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 int queue_zone_wlock_show(void *data, struct seq_file *m)
 210 {
 211         struct request_queue *q = data;
 212         unsigned int i;
 213
 214         if (!q->seq_zones_wlock)
 215                 return 0;
 216
 217         for (i = 0; i < blk_queue_nr_zones(q); i++)
 218                 if (test_bit(i, q->seq_zones_wlock))
 219                         seq_printf(m, "%u\n", i);
 220
 221         return 0;
 222 }
 223
 224 static const struct blk_mq_debugfs_attr blk_mq_debugfs_queue_attrs[] = {
 225         { "poll_stat", 0400, queue_poll_stat_show },
 226         { "requeue_list", 0400, .seq_ops = &queue_requeue_list_seq_ops },
 227         { "state", 0600, queue_state_show, queue_state_write },
 228         { "write_hints", 0600, queue_write_hint_show, queue_write_hint_store },
 229         { "zone_wlock", 0400, queue_zone_wlock_show, NULL },
 230         { },
 231 };
 232
 233 #define HCTX_STATE_NAME(name) [BLK_MQ_S_##name] = #name
 234 static const char *const hctx_state_name[] = {
 235         HCTX_STATE_NAME(STOPPED),
 236         HCTX_STATE_NAME(TAG_ACTIVE),
 237         HCTX_STATE_NAME(SCHED_RESTART),
 238 };
 239 #undef HCTX_STATE_NAME
 240
 241 static int hctx_state_show(void *data, struct seq_file *m)
 242 {
 243         struct blk_mq_hw_ctx *hctx = data;
 244
 245         blk_flags_show(m, hctx->state, hctx_state_name,
 246                        ARRAY_SIZE(hctx_state_name));
 247         seq_puts(m, "\n");
 248         return 0;
 249 }
 250
 251 #define BLK_TAG_ALLOC_NAME(name) [BLK_TAG_ALLOC_##name] = #name
 252 static const char *const alloc_policy_name[] = {
 253         BLK_TAG_ALLOC_NAME(FIFO),
 254         BLK_TAG_ALLOC_NAME(RR),
 255 };
 256 #undef BLK_TAG_ALLOC_NAME
 257
 258 #define HCTX_FLAG_NAME(name) [ilog2(BLK_MQ_F_##name)] = #name
 259 static const char *const hctx_flag_name[] = {
 260         HCTX_FLAG_NAME(SHOULD_MERGE),
 261         HCTX_FLAG_NAME(TAG_SHARED),
 262         HCTX_FLAG_NAME(SG_MERGE),
 263         HCTX_FLAG_NAME(BLOCKING),
 264         HCTX_FLAG_NAME(NO_SCHED),
 265 };
 266 #undef HCTX_FLAG_NAME
 267
 268 static int hctx_flags_show(void *data, struct seq_file *m)
 269 {
 270         struct blk_mq_hw_ctx *hctx = data;
 271         const int alloc_policy = BLK_MQ_FLAG_TO_ALLOC_POLICY(hctx->flags);
 272
 273         seq_puts(m, "alloc_policy=");
 274         if (alloc_policy < ARRAY_SIZE(alloc_policy_name) &&
 275             alloc_policy_name[alloc_policy])
 276                 seq_puts(m, alloc_policy_name[alloc_policy]);
 277         else
 278                 seq_printf(m, "%d", alloc_policy);
 279         seq_puts(m, " ");
 280         blk_flags_show(m,
 281                        hctx->flags ^ BLK_ALLOC_POLICY_TO_MQ_FLAG(alloc_policy),
 282                        hctx_flag_name, ARRAY_SIZE(hctx_flag_name));
 283         seq_puts(m, "\n");
 284         return 0;
 285 }
 286
 287 #define REQ_OP_NAME(name) [REQ_OP_##name] = #name
 288 static const char *const op_name[] = {
 289         REQ_OP_NAME(READ),
 290         REQ_OP_NAME(WRITE),
 291         REQ_OP_NAME(FLUSH),
 292         REQ_OP_NAME(DISCARD),
 293         REQ_OP_NAME(ZONE_REPORT),
 294         REQ_OP_NAME(SECURE_ERASE),
 295         REQ_OP_NAME(ZONE_RESET),
 296         REQ_OP_NAME(WRITE_SAME),
 297         REQ_OP_NAME(WRITE_ZEROES),
 298         REQ_OP_NAME(SCSI_IN),
 299         REQ_OP_NAME(SCSI_OUT),
 300         REQ_OP_NAME(DRV_IN),
