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 {
 118                 pr_err("%s: unsupported operation '%s'\n", __func__, op);
 119 inval:
 120                 pr_err("%s: use either 'run' or 'start'\n", __func__);
 121                 return -EINVAL;
 122         }
 123         return count;
 124 }
 125
 126 static void print_stat(struct seq_file *m, struct blk_rq_stat *stat)
 127 {
 128         if (stat->nr_samples) {
 129                 seq_printf(m, "samples=%d, mean=%lld, min=%llu, max=%llu",
 130                            stat->nr_samples, stat->mean, stat->min, stat->max);
 131         } else {
 132                 seq_puts(m, "samples=0");
 133         }
 134 }
 135
 136 static int queue_poll_stat_show(void *data, struct seq_file *m)
 137 {
 138         struct request_queue *q = data;
 139         int bucket;
 140
 141         for (bucket = 0; bucket < BLK_MQ_POLL_STATS_BKTS/2; bucket++) {
 142                 seq_printf(m, "read  (%d Bytes): ", 1 << (9+bucket));
 143                 print_stat(m, &q->poll_stat[2*bucket]);
 144                 seq_puts(m, "\n");
 145
 146                 seq_printf(m, "write (%d Bytes): ",  1 << (9+bucket));
 147                 print_stat(m, &q->poll_stat[2*bucket+1]);
 148                 seq_puts(m, "\n");
 149         }
 150         return 0;
 151 }
 152
 153 #define HCTX_STATE_NAME(name) [BLK_MQ_S_##name] = #name
 154 static const char *const hctx_state_name[] = {
 155         HCTX_STATE_NAME(STOPPED),
 156         HCTX_STATE_NAME(TAG_ACTIVE),
 157         HCTX_STATE_NAME(SCHED_RESTART),
 158         HCTX_STATE_NAME(TAG_WAITING),
 159         HCTX_STATE_NAME(START_ON_RUN),
 160 };
 161 #undef HCTX_STATE_NAME
 162
 163 static int hctx_state_show(void *data, struct seq_file *m)
 164 {
 165         struct blk_mq_hw_ctx *hctx = data;
 166
 167         blk_flags_show(m, hctx->state, hctx_state_name,
 168                        ARRAY_SIZE(hctx_state_name));
 169         seq_puts(m, "\n");
 170         return 0;
 171 }
 172
 173 #define BLK_TAG_ALLOC_NAME(name) [BLK_TAG_ALLOC_##name] = #name
 174 static const char *const alloc_policy_name[] = {
 175         BLK_TAG_ALLOC_NAME(FIFO),
 176         BLK_TAG_ALLOC_NAME(RR),
 177 };
 178 #undef BLK_TAG_ALLOC_NAME
 179
 180 #define HCTX_FLAG_NAME(name) [ilog2(BLK_MQ_F_##name)] = #name
 181 static const char *const hctx_flag_name[] = {
 182         HCTX_FLAG_NAME(SHOULD_MERGE),
 183         HCTX_FLAG_NAME(TAG_SHARED),
 184         HCTX_FLAG_NAME(SG_MERGE),
 185         HCTX_FLAG_NAME(BLOCKING),
 186         HCTX_FLAG_NAME(NO_SCHED),
 187 };
 188 #undef HCTX_FLAG_NAME
 189
 190 static int hctx_flags_show(void *data, struct seq_file *m)
 191 {
 192         struct blk_mq_hw_ctx *hctx = data;
 193         const int alloc_policy = BLK_MQ_FLAG_TO_ALLOC_POLICY(hctx->flags);
 194
 195         seq_puts(m, "alloc_policy=");
 196         if (alloc_policy < ARRAY_SIZE(alloc_policy_name) &&
 197             alloc_policy_name[alloc_policy])
 198                 seq_puts(m, alloc_policy_name[alloc_policy]);
 199         else
 200                 seq_printf(m, "%d", alloc_policy);
 201         seq_puts(m, " ");
 202         blk_flags_show(m,
 203                        hctx->flags ^ BLK_ALLOC_POLICY_TO_MQ_FLAG(alloc_policy),
