Merge tag 'staging-5.0-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh...
[sfrench/cifs-2.6.git] / 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 #include "blk-rq-qos.h"
27
28 static void print_stat(struct seq_file *m, struct blk_rq_stat *stat)
29 {
30         if (stat->nr_samples) {
31                 seq_printf(m, "samples=%d, mean=%lld, min=%llu, max=%llu",
32                            stat->nr_samples, stat->mean, stat->min, stat->max);
33         } else {
34                 seq_puts(m, "samples=0");
35         }
36 }
37
38 static int queue_poll_stat_show(void *data, struct seq_file *m)
39 {
40         struct request_queue *q = data;
41         int bucket;
42
43         for (bucket = 0; bucket < BLK_MQ_POLL_STATS_BKTS/2; bucket++) {
44                 seq_printf(m, "read  (%d Bytes): ", 1 << (9+bucket));
45                 print_stat(m, &q->poll_stat[2*bucket]);
46                 seq_puts(m, "\n");
47
48                 seq_printf(m, "write (%d Bytes): ",  1 << (9+bucket));
49                 print_stat(m, &q->poll_stat[2*bucket+1]);
50                 seq_puts(m, "\n");
51         }
52         return 0;
53 }
54
55 static void *queue_requeue_list_start(struct seq_file *m, loff_t *pos)
56         __acquires(&q->requeue_lock)
57 {
58         struct request_queue *q = m->private;
59
60         spin_lock_irq(&q->requeue_lock);
61         return seq_list_start(&q->requeue_list, *pos);
62 }
63
64 static void *queue_requeue_list_next(struct seq_file *m, void *v, loff_t *pos)
65 {
66         struct request_queue *q = m->private;
67
68         return seq_list_next(v, &q->requeue_list, pos);
69 }
70
71 static void queue_requeue_list_stop(struct seq_file *m, void *v)
72         __releases(&q->requeue_lock)
73 {
74         struct request_queue *q = m->private;
75
76         spin_unlock_irq(&q->requeue_lock);
77 }
78
79 static const struct seq_operations queue_requeue_list_seq_ops = {
80         .start  = queue_requeue_list_start,
81         .next   = queue_requeue_list_next,
82         .stop   = queue_requeue_list_stop,
83         .show   = blk_mq_debugfs_rq_show,
84 };
85
86 static int blk_flags_show(struct seq_file *m, const unsigned long flags,
87                           const char *const *flag_name, int flag_name_count)
88 {
89         bool sep = false;
90         int i;
91
92         for (i = 0; i < sizeof(flags) * BITS_PER_BYTE; i++) {
93                 if (!(flags & BIT(i)))
94                         continue;
95                 if (sep)
96                         seq_puts(m, "|");
97                 sep = true;
98                 if (i < flag_name_count && flag_name[i])
99                         seq_puts(m, flag_name[i]);
100                 else
101                         seq_printf(m, "%d", i);
102         }
103         return 0;
104 }
105
106 static int queue_pm_only_show(void *data, struct seq_file *m)
107 {
108         struct request_queue *q = data;
109
110         seq_printf(m, "%d\n", atomic_read(&q->pm_only));
111         return 0;
112 }
113
114 #define QUEUE_FLAG_NAME(name) [QUEUE_FLAG_##name] = #name
115 static const char *const blk_queue_flag_name[] = {
116         QUEUE_FLAG_NAME(STOPPED),
117         QUEUE_FLAG_NAME(DYING),
118         QUEUE_FLAG_NAME(BIDI),
119         QUEUE_FLAG_NAME(NOMERGES),
120         QUEUE_FLAG_NAME(SAME_COMP),
121         QUEUE_FLAG_NAME(FAIL_IO),
122         QUEUE_FLAG_NAME(NONROT),
123         QUEUE_FLAG_NAME(IO_STAT),
124         QUEUE_FLAG_NAME(DISCARD),
125         QUEUE_FLAG_NAME(NOXMERGES),
126         QUEUE_FLAG_NAME(ADD_RANDOM),
127         QUEUE_FLAG_NAME(SECERASE),
128         QUEUE_FLAG_NAME(SAME_FORCE),
129         QUEUE_FLAG_NAME(DEAD),
130         QUEUE_FLAG_NAME(INIT_DONE),
131         QUEUE_FLAG_NAME(NO_SG_MERGE),
132         QUEUE_FLAG_NAME(POLL),
133         QUEUE_FLAG_NAME(WC),
134         QUEUE_FLAG_NAME(FUA),
135         QUEUE_FLAG_NAME(FLUSH_NQ),
136         QUEUE_FLAG_NAME(DAX),
137         QUEUE_FLAG_NAME(STATS),
138         QUEUE_FLAG_NAME(POLL_STATS),
139         QUEUE_FLAG_NAME(REGISTERED),
140         QUEUE_FLAG_NAME(SCSI_PASSTHROUGH),
141         QUEUE_FLAG_NAME(QUIESCED),
142 };
143 #undef QUEUE_FLAG_NAME
144
145 static int queue_state_show(void *data, struct seq_file *m)
146 {
147         struct request_queue *q = data;
148
149         blk_flags_show(m, q->queue_flags, blk_queue_flag_name,
150                        ARRAY_SIZE(blk_queue_flag_name));
151         seq_puts(m, "\n");
152         return 0;
153 }
154
155 static ssize_t queue_state_write(void *data, const char __user *buf,
156                                  size_t count, loff_t *ppos)
157 {
158         struct request_queue *q = data;
159         char opbuf[16] = { }, *op;
160
161         /*
162          * The "state" attribute is removed after blk_cleanup_queue() has called
163          * blk_mq_free_queue(). Return if QUEUE_FLAG_DEAD has been set to avoid
164          * triggering a use-after-free.
