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(SYNCFULL),
  52         QUEUE_FLAG_NAME(ASYNCFULL),
  53         QUEUE_FLAG_NAME(DYING),
  54         QUEUE_FLAG_NAME(BYPASS),
  55         QUEUE_FLAG_NAME(BIDI),
  56         QUEUE_FLAG_NAME(NOMERGES),
  57         QUEUE_FLAG_NAME(SAME_COMP),
  58         QUEUE_FLAG_NAME(FAIL_IO),
  59         QUEUE_FLAG_NAME(STACKABLE),
  60         QUEUE_FLAG_NAME(NONROT),
  61         QUEUE_FLAG_NAME(IO_STAT),
  62         QUEUE_FLAG_NAME(DISCARD),
  63         QUEUE_FLAG_NAME(NOXMERGES),
  64         QUEUE_FLAG_NAME(ADD_RANDOM),
  65         QUEUE_FLAG_NAME(SECERASE),
  66         QUEUE_FLAG_NAME(SAME_FORCE),
  67         QUEUE_FLAG_NAME(DEAD),
  68         QUEUE_FLAG_NAME(INIT_DONE),
  69         QUEUE_FLAG_NAME(NO_SG_MERGE),
  70         QUEUE_FLAG_NAME(POLL),
  71         QUEUE_FLAG_NAME(WC),
  72         QUEUE_FLAG_NAME(FUA),
  73         QUEUE_FLAG_NAME(FLUSH_NQ),
  74         QUEUE_FLAG_NAME(DAX),
  75         QUEUE_FLAG_NAME(STATS),
  76         QUEUE_FLAG_NAME(POLL_STATS),
  77         QUEUE_FLAG_NAME(REGISTERED),
  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(TAG_WAITING),
 184         HCTX_STATE_NAME(START_ON_RUN),
 185 };
 186 #undef HCTX_STATE_NAME
 187
 188 static int hctx_state_show(void *data, struct seq_file *m)
 189 {
 190         struct blk_mq_hw_ctx *hctx = data;
 191
 192         blk_flags_show(m, hctx->state, hctx_state_name,
 193                        ARRAY_SIZE(hctx_state_name));
 194         seq_puts(m, "\n");
 195         return 0;
 196 }
 197
 198 #define BLK_TAG_ALLOC_NAME(name) [BLK_TAG_ALLOC_##name] = #name
 199 static const char *const alloc_policy_name[] = {
 200         BLK_TAG_ALLOC_NAME(FIFO),
 201         BLK_TAG_ALLOC_NAME(RR),
 202 };
 203 #undef BLK_TAG_ALLOC_NAME
 204
 205 #define HCTX_FLAG_NAME(name) [ilog2(BLK_MQ_F_##name)] = #name
 206 static const char *const hctx_flag_name[] = {
 207         HCTX_FLAG_NAME(SHOULD_MERGE),
 208         HCTX_FLAG_NAME(TAG_SHARED),
 209         HCTX_FLAG_NAME(SG_MERGE),
 210         HCTX_FLAG_NAME(BLOCKING),
 211         HCTX_FLAG_NAME(NO_SCHED),
 212 };
 213 #undef HCTX_FLAG_NAME
 214
 215 static int hctx_flags_show(void *data, struct seq_file *m)
 216 {
 217         struct blk_mq_hw_ctx *hctx = data;
 218         const int alloc_policy = BLK_MQ_FLAG_TO_ALLOC_POLICY(hctx->flags);
 219
 220         seq_puts(m, "alloc_policy=");
 221         if (alloc_policy < ARRAY_SIZE(alloc_policy_name) &&
 222             alloc_policy_name[alloc_policy])
 223                 seq_puts(m, alloc_policy_name[alloc_policy]);
 224         else
 225                 seq_printf(m, "%d", alloc_policy);
 226         seq_puts(m, " ");
 227         blk_flags_show(m,
 228                        hctx->flags ^ BLK_ALLOC_POLICY_TO_MQ_FLAG(alloc_policy),
 229                        hctx_flag_name, ARRAY_SIZE(hctx_flag_name));
 230         seq_puts(m, "\n");
 231         return 0;
 232 }
 233
 234 #define REQ_OP_NAME(name) [REQ_OP_##name] = #name
 235 static const char *const op_name[] = {
 236         REQ_OP_NAME(READ),
 237         REQ_OP_NAME(WRITE),
 238         REQ_OP_NAME(FLUSH),
 239         REQ_OP_NAME(DISCARD),
 240         REQ_OP_NAME(ZONE_REPORT),
 241         REQ_OP_NAME(SECURE_ERASE),
 242         REQ_OP_NAME(ZONE_RESET),
 243         REQ_OP_NAME(WRITE_SAME),
 244         REQ_OP_NAME(WRITE_ZEROES),
 245         REQ_OP_NAME(SCSI_IN),
 246         REQ_OP_NAME(SCSI_OUT),