 204                        hctx_flag_name, ARRAY_SIZE(hctx_flag_name));
 205         seq_puts(m, "\n");
 206         return 0;
 207 }
 208
 209 #define REQ_OP_NAME(name) [REQ_OP_##name] = #name
 210 static const char *const op_name[] = {
 211         REQ_OP_NAME(READ),
 212         REQ_OP_NAME(WRITE),
 213         REQ_OP_NAME(FLUSH),
 214         REQ_OP_NAME(DISCARD),
 215         REQ_OP_NAME(ZONE_REPORT),
 216         REQ_OP_NAME(SECURE_ERASE),
 217         REQ_OP_NAME(ZONE_RESET),
 218         REQ_OP_NAME(WRITE_SAME),
 219         REQ_OP_NAME(WRITE_ZEROES),
 220         REQ_OP_NAME(SCSI_IN),
 221         REQ_OP_NAME(SCSI_OUT),
 222         REQ_OP_NAME(DRV_IN),
 223         REQ_OP_NAME(DRV_OUT),
 224 };
 225 #undef REQ_OP_NAME
 226
 227 #define CMD_FLAG_NAME(name) [__REQ_##name] = #name
 228 static const char *const cmd_flag_name[] = {
 229         CMD_FLAG_NAME(FAILFAST_DEV),
 230         CMD_FLAG_NAME(FAILFAST_TRANSPORT),
 231         CMD_FLAG_NAME(FAILFAST_DRIVER),
 232         CMD_FLAG_NAME(SYNC),
 233         CMD_FLAG_NAME(META),
 234         CMD_FLAG_NAME(PRIO),
 235         CMD_FLAG_NAME(NOMERGE),
 236         CMD_FLAG_NAME(IDLE),
 237         CMD_FLAG_NAME(INTEGRITY),
 238         CMD_FLAG_NAME(FUA),
 239         CMD_FLAG_NAME(PREFLUSH),
 240         CMD_FLAG_NAME(RAHEAD),
 241         CMD_FLAG_NAME(BACKGROUND),
 242         CMD_FLAG_NAME(NOUNMAP),
 243 };
 244 #undef CMD_FLAG_NAME
 245
 246 #define RQF_NAME(name) [ilog2((__force u32)RQF_##name)] = #name
 247 static const char *const rqf_name[] = {
 248         RQF_NAME(SORTED),
 249         RQF_NAME(STARTED),
 250         RQF_NAME(QUEUED),
 251         RQF_NAME(SOFTBARRIER),
 252         RQF_NAME(FLUSH_SEQ),
 253         RQF_NAME(MIXED_MERGE),
 254         RQF_NAME(MQ_INFLIGHT),
 255         RQF_NAME(DONTPREP),
 256         RQF_NAME(PREEMPT),
 257         RQF_NAME(COPY_USER),
 258         RQF_NAME(FAILED),
 259         RQF_NAME(QUIET),
 260         RQF_NAME(ELVPRIV),
 261         RQF_NAME(IO_STAT),
 262         RQF_NAME(ALLOCED),
 263         RQF_NAME(PM),
 264         RQF_NAME(HASHED),
 265         RQF_NAME(STATS),
 266         RQF_NAME(SPECIAL_PAYLOAD),
 267 };
 268 #undef RQF_NAME
 269
 270 int __blk_mq_debugfs_rq_show(struct seq_file *m, struct request *rq)
 271 {
 272         const struct blk_mq_ops *const mq_ops = rq->q->mq_ops;
 273         const unsigned int op = rq->cmd_flags & REQ_OP_MASK;
 274
 275         seq_printf(m, "%p {.op=", rq);
 276         if (op < ARRAY_SIZE(op_name) && op_name[op])
 277                 seq_printf(m, "%s", op_name[op]);
 278         else
 279                 seq_printf(m, "%d", op);
 280         seq_puts(m, ", .cmd_flags=");
 281         blk_flags_show(m, rq->cmd_flags & ~REQ_OP_MASK, cmd_flag_name,
 282                        ARRAY_SIZE(cmd_flag_name));
 283         seq_puts(m, ", .rq_flags=");
 284         blk_flags_show(m, (__force unsigned int)rq->rq_flags, rqf_name,
 285                        ARRAY_SIZE(rqf_name));
 286         seq_printf(m, ", .tag=%d, .internal_tag=%d", rq->tag,
 287                    rq->internal_tag);
 288         if (mq_ops->show_rq)
 289                 mq_ops->show_rq(m, rq);
 290         seq_puts(m, "}\n");
 291         return 0;
 292 }
 293 EXPORT_SYMBOL_GPL(__blk_mq_debugfs_rq_show);