165          */
166         if (blk_queue_dead(q))
167                 return -ENOENT;
168
169         if (count >= sizeof(opbuf)) {
170                 pr_err("%s: operation too long\n", __func__);
171                 goto inval;
172         }
173
174         if (copy_from_user(opbuf, buf, count))
175                 return -EFAULT;
176         op = strstrip(opbuf);
177         if (strcmp(op, "run") == 0) {
178                 blk_mq_run_hw_queues(q, true);
179         } else if (strcmp(op, "start") == 0) {
180                 blk_mq_start_stopped_hw_queues(q, true);
181         } else if (strcmp(op, "kick") == 0) {
182                 blk_mq_kick_requeue_list(q);
183         } else {
184                 pr_err("%s: unsupported operation '%s'\n", __func__, op);
185 inval:
186                 pr_err("%s: use 'run', 'start' or 'kick'\n", __func__);
187                 return -EINVAL;
188         }
189         return count;
190 }
191
192 static int queue_write_hint_show(void *data, struct seq_file *m)
193 {
194         struct request_queue *q = data;
195         int i;
196
197         for (i = 0; i < BLK_MAX_WRITE_HINTS; i++)
198                 seq_printf(m, "hint%d: %llu\n", i, q->write_hints[i]);
199
200         return 0;
201 }
202
203 static ssize_t queue_write_hint_store(void *data, const char __user *buf,
204                                       size_t count, loff_t *ppos)
205 {
206         struct request_queue *q = data;
207         int i;
208
209         for (i = 0; i < BLK_MAX_WRITE_HINTS; i++)
210                 q->write_hints[i] = 0;
211
212         return count;
213 }
214
215 static const struct blk_mq_debugfs_attr blk_mq_debugfs_queue_attrs[] = {
216         { "poll_stat", 0400, queue_poll_stat_show },
217         { "requeue_list", 0400, .seq_ops = &queue_requeue_list_seq_ops },
218         { "pm_only", 0600, queue_pm_only_show, NULL },
219         { "state", 0600, queue_state_show, queue_state_write },
220         { "write_hints", 0600, queue_write_hint_show, queue_write_hint_store },
221         { "zone_wlock", 0400, queue_zone_wlock_show, NULL },
222         { },
223 };
224
225 #define HCTX_STATE_NAME(name) [BLK_MQ_S_##name] = #name
226 static const char *const hctx_state_name[] = {
227         HCTX_STATE_NAME(STOPPED),
228         HCTX_STATE_NAME(TAG_ACTIVE),
229         HCTX_STATE_NAME(SCHED_RESTART),
230 };
231 #undef HCTX_STATE_NAME
232
233 static int hctx_state_show(void *data, struct seq_file *m)
234 {
235         struct blk_mq_hw_ctx *hctx = data;
236
237         blk_flags_show(m, hctx->state, hctx_state_name,
238                        ARRAY_SIZE(hctx_state_name));
239         seq_puts(m, "\n");
240         return 0;
241 }
242
243 #define BLK_TAG_ALLOC_NAME(name) [BLK_TAG_ALLOC_##name] = #name
244 static const char *const alloc_policy_name[] = {
245         BLK_TAG_ALLOC_NAME(FIFO),
246         BLK_TAG_ALLOC_NAME(RR),
247 };
248 #undef BLK_TAG_ALLOC_NAME
249
250 #define HCTX_FLAG_NAME(name) [ilog2(BLK_MQ_F_##name)] = #name
251 static const char *const hctx_flag_name[] = {
252         HCTX_FLAG_NAME(SHOULD_MERGE),
253         HCTX_FLAG_NAME(TAG_SHARED),
254         HCTX_FLAG_NAME(SG_MERGE),
255         HCTX_FLAG_NAME(BLOCKING),
256         HCTX_FLAG_NAME(NO_SCHED),
257 };
258 #undef HCTX_FLAG_NAME
259
260 static int hctx_flags_show(void *data, struct seq_file *m)
261 {
262         struct blk_mq_hw_ctx *hctx = data;
263         const int alloc_policy = BLK_MQ_FLAG_TO_ALLOC_POLICY(hctx->flags);
264
265         seq_puts(m, "alloc_policy=");
266         if (alloc_policy < ARRAY_SIZE(alloc_policy_name) &&
267             alloc_policy_name[alloc_policy])
268                 seq_puts(m, alloc_policy_name[alloc_policy]);
269         else
270                 seq_printf(m, "%d", alloc_policy);
271         seq_puts(m, " ");
272         blk_flags_show(m,
273                        hctx->flags ^ BLK_ALLOC_POLICY_TO_MQ_FLAG(alloc_policy),
274                        hctx_flag_name, ARRAY_SIZE(hctx_flag_name));
275         seq_puts(m, "\n");
276         return 0;
277 }
278
279 #define REQ_OP_NAME(name) [REQ_OP_##name] = #name
280 static const char *const op_name[] = {
281         REQ_OP_NAME(READ),
282         REQ_OP_NAME(WRITE),
283         REQ_OP_NAME(FLUSH),
284         REQ_OP_NAME(DISCARD),
285         REQ_OP_NAME(SECURE_ERASE),
286         REQ_OP_NAME(ZONE_RESET),
287         REQ_OP_NAME(WRITE_SAME),
288         REQ_OP_NAME(WRITE_ZEROES),
289         REQ_OP_NAME(SCSI_IN),
290         REQ_OP_NAME(SCSI_OUT),
291         REQ_OP_NAME(DRV_IN),
292         REQ_OP_NAME(DRV_OUT),
293 };
294 #undef REQ_OP_NAME
295
296 #define CMD_FLAG_NAME(name) [__REQ_##name] = #name