 247         REQ_OP_NAME(DRV_IN),
 248         REQ_OP_NAME(DRV_OUT),
 249 };
 250 #undef REQ_OP_NAME
 251
 252 #define CMD_FLAG_NAME(name) [__REQ_##name] = #name
 253 static const char *const cmd_flag_name[] = {
 254         CMD_FLAG_NAME(FAILFAST_DEV),
 255         CMD_FLAG_NAME(FAILFAST_TRANSPORT),
 256         CMD_FLAG_NAME(FAILFAST_DRIVER),
 257         CMD_FLAG_NAME(SYNC),
 258         CMD_FLAG_NAME(META),
 259         CMD_FLAG_NAME(PRIO),
 260         CMD_FLAG_NAME(NOMERGE),
 261         CMD_FLAG_NAME(IDLE),
 262         CMD_FLAG_NAME(INTEGRITY),
 263         CMD_FLAG_NAME(FUA),
 264         CMD_FLAG_NAME(PREFLUSH),
 265         CMD_FLAG_NAME(RAHEAD),
 266         CMD_FLAG_NAME(BACKGROUND),
 267         CMD_FLAG_NAME(NOUNMAP),
 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 };
 293 #undef RQF_NAME
 294
 295 #define RQAF_NAME(name) [REQ_ATOM_##name] = #name
 296 static const char *const rqaf_name[] = {
 297         RQAF_NAME(COMPLETE),
 298         RQAF_NAME(STARTED),
 299         RQAF_NAME(POLL_SLEPT),
 300 };
 301 #undef RQAF_NAME
 302
 303 int __blk_mq_debugfs_rq_show(struct seq_file *m, struct request *rq)
 304 {
 305         const struct blk_mq_ops *const mq_ops = rq->q->mq_ops;
 306         const unsigned int op = rq->cmd_flags & REQ_OP_MASK;
 307
 308         seq_printf(m, "%p {.op=", rq);
 309         if (op < ARRAY_SIZE(op_name) && op_name[op])
 310                 seq_printf(m, "%s", op_name[op]);
 311         else
 312                 seq_printf(m, "%d", op);
 313         seq_puts(m, ", .cmd_flags=");
 314         blk_flags_show(m, rq->cmd_flags & ~REQ_OP_MASK, cmd_flag_name,
 315                        ARRAY_SIZE(cmd_flag_name));
 316         seq_puts(m, ", .rq_flags=");
 317         blk_flags_show(m, (__force unsigned int)rq->rq_flags, rqf_name,
 318                        ARRAY_SIZE(rqf_name));
 319         seq_puts(m, ", .atomic_flags=");
 320         blk_flags_show(m, rq->atomic_flags, rqaf_name, ARRAY_SIZE(rqaf_name));
 321         seq_printf(m, ", .tag=%d, .internal_tag=%d", rq->tag,
 322                    rq->internal_tag);
 323         if (mq_ops->show_rq)
 324                 mq_ops->show_rq(m, rq);
 325         seq_puts(m, "}\n");
 326         return 0;
 327 }
 328 EXPORT_SYMBOL_GPL(__blk_mq_debugfs_rq_show);
 329
 330 int blk_mq_debugfs_rq_show(struct seq_file *m, void *v)
 331 {
 332         return __blk_mq_debugfs_rq_show(m, list_entry_rq(v));
 333 }
 334 EXPORT_SYMBOL_GPL(blk_mq_debugfs_rq_show);
 335
 336 static void *queue_requeue_list_start(struct seq_file *m, loff_t *pos)
 337         __acquires(&q->requeue_lock)
 338 {
 339         struct request_queue *q = m->private;
 340
 341         spin_lock_irq(&q->requeue_lock);
 342         return seq_list_start(&q->requeue_list, *pos);
 343 }
 344
 345 static void *queue_requeue_list_next(struct seq_file *m, void *v, loff_t *pos)
 346 {
 347         struct request_queue *q = m->private;
 348
 349         return seq_list_next(v, &q->requeue_list, pos);
 350 }
 351
 352 static void queue_requeue_list_stop(struct seq_file *m, void *v)
 353         __releases(&q->requeue_lock)
 354 {
 355         struct request_queue *q = m->private;
 356
 357         spin_unlock_irq(&q->requeue_lock);
 358 }
 359
 360 static const struct seq_operations queue_requeue_list_seq_ops = {
 361         .start  = queue_requeue_list_start,
 362         .next   = queue_requeue_list_next,
 363         .stop   = queue_requeue_list_stop,
