blk-mq: protect debugfs_create_files() from failures
[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(NOUNMAP),
312         CMD_FLAG_NAME(NOWAIT),
313 };
314 #undef CMD_FLAG_NAME
315
316 #define RQF_NAME(name) [ilog2((__force u32)RQF_##name)] = #name
317 static const char *const rqf_name[] = {
318         RQF_NAME(SORTED),
319         RQF_NAME(STARTED),
320         RQF_NAME(SOFTBARRIER),
321         RQF_NAME(FLUSH_SEQ),
322         RQF_NAME(MIXED_MERGE),
323         RQF_NAME(MQ_INFLIGHT),
324         RQF_NAME(DONTPREP),
325         RQF_NAME(PREEMPT),
326         RQF_NAME(COPY_USER),
327         RQF_NAME(FAILED),
328         RQF_NAME(QUIET),
329         RQF_NAME(ELVPRIV),
330         RQF_NAME(IO_STAT),
331         RQF_NAME(ALLOCED),
332         RQF_NAME(PM),
333         RQF_NAME(HASHED),
334         RQF_NAME(STATS),
335         RQF_NAME(SPECIAL_PAYLOAD),
336         RQF_NAME(ZONE_WRITE_LOCKED),
337         RQF_NAME(MQ_POLL_SLEPT),
338 };
339 #undef RQF_NAME
340
341 static const char *const blk_mq_rq_state_name_array[] = {
342         [MQ_RQ_IDLE]            = "idle",
343         [MQ_RQ_IN_FLIGHT]       = "in_flight",
344         [MQ_RQ_COMPLETE]        = "complete",
345 };
346
347 static const char *blk_mq_rq_state_name(enum mq_rq_state rq_state)
348 {
349         if (WARN_ON_ONCE((unsigned int)rq_state >=
350                          ARRAY_SIZE(blk_mq_rq_state_name_array)))
351                 return "(?)";
352         return blk_mq_rq_state_name_array[rq_state];
353 }
354
355 int __blk_mq_debugfs_rq_show(struct seq_file *m, struct request *rq)
356 {
357         const struct blk_mq_ops *const mq_ops = rq->q->mq_ops;
358         const unsigned int op = rq->cmd_flags & REQ_OP_MASK;
359
360         seq_printf(m, "%p {.op=", rq);
361         if (op < ARRAY_SIZE(op_name) && op_name[op])
362                 seq_printf(m, "%s", op_name[op]);
363         else
364                 seq_printf(m, "%d", op);
365         seq_puts(m, ", .cmd_flags=");
366         blk_flags_show(m, rq->cmd_flags & ~REQ_OP_MASK, cmd_flag_name,
367                        ARRAY_SIZE(cmd_flag_name));
368         seq_puts(m, ", .rq_flags=");
369         blk_flags_show(m, (__force unsigned int)rq->rq_flags, rqf_name,
370                        ARRAY_SIZE(rqf_name));
371         seq_printf(m, ", .state=%s", blk_mq_rq_state_name(blk_mq_rq_state(rq)));
372         seq_printf(m, ", .tag=%d, .internal_tag=%d", rq->tag,
373                    rq->internal_tag);
374         if (mq_ops->show_rq)
375                 mq_ops->show_rq(m, rq);
376         seq_puts(m, "}\n");
377         return 0;
378 }
379 EXPORT_SYMBOL_GPL(__blk_mq_debugfs_rq_show);
380
381 int blk_mq_debugfs_rq_show(struct seq_file *m, void *v)
382 {
383         return __blk_mq_debugfs_rq_show(m, list_entry_rq(v));
384 }
385 EXPORT_SYMBOL_GPL(blk_mq_debugfs_rq_show);
386
387 static void *hctx_dispatch_start(struct seq_file *m, loff_t *pos)
388         __acquires(&hctx->lock)
389 {
390         struct blk_mq_hw_ctx *hctx = m->private;
391
392         spin_lock(&hctx->lock);
393         return seq_list_start(&hctx->dispatch, *pos);
394 }
395
396 static void *hctx_dispatch_next(struct seq_file *m, void *v, loff_t *pos)
397 {
398         struct blk_mq_hw_ctx *hctx = m->private;
399
400         return seq_list_next(v, &hctx->dispatch, pos);
401 }
402
403 static void hctx_dispatch_stop(struct seq_file *m, void *v)
404         __releases(&hctx->lock)
405 {
406         struct blk_mq_hw_ctx *hctx = m->private;
407
408         spin_unlock(&hctx->lock);
409 }
410
411 static const struct seq_operations hctx_dispatch_seq_ops = {
412         .start  = hctx_dispatch_start,
413         .next   = hctx_dispatch_next,
414         .stop   = hctx_dispatch_stop,
415         .show   = blk_mq_debugfs_rq_show,
416 };
417
418 struct show_busy_params {
419         struct seq_file         *m;
420         struct blk_mq_hw_ctx    *hctx;
421 };
422
423 /*
424  * Note: the state of a request may change while this function is in progress,
425  * e.g. due to a concurrent blk_mq_finish_request() call. Returns true to
426  * keep iterating requests.