297 static const char *const cmd_flag_name[] = {
298         CMD_FLAG_NAME(FAILFAST_DEV),
299         CMD_FLAG_NAME(FAILFAST_TRANSPORT),
300         CMD_FLAG_NAME(FAILFAST_DRIVER),
301         CMD_FLAG_NAME(SYNC),
302         CMD_FLAG_NAME(META),
303         CMD_FLAG_NAME(PRIO),
304         CMD_FLAG_NAME(NOMERGE),
305         CMD_FLAG_NAME(IDLE),
306         CMD_FLAG_NAME(INTEGRITY),
307         CMD_FLAG_NAME(FUA),
308         CMD_FLAG_NAME(PREFLUSH),
309         CMD_FLAG_NAME(RAHEAD),
310         CMD_FLAG_NAME(BACKGROUND),
311         CMD_FLAG_NAME(NOWAIT),
312         CMD_FLAG_NAME(NOUNMAP),
313         CMD_FLAG_NAME(HIPRI),
314 };
315 #undef CMD_FLAG_NAME
316
317 #define RQF_NAME(name) [ilog2((__force u32)RQF_##name)] = #name
318 static const char *const rqf_name[] = {
319         RQF_NAME(SORTED),
320         RQF_NAME(STARTED),
321         RQF_NAME(SOFTBARRIER),
322         RQF_NAME(FLUSH_SEQ),
323         RQF_NAME(MIXED_MERGE),
324         RQF_NAME(MQ_INFLIGHT),
325         RQF_NAME(DONTPREP),
326         RQF_NAME(PREEMPT),
327         RQF_NAME(COPY_USER),
328         RQF_NAME(FAILED),
329         RQF_NAME(QUIET),
330         RQF_NAME(ELVPRIV),
331         RQF_NAME(IO_STAT),
332         RQF_NAME(ALLOCED),
333         RQF_NAME(PM),
334         RQF_NAME(HASHED),
335         RQF_NAME(STATS),
336         RQF_NAME(SPECIAL_PAYLOAD),
337         RQF_NAME(ZONE_WRITE_LOCKED),
338         RQF_NAME(MQ_POLL_SLEPT),
339 };
340 #undef RQF_NAME
341
342 static const char *const blk_mq_rq_state_name_array[] = {
343         [MQ_RQ_IDLE]            = "idle",
344         [MQ_RQ_IN_FLIGHT]       = "in_flight",
345         [MQ_RQ_COMPLETE]        = "complete",
346 };
347
348 static const char *blk_mq_rq_state_name(enum mq_rq_state rq_state)
349 {
350         if (WARN_ON_ONCE((unsigned int)rq_state >=
351                          ARRAY_SIZE(blk_mq_rq_state_name_array)))
352                 return "(?)";
353         return blk_mq_rq_state_name_array[rq_state];
354 }
355
356 int __blk_mq_debugfs_rq_show(struct seq_file *m, struct request *rq)
357 {
358         const struct blk_mq_ops *const mq_ops = rq->q->mq_ops;
359         const unsigned int op = rq->cmd_flags & REQ_OP_MASK;
360
361         seq_printf(m, "%p {.op=", rq);
362         if (op < ARRAY_SIZE(op_name) && op_name[op])
363                 seq_printf(m, "%s", op_name[op]);
364         else
365                 seq_printf(m, "%d", op);
366         seq_puts(m, ", .cmd_flags=");
367         blk_flags_show(m, rq->cmd_flags & ~REQ_OP_MASK, cmd_flag_name,
368                        ARRAY_SIZE(cmd_flag_name));
369         seq_puts(m, ", .rq_flags=");
370         blk_flags_show(m, (__force unsigned int)rq->rq_flags, rqf_name,
371                        ARRAY_SIZE(rqf_name));
372         seq_printf(m, ", .state=%s", blk_mq_rq_state_name(blk_mq_rq_state(rq)));
373         seq_printf(m, ", .tag=%d, .internal_tag=%d", rq->tag,
374                    rq->internal_tag);
375         if (mq_ops->show_rq)
376                 mq_ops->show_rq(m, rq);
377         seq_puts(m, "}\n");
378         return 0;
379 }
380 EXPORT_SYMBOL_GPL(__blk_mq_debugfs_rq_show);
381
382 int blk_mq_debugfs_rq_show(struct seq_file *m, void *v)
383 {
384         return __blk_mq_debugfs_rq_show(m, list_entry_rq(v));
385 }
386 EXPORT_SYMBOL_GPL(blk_mq_debugfs_rq_show);
387
388 static void *hctx_dispatch_start(struct seq_file *m, loff_t *pos)
389         __acquires(&hctx->lock)
390 {
391         struct blk_mq_hw_ctx *hctx = m->private;
392
393         spin_lock(&hctx->lock);
394         return seq_list_start(&hctx->dispatch, *pos);
395 }
396
397 static void *hctx_dispatch_next(struct seq_file *m, void *v, loff_t *pos)
398 {
399         struct blk_mq_hw_ctx *hctx = m->private;
400
401         return seq_list_next(v, &hctx->dispatch, pos);
402 }
403
404 static void hctx_dispatch_stop(struct seq_file *m, void *v)
405         __releases(&hctx->lock)
406 {
407         struct blk_mq_hw_ctx *hctx = m->private;
408
409         spin_unlock(&hctx->lock);
410 }
411
412 static const struct seq_operations hctx_dispatch_seq_ops = {
413         .start  = hctx_dispatch_start,
414         .next   = hctx_dispatch_next,
415         .stop   = hctx_dispatch_stop,
416         .show   = blk_mq_debugfs_rq_show,
417 };
418
419 struct show_busy_params {
420         struct seq_file         *m;
421         struct blk_mq_hw_ctx    *hctx;
422 };
423
424 /*
425  * Note: the state of a request may change while this function is in progress,
426  * e.g. due to a concurrent blk_mq_finish_request() call. Returns true to
427  * keep iterating requests.
428  */