 364         .show   = blk_mq_debugfs_rq_show,
 365 };
 366
 367 static void *hctx_dispatch_start(struct seq_file *m, loff_t *pos)
 368         __acquires(&hctx->lock)
 369 {
 370         struct blk_mq_hw_ctx *hctx = m->private;
 371
 372         spin_lock(&hctx->lock);
 373         return seq_list_start(&hctx->dispatch, *pos);
 374 }
 375
 376 static void *hctx_dispatch_next(struct seq_file *m, void *v, loff_t *pos)
 377 {
 378         struct blk_mq_hw_ctx *hctx = m->private;
 379
 380         return seq_list_next(v, &hctx->dispatch, pos);
 381 }
 382
 383 static void hctx_dispatch_stop(struct seq_file *m, void *v)
 384         __releases(&hctx->lock)
 385 {
 386         struct blk_mq_hw_ctx *hctx = m->private;
 387
 388         spin_unlock(&hctx->lock);
 389 }
 390
 391 static const struct seq_operations hctx_dispatch_seq_ops = {
 392         .start  = hctx_dispatch_start,
 393         .next   = hctx_dispatch_next,
 394         .stop   = hctx_dispatch_stop,
 395         .show   = blk_mq_debugfs_rq_show,
 396 };
 397
 398 struct show_busy_params {
 399         struct seq_file         *m;
 400         struct blk_mq_hw_ctx    *hctx;
 401 };
 402
 403 /*
 404  * Note: the state of a request may change while this function is in progress,
 405  * e.g. due to a concurrent blk_mq_finish_request() call.
 406  */
 407 static void hctx_show_busy_rq(struct request *rq, void *data, bool reserved)
 408 {
 409         const struct show_busy_params *params = data;
 410
 411         if (blk_mq_map_queue(rq->q, rq->mq_ctx->cpu) == params->hctx &&
 412             test_bit(REQ_ATOM_STARTED, &rq->atomic_flags))
 413                 __blk_mq_debugfs_rq_show(params->m,
 414                                          list_entry_rq(&rq->queuelist));
 415 }
 416
 417 static int hctx_busy_show(void *data, struct seq_file *m)
 418 {
 419         struct blk_mq_hw_ctx *hctx = data;
 420         struct show_busy_params params = { .m = m, .hctx = hctx };
 421
 422         blk_mq_tagset_busy_iter(hctx->queue->tag_set, hctx_show_busy_rq,
 423                                 &params);
 424
 425         return 0;
 426 }
 427
 428 static int hctx_ctx_map_show(void *data, struct seq_file *m)
 429 {
 430         struct blk_mq_hw_ctx *hctx = data;
 431
 432         sbitmap_bitmap_show(&hctx->ctx_map, m);
 433         return 0;
 434 }
 435
 436 static void blk_mq_debugfs_tags_show(struct seq_file *m,
 437                                      struct blk_mq_tags *tags)
 438 {
 439         seq_printf(m, "nr_tags=%u\n", tags->nr_tags);
 440         seq_printf(m, "nr_reserved_tags=%u\n", tags->nr_reserved_tags);
 441         seq_printf(m, "active_queues=%d\n",
 442                    atomic_read(&tags->active_queues));
 443
 444         seq_puts(m, "\nbitmap_tags:\n");
 445         sbitmap_queue_show(&tags->bitmap_tags, m);
 446
 447         if (tags->nr_reserved_tags) {
 448                 seq_puts(m, "\nbreserved_tags:\n");
 449                 sbitmap_queue_show(&tags->breserved_tags, m);
 450         }
 451 }
 452
 453 static int hctx_tags_show(void *data, struct seq_file *m)
 454 {
 455         struct blk_mq_hw_ctx *hctx = data;
 456         struct request_queue *q = hctx->queue;
 457         int res;
 458
 459         res = mutex_lock_interruptible(&q->sysfs_lock);
 460         if (res)
 461                 goto out;
 462         if (hctx->tags)
 463                 blk_mq_debugfs_tags_show(m, hctx->tags);