427  */
428 static bool hctx_show_busy_rq(struct request *rq, void *data, bool reserved)
429 {
430         const struct show_busy_params *params = data;
431
432         if (rq->mq_hctx == params->hctx)
433                 __blk_mq_debugfs_rq_show(params->m,
434                                          list_entry_rq(&rq->queuelist));
435
436         return true;
437 }
438
439 static int hctx_busy_show(void *data, struct seq_file *m)
440 {
441         struct blk_mq_hw_ctx *hctx = data;
442         struct show_busy_params params = { .m = m, .hctx = hctx };
443
444         blk_mq_tagset_busy_iter(hctx->queue->tag_set, hctx_show_busy_rq,
445                                 &params);
446
447         return 0;
448 }
449
450 static const char *const hctx_types[] = {
451         [HCTX_TYPE_DEFAULT]     = "default",
452         [HCTX_TYPE_READ]        = "read",
453         [HCTX_TYPE_POLL]        = "poll",
454 };
455
456 static int hctx_type_show(void *data, struct seq_file *m)
457 {
458         struct blk_mq_hw_ctx *hctx = data;
459
460         BUILD_BUG_ON(ARRAY_SIZE(hctx_types) != HCTX_MAX_TYPES);
461         seq_printf(m, "%s\n", hctx_types[hctx->type]);
462         return 0;
463 }
464
465 static int hctx_ctx_map_show(void *data, struct seq_file *m)
466 {
467         struct blk_mq_hw_ctx *hctx = data;
468
469         sbitmap_bitmap_show(&hctx->ctx_map, m);
470         return 0;
471 }
472
473 static void blk_mq_debugfs_tags_show(struct seq_file *m,
474                                      struct blk_mq_tags *tags)
475 {
476         seq_printf(m, "nr_tags=%u\n", tags->nr_tags);
477         seq_printf(m, "nr_reserved_tags=%u\n", tags->nr_reserved_tags);
478         seq_printf(m, "active_queues=%d\n",
479                    atomic_read(&tags->active_queues));
480
481         seq_puts(m, "\nbitmap_tags:\n");
482         sbitmap_queue_show(&tags->bitmap_tags, m);
483
484         if (tags->nr_reserved_tags) {
485                 seq_puts(m, "\nbreserved_tags:\n");
486                 sbitmap_queue_show(&tags->breserved_tags, m);
487         }
488 }
489
490 static int hctx_tags_show(void *data, struct seq_file *m)
491 {
492         struct blk_mq_hw_ctx *hctx = data;
493         struct request_queue *q = hctx->queue;
494         int res;
495
496         res = mutex_lock_interruptible(&q->sysfs_lock);
497         if (res)
498                 goto out;
499         if (hctx->tags)
500                 blk_mq_debugfs_tags_show(m, hctx->tags);
501         mutex_unlock(&q->sysfs_lock);
502
503 out:
504         return res;
505 }
506
507 static int hctx_tags_bitmap_show(void *data, struct seq_file *m)
508 {
509         struct blk_mq_hw_ctx *hctx = data;
510         struct request_queue *q = hctx->queue;
511         int res;
512
513         res = mutex_lock_interruptible(&q->sysfs_lock);
514         if (res)
515                 goto out;
516         if (hctx->tags)
517                 sbitmap_bitmap_show(&hctx->tags->bitmap_tags.sb, m);
518         mutex_unlock(&q->sysfs_lock);
519
520 out:
521         return res;
522 }
523
524 static int hctx_sched_tags_show(void *data, struct seq_file *m)
525 {
526         struct blk_mq_hw_ctx *hctx = data;
527         struct request_queue *q = hctx->queue;
528         int res;
529
530         res = mutex_lock_interruptible(&q->sysfs_lock);
531         if (res)
532                 goto out;
533         if (hctx->sched_tags)
534                 blk_mq_debugfs_tags_show(m, hctx->sched_tags);
535         mutex_unlock(&q->sysfs_lock);
536
537 out:
538         return res;
539 }
540
541 static int hctx_sched_tags_bitmap_show(void *data, struct seq_file *m)
542 {
543         struct blk_mq_hw_ctx *hctx = data;
544         struct request_queue *q = hctx->queue;
545         int res;
546
547         res = mutex_lock_interruptible(&q->sysfs_lock);
548         if (res)
549                 goto out;
550         if (hctx->sched_tags)
551                 sbitmap_bitmap_show(&hctx->sched_tags->bitmap_tags.sb, m);