 294
 295 int blk_mq_debugfs_rq_show(struct seq_file *m, void *v)
 296 {
 297         return __blk_mq_debugfs_rq_show(m, list_entry_rq(v));
 298 }
 299 EXPORT_SYMBOL_GPL(blk_mq_debugfs_rq_show);
 300
 301 static void *hctx_dispatch_start(struct seq_file *m, loff_t *pos)
 302         __acquires(&hctx->lock)
 303 {
 304         struct blk_mq_hw_ctx *hctx = m->private;
 305
 306         spin_lock(&hctx->lock);
 307         return seq_list_start(&hctx->dispatch, *pos);
 308 }
 309
 310 static void *hctx_dispatch_next(struct seq_file *m, void *v, loff_t *pos)
 311 {
 312         struct blk_mq_hw_ctx *hctx = m->private;
 313
 314         return seq_list_next(v, &hctx->dispatch, pos);
 315 }
 316
 317 static void hctx_dispatch_stop(struct seq_file *m, void *v)
 318         __releases(&hctx->lock)
 319 {
 320         struct blk_mq_hw_ctx *hctx = m->private;
 321
 322         spin_unlock(&hctx->lock);
 323 }
 324
 325 static const struct seq_operations hctx_dispatch_seq_ops = {
 326         .start  = hctx_dispatch_start,
 327         .next   = hctx_dispatch_next,
 328         .stop   = hctx_dispatch_stop,
 329         .show   = blk_mq_debugfs_rq_show,
 330 };
 331
 332 static int hctx_ctx_map_show(void *data, struct seq_file *m)
 333 {
 334         struct blk_mq_hw_ctx *hctx = data;
 335
 336         sbitmap_bitmap_show(&hctx->ctx_map, m);
 337         return 0;
 338 }
 339
 340 static void blk_mq_debugfs_tags_show(struct seq_file *m,
 341                                      struct blk_mq_tags *tags)
 342 {
 343         seq_printf(m, "nr_tags=%u\n", tags->nr_tags);
 344         seq_printf(m, "nr_reserved_tags=%u\n", tags->nr_reserved_tags);
 345         seq_printf(m, "active_queues=%d\n",
 346                    atomic_read(&tags->active_queues));
 347
 348         seq_puts(m, "\nbitmap_tags:\n");
 349         sbitmap_queue_show(&tags->bitmap_tags, m);
 350
 351         if (tags->nr_reserved_tags) {
 352                 seq_puts(m, "\nbreserved_tags:\n");
 353                 sbitmap_queue_show(&tags->breserved_tags, m);
 354         }
 355 }
 356
 357 static int hctx_tags_show(void *data, struct seq_file *m)
 358 {
 359         struct blk_mq_hw_ctx *hctx = data;
 360         struct request_queue *q = hctx->queue;
 361         int res;
 362
 363         res = mutex_lock_interruptible(&q->sysfs_lock);
 364         if (res)
 365                 goto out;
 366         if (hctx->tags)
 367                 blk_mq_debugfs_tags_show(m, hctx->tags);
 368         mutex_unlock(&q->sysfs_lock);
 369
 370 out:
 371         return res;
 372 }
 373
 374 static int hctx_tags_bitmap_show(void *data, struct seq_file *m)
 375 {
 376         struct blk_mq_hw_ctx *hctx = data;
 377         struct request_queue *q = hctx->queue;
 378         int res;
 379
 380         res = mutex_lock_interruptible(&q->sysfs_lock);
 381         if (res)
 382                 goto out;
 383         if (hctx->tags)
 384                 sbitmap_bitmap_show(&hctx->tags->bitmap_tags.sb, m);
 385         mutex_unlock(&q->sysfs_lock);
 386
 387 out:
 388         return res;
 389 }
 390
 391 static int hctx_sched_tags_show(void *data, struct seq_file *m)
 392 {
 393         struct blk_mq_hw_ctx *hctx = data;