 301         REQ_OP_NAME(DRV_OUT),
 302 };
 303 #undef REQ_OP_NAME
 304
 305 #define CMD_FLAG_NAME(name) [__REQ_##name] = #name
 306 static const char *const cmd_flag_name[] = {
 307         CMD_FLAG_NAME(FAILFAST_DEV),
 308         CMD_FLAG_NAME(FAILFAST_TRANSPORT),
 309         CMD_FLAG_NAME(FAILFAST_DRIVER),
 310         CMD_FLAG_NAME(SYNC),
 311         CMD_FLAG_NAME(META),
 312         CMD_FLAG_NAME(PRIO),
 313         CMD_FLAG_NAME(NOMERGE),
 314         CMD_FLAG_NAME(IDLE),
 315         CMD_FLAG_NAME(INTEGRITY),
 316         CMD_FLAG_NAME(FUA),
 317         CMD_FLAG_NAME(PREFLUSH),
 318         CMD_FLAG_NAME(RAHEAD),
 319         CMD_FLAG_NAME(BACKGROUND),
 320         CMD_FLAG_NAME(NOUNMAP),
 321         CMD_FLAG_NAME(NOWAIT),
 322 };
 323 #undef CMD_FLAG_NAME
 324
 325 #define RQF_NAME(name) [ilog2((__force u32)RQF_##name)] = #name
 326 static const char *const rqf_name[] = {
 327         RQF_NAME(SORTED),
 328         RQF_NAME(STARTED),
 329         RQF_NAME(QUEUED),
 330         RQF_NAME(SOFTBARRIER),
 331         RQF_NAME(FLUSH_SEQ),
 332         RQF_NAME(MIXED_MERGE),
 333         RQF_NAME(MQ_INFLIGHT),
 334         RQF_NAME(DONTPREP),
 335         RQF_NAME(PREEMPT),
 336         RQF_NAME(COPY_USER),
 337         RQF_NAME(FAILED),
 338         RQF_NAME(QUIET),
 339         RQF_NAME(ELVPRIV),
 340         RQF_NAME(IO_STAT),
 341         RQF_NAME(ALLOCED),
 342         RQF_NAME(PM),
 343         RQF_NAME(HASHED),
 344         RQF_NAME(STATS),
 345         RQF_NAME(SPECIAL_PAYLOAD),
 346         RQF_NAME(ZONE_WRITE_LOCKED),
 347         RQF_NAME(MQ_POLL_SLEPT),
 348 };
 349 #undef RQF_NAME
 350
 351 static const char *const blk_mq_rq_state_name_array[] = {
 352         [MQ_RQ_IDLE]            = "idle",
 353         [MQ_RQ_IN_FLIGHT]       = "in_flight",
 354         [MQ_RQ_COMPLETE]        = "complete",
 355 };
 356
 357 static const char *blk_mq_rq_state_name(enum mq_rq_state rq_state)
 358 {
 359         if (WARN_ON_ONCE((unsigned int)rq_state >=
 360                          ARRAY_SIZE(blk_mq_rq_state_name_array)))
 361                 return "(?)";
 362         return blk_mq_rq_state_name_array[rq_state];
 363 }
 364
 365 int __blk_mq_debugfs_rq_show(struct seq_file *m, struct request *rq)
 366 {
 367         const struct blk_mq_ops *const mq_ops = rq->q->mq_ops;
 368         const unsigned int op = rq->cmd_flags & REQ_OP_MASK;
 369
 370         seq_printf(m, "%p {.op=", rq);
 371         if (op < ARRAY_SIZE(op_name) && op_name[op])
 372                 seq_printf(m, "%s", op_name[op]);
 373         else
 374                 seq_printf(m, "%d", op);
 375         seq_puts(m, ", .cmd_flags=");
 376         blk_flags_show(m, rq->cmd_flags & ~REQ_OP_MASK, cmd_flag_name,
 377                        ARRAY_SIZE(cmd_flag_name));
 378         seq_puts(m, ", .rq_flags=");
 379         blk_flags_show(m, (__force unsigned int)rq->rq_flags, rqf_name,
 380                        ARRAY_SIZE(rqf_name));
 381         seq_printf(m, ", .state=%s", blk_mq_rq_state_name(blk_mq_rq_state(rq)));
 382         seq_printf(m, ", .tag=%d, .internal_tag=%d", rq->tag,
 383                    rq->internal_tag);
 384         if (mq_ops->show_rq)
 385                 mq_ops->show_rq(m, rq);
 386         seq_puts(m, "}\n");
 387         return 0;
 388 }
 389 EXPORT_SYMBOL_GPL(__blk_mq_debugfs_rq_show);
 390
 391 int blk_mq_debugfs_rq_show(struct seq_file *m, void *v)
 392 {