429 static bool hctx_show_busy_rq(struct request *rq, void *data, bool reserved)
430 {
431         const struct show_busy_params *params = data;
432
433         if (rq->mq_hctx == params->hctx)
434                 __blk_mq_debugfs_rq_show(params->m,
435                                          list_entry_rq(&rq->queuelist));
436
437         return true;
438 }
439
440 static int hctx_busy_show(void *data, struct seq_file *m)
441 {
442         struct blk_mq_hw_ctx *hctx = data;
443         struct show_busy_params params = { .m = m, .hctx = hctx };
444
445         blk_mq_tagset_busy_iter(hctx->queue->tag_set, hctx_show_busy_rq,
446                                 &params);
447
448         return 0;
449 }
450
451 static const char *const hctx_types[] = {
452         [HCTX_TYPE_DEFAULT]     = "default",
453         [HCTX_TYPE_READ]        = "read",
454         [HCTX_TYPE_POLL]        = "poll",
455 };
456
457 static int hctx_type_show(void *data, struct seq_file *m)
458 {
459         struct blk_mq_hw_ctx *hctx = data;
460
461         BUILD_BUG_ON(ARRAY_SIZE(hctx_types) != HCTX_MAX_TYPES);
462         seq_printf(m, "%s\n", hctx_types[hctx->type]);
463         return 0;
464 }
465
466 static int hctx_ctx_map_show(void *data, struct seq_file *m)
467 {
468         struct blk_mq_hw_ctx *hctx = data;
469
470         sbitmap_bitmap_show(&hctx->ctx_map, m);
471         return 0;
472 }
473
474 static void blk_mq_debugfs_tags_show(struct seq_file *m,
475                                      struct blk_mq_tags *tags)
476 {
477         seq_printf(m, "nr_tags=%u\n", tags->nr_tags);
478         seq_printf(m, "nr_reserved_tags=%u\n", tags->nr_reserved_tags);
479         seq_printf(m, "active_queues=%d\n",
480                    atomic_read(&tags->active_queues));
481
482         seq_puts(m, "\nbitmap_tags:\n");
483         sbitmap_queue_show(&tags->bitmap_tags, m);
484
485         if (tags->nr_reserved_tags) {
486                 seq_puts(m, "\nbreserved_tags:\n");
487                 sbitmap_queue_show(&tags->breserved_tags, m);
488         }
489 }
490
491 static int hctx_tags_show(void *data, struct seq_file *m)
492 {
493         struct blk_mq_hw_ctx *hctx = data;
494         struct request_queue *q = hctx->queue;
495         int res;
496
497         res = mutex_lock_interruptible(&q->sysfs_lock);
498         if (res)
499                 goto out;
500         if (hctx->tags)
501                 blk_mq_debugfs_tags_show(m, hctx->tags);
502         mutex_unlock(&q->sysfs_lock);
503
504 out:
505         return res;
506 }
507
508 static int hctx_tags_bitmap_show(void *data, struct seq_file *m)
509 {
510         struct blk_mq_hw_ctx *hctx = data;
511         struct request_queue *q = hctx->queue;
512         int res;
513
514         res = mutex_lock_interruptible(&q->sysfs_lock);
515         if (res)
516                 goto out;
517         if (hctx->tags)
518                 sbitmap_bitmap_show(&hctx->tags->bitmap_tags.sb, m);
519         mutex_unlock(&q->sysfs_lock);
520
521 out:
522         return res;
523 }
524
525 static int hctx_sched_tags_show(void *data, struct seq_file *m)
526 {
527         struct blk_mq_hw_ctx *hctx = data;
528         struct request_queue *q = hctx->queue;
529         int res;
530
531         res = mutex_lock_interruptible(&q->sysfs_lock);
532         if (res)
533                 goto out;
534         if (hctx->sched_tags)
535                 blk_mq_debugfs_tags_show(m, hctx->sched_tags);
536         mutex_unlock(&q->sysfs_lock);
537
538 out:
539         return res;
540 }
541
542 static int hctx_sched_tags_bitmap_show(void *data, struct seq_file *m)
543 {
544         struct blk_mq_hw_ctx *hctx = data;
545         struct request_queue *q = hctx->queue;
546         int res;
547
548         res = mutex_lock_interruptible(&q->sysfs_lock);
549         if (res)
550                 goto out;
551         if (hctx->sched_tags)
552                 sbitmap_bitmap_show(&hctx->sched_tags->bitmap_tags.sb, m);
553         mutex_unlock(&q->sysfs_lock);
554
555 out:
556         return res;
557 }
558
559 static int hctx_io_poll_show(void *data, struct seq_file *m)
560 {
561         struct blk_mq_hw_ctx *hctx = data;
562
563         seq_printf(m, "considered=%lu\n", hctx->poll_considered);
564         seq_printf(m, "invoked=%lu\n", hctx->poll_invoked);
565         seq_printf(m, "success=%lu\n", hctx->poll_success);
566         return 0;
567 }
568
569 static ssize_t hctx_io_poll_write(void *data, const char __user *buf,
570                                   size_t count, loff_t *ppos)
571 {
572         struct blk_mq_hw_ctx *hctx = data;
573