 464         mutex_unlock(&q->sysfs_lock);
 465
 466 out:
 467         return res;
 468 }
 469
 470 static int hctx_tags_bitmap_show(void *data, struct seq_file *m)
 471 {
 472         struct blk_mq_hw_ctx *hctx = data;
 473         struct request_queue *q = hctx->queue;
 474         int res;
 475
 476         res = mutex_lock_interruptible(&q->sysfs_lock);
 477         if (res)
 478                 goto out;
 479         if (hctx->tags)
 480                 sbitmap_bitmap_show(&hctx->tags->bitmap_tags.sb, m);
 481         mutex_unlock(&q->sysfs_lock);
 482
 483 out:
 484         return res;
 485 }
 486
 487 static int hctx_sched_tags_show(void *data, struct seq_file *m)
 488 {
 489         struct blk_mq_hw_ctx *hctx = data;
 490         struct request_queue *q = hctx->queue;
 491         int res;
 492
 493         res = mutex_lock_interruptible(&q->sysfs_lock);
 494         if (res)
 495                 goto out;
 496         if (hctx->sched_tags)
 497                 blk_mq_debugfs_tags_show(m, hctx->sched_tags);
 498         mutex_unlock(&q->sysfs_lock);
 499
 500 out:
 501         return res;
 502 }
 503
 504 static int hctx_sched_tags_bitmap_show(void *data, struct seq_file *m)
 505 {
 506         struct blk_mq_hw_ctx *hctx = data;
 507         struct request_queue *q = hctx->queue;
 508         int res;
 509
 510         res = mutex_lock_interruptible(&q->sysfs_lock);
 511         if (res)
 512                 goto out;
 513         if (hctx->sched_tags)
 514                 sbitmap_bitmap_show(&hctx->sched_tags->bitmap_tags.sb, m);
 515         mutex_unlock(&q->sysfs_lock);
 516
 517 out:
 518         return res;
 519 }
 520
 521 static int hctx_io_poll_show(void *data, struct seq_file *m)
 522 {
 523         struct blk_mq_hw_ctx *hctx = data;
 524
 525         seq_printf(m, "considered=%lu\n", hctx->poll_considered);
 526         seq_printf(m, "invoked=%lu\n", hctx->poll_invoked);
 527         seq_printf(m, "success=%lu\n", hctx->poll_success);
 528         return 0;
 529 }
 530
 531 static ssize_t hctx_io_poll_write(void *data, const char __user *buf,
 532                                   size_t count, loff_t *ppos)
 533 {
 534         struct blk_mq_hw_ctx *hctx = data;
 535
 536         hctx->poll_considered = hctx->poll_invoked = hctx->poll_success = 0;
 537         return count;
 538 }
 539
 540 static int hctx_dispatched_show(void *data, struct seq_file *m)
 541 {
 542         struct blk_mq_hw_ctx *hctx = data;
 543         int i;
 544
 545         seq_printf(m, "%8u\t%lu\n", 0U, hctx->dispatched[0]);
 546
 547         for (i = 1; i < BLK_MQ_MAX_DISPATCH_ORDER - 1; i++) {
 548                 unsigned int d = 1U << (i - 1);
 549
 550                 seq_printf(m, "%8u\t%lu\n", d, hctx->dispatched[i]);
 551         }
 552
 553         seq_printf(m, "%8u+\t%lu\n", 1U << (i - 1), hctx->dispatched[i]);
 554         return 0;
 555 }
 556
 557 static ssize_t hctx_dispatched_write(void *data, const char __user *buf,
 558                                      size_t count, loff_t *ppos)
 559 {
 560         struct blk_mq_hw_ctx *hctx = data;
 561         int i;
 562
 563         for (i = 0; i < BLK_MQ_MAX_DISPATCH_ORDER; i++)
 564                 hctx->dispatched[i] = 0;
 565         return count;
 566 }
 567
 568 static int hctx_queued_show(void *data, struct seq_file *m)
 569 {
 570         struct blk_mq_hw_ctx *hctx = data;
 571
 572         seq_printf(m, "%lu\n", hctx->queued);
 573         return 0;