 393         return __blk_mq_debugfs_rq_show(m, list_entry_rq(v));
 394 }
 395 EXPORT_SYMBOL_GPL(blk_mq_debugfs_rq_show);
 396
 397 static void *hctx_dispatch_start(struct seq_file *m, loff_t *pos)
 398         __acquires(&hctx->lock)
 399 {
 400         struct blk_mq_hw_ctx *hctx = m->private;
 401
 402         spin_lock(&hctx->lock);
 403         return seq_list_start(&hctx->dispatch, *pos);
 404 }
 405
 406 static void *hctx_dispatch_next(struct seq_file *m, void *v, loff_t *pos)
 407 {
 408         struct blk_mq_hw_ctx *hctx = m->private;
 409
 410         return seq_list_next(v, &hctx->dispatch, pos);
 411 }
 412
 413 static void hctx_dispatch_stop(struct seq_file *m, void *v)
 414         __releases(&hctx->lock)
 415 {
 416         struct blk_mq_hw_ctx *hctx = m->private;
 417
 418         spin_unlock(&hctx->lock);
 419 }
 420
 421 static const struct seq_operations hctx_dispatch_seq_ops = {
 422         .start  = hctx_dispatch_start,
 423         .next   = hctx_dispatch_next,
 424         .stop   = hctx_dispatch_stop,
 425         .show   = blk_mq_debugfs_rq_show,
 426 };
 427
 428 struct show_busy_params {
 429         struct seq_file         *m;
 430         struct blk_mq_hw_ctx    *hctx;
 431 };
 432
 433 /*
 434  * Note: the state of a request may change while this function is in progress,
 435  * e.g. due to a concurrent blk_mq_finish_request() call.
 436  */
 437 static void hctx_show_busy_rq(struct request *rq, void *data, bool reserved)
 438 {
 439         const struct show_busy_params *params = data;
 440
 441         if (blk_mq_map_queue(rq->q, rq->mq_ctx->cpu) == params->hctx &&
 442             blk_mq_rq_state(rq) != MQ_RQ_IDLE)
 443                 __blk_mq_debugfs_rq_show(params->m,
 444                                          list_entry_rq(&rq->queuelist));
 445 }
 446
 447 static int hctx_busy_show(void *data, struct seq_file *m)
 448 {
 449         struct blk_mq_hw_ctx *hctx = data;
 450         struct show_busy_params params = { .m = m, .hctx = hctx };
 451
 452         blk_mq_tagset_busy_iter(hctx->queue->tag_set, hctx_show_busy_rq,
 453                                 &params);
 454
 455         return 0;
 456 }
 457
 458 static int hctx_ctx_map_show(void *data, struct seq_file *m)
 459 {
 460         struct blk_mq_hw_ctx *hctx = data;
 461
 462         sbitmap_bitmap_show(&hctx->ctx_map, m);
 463         return 0;
 464 }
 465
 466 static void blk_mq_debugfs_tags_show(struct seq_file *m,
 467                                      struct blk_mq_tags *tags)
 468 {
 469         seq_printf(m, "nr_tags=%u\n", tags->nr_tags);
 470         seq_printf(m, "nr_reserved_tags=%u\n", tags->nr_reserved_tags);
 471         seq_printf(m, "active_queues=%d\n",
 472                    atomic_read(&tags->active_queues));
 473
 474         seq_puts(m, "\nbitmap_tags:\n");
 475         sbitmap_queue_show(&tags->bitmap_tags, m);
 476
 477         if (tags->nr_reserved_tags) {
 478                 seq_puts(m, "\nbreserved_tags:\n");
 479                 sbitmap_queue_show(&tags->breserved_tags, m);
 480         }
 481 }
 482
 483 static int hctx_tags_show(void *data, struct seq_file *m)
 484 {
 485         struct blk_mq_hw_ctx *hctx = data;
 486         struct request_queue *q = hctx->queue;
 487         int res;
 488
 489         res = mutex_lock_interruptible(&q->sysfs_lock);
 490         if (res)
 491                 goto out;
 492         if (hctx->tags)
 493                 blk_mq_debugfs_tags_show(m, hctx->tags);