574         hctx->poll_considered = hctx->poll_invoked = hctx->poll_success = 0;
575         return count;
576 }
577
578 static int hctx_dispatched_show(void *data, struct seq_file *m)
579 {
580         struct blk_mq_hw_ctx *hctx = data;
581         int i;
582
583         seq_printf(m, "%8u\t%lu\n", 0U, hctx->dispatched[0]);
584
585         for (i = 1; i < BLK_MQ_MAX_DISPATCH_ORDER - 1; i++) {
586                 unsigned int d = 1U << (i - 1);
587
588                 seq_printf(m, "%8u\t%lu\n", d, hctx->dispatched[i]);
589         }
590
591         seq_printf(m, "%8u+\t%lu\n", 1U << (i - 1), hctx->dispatched[i]);
592         return 0;
593 }
594
595 static ssize_t hctx_dispatched_write(void *data, const char __user *buf,
596                                      size_t count, loff_t *ppos)
597 {
598         struct blk_mq_hw_ctx *hctx = data;
599         int i;
600
601         for (i = 0; i < BLK_MQ_MAX_DISPATCH_ORDER; i++)
602                 hctx->dispatched[i] = 0;
603         return count;
604 }
605
606 static int hctx_queued_show(void *data, struct seq_file *m)
607 {
608         struct blk_mq_hw_ctx *hctx = data;
609
610         seq_printf(m, "%lu\n", hctx->queued);
611         return 0;
612 }
613
614 static ssize_t hctx_queued_write(void *data, const char __user *buf,
615                                  size_t count, loff_t *ppos)
616 {
617         struct blk_mq_hw_ctx *hctx = data;
618
619         hctx->queued = 0;
620         return count;
621 }
622
623 static int hctx_run_show(void *data, struct seq_file *m)
624 {
625         struct blk_mq_hw_ctx *hctx = data;
626
627         seq_printf(m, "%lu\n", hctx->run);
628         return 0;
629 }
630
631 static ssize_t hctx_run_write(void *data, const char __user *buf, size_t count,
632                               loff_t *ppos)
633 {
634         struct blk_mq_hw_ctx *hctx = data;
635
636         hctx->run = 0;
637         return count;
638 }
639
640 static int hctx_active_show(void *data, struct seq_file *m)
641 {
642         struct blk_mq_hw_ctx *hctx = data;
643
644         seq_printf(m, "%d\n", atomic_read(&hctx->nr_active));
645         return 0;
646 }
647
648 static int hctx_dispatch_busy_show(void *data, struct seq_file *m)
649 {
650         struct blk_mq_hw_ctx *hctx = data;
651
652         seq_printf(m, "%u\n", hctx->dispatch_busy);
653         return 0;
654 }
655
656 #define CTX_RQ_SEQ_OPS(name, type)                                      \
657 static void *ctx_##name##_rq_list_start(struct seq_file *m, loff_t *pos) \
658         __acquires(&ctx->lock)                                          \
659 {                                                                       \
660         struct blk_mq_ctx *ctx = m->private;                            \
661                                                                         \
662         spin_lock(&ctx->lock);                                          \
663         return seq_list_start(&ctx->rq_lists[type], *pos);              \
664 }                                                                       \
665                                                                         \
666 static void *ctx_##name##_rq_list_next(struct seq_file *m, void *v,     \
667                                      loff_t *pos)                       \
668 {                                                                       \
669         struct blk_mq_ctx *ctx = m->private;                            \
670                                                                         \
671         return seq_list_next(v, &ctx->rq_lists[type], pos);             \
672 }                                                                       \
673                                                                         \
674 static void ctx_##name##_rq_list_stop(struct seq_file *m, void *v)      \
675         __releases(&ctx->lock)                                          \
676 {                                                                       \
677         struct blk_mq_ctx *ctx = m->private;                            \
678                                                                         \
679         spin_unlock(&ctx->lock);                                        \
680 }                                                                       \
681                                                                         \
682 static const struct seq_operations ctx_##name##_rq_list_seq_ops = {     \
683         .start  = ctx_##name##_rq_list_start,                           \
684         .next   = ctx_##name##_rq_list_next,                            \
685         .stop   = ctx_##name##_rq_list_stop,                            \