 394         struct request_queue *q = hctx->queue;
 395         int res;
 396
 397         res = mutex_lock_interruptible(&q->sysfs_lock);
 398         if (res)
 399                 goto out;
 400         if (hctx->sched_tags)
 401                 blk_mq_debugfs_tags_show(m, hctx->sched_tags);
 402         mutex_unlock(&q->sysfs_lock);
 403
 404 out:
 405         return res;
 406 }
 407
 408 static int hctx_sched_tags_bitmap_show(void *data, struct seq_file *m)
 409 {
 410         struct blk_mq_hw_ctx *hctx = data;
 411         struct request_queue *q = hctx->queue;
 412         int res;
 413
 414         res = mutex_lock_interruptible(&q->sysfs_lock);
 415         if (res)
 416                 goto out;
 417         if (hctx->sched_tags)
 418                 sbitmap_bitmap_show(&hctx->sched_tags->bitmap_tags.sb, m);
 419         mutex_unlock(&q->sysfs_lock);
 420
 421 out:
 422         return res;
 423 }
 424
 425 static int hctx_io_poll_show(void *data, struct seq_file *m)
 426 {
 427         struct blk_mq_hw_ctx *hctx = data;
 428
 429         seq_printf(m, "considered=%lu\n", hctx->poll_considered);
 430         seq_printf(m, "invoked=%lu\n", hctx->poll_invoked);
 431         seq_printf(m, "success=%lu\n", hctx->poll_success);
 432         return 0;
 433 }
 434
 435 static ssize_t hctx_io_poll_write(void *data, const char __user *buf,
 436                                   size_t count, loff_t *ppos)
 437 {
 438         struct blk_mq_hw_ctx *hctx = data;
 439
 440         hctx->poll_considered = hctx->poll_invoked = hctx->poll_success = 0;
 441         return count;
 442 }
 443
 444 static int hctx_dispatched_show(void *data, struct seq_file *m)
 445 {
 446         struct blk_mq_hw_ctx *hctx = data;
 447         int i;
 448
 449         seq_printf(m, "%8u\t%lu\n", 0U, hctx->dispatched[0]);
 450
 451         for (i = 1; i < BLK_MQ_MAX_DISPATCH_ORDER - 1; i++) {
 452                 unsigned int d = 1U << (i - 1);
 453
 454                 seq_printf(m, "%8u\t%lu\n", d, hctx->dispatched[i]);
 455         }
 456
 457         seq_printf(m, "%8u+\t%lu\n", 1U << (i - 1), hctx->dispatched[i]);
 458         return 0;
 459 }
 460
 461 static ssize_t hctx_dispatched_write(void *data, const char __user *buf,
 462                                      size_t count, loff_t *ppos)
 463 {
 464         struct blk_mq_hw_ctx *hctx = data;
 465         int i;
 466
 467         for (i = 0; i < BLK_MQ_MAX_DISPATCH_ORDER; i++)
 468                 hctx->dispatched[i] = 0;
 469         return count;
 470 }
 471
 472 static int hctx_queued_show(void *data, struct seq_file *m)
 473 {
 474         struct blk_mq_hw_ctx *hctx = data;
 475
 476         seq_printf(m, "%lu\n", hctx->queued);
 477         return 0;
 478 }
 479
 480 static ssize_t hctx_queued_write(void *data, const char __user *buf,
 481                                  size_t count, loff_t *ppos)
 482 {
 483         struct blk_mq_hw_ctx *hctx = data;
 484
 485         hctx->queued = 0;
 486         return count;
 487 }
 488
 489 static int hctx_run_show(void *data, struct seq_file *m)
 490 {
 491         struct blk_mq_hw_ctx *hctx = data;
 492
 493         seq_printf(m, "%lu\n", hctx->run);
 494         return 0;
 495 }
 496
 497 static ssize_t hctx_run_write(void *data, const char __user *buf, size_t count,