 494         mutex_unlock(&q->sysfs_lock);
 495
 496 out:
 497         return res;
 498 }
 499
 500 static int hctx_tags_bitmap_show(void *data, struct seq_file *m)
 501 {
 502         struct blk_mq_hw_ctx *hctx = data;
 503         struct request_queue *q = hctx->queue;
 504         int res;
 505
 506         res = mutex_lock_interruptible(&q->sysfs_lock);
 507         if (res)
 508                 goto out;
 509         if (hctx->tags)
 510                 sbitmap_bitmap_show(&hctx->tags->bitmap_tags.sb, m);
 511         mutex_unlock(&q->sysfs_lock);
 512
 513 out:
 514         return res;
 515 }
 516
 517 static int hctx_sched_tags_show(void *data, struct seq_file *m)
 518 {
 519         struct blk_mq_hw_ctx *hctx = data;
 520         struct request_queue *q = hctx->queue;
 521         int res;
 522
 523         res = mutex_lock_interruptible(&q->sysfs_lock);
 524         if (res)
 525                 goto out;
 526         if (hctx->sched_tags)
 527                 blk_mq_debugfs_tags_show(m, hctx->sched_tags);
 528         mutex_unlock(&q->sysfs_lock);
 529
 530 out:
 531         return res;
 532 }
 533
 534 static int hctx_sched_tags_bitmap_show(void *data, struct seq_file *m)
 535 {
 536         struct blk_mq_hw_ctx *hctx = data;
 537         struct request_queue *q = hctx->queue;
 538         int res;
 539
 540         res = mutex_lock_interruptible(&q->sysfs_lock);
 541         if (res)
 542                 goto out;
 543         if (hctx->sched_tags)
 544                 sbitmap_bitmap_show(&hctx->sched_tags->bitmap_tags.sb, m);
 545         mutex_unlock(&q->sysfs_lock);
 546
 547 out:
 548         return res;
 549 }
 550
 551 static int hctx_io_poll_show(void *data, struct seq_file *m)
 552 {
 553         struct blk_mq_hw_ctx *hctx = data;
 554
 555         seq_printf(m, "considered=%lu\n", hctx->poll_considered);
 556         seq_printf(m, "invoked=%lu\n", hctx->poll_invoked);
 557         seq_printf(m, "success=%lu\n", hctx->poll_success);
 558         return 0;
 559 }
 560
 561 static ssize_t hctx_io_poll_write(void *data, const char __user *buf,
 562                                   size_t count, loff_t *ppos)
 563 {
 564         struct blk_mq_hw_ctx *hctx = data;
 565
 566         hctx->poll_considered = hctx->poll_invoked = hctx->poll_success = 0;
 567         return count;
 568 }
 569
 570 static int hctx_dispatched_show(void *data, struct seq_file *m)
 571 {
 572         struct blk_mq_hw_ctx *hctx = data;
 573         int i;
 574
 575         seq_printf(m, "%8u\t%lu\n", 0U, hctx->dispatched[0]);
 576
 577         for (i = 1; i < BLK_MQ_MAX_DISPATCH_ORDER - 1; i++) {
 578                 unsigned int d = 1U << (i - 1);
 579
 580                 seq_printf(m, "%8u\t%lu\n", d, hctx->dispatched[i]);
 581         }
 582
 583         seq_printf(m, "%8u+\t%lu\n", 1U << (i - 1), hctx->dispatched[i]);
 584         return 0;
 585 }
 586
 587 static ssize_t hctx_dispatched_write(void *data, const char __user *buf,
 588                                      size_t count, loff_t *ppos)
 589 {
 590         struct blk_mq_hw_ctx *hctx = data;
 591         int i;
 592
 593         for (i = 0; i < BLK_MQ_MAX_DISPATCH_ORDER; i++)
 594                 hctx->dispatched[i] = 0;
 595         return count;
 596 }
 597
 598 static int hctx_queued_show(void *data, struct seq_file *m)
 599 {
 600         struct blk_mq_hw_ctx *hctx = data;
 601
 602         seq_printf(m, "%lu\n", hctx->queued);