552         mutex_unlock(&q->sysfs_lock);
553
554 out:
555         return res;
556 }
557
558 static int hctx_io_poll_show(void *data, struct seq_file *m)
559 {
560         struct blk_mq_hw_ctx *hctx = data;
561
562         seq_printf(m, "considered=%lu\n", hctx->poll_considered);
563         seq_printf(m, "invoked=%lu\n", hctx->poll_invoked);
564         seq_printf(m, "success=%lu\n", hctx->poll_success);
565         return 0;
566 }
567
568 static ssize_t hctx_io_poll_write(void *data, const char __user *buf,
569                                   size_t count, loff_t *ppos)
570 {
571         struct blk_mq_hw_ctx *hctx = data;
572
573         hctx->poll_considered = hctx->poll_invoked = hctx->poll_success = 0;
574         return count;
575 }
576
577 static int hctx_dispatched_show(void *data, struct seq_file *m)
578 {
579         struct blk_mq_hw_ctx *hctx = data;
580         int i;
581
582         seq_printf(m, "%8u\t%lu\n", 0U, hctx->dispatched[0]);
583
584         for (i = 1; i < BLK_MQ_MAX_DISPATCH_ORDER - 1; i++) {
585                 unsigned int d = 1U << (i - 1);
586
587                 seq_printf(m, "%8u\t%lu\n", d, hctx->dispatched[i]);
588         }
589
590         seq_printf(m, "%8u+\t%lu\n", 1U << (i - 1), hctx->dispatched[i]);
591         return 0;
592 }
593
594 static ssize_t hctx_dispatched_write(void *data, const char __user *buf,
595                                      size_t count, loff_t *ppos)
596 {
597         struct blk_mq_hw_ctx *hctx = data;
598         int i;
599
600         for (i = 0; i < BLK_MQ_MAX_DISPATCH_ORDER; i++)
601                 hctx->dispatched[i] = 0;
602         return count;
603 }
604
605 static int hctx_queued_show(void *data, struct seq_file *m)
606 {
607         struct blk_mq_hw_ctx *hctx = data;
608
609         seq_printf(m, "%lu\n", hctx->queued);
610         return 0;
611 }
612
613 static ssize_t hctx_queued_write(void *data, const char __user *buf,
614                                  size_t count, loff_t *ppos)
615 {
616         struct blk_mq_hw_ctx *hctx = data;
617
618         hctx->queued = 0;
619         return count;
620 }
621
622 static int hctx_run_show(void *data, struct seq_file *m)
623 {
624         struct blk_mq_hw_ctx *hctx = data;
625
626         seq_printf(m, "%lu\n", hctx->run);
627         return 0;
628 }
629
630 static ssize_t hctx_run_write(void *data, const char __user *buf, size_t count,
631                               loff_t *ppos)
632 {
633         struct blk_mq_hw_ctx *hctx = data;
634
635         hctx->run = 0;
636         return count;
637 }
638
639 static int hctx_active_show(void *data, struct seq_file *m)
640 {
641         struct blk_mq_hw_ctx *hctx = data;
642
643         seq_printf(m, "%d\n", atomic_read(&hctx->nr_active));
644         return 0;
645 }
646
647 static int hctx_dispatch_busy_show(void *data, struct seq_file *m)
648 {
649         struct blk_mq_hw_ctx *hctx = data;
650
651         seq_printf(m, "%u\n", hctx->dispatch_busy);
652         return 0;
653 }
654
655 #define CTX_RQ_SEQ_OPS(name, type)                                      \
656 static void *ctx_##name##_rq_list_start(struct seq_file *m, loff_t *pos) \
657         __acquires(&ctx->lock)                                          \
658 {                                                                       \
659         struct blk_mq_ctx *ctx = m->private;                            \
660                                                                         \
661         spin_lock(&ctx->lock);                                          \
662         return seq_list_start(&ctx->rq_lists[type], *pos);              \
663 }                                                                       \
664                                                                         \
665 static void *ctx_##name##_rq_list_next(struct seq_file *m, void *v,     \
666                                      loff_t *pos)                       \