686         .show   = blk_mq_debugfs_rq_show,                               \
687 }
688
689 CTX_RQ_SEQ_OPS(default, HCTX_TYPE_DEFAULT);
690 CTX_RQ_SEQ_OPS(read, HCTX_TYPE_READ);
691 CTX_RQ_SEQ_OPS(poll, HCTX_TYPE_POLL);
692
693 static int ctx_dispatched_show(void *data, struct seq_file *m)
694 {
695         struct blk_mq_ctx *ctx = data;
696
697         seq_printf(m, "%lu %lu\n", ctx->rq_dispatched[1], ctx->rq_dispatched[0]);
698         return 0;
699 }
700
701 static ssize_t ctx_dispatched_write(void *data, const char __user *buf,
702                                     size_t count, loff_t *ppos)
703 {
704         struct blk_mq_ctx *ctx = data;
705
706         ctx->rq_dispatched[0] = ctx->rq_dispatched[1] = 0;
707         return count;
708 }
709
710 static int ctx_merged_show(void *data, struct seq_file *m)
711 {
712         struct blk_mq_ctx *ctx = data;
713
714         seq_printf(m, "%lu\n", ctx->rq_merged);
715         return 0;
716 }
717
718 static ssize_t ctx_merged_write(void *data, const char __user *buf,
719                                 size_t count, loff_t *ppos)
720 {
721         struct blk_mq_ctx *ctx = data;
722
723         ctx->rq_merged = 0;
724         return count;
725 }
726
727 static int ctx_completed_show(void *data, struct seq_file *m)
728 {
729         struct blk_mq_ctx *ctx = data;
730
731         seq_printf(m, "%lu %lu\n", ctx->rq_completed[1], ctx->rq_completed[0]);
732         return 0;
733 }
734
735 static ssize_t ctx_completed_write(void *data, const char __user *buf,
736                                    size_t count, loff_t *ppos)
737 {
738         struct blk_mq_ctx *ctx = data;
739
740         ctx->rq_completed[0] = ctx->rq_completed[1] = 0;
741         return count;
742 }
743
744 static int blk_mq_debugfs_show(struct seq_file *m, void *v)
745 {
746         const struct blk_mq_debugfs_attr *attr = m->private;
747         void *data = d_inode(m->file->f_path.dentry->d_parent)->i_private;
748
749         return attr->show(data, m);
750 }
751
752 static ssize_t blk_mq_debugfs_write(struct file *file, const char __user *buf,
753                                     size_t count, loff_t *ppos)
754 {
755         struct seq_file *m = file->private_data;
756         const struct blk_mq_debugfs_attr *attr = m->private;
757         void *data = d_inode(file->f_path.dentry->d_parent)->i_private;
758
759         /*
760          * Attributes that only implement .seq_ops are read-only and 'attr' is
761          * the same with 'data' in this case.
762          */
763         if (attr == data || !attr->write)
764                 return -EPERM;
765
766         return attr->write(data, buf, count, ppos);
767 }
768
769 static int blk_mq_debugfs_open(struct inode *inode, struct file *file)
770 {
771         const struct blk_mq_debugfs_attr *attr = inode->i_private;
772         void *data = d_inode(file->f_path.dentry->d_parent)->i_private;
773         struct seq_file *m;
774         int ret;
775
776         if (attr->seq_ops) {
777                 ret = seq_open(file, attr->seq_ops);
778                 if (!ret) {
779                         m = file->private_data;
780                         m->private = data;
781                 }
782                 return ret;
783         }
784
785         if (WARN_ON_ONCE(!attr->show))
786                 return -EPERM;
787
788         return single_open(file, blk_mq_debugfs_show, inode->i_private);
789 }
790
791 static int blk_mq_debugfs_release(struct inode *inode, struct file *file)
792 {
793         const struct blk_mq_debugfs_attr *attr = inode->i_private;
794
795         if (attr->show)
796                 return single_release(inode, file);
797         else
798                 return seq_release(inode, file);
799 }
800
801 static const struct file_operations blk_mq_debugfs_fops = {
802         .open           = blk_mq_debugfs_open,
803         .read           = seq_read,
804         .write          = blk_mq_debugfs_write,
805         .llseek         = seq_lseek,
806         .release        = blk_mq_debugfs_release,
807 };
808
809 static const struct blk_mq_debugfs_attr blk_mq_debugfs_hctx_attrs[] = {
810         {"state", 0400, hctx_state_show},
811         {"flags", 0400, hctx_flags_show},
812         {"dispatch", 0400, .seq_ops = &hctx_dispatch_seq_ops},
813         {"busy", 0400, hctx_busy_show},
814         {"ctx_map", 0400, hctx_ctx_map_show},
815         {"tags", 0400, hctx_tags_show},
816         {"tags_bitmap", 0400, hctx_tags_bitmap_show},
817         {"sched_tags", 0400, hctx_sched_tags_show},
818         {"sched_tags_bitmap", 0400, hctx_sched_tags_bitmap_show},