 603         return 0;
 604 }
 605
 606 static ssize_t hctx_queued_write(void *data, const char __user *buf,
 607                                  size_t count, loff_t *ppos)
 608 {
 609         struct blk_mq_hw_ctx *hctx = data;
 610
 611         hctx->queued = 0;
 612         return count;
 613 }
 614
 615 static int hctx_run_show(void *data, struct seq_file *m)
 616 {
 617         struct blk_mq_hw_ctx *hctx = data;
 618
 619         seq_printf(m, "%lu\n", hctx->run);
 620         return 0;
 621 }
 622
 623 static ssize_t hctx_run_write(void *data, const char __user *buf, size_t count,
 624                               loff_t *ppos)
 625 {
 626         struct blk_mq_hw_ctx *hctx = data;
 627
 628         hctx->run = 0;
 629         return count;
 630 }
 631
 632 static int hctx_active_show(void *data, struct seq_file *m)
 633 {
 634         struct blk_mq_hw_ctx *hctx = data;
 635
 636         seq_printf(m, "%d\n", atomic_read(&hctx->nr_active));
 637         return 0;
 638 }
 639
 640 static void *ctx_rq_list_start(struct seq_file *m, loff_t *pos)
 641         __acquires(&ctx->lock)
 642 {
 643         struct blk_mq_ctx *ctx = m->private;
 644
 645         spin_lock(&ctx->lock);
 646         return seq_list_start(&ctx->rq_list, *pos);
 647 }
 648
 649 static void *ctx_rq_list_next(struct seq_file *m, void *v, loff_t *pos)
 650 {
 651         struct blk_mq_ctx *ctx = m->private;
 652
 653         return seq_list_next(v, &ctx->rq_list, pos);
 654 }
 655
 656 static void ctx_rq_list_stop(struct seq_file *m, void *v)
 657         __releases(&ctx->lock)
 658 {
 659         struct blk_mq_ctx *ctx = m->private;
 660
 661         spin_unlock(&ctx->lock);
 662 }
 663
 664 static const struct seq_operations ctx_rq_list_seq_ops = {
 665         .start  = ctx_rq_list_start,
 666         .next   = ctx_rq_list_next,
 667         .stop   = ctx_rq_list_stop,
 668         .show   = blk_mq_debugfs_rq_show,
 669 };
 670 static int ctx_dispatched_show(void *data, struct seq_file *m)
 671 {
 672         struct blk_mq_ctx *ctx = data;
 673
 674         seq_printf(m, "%lu %lu\n", ctx->rq_dispatched[1], ctx->rq_dispatched[0]);
 675         return 0;
 676 }
 677
 678 static ssize_t ctx_dispatched_write(void *data, const char __user *buf,
 679                                     size_t count, loff_t *ppos)
 680 {
 681         struct blk_mq_ctx *ctx = data;
 682
 683         ctx->rq_dispatched[0] = ctx->rq_dispatched[1] = 0;
 684         return count;
 685 }
 686
 687 static int ctx_merged_show(void *data, struct seq_file *m)
 688 {
 689         struct blk_mq_ctx *ctx = data;
 690
 691         seq_printf(m, "%lu\n", ctx->rq_merged);
 692         return 0;
 693 }
 694
 695 static ssize_t ctx_merged_write(void *data, const char __user *buf,
 696                                 size_t count, loff_t *ppos)
 697 {
 698         struct blk_mq_ctx *ctx = data;
 699
 700         ctx->rq_merged = 0;
 701         return count;
 702 }
 703
 704 static int ctx_completed_show(void *data, struct seq_file *m)
 705 {
 706         struct blk_mq_ctx *ctx = data;
 707
 708         seq_printf(m, "%lu %lu\n", ctx->rq_completed[1], ctx->rq_completed[0]);
 709         return 0;
 710 }
 711
 712 static ssize_t ctx_completed_write(void *data, const char __user *buf,
 713                                    size_t count, loff_t *ppos)
 714 {
 715         struct blk_mq_ctx *ctx = data;
 716
 717         ctx->rq_completed[0] = ctx->rq_completed[1] = 0;