 498                               loff_t *ppos)
 499 {
 500         struct blk_mq_hw_ctx *hctx = data;
 501
 502         hctx->run = 0;
 503         return count;
 504 }
 505
 506 static int hctx_active_show(void *data, struct seq_file *m)
 507 {
 508         struct blk_mq_hw_ctx *hctx = data;
 509
 510         seq_printf(m, "%d\n", atomic_read(&hctx->nr_active));
 511         return 0;
 512 }
 513
 514 static void *ctx_rq_list_start(struct seq_file *m, loff_t *pos)
 515         __acquires(&ctx->lock)
 516 {
 517         struct blk_mq_ctx *ctx = m->private;
 518
 519         spin_lock(&ctx->lock);
 520         return seq_list_start(&ctx->rq_list, *pos);
 521 }
 522
 523 static void *ctx_rq_list_next(struct seq_file *m, void *v, loff_t *pos)
 524 {
 525         struct blk_mq_ctx *ctx = m->private;
 526
 527         return seq_list_next(v, &ctx->rq_list, pos);
 528 }
 529
 530 static void ctx_rq_list_stop(struct seq_file *m, void *v)
 531         __releases(&ctx->lock)
 532 {
 533         struct blk_mq_ctx *ctx = m->private;
 534
 535         spin_unlock(&ctx->lock);
 536 }
 537
 538 static const struct seq_operations ctx_rq_list_seq_ops = {
 539         .start  = ctx_rq_list_start,
 540         .next   = ctx_rq_list_next,
 541         .stop   = ctx_rq_list_stop,
 542         .show   = blk_mq_debugfs_rq_show,
 543 };
 544 static int ctx_dispatched_show(void *data, struct seq_file *m)
 545 {
 546         struct blk_mq_ctx *ctx = data;
 547
 548         seq_printf(m, "%lu %lu\n", ctx->rq_dispatched[1], ctx->rq_dispatched[0]);
 549         return 0;
 550 }
 551
 552 static ssize_t ctx_dispatched_write(void *data, const char __user *buf,
 553                                     size_t count, loff_t *ppos)
 554 {
 555         struct blk_mq_ctx *ctx = data;
 556
 557         ctx->rq_dispatched[0] = ctx->rq_dispatched[1] = 0;
 558         return count;
 559 }
 560
 561 static int ctx_merged_show(void *data, struct seq_file *m)
 562 {
 563         struct blk_mq_ctx *ctx = data;
 564
 565         seq_printf(m, "%lu\n", ctx->rq_merged);
 566         return 0;
 567 }
 568
 569 static ssize_t ctx_merged_write(void *data, const char __user *buf,
 570                                 size_t count, loff_t *ppos)
 571 {
 572         struct blk_mq_ctx *ctx = data;
 573
 574         ctx->rq_merged = 0;
 575         return count;
 576 }
 577
 578 static int ctx_completed_show(void *data, struct seq_file *m)
 579 {
 580         struct blk_mq_ctx *ctx = data;
 581
 582         seq_printf(m, "%lu %lu\n", ctx->rq_completed[1], ctx->rq_completed[0]);
 583         return 0;
 584 }
 585
 586 static ssize_t ctx_completed_write(void *data, const char __user *buf,
 587                                    size_t count, loff_t *ppos)
 588 {
 589         struct blk_mq_ctx *ctx = data;
 590
 591         ctx->rq_completed[0] = ctx->rq_completed[1] = 0;
 592         return count;
 593 }
 594
 595 static int blk_mq_debugfs_show(struct seq_file *m, void *v)
 596 {
 597         const struct blk_mq_debugfs_attr *attr = m->private;
 598         void *data = d_inode(m->file->f_path.dentry->d_parent)->i_private;
 599
 600         return attr->show(data, m);
 601 }
 602
 603 static ssize_t blk_mq_debugfs_write(struct file *file, const char __user *buf,