 574 }
 575
 576 static ssize_t hctx_queued_write(void *data, const char __user *buf,
 577                                  size_t count, loff_t *ppos)
 578 {
 579         struct blk_mq_hw_ctx *hctx = data;
 580
 581         hctx->queued = 0;
 582         return count;
 583 }
 584
 585 static int hctx_run_show(void *data, struct seq_file *m)
 586 {
 587         struct blk_mq_hw_ctx *hctx = data;
 588
 589         seq_printf(m, "%lu\n", hctx->run);
 590         return 0;
 591 }
 592
 593 static ssize_t hctx_run_write(void *data, const char __user *buf, size_t count,
 594                               loff_t *ppos)
 595 {
 596         struct blk_mq_hw_ctx *hctx = data;
 597
 598         hctx->run = 0;
 599         return count;
 600 }
 601
 602 static int hctx_active_show(void *data, struct seq_file *m)
 603 {
 604         struct blk_mq_hw_ctx *hctx = data;
 605
 606         seq_printf(m, "%d\n", atomic_read(&hctx->nr_active));
 607         return 0;
 608 }
 609
 610 static void *ctx_rq_list_start(struct seq_file *m, loff_t *pos)
 611         __acquires(&ctx->lock)
 612 {
 613         struct blk_mq_ctx *ctx = m->private;
 614
 615         spin_lock(&ctx->lock);
 616         return seq_list_start(&ctx->rq_list, *pos);
 617 }
 618
 619 static void *ctx_rq_list_next(struct seq_file *m, void *v, loff_t *pos)
 620 {
 621         struct blk_mq_ctx *ctx = m->private;
 622
 623         return seq_list_next(v, &ctx->rq_list, pos);
 624 }
 625
 626 static void ctx_rq_list_stop(struct seq_file *m, void *v)
 627         __releases(&ctx->lock)
 628 {
 629         struct blk_mq_ctx *ctx = m->private;
 630
 631         spin_unlock(&ctx->lock);
 632 }
 633
 634 static const struct seq_operations ctx_rq_list_seq_ops = {
 635         .start  = ctx_rq_list_start,
 636         .next   = ctx_rq_list_next,
 637         .stop   = ctx_rq_list_stop,
 638         .show   = blk_mq_debugfs_rq_show,
 639 };
 640 static int ctx_dispatched_show(void *data, struct seq_file *m)
 641 {
 642         struct blk_mq_ctx *ctx = data;
 643
 644         seq_printf(m, "%lu %lu\n", ctx->rq_dispatched[1], ctx->rq_dispatched[0]);
 645         return 0;
 646 }
 647
 648 static ssize_t ctx_dispatched_write(void *data, const char __user *buf,
 649                                     size_t count, loff_t *ppos)
 650 {
 651         struct blk_mq_ctx *ctx = data;
 652
 653         ctx->rq_dispatched[0] = ctx->rq_dispatched[1] = 0;
 654         return count;
 655 }
 656
 657 static int ctx_merged_show(void *data, struct seq_file *m)
 658 {
 659         struct blk_mq_ctx *ctx = data;
 660
 661         seq_printf(m, "%lu\n", ctx->rq_merged);
 662         return 0;
 663 }
 664
 665 static ssize_t ctx_merged_write(void *data, const char __user *buf,
 666                                 size_t count, loff_t *ppos)
 667 {
 668         struct blk_mq_ctx *ctx = data;
 669
 670         ctx->rq_merged = 0;
 671         return count;
 672 }
 673
 674 static int ctx_completed_show(void *data, struct seq_file *m)
 675 {
 676         struct blk_mq_ctx *ctx = data;
 677
 678         seq_printf(m, "%lu %lu\n", ctx->rq_completed[1], ctx->rq_completed[0]);
 679         return 0;
 680 }
 681
 682 static ssize_t ctx_completed_write(void *data, const char __user *buf,
 683                                    size_t count, loff_t *ppos)
 684 {
 685         struct blk_mq_ctx *ctx = data;
 686
 687         ctx->rq_completed[0] = ctx->rq_completed[1] = 0;