 718         return count;
 719 }
 720
 721 static int blk_mq_debugfs_show(struct seq_file *m, void *v)
 722 {
 723         const struct blk_mq_debugfs_attr *attr = m->private;
 724         void *data = d_inode(m->file->f_path.dentry->d_parent)->i_private;
 725
 726         return attr->show(data, m);
 727 }
 728
 729 static ssize_t blk_mq_debugfs_write(struct file *file, const char __user *buf,
 730                                     size_t count, loff_t *ppos)
 731 {
 732         struct seq_file *m = file->private_data;
 733         const struct blk_mq_debugfs_attr *attr = m->private;
 734         void *data = d_inode(file->f_path.dentry->d_parent)->i_private;
 735
 736         /*
 737          * Attributes that only implement .seq_ops are read-only and 'attr' is
 738          * the same with 'data' in this case.
 739          */
 740         if (attr == data || !attr->write)
 741                 return -EPERM;
 742
 743         return attr->write(data, buf, count, ppos);
 744 }
 745
 746 static int blk_mq_debugfs_open(struct inode *inode, struct file *file)
 747 {
 748         const struct blk_mq_debugfs_attr *attr = inode->i_private;
 749         void *data = d_inode(file->f_path.dentry->d_parent)->i_private;
 750         struct seq_file *m;
 751         int ret;
 752
 753         if (attr->seq_ops) {
 754                 ret = seq_open(file, attr->seq_ops);
 755                 if (!ret) {
 756                         m = file->private_data;
 757                         m->private = data;
 758                 }
 759                 return ret;
 760         }
 761
 762         if (WARN_ON_ONCE(!attr->show))
 763                 return -EPERM;
 764
 765         return single_open(file, blk_mq_debugfs_show, inode->i_private);
 766 }
 767
 768 static int blk_mq_debugfs_release(struct inode *inode, struct file *file)
 769 {
 770         const struct blk_mq_debugfs_attr *attr = inode->i_private;
 771
 772         if (attr->show)
 773                 return single_release(inode, file);
 774         else
 775                 return seq_release(inode, file);
 776 }
 777
 778 static const struct file_operations blk_mq_debugfs_fops = {
 779         .open           = blk_mq_debugfs_open,
 780         .read           = seq_read,
 781         .write          = blk_mq_debugfs_write,
 782         .llseek         = seq_lseek,
 783         .release        = blk_mq_debugfs_release,
 784 };
 785
 786 static const struct blk_mq_debugfs_attr blk_mq_debugfs_hctx_attrs[] = {
 787         {"state", 0400, hctx_state_show},
 788         {"flags", 0400, hctx_flags_show},
 789         {"dispatch", 0400, .seq_ops = &hctx_dispatch_seq_ops},
 790         {"busy", 0400, hctx_busy_show},
 791         {"ctx_map", 0400, hctx_ctx_map_show},
 792         {"tags", 0400, hctx_tags_show},
 793         {"tags_bitmap", 0400, hctx_tags_bitmap_show},
 794         {"sched_tags", 0400, hctx_sched_tags_show},
 795         {"sched_tags_bitmap", 0400, hctx_sched_tags_bitmap_show},
 796         {"io_poll", 0600, hctx_io_poll_show, hctx_io_poll_write},
 797         {"dispatched", 0600, hctx_dispatched_show, hctx_dispatched_write},
 798         {"queued", 0600, hctx_queued_show, hctx_queued_write},
 799         {"run", 0600, hctx_run_show, hctx_run_write},
 800         {"active", 0400, hctx_active_show},
 801         {},
 802 };
 803
 804 static const struct blk_mq_debugfs_attr blk_mq_debugfs_ctx_attrs[] = {