667 {                                                                       \
668         struct blk_mq_ctx *ctx = m->private;                            \
669                                                                         \
670         return seq_list_next(v, &ctx->rq_lists[type], pos);             \
671 }                                                                       \
672                                                                         \
673 static void ctx_##name##_rq_list_stop(struct seq_file *m, void *v)      \
674         __releases(&ctx->lock)                                          \
675 {                                                                       \
676         struct blk_mq_ctx *ctx = m->private;                            \
677                                                                         \
678         spin_unlock(&ctx->lock);                                        \
679 }                                                                       \
680                                                                         \
681 static const struct seq_operations ctx_##name##_rq_list_seq_ops = {     \
682         .start  = ctx_##name##_rq_list_start,                           \
683         .next   = ctx_##name##_rq_list_next,                            \
684         .stop   = ctx_##name##_rq_list_stop,                            \
685         .show   = blk_mq_debugfs_rq_show,                               \
686 }
687
688 CTX_RQ_SEQ_OPS(default, HCTX_TYPE_DEFAULT);
689 CTX_RQ_SEQ_OPS(read, HCTX_TYPE_READ);
690 CTX_RQ_SEQ_OPS(poll, HCTX_TYPE_POLL);
691
692 static int ctx_dispatched_show(void *data, struct seq_file *m)
693 {
694         struct blk_mq_ctx *ctx = data;
695
696         seq_printf(m, "%lu %lu\n", ctx->rq_dispatched[1], ctx->rq_dispatched[0]);
697         return 0;
698 }
699
700 static ssize_t ctx_dispatched_write(void *data, const char __user *buf,
701                                     size_t count, loff_t *ppos)
702 {
703         struct blk_mq_ctx *ctx = data;
704
705         ctx->rq_dispatched[0] = ctx->rq_dispatched[1] = 0;
706         return count;
707 }
708
709 static int ctx_merged_show(void *data, struct seq_file *m)
710 {
711         struct blk_mq_ctx *ctx = data;
712
713         seq_printf(m, "%lu\n", ctx->rq_merged);
714         return 0;
715 }
716
717 static ssize_t ctx_merged_write(void *data, const char __user *buf,
718                                 size_t count, loff_t *ppos)
719 {
720         struct blk_mq_ctx *ctx = data;
721
722         ctx->rq_merged = 0;
723         return count;
724 }
725
726 static int ctx_completed_show(void *data, struct seq_file *m)
727 {
728         struct blk_mq_ctx *ctx = data;
729
730         seq_printf(m, "%lu %lu\n", ctx->rq_completed[1], ctx->rq_completed[0]);
731         return 0;
732 }
733
734 static ssize_t ctx_completed_write(void *data, const char __user *buf,
735                                    size_t count, loff_t *ppos)
736 {
737         struct blk_mq_ctx *ctx = data;
738
739         ctx->rq_completed[0] = ctx->rq_completed[1] = 0;
740         return count;
741 }
742
743 static int blk_mq_debugfs_show(struct seq_file *m, void *v)
744 {
745         const struct blk_mq_debugfs_attr *attr = m->private;
746         void *data = d_inode(m->file->f_path.dentry->d_parent)->i_private;
747
748         return attr->show(data, m);
749 }
750
751 static ssize_t blk_mq_debugfs_write(struct file *file, const char __user *buf,
752                                     size_t count, loff_t *ppos)
753 {
754         struct seq_file *m = file->private_data;
755         const struct blk_mq_debugfs_attr *attr = m->private;
756         void *data = d_inode(file->f_path.dentry->d_parent)->i_private;
757
758         /*
759          * Attributes that only implement .seq_ops are read-only and 'attr' is
760          * the same with 'data' in this case.