 604                                     size_t count, loff_t *ppos)
 605 {
 606         struct seq_file *m = file->private_data;
 607         const struct blk_mq_debugfs_attr *attr = m->private;
 608         void *data = d_inode(file->f_path.dentry->d_parent)->i_private;
 609
 610         if (!attr->write)
 611                 return -EPERM;
 612
 613         return attr->write(data, buf, count, ppos);
 614 }
 615
 616 static int blk_mq_debugfs_open(struct inode *inode, struct file *file)
 617 {
 618         const struct blk_mq_debugfs_attr *attr = inode->i_private;
 619         void *data = d_inode(file->f_path.dentry->d_parent)->i_private;
 620         struct seq_file *m;
 621         int ret;
 622
 623         if (attr->seq_ops) {
 624                 ret = seq_open(file, attr->seq_ops);
 625                 if (!ret) {
 626                         m = file->private_data;
 627                         m->private = data;
 628                 }
 629                 return ret;
 630         }
 631
 632         if (WARN_ON_ONCE(!attr->show))
 633                 return -EPERM;
 634
 635         return single_open(file, blk_mq_debugfs_show, inode->i_private);
 636 }
 637
 638 static int blk_mq_debugfs_release(struct inode *inode, struct file *file)
 639 {
 640         const struct blk_mq_debugfs_attr *attr = inode->i_private;
 641
 642         if (attr->show)
 643                 return single_release(inode, file);
 644         else
 645                 return seq_release(inode, file);
 646 }
 647
 648 const struct file_operations blk_mq_debugfs_fops = {
 649         .open           = blk_mq_debugfs_open,
 650         .read           = seq_read,
 651         .write          = blk_mq_debugfs_write,
 652         .llseek         = seq_lseek,
 653         .release        = blk_mq_debugfs_release,
 654 };
 655
 656 static const struct blk_mq_debugfs_attr blk_mq_debugfs_queue_attrs[] = {
 657         {"poll_stat", 0400, queue_poll_stat_show},
 658         {"state", 0600, queue_state_show, queue_state_write},
 659         {},
 660 };
 661
 662 static const struct blk_mq_debugfs_attr blk_mq_debugfs_hctx_attrs[] = {
 663         {"state", 0400, hctx_state_show},
 664         {"flags", 0400, hctx_flags_show},
 665         {"dispatch", 0400, .seq_ops = &hctx_dispatch_seq_ops},
 666         {"ctx_map", 0400, hctx_ctx_map_show},
 667         {"tags", 0400, hctx_tags_show},
 668         {"tags_bitmap", 0400, hctx_tags_bitmap_show},
 669         {"sched_tags", 0400, hctx_sched_tags_show},
 670         {"sched_tags_bitmap", 0400, hctx_sched_tags_bitmap_show},
 671         {"io_poll", 0600, hctx_io_poll_show, hctx_io_poll_write},
 672         {"dispatched", 0600, hctx_dispatched_show, hctx_dispatched_write},
 673         {"queued", 0600, hctx_queued_show, hctx_queued_write},
 674         {"run", 0600, hctx_run_show, hctx_run_write},
 675         {"active", 0400, hctx_active_show},
 676         {},
 677 };
 678
 679 static const struct blk_mq_debugfs_attr blk_mq_debugfs_ctx_attrs[] = {
 680         {"rq_list", 0400, .seq_ops = &ctx_rq_list_seq_ops},
 681         {"dispatched", 0600, ctx_dispatched_show, ctx_dispatched_write},
 682         {"merged", 0600, ctx_merged_show, ctx_merged_write},