 688         return count;
 689 }
 690
 691 static int blk_mq_debugfs_show(struct seq_file *m, void *v)
 692 {
 693         const struct blk_mq_debugfs_attr *attr = m->private;
 694         void *data = d_inode(m->file->f_path.dentry->d_parent)->i_private;
 695
 696         return attr->show(data, m);
 697 }
 698
 699 static ssize_t blk_mq_debugfs_write(struct file *file, const char __user *buf,
 700                                     size_t count, loff_t *ppos)
 701 {
 702         struct seq_file *m = file->private_data;
 703         const struct blk_mq_debugfs_attr *attr = m->private;
 704         void *data = d_inode(file->f_path.dentry->d_parent)->i_private;
 705
 706         if (!attr->write)
 707                 return -EPERM;
 708
 709         return attr->write(data, buf, count, ppos);
 710 }
 711
 712 static int blk_mq_debugfs_open(struct inode *inode, struct file *file)
 713 {
 714         const struct blk_mq_debugfs_attr *attr = inode->i_private;
 715         void *data = d_inode(file->f_path.dentry->d_parent)->i_private;
 716         struct seq_file *m;
 717         int ret;
 718
 719         if (attr->seq_ops) {
 720                 ret = seq_open(file, attr->seq_ops);
 721                 if (!ret) {
 722                         m = file->private_data;
 723                         m->private = data;
 724                 }
 725                 return ret;
 726         }
 727
 728         if (WARN_ON_ONCE(!attr->show))
 729                 return -EPERM;
 730
 731         return single_open(file, blk_mq_debugfs_show, inode->i_private);
 732 }
 733
 734 static int blk_mq_debugfs_release(struct inode *inode, struct file *file)
 735 {
 736         const struct blk_mq_debugfs_attr *attr = inode->i_private;
 737
 738         if (attr->show)
 739                 return single_release(inode, file);
 740         else
 741                 return seq_release(inode, file);
 742 }
 743
 744 const struct file_operations blk_mq_debugfs_fops = {
 745         .open           = blk_mq_debugfs_open,
 746         .read           = seq_read,
 747         .write          = blk_mq_debugfs_write,
 748         .llseek         = seq_lseek,
 749         .release        = blk_mq_debugfs_release,
 750 };
 751
 752 static const struct blk_mq_debugfs_attr blk_mq_debugfs_queue_attrs[] = {
 753         {"poll_stat", 0400, queue_poll_stat_show},
 754         {"requeue_list", 0400, .seq_ops = &queue_requeue_list_seq_ops},
 755         {"state", 0600, queue_state_show, queue_state_write},
 756         {"write_hints", 0600, queue_write_hint_show, queue_write_hint_store},
 757         {},
 758 };
 759
 760 static const struct blk_mq_debugfs_attr blk_mq_debugfs_hctx_attrs[] = {
 761         {"state", 0400, hctx_state_show},
 762         {"flags", 0400, hctx_flags_show},
 763         {"dispatch", 0400, .seq_ops = &hctx_dispatch_seq_ops},
 764         {"busy", 0400, hctx_busy_show},
 765         {"ctx_map", 0400, hctx_ctx_map_show},
 766         {"tags", 0400, hctx_tags_show},
 767         {"tags_bitmap", 0400, hctx_tags_bitmap_show},
 768         {"sched_tags", 0400, hctx_sched_tags_show},
 769         {"sched_tags_bitmap", 0400, hctx_sched_tags_bitmap_show},
 770         {"io_poll", 0600, hctx_io_poll_show, hctx_io_poll_write},
 771         {"dispatched", 0600, hctx_dispatched_show, hctx_dispatched_write},
 772         {"queued", 0600, hctx_queued_show, hctx_queued_write},
 773         {"run", 0600, hctx_run_show, hctx_run_write},
