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