hctx(hctx);
 942 }
 943
 944 int blk_mq_debugfs_register_sched(struct request_queue *q)
 945 {
 946         struct elevator_type *e = q->elevator->type;
 947
 948         if (!q->debugfs_dir)
 949                 return -ENOENT;
 950
 951         if (!e->queue_debugfs_attrs)
 952                 return 0;
 953
 954         q->sched_debugfs_dir = debugfs_create_dir("sched", q->debugfs_dir);
 955         if (!q->sched_debugfs_dir)
 956                 return -ENOMEM;
 957
 958         if (!debugfs_create_files(q->sched_debugfs_dir, q,
 959                                   e->queue_debugfs_attrs))
 960                 goto err;
 961
 962         return 0;
 963
 964 err:
 965         blk_mq_debugfs_unregister_sched(q);
 966         return -ENOMEM;
 967 }
 968
 969 void blk_mq_debugfs_unregister_sched(struct request_queue *q)
 970 {
 971         debugfs_remove_recursive(q->sched_debugfs_dir);
 972         q->sched_debugfs_dir = NULL;
 973 }
 974
 975 int blk_mq_debugfs_register_sched_hctx(struct request_queue *q,
 976                                        struct blk_mq_hw_ctx *hctx)
 977 {
 978         struct elevator_type *e = q->elevator->type;
 979
 980         if (!hctx->debugfs_dir)
 981                 return -ENOENT;
 982
 983         if (!e->hctx_debugfs_attrs)
 984                 return 0;
 985
 986         hctx->sched_debugfs_dir = debugfs_create_dir("sched",
 987                                                      hctx->debugfs_dir);
 988         if (!hctx->sched_debugfs_dir)
 989                 return -ENOMEM;
 990
 991         if (!debugfs_create_files(hctx->sched_debugfs_dir, hctx,
 992                                   e->hctx_debugfs_attrs))
 993                 return -ENOMEM;
 994
 995         return 0;
 996 }
 997
 998 void blk_mq_debugfs_unregister_sched_hctx(struct blk_mq_hw_ctx *hctx)
 999 {
1000         debugfs_remove_recursive(hctx->sched_debugfs_dir);
1001         hctx->sched_debugfs_dir = NULL;
1002 }