 774         {"active", 0400, hctx_active_show},
 775         {},
 776 };
 777
 778 static const struct blk_mq_debugfs_attr blk_mq_debugfs_ctx_attrs[] = {
 779         {"rq_list", 0400, .seq_ops = &ctx_rq_list_seq_ops},
 780         {"dispatched", 0600, ctx_dispatched_show, ctx_dispatched_write},
 781         {"merged", 0600, ctx_merged_show, ctx_merged_write},
 782         {"completed", 0600, ctx_completed_show, ctx_completed_write},
 783         {},
 784 };
 785
 786 static bool debugfs_create_files(struct dentry *parent, void *data,
 787                                  const struct blk_mq_debugfs_attr *attr)
 788 {
 789         d_inode(parent)->i_private = data;
 790
 791         for (; attr->name; attr++) {
 792                 if (!debugfs_create_file(attr->name, attr->mode, parent,
 793                                          (void *)attr, &blk_mq_debugfs_fops))
 794                         return false;
 795         }
 796         return true;
 797 }
 798
 799 int blk_mq_debugfs_register(struct request_queue *q)
 800 {
 801         struct blk_mq_hw_ctx *hctx;
 802         int i;
 803
 804         if (!blk_debugfs_root)
 805                 return -ENOENT;
 806
 807         q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
 808                                             blk_debugfs_root);
 809         if (!q->debugfs_dir)
 810                 return -ENOMEM;
 811
 812         if (!debugfs_create_files(q->debugfs_dir, q,
 813                                   blk_mq_debugfs_queue_attrs))
 814                 goto err;
 815
 816         /*
 817          * blk_mq_init_hctx() attempted to do this already, but q->debugfs_dir
 818          * didn't exist yet (because we don't know what to name the directory
 819          * until the queue is registered to a gendisk).
 820          */
 821         queue_for_each_hw_ctx(q, hctx, i) {
 822                 if (!hctx->debugfs_dir && blk_mq_debugfs_register_hctx(q, hctx))
 823                         goto err;
 824                 if (q->elevator && !hctx->sched_debugfs_dir &&
 825                     blk_mq_debugfs_register_sched_hctx(q, hctx))
 826                         goto err;
 827         }
 828
 829         return 0;
 830
 831 err:
 832         blk_mq_debugfs_unregister(q);
 833         return -ENOMEM;
 834 }
 835
 836 void blk_mq_debugfs_unregister(struct request_queue *q)
 837 {
 838         debugfs_remove_recursive(q->debugfs_dir);
 839         q->sched_debugfs_dir = NULL;
 840         q->debugfs_dir = NULL;
 841 }
 842
 843 static int blk_mq_debugfs_register_ctx(struct blk_mq_hw_ctx *hctx,
 844                                        struct blk_mq_ctx *ctx)
 845 {
 846         struct dentry *ctx_dir;
 847         char name[20];
 848
 849         snprintf(name, sizeof(name), "cpu%u", ctx->cpu);
 850         ctx_dir = debugfs_create_dir(name, hctx->debugfs_dir);
 851         if (!ctx_dir)
 852                 return -ENOMEM;
 853
 854         if (!debugfs_create_files(ctx_dir, ctx, blk_mq_debugfs_ctx_attrs))
 855                 return -ENOMEM;
 856
 857         return 0;
 858 }
 859
 860 int blk_mq_debugfs_register_hctx(struct request_queue *q,
 861                                  struct blk_mq_hw_ctx *hctx)
 862 {
 863         struct blk_mq_ctx *ctx;
 864         char name[20];
 865         int i;
 866
 867         if (!q->debugfs_dir)
 868                 return -ENOENT;
 869