819         {"io_poll", 0600, hctx_io_poll_show, hctx_io_poll_write},
820         {"dispatched", 0600, hctx_dispatched_show, hctx_dispatched_write},
821         {"queued", 0600, hctx_queued_show, hctx_queued_write},
822         {"run", 0600, hctx_run_show, hctx_run_write},
823         {"active", 0400, hctx_active_show},
824         {"dispatch_busy", 0400, hctx_dispatch_busy_show},
825         {"type", 0400, hctx_type_show},
826         {},
827 };
828
829 static const struct blk_mq_debugfs_attr blk_mq_debugfs_ctx_attrs[] = {
830         {"default_rq_list", 0400, .seq_ops = &ctx_default_rq_list_seq_ops},
831         {"read_rq_list", 0400, .seq_ops = &ctx_read_rq_list_seq_ops},
832         {"poll_rq_list", 0400, .seq_ops = &ctx_poll_rq_list_seq_ops},
833         {"dispatched", 0600, ctx_dispatched_show, ctx_dispatched_write},
834         {"merged", 0600, ctx_merged_show, ctx_merged_write},
835         {"completed", 0600, ctx_completed_show, ctx_completed_write},
836         {},
837 };
838
839 static bool debugfs_create_files(struct dentry *parent, void *data,
840                                  const struct blk_mq_debugfs_attr *attr)
841 {
842         d_inode(parent)->i_private = data;
843
844         for (; attr->name; attr++) {
845                 if (!debugfs_create_file(attr->name, attr->mode, parent,
846                                          (void *)attr, &blk_mq_debugfs_fops))
847                         return false;
848         }
849         return true;
850 }
851
852 int blk_mq_debugfs_register(struct request_queue *q)
853 {
854         struct blk_mq_hw_ctx *hctx;
855         int i;
856
857         if (!blk_debugfs_root)
858                 return -ENOENT;
859
860         q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
861                                             blk_debugfs_root);
862         if (!q->debugfs_dir)
863                 return -ENOMEM;
864
865         if (!debugfs_create_files(q->debugfs_dir, q,
866                                   blk_mq_debugfs_queue_attrs))
867                 goto err;
868
869         /*
870          * blk_mq_init_sched() attempted to do this already, but q->debugfs_dir
871          * didn't exist yet (because we don't know what to name the directory
872          * until the queue is registered to a gendisk).
873          */
874         if (q->elevator && !q->sched_debugfs_dir)
875                 blk_mq_debugfs_register_sched(q);
876
877         /* Similarly, blk_mq_init_hctx() couldn't do this previously. */
878         queue_for_each_hw_ctx(q, hctx, i) {
879                 if (!hctx->debugfs_dir && blk_mq_debugfs_register_hctx(q, hctx))
880                         goto err;
881                 if (q->elevator && !hctx->sched_debugfs_dir &&
882                     blk_mq_debugfs_register_sched_hctx(q, hctx))
883                         goto err;
884         }
885
886         if (q->rq_qos) {
887                 struct rq_qos *rqos = q->rq_qos;
888
889                 while (rqos) {
890                         blk_mq_debugfs_register_rqos(rqos);
891                         rqos = rqos->next;
892                 }
893         }
894
895         return 0;
896
897 err:
898         blk_mq_debugfs_unregister(q);
899         return -ENOMEM;
900 }
901
902 void blk_mq_debugfs_unregister(struct request_queue *q)
903 {
904         debugfs_remove_recursive(q->debugfs_dir);
905         q->sched_debugfs_dir = NULL;
906         q->debugfs_dir = NULL;
907 }
908
909 static int blk_mq_debugfs_register_ctx(struct blk_mq_hw_ctx *hctx,
910                                        struct blk_mq_ctx *ctx)
911 {
912         struct dentry *ctx_dir;
913         char name[20];
914
915         snprintf(name, sizeof(name), "cpu%u", ctx->cpu);
916         ctx_dir = debugfs_create_dir(name, hctx->debugfs_dir);
917         if (!ctx_dir)
918                 return -ENOMEM;
919
920         if (!debugfs_create_files(ctx_dir, ctx, blk_mq_debugfs_ctx_attrs))
921                 return -ENOMEM;
922
923         return 0;
924 }
925
926 int blk_mq_debugfs_register_hctx(struct request_queue *q,
927                                  struct blk_mq_hw_ctx *hctx)
928 {
929         struct blk_mq_ctx *ctx;
930         char name[20];
931         int i;
932
933         if (!q->debugfs_dir)
934                 return -ENOENT;
935
936         snprintf(name, sizeof(name), "hctx%u", hctx->queue_num);
937         hctx->debugfs_dir = debugfs_create_dir(name, q->debugfs_dir);
938         if (!hctx->debugfs_dir)
939                 return -ENOMEM;
940
941         if (!debugfs_create_files(hctx->debugfs_dir, hctx,