 683         {"completed", 0600, ctx_completed_show, ctx_completed_write},
 684         {},
 685 };
 686
 687 static bool debugfs_create_files(struct dentry *parent, void *data,
 688                                  const struct blk_mq_debugfs_attr *attr)
 689 {
 690         d_inode(parent)->i_private = data;
 691
 692         for (; attr->name; attr++) {
 693                 if (!debugfs_create_file(attr->name, attr->mode, parent,
 694                                          (void *)attr, &blk_mq_debugfs_fops))
 695                         return false;
 696         }
 697         return true;
 698 }
 699
 700 int blk_mq_debugfs_register(struct request_queue *q)
 701 {
 702         struct blk_mq_hw_ctx *hctx;
 703         int i;
 704
 705         if (!blk_debugfs_root)
 706                 return -ENOENT;
 707
 708         q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
 709                                             blk_debugfs_root);
 710         if (!q->debugfs_dir)
 711                 return -ENOMEM;
 712
 713         if (!debugfs_create_files(q->debugfs_dir, q,
 714                                   blk_mq_debugfs_queue_attrs))
 715                 goto err;
 716
 717         /*
 718          * blk_mq_init_hctx() attempted to do this already, but q->debugfs_dir
 719          * didn't exist yet (because we don't know what to name the directory
 720          * until the queue is registered to a gendisk).
 721          */
 722         queue_for_each_hw_ctx(q, hctx, i) {
 723                 if (!hctx->debugfs_dir && blk_mq_debugfs_register_hctx(q, hctx))
 724                         goto err;
 725                 if (q->elevator && !hctx->sched_debugfs_dir &&
 726                     blk_mq_debugfs_register_sched_hctx(q, hctx))
 727                         goto err;
 728         }
 729
 730         return 0;
 731
 732 err:
 733         blk_mq_debugfs_unregister(q);
 734         return -ENOMEM;
 735 }
 736
 737 void blk_mq_debugfs_unregister(struct request_queue *q)
 738 {
 739         debugfs_remove_recursive(q->debugfs_dir);
 740         q->sched_debugfs_dir = NULL;
 741         q->debugfs_dir = NULL;
 742 }
 743
 744 static int blk_mq_debugfs_register_ctx(struct blk_mq_hw_ctx *hctx,
 745                                        struct blk_mq_ctx *ctx)
 746 {
 747         struct dentry *ctx_dir;
 748         char name[20];
 749
 750         snprintf(name, sizeof(name), "cpu%u", ctx->cpu);
 751         ctx_dir = debugfs_create_dir(name, hctx->debugfs_dir);
 752         if (!ctx_dir)
 753                 return -ENOMEM;
 754
 755         if (!debugfs_create_files(ctx_dir, ctx, blk_mq_debugfs_ctx_attrs))
 756                 return -ENOMEM;
 757
 758         return 0;
 759 }
 760
 761 int blk_mq_debugfs_register_hctx(struct request_queue *q,
 762                                  struct blk_mq_hw_ctx *hctx)
 763 {
 764         struct blk_mq_ctx *ctx;
 765         char name[20];
 766         int i;
 767
 768         if (!q->debugfs_dir)
 769                 return -ENOENT;
 770
 771         snprintf(name, sizeof(name), "hctx%u", hctx->queue_num);
 772         hctx->debugfs_dir = debugfs_create_dir(name, q->debugfs_dir);
 773         if (!hctx->debugfs_dir)
 774                 return -ENOMEM;
