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