 805         {"rq_list", 0400, .seq_ops = &ctx_rq_list_seq_ops},
 806         {"dispatched", 0600, ctx_dispatched_show, ctx_dispatched_write},
 807         {"merged", 0600, ctx_merged_show, ctx_merged_write},
 808         {"completed", 0600, ctx_completed_show, ctx_completed_write},
 809         {},
 810 };
 811
 812 static bool debugfs_create_files(struct dentry *parent, void *data,
 813                                  const struct blk_mq_debugfs_attr *attr)
 814 {
 815         d_inode(parent)->i_private = data;
 816
 817         for (; attr->name; attr++) {
 818                 if (!debugfs_create_file(attr->name, attr->mode, parent,
 819                                          (void *)attr, &blk_mq_debugfs_fops))
 820                         return false;
 821         }
 822         return true;
 823 }
 824
 825 int blk_mq_debugfs_register(struct request_queue *q)
 826 {
 827         struct blk_mq_hw_ctx *hctx;
 828         int i;
 829
 830         if (!blk_debugfs_root)
 831                 return -ENOENT;
 832
 833         q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
 834                                             blk_debugfs_root);
 835         if (!q->debugfs_dir)
 836                 return -ENOMEM;
 837
 838         if (!debugfs_create_files(q->debugfs_dir, q,
 839                                   blk_mq_debugfs_queue_attrs))
 840                 goto err;
 841
 842         /*
 843          * blk_mq_init_sched() attempted to do this already, but q->debugfs_dir
 844          * didn't exist yet (because we don't know what to name the directory
 845          * until the queue is registered to a gendisk).
 846          */
 847         if (q->elevator && !q->sched_debugfs_dir)
 848                 blk_mq_debugfs_register_sched(q);
 849
 850         /* Similarly, blk_mq_init_hctx() couldn't do this previously. */
 851         queue_for_each_hw_ctx(q, hctx, i) {
 852                 if (!hctx->debugfs_dir && blk_mq_debugfs_register_hctx(q, hctx))
 853                         goto err;
 854                 if (q->elevator && !hctx->sched_debugfs_dir &&
 855                     blk_mq_debugfs_register_sched_hctx(q, hctx))
 856                         goto err;
 857         }
 858
 859         return 0;
 860
 861 err:
 862         blk_mq_debugfs_unregister(q);
 863         return -ENOMEM;
 864 }
 865
 866 void blk_mq_debugfs_unregister(struct request_queue *q)
 867 {
 868         debugfs_remove_recursive(q->debugfs_dir);
 869         q->sched_debugfs_dir = NULL;
 870         q->debugfs_dir = NULL;
 871 }
 872
 873 static int blk_mq_debugfs_register_ctx(struct blk_mq_hw_ctx *hctx,
 874                                        struct blk_mq_ctx *ctx)
 875 {
 876         struct dentry *ctx_dir;
 877         char name[20];
 878
 879         snprintf(name, sizeof(name), "cpu%u", ctx->cpu);
 880         ctx_dir = debugfs_create_dir(name, hctx->debugfs_dir);
 881         if (!ctx_dir)
 882                 return -ENOMEM;
 883
 884         if (!debugfs_create_files(ctx_dir, ctx, blk_mq_debugfs_ctx_attrs))
 885                 return -ENOMEM;
 886
 887         return 0;
 888 }
 889
 890 int blk_mq_debugfs_register_hctx(struct request_queue *q,
 891                                  struct blk_mq_hw_ctx *hctx)
 892 {
 893         struct blk_mq_ctx *ctx;
 894         char name[20];
 895         int i;
 896
 897         if (!q->debugfs_dir)
 898                 return -ENOENT;
 899