 775
 776         if (!debugfs_create_files(hctx->debugfs_dir, hctx,
 777                                   blk_mq_debugfs_hctx_attrs))
 778                 goto err;
 779
 780         hctx_for_each_ctx(hctx, ctx, i) {
 781                 if (blk_mq_debugfs_register_ctx(hctx, ctx))
 782                         goto err;
 783         }
 784
 785         return 0;
 786
 787 err:
 788         blk_mq_debugfs_unregister_hctx(hctx);
 789         return -ENOMEM;
 790 }
 791
 792 void blk_mq_debugfs_unregister_hctx(struct blk_mq_hw_ctx *hctx)
 793 {
 794         debugfs_remove_recursive(hctx->debugfs_dir);
 795         hctx->sched_debugfs_dir = NULL;
 796         hctx->debugfs_dir = NULL;
 797 }
 798
 799 int blk_mq_debugfs_register_hctxs(struct request_queue *q)
 800 {
 801         struct blk_mq_hw_ctx *hctx;
 802         int i;
 803
 804         queue_for_each_hw_ctx(q, hctx, i) {
 805                 if (blk_mq_debugfs_register_hctx(q, hctx))
 806                         return -ENOMEM;
 807         }
 808
 809         return 0;
 810 }
 811
 812 void blk_mq_debugfs_unregister_hctxs(struct request_queue *q)
 813 {
 814         struct blk_mq_hw_ctx *hctx;
 815         int i;
 816
 817         queue_for_each_hw_ctx(q, hctx, i)
 818                 blk_mq_debugfs_unregister_hctx(hctx);
 819 }
 820
 821 int blk_mq_debugfs_register_sched(struct request_queue *q)
 822 {
 823         struct elevator_type *e = q->elevator->type;
 824
 825         if (!q->debugfs_dir)
 826                 return -ENOENT;
 827
 828         if (!e->queue_debugfs_attrs)
 829                 return 0;
 830
 831         q->sched_debugfs_dir = debugfs_create_dir("sched", q->debugfs_dir);
 832         if (!q->sched_debugfs_dir)
 833                 return -ENOMEM;
 834
 835         if (!debugfs_create_files(q->sched_debugfs_dir, q,
 836                                   e->queue_debugfs_attrs))
 837                 goto err;
 838
 839         return 0;
 840
 841 err:
 842         blk_mq_debugfs_unregister_sched(q);
 843         return -ENOMEM;
 844 }
 845
 846 void blk_mq_debugfs_unregister_sched(struct request_queue *q)
 847 {
 848         debugfs_remove_recursive(q->sched_debugfs_dir);
 849         q->sched_debugfs_dir = NULL;
 850 }
 851
 852 int blk_mq_debugfs_register_sched_hctx(struct request_queue *q,
 853                                        struct blk_mq_hw_ctx *hctx)
 854 {
 855         struct elevator_type *e = q->elevator->type;
 856
 857         if (!hctx->debugfs_dir)
 858                 return -ENOENT;
 859
 860         if (!e->hctx_debugfs_attrs)
 861                 return 0;
 862
 863         hctx->sched_debugfs_dir = debugfs_create_dir("sched",
 864                                                      hctx->debugfs_dir);
 865         if (!hctx->sched_debugfs_dir)
 866                 return -ENOMEM;
 867
 868         if (!debugfs_create_files(hctx->sched_debugfs_dir, hctx,
 869                                   e->hctx_debugfs_attrs))
 870                 return -ENOMEM;
 871
 872         return 0;
 873 }
 874
 875 void blk_mq_debugfs_unregister_sched_hctx(struct blk_mq_hw_ctx *hctx)
 876 {
 877         debugfs_remove_recursive(hctx->sched_debugfs_dir);
 878         hctx->sched_debugfs_dir = NULL;
 879 }