 870         snprintf(name, sizeof(name), "hctx%u", hctx->queue_num);
 871         hctx->debugfs_dir = debugfs_create_dir(name, q->debugfs_dir);
 872         if (!hctx->debugfs_dir)
 873                 return -ENOMEM;
 874
 875         if (!debugfs_create_files(hctx->debugfs_dir, hctx,
 876                                   blk_mq_debugfs_hctx_attrs))
 877                 goto err;
 878
 879         hctx_for_each_ctx(hctx, ctx, i) {
 880                 if (blk_mq_debugfs_register_ctx(hctx, ctx))
 881                         goto err;
 882         }
 883
 884         return 0;
 885
 886 err:
 887         blk_mq_debugfs_unregister_hctx(hctx);
 888         return -ENOMEM;
 889 }
 890
 891 void blk_mq_debugfs_unregister_hctx(struct blk_mq_hw_ctx *hctx)
 892 {
 893         debugfs_remove_recursive(hctx->debugfs_dir);
 894         hctx->sched_debugfs_dir = NULL;
 895         hctx->debugfs_dir = NULL;
 896 }
 897
 898 int blk_mq_debugfs_register_hctxs(struct request_queue *q)
 899 {
 900         struct blk_mq_hw_ctx *hctx;
 901         int i;
 902
 903         queue_for_each_hw_ctx(q, hctx, i) {
 904                 if (blk_mq_debugfs_register_hctx(q, hctx))
 905                         return -ENOMEM;
 906         }
 907
 908         return 0;
 909 }
 910
 911 void blk_mq_debugfs_unregister_hctxs(struct request_queue *q)
 912 {
 913         struct blk_mq_hw_ctx *hctx;
 914         int i;
 915
 916         queue_for_each_hw_ctx(q, hctx, i)
 917                 blk_mq_debugfs_unregister_hctx(hctx);
 918 }
 919
 920 int blk_mq_debugfs_register_sched(struct request_queue *q)
 921 {
 922         struct elevator_type *e = q->elevator->type;
 923
 924         if (!q->debugfs_dir)
 925                 return -ENOENT;
 926
 927         if (!e->queue_debugfs_attrs)
 928                 return 0;
 929
 930         q->sched_debugfs_dir = debugfs_create_dir("sched", q->debugfs_dir);
 931         if (!q->sched_debugfs_dir)
 932                 return -ENOMEM;
 933
 934         if (!debugfs_create_files(q->sched_debugfs_dir, q,
 935                                   e->queue_debugfs_attrs))
 936                 goto err;
 937
 938         return 0;
 939
 940 err:
 941         blk_mq_debugfs_unregister_sched(q);
 942         return -ENOMEM;
 943 }
 944
 945 void blk_mq_debugfs_unregister_sched(struct request_queue *q)
 946 {
 947         debugfs_remove_recursive(q->sched_debugfs_dir);
 948         q->sched_debugfs_dir = NULL;
 949 }
 950
 951 int blk_mq_debugfs_register_sched_hctx(struct request_queue *q,
 952                                        struct blk_mq_hw_ctx *hctx)
 953 {
 954         struct elevator_type *e = q->elevator->type;
 955
 956         if (!hctx->debugfs_dir)
 957                 return -ENOENT;
 958
 959         if (!e->hctx_debugfs_attrs)
 960                 return 0;
 961
 962         hctx->sched_debugfs_dir = debugfs_create_dir("sched",
 963                                                      hctx->debugfs_dir);
 964         if (!hctx->sched_debugfs_dir)
 965                 return -ENOMEM;
 966
 967         if (!debugfs_create_files(hctx->sched_debugfs_dir, hctx,
 968                                   e->hctx_debugfs_attrs))
 969                 return -ENOMEM;
 970
 971         return 0;
 972 }
 973
 974 void blk_mq_debugfs_unregister_sched_hctx(struct blk_mq_hw_ctx *hctx)
 975 {
 976         debugfs_remove_recursive(hctx->sched_debugfs_dir);
 977         hctx->sched_debugfs_dir = NULL;
 978 }