 900         snprintf(name, sizeof(name), "hctx%u", hctx->queue_num);
 901         hctx->debugfs_dir = debugfs_create_dir(name, q->debugfs_dir);
 902         if (!hctx->debugfs_dir)
 903                 return -ENOMEM;
 904
 905         if (!debugfs_create_files(hctx->debugfs_dir, hctx,
 906                                   blk_mq_debugfs_hctx_attrs))
 907                 goto err;
 908
 909         hctx_for_each_ctx(hctx, ctx, i) {
 910                 if (blk_mq_debugfs_register_ctx(hctx, ctx))
 911                         goto err;
 912         }
 913
 914         return 0;
 915
 916 err:
 917         blk_mq_debugfs_unregister_hctx(hctx);
 918         return -ENOMEM;
 919 }
 920
 921 void blk_mq_debugfs_unregister_hctx(struct blk_mq_hw_ctx *hctx)
 922 {
 923         debugfs_remove_recursive(hctx->debugfs_dir);
 924         hctx->sched_debugfs_dir = NULL;
 925         hctx->debugfs_dir = NULL;
 926 }
 927
 928 int blk_mq_debugfs_register_hctxs(struct request_queue *q)
 929 {
 930         struct blk_mq_hw_ctx *hctx;
 931         int i;
 932
 933         queue_for_each_hw_ctx(q, hctx, i) {
 934                 if (blk_mq_debugfs_register_hctx(q, hctx))
 935                         return -ENOMEM;
 936         }
 937
 938         return 0;
 939 }
 940
 941 void blk_mq_debugfs_unregister_hctxs(struct request_queue *q)
 942 {
 943         struct blk_mq_hw_ctx *hctx;
 944         int i;
 945
 946         queue_for_each_hw_ctx(q, hctx, i)
 947                 blk_mq_debugfs_unregister_hctx(hctx);
 948 }
 949
 950 int blk_mq_debugfs_register_sched(struct request_queue *q)
 951 {
 952         struct elevator_type *e = q->elevator->type;
 953
 954         if (!q->debugfs_dir)
 955                 return -ENOENT;
 956
 957         if (!e->queue_debugfs_attrs)
 958                 return 0;
 959
 960         q->sched_debugfs_dir = debugfs_create_dir("sched", q->debugfs_dir);
 961         if (!q->sched_debugfs_dir)
 962                 return -ENOMEM;
 963
 964         if (!debugfs_create_files(q->sched_debugfs_dir, q,
 965                                   e->queue_debugfs_attrs))
 966                 goto err;
 967
 968         return 0;
 969
 970 err:
 971         blk_mq_debugfs_unregister_sched(q);
 972         return -ENOMEM;
 973 }
 974
 975 void blk_mq_debugfs_unregister_sched(struct request_queue *q)
 976 {
 977         debugfs_remove_recursive(q->sched_debugfs_dir);
 978         q->sched_debugfs_dir = NULL;
 979 }
 980
 981 int blk_mq_debugfs_register_sched_hctx(struct request_queue *q,
 982                                        struct blk_mq_hw_ctx *hctx)
 983 {
 984         struct elevator_type *e = q->elevator->type;
 985
 986         if (!hctx->debugfs_dir)
 987                 return -ENOENT;
 988
 989         if (!e->hctx_debugfs_attrs)
 990                 return 0;
 991
 992         hctx->sched_debugfs_dir = debugfs_create_dir("sched",
 993                                                      hctx->debugfs_dir);
 994         if (!hctx->sched_debugfs_dir)
 995                 return -ENOMEM;
 996
 997         if (!debugfs_create_files(hctx->sched_debugfs_dir, hctx,
 998                                   e->hctx_debugfs_attrs))
 999                 return -ENOMEM;
1000
1001         return 0;
1002 }
1003
1004 void blk_mq_debugfs_unregister_sched_hctx(struct blk_mq_hw_ctx *hctx)
1005 {
1006         debugfs_remove_recursive(hctx->sched_debugfs_dir);
1007         hctx->sched_debugfs_dir = NULL;
1008 }