942                                   blk_mq_debugfs_hctx_attrs))
943                 goto err;
944
945         hctx_for_each_ctx(hctx, ctx, i) {
946                 if (blk_mq_debugfs_register_ctx(hctx, ctx))
947                         goto err;
948         }
949
950         return 0;
951
952 err:
953         blk_mq_debugfs_unregister_hctx(hctx);
954         return -ENOMEM;
955 }
956
957 void blk_mq_debugfs_unregister_hctx(struct blk_mq_hw_ctx *hctx)
958 {
959         debugfs_remove_recursive(hctx->debugfs_dir);
960         hctx->sched_debugfs_dir = NULL;
961         hctx->debugfs_dir = NULL;
962 }
963
964 int blk_mq_debugfs_register_hctxs(struct request_queue *q)
965 {
966         struct blk_mq_hw_ctx *hctx;
967         int i;
968
969         queue_for_each_hw_ctx(q, hctx, i) {
970                 if (blk_mq_debugfs_register_hctx(q, hctx))
971                         return -ENOMEM;
972         }
973
974         return 0;
975 }
976
977 void blk_mq_debugfs_unregister_hctxs(struct request_queue *q)
978 {
979         struct blk_mq_hw_ctx *hctx;
980         int i;
981
982         queue_for_each_hw_ctx(q, hctx, i)
983                 blk_mq_debugfs_unregister_hctx(hctx);
984 }
985
986 int blk_mq_debugfs_register_sched(struct request_queue *q)
987 {
988         struct elevator_type *e = q->elevator->type;
989
990         if (!q->debugfs_dir)
991                 return -ENOENT;
992
993         if (!e->queue_debugfs_attrs)
994                 return 0;
995
996         q->sched_debugfs_dir = debugfs_create_dir("sched", q->debugfs_dir);
997         if (!q->sched_debugfs_dir)
998                 return -ENOMEM;
999
1000         if (!debugfs_create_files(q->sched_debugfs_dir, q,
1001                                   e->queue_debugfs_attrs))
1002                 goto err;
1003
1004         return 0;
1005
1006 err:
1007         blk_mq_debugfs_unregister_sched(q);
1008         return -ENOMEM;
1009 }
1010
1011 void blk_mq_debugfs_unregister_sched(struct request_queue *q)
1012 {
1013         debugfs_remove_recursive(q->sched_debugfs_dir);
1014         q->sched_debugfs_dir = NULL;
1015 }
1016
1017 void blk_mq_debugfs_unregister_rqos(struct rq_qos *rqos)
1018 {
1019         debugfs_remove_recursive(rqos->debugfs_dir);
1020         rqos->debugfs_dir = NULL;
1021 }
1022
1023 int blk_mq_debugfs_register_rqos(struct rq_qos *rqos)
1024 {
1025         struct request_queue *q = rqos->q;
1026         const char *dir_name = rq_qos_id_to_name(rqos->id);
1027
1028         if (!q->debugfs_dir)
1029                 return -ENOENT;
1030
1031         if (rqos->debugfs_dir || !rqos->ops->debugfs_attrs)
1032                 return 0;
1033
1034         if (!q->rqos_debugfs_dir) {
1035                 q->rqos_debugfs_dir = debugfs_create_dir("rqos",
1036                                                          q->debugfs_dir);
1037                 if (!q->rqos_debugfs_dir)
1038                         return -ENOMEM;
1039         }
1040
1041         rqos->debugfs_dir = debugfs_create_dir(dir_name,
1042                                                rqos->q->rqos_debugfs_dir);
1043         if (!rqos->debugfs_dir)
1044                 return -ENOMEM;
1045
1046         if (!debugfs_create_files(rqos->debugfs_dir, rqos,
1047                                   rqos->ops->debugfs_attrs))
1048                 goto err;
1049         return 0;
1050  err:
1051         blk_mq_debugfs_unregister_rqos(rqos);
1052         return -ENOMEM;
1053 }
1054
1055 void blk_mq_debugfs_unregister_queue_rqos(struct request_queue *q)
1056 {
1057         debugfs_remove_recursive(q->rqos_debugfs_dir);
1058         q->rqos_debugfs_dir = NULL;
1059 }
1060
1061 int blk_mq_debugfs_register_sched_hctx(struct request_queue *q,
1062                                        struct blk_mq_hw_ctx *hctx)
1063 {
1064         struct elevator_type *e = q->elevator->type;
1065
1066         if (!hctx->debugfs_dir)
1067                 return -ENOENT;
1068
1069         if (!e->hctx_debugfs_attrs)
1070                 return 0;
1071
1072         hctx->sched_debugfs_dir = debugfs_create_dir("sched",
1073                                                      hctx->debugfs_dir);
1074         if (!hctx->sched_debugfs_dir)
1075                 return -ENOMEM;
1076
1077         if (!debugfs_create_files(hctx->sched_debugfs_dir, hctx,
1078                                   e->hctx_debugfs_attrs))
1079                 return -ENOMEM;
1080
1081         return 0;
1082 }
1083
1084 void blk_mq_debugfs_unregister_sched_hctx(struct blk_mq_hw_ctx *hctx)
1085 {
1086         debugfs_remove_recursive(hctx->sched_debugfs_dir);
1087         hctx->sched_debugfs_dir = NULL;
1088 }