761          */
762         if (attr == data || !attr->write)
763                 return -EPERM;
764
765         return attr->write(data, buf, count, ppos);
766 }
767
768 static int blk_mq_debugfs_open(struct inode *inode, struct file *file)
769 {
770         const struct blk_mq_debugfs_attr *attr = inode->i_private;
771         void *data = d_inode(file->f_path.dentry->d_parent)->i_private;
772         struct seq_file *m;
773         int ret;
774
775         if (attr->seq_ops) {
776                 ret = seq_open(file, attr->seq_ops);
777                 if (!ret) {
778                         m = file->private_data;
779                         m->private = data;
780                 }
781                 return ret;
782         }
783
784         if (WARN_ON_ONCE(!attr->show))
785                 return -EPERM;
786
787         return single_open(file, blk_mq_debugfs_show, inode->i_private);
788 }
789
790 static int blk_mq_debugfs_release(struct inode *inode, struct file *file)
791 {
792         const struct blk_mq_debugfs_attr *attr = inode->i_private;
793
794         if (attr->show)
795                 return single_release(inode, file);
796         else
797                 return seq_release(inode, file);
798 }
799
800 static const struct file_operations blk_mq_debugfs_fops = {
801         .open           = blk_mq_debugfs_open,
802         .read           = seq_read,
803         .write          = blk_mq_debugfs_write,
804         .llseek         = seq_lseek,
805         .release        = blk_mq_debugfs_release,
806 };
807
808 static const struct blk_mq_debugfs_attr blk_mq_debugfs_hctx_attrs[] = {
809         {"state", 0400, hctx_state_show},
810         {"flags", 0400, hctx_flags_show},
811         {"dispatch", 0400, .seq_ops = &hctx_dispatch_seq_ops},
812         {"busy", 0400, hctx_busy_show},
813         {"ctx_map", 0400, hctx_ctx_map_show},
814         {"tags", 0400, hctx_tags_show},
815         {"tags_bitmap", 0400, hctx_tags_bitmap_show},
816         {"sched_tags", 0400, hctx_sched_tags_show},
817         {"sched_tags_bitmap", 0400, hctx_sched_tags_bitmap_show},
818         {"io_poll", 0600, hctx_io_poll_show, hctx_io_poll_write},
819         {"dispatched", 0600, hctx_dispatched_show, hctx_dispatched_write},
820         {"queued", 0600, hctx_queued_show, hctx_queued_write},
821         {"run", 0600, hctx_run_show, hctx_run_write},
822         {"active", 0400, hctx_active_show},
823         {"dispatch_busy", 0400, hctx_dispatch_busy_show},
824         {"type", 0400, hctx_type_show},
825         {},
826 };
827
828 static const struct blk_mq_debugfs_attr blk_mq_debugfs_ctx_attrs[] = {
829         {"default_rq_list", 0400, .seq_ops = &ctx_default_rq_list_seq_ops},
830         {"read_rq_list", 0400, .seq_ops = &ctx_read_rq_list_seq_ops},
831         {"poll_rq_list", 0400, .seq_ops = &ctx_poll_rq_list_seq_ops},
832         {"dispatched", 0600, ctx_dispatched_show, ctx_dispatched_write},
833         {"merged", 0600, ctx_merged_show, ctx_merged_write},
834         {"completed", 0600, ctx_completed_show, ctx_completed_write},
835         {},
836 };
837
838 static bool debugfs_create_files(struct dentry *parent, void *data,
839                                  const struct blk_mq_debugfs_attr *attr)
840 {
841         if (IS_ERR_OR_NULL(parent))
842                 return false;
843
844         d_inode(parent)->i_private = data;
845
846         for (; attr->name; attr++) {
847                 if (!debugfs_create_file(attr->name, attr->mode, parent,
848                                          (void *)attr, &blk_mq_debugfs_fops))
849                         return false;
850         }
851         return true;
852 }
853
854 int blk_mq_debugfs_register(struct request_queue *q)
855 {
856         struct blk_mq_hw_ctx *hctx;
857         int i;
858
859         if (!blk_debugfs_root)
860                 return -ENOENT;
861
862         q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
863                                             blk_debugfs_root);
864         if (!q->debugfs_dir)
865                 return -ENOMEM;
866
867         if (!debugfs_create_files(q->debugfs_dir, q,
868                                   blk_mq_debugfs_queue_attrs))
869                 goto err;
870
871         /*
872          * blk_mq_init_sched() attempted to do this already, but q->debugfs_dir
873          * didn't exist yet (because we don't know what to name the directory
874          * until the queue is registered to a gendisk).
875          */
876         if (q->elevator && !q->sched_debugfs_dir)
877                 blk_mq_debugfs_register_sched(q);
878
879         /* Similarly, blk_mq_init_hctx() couldn't do this previously. */
880         queue_for_each_hw_ctx(q, hctx, i) {
881                 if (!hctx->debugfs_dir && blk_mq_debugfs_register_hctx(q, hctx))
882                         goto err;
883                 if (q->elevator && !hctx->sched_debugfs_dir &&
884                     blk_mq_debugfs_register_sched_hctx(q, hctx))
885                         goto err;
886         }
887
888         if (q->rq_qos) {
889                 struct rq_qos *rqos = q->rq_qos;
890
891                 while (rqos) {
892                         blk_mq_debugfs_register_rqos(rqos);
893                         rqos = rqos->next;
894                 }
895         }
896
897         return 0;
898
899 err:
900         blk_mq_debugfs_unregister(q);
901         return -ENOMEM;
902 }
903
904 void blk_mq_debugfs_unregister(struct request_queue *q)
905 {
906         debugfs_remove_recursive(q->debugfs_dir);
907         q->sched_debugfs_dir = NULL;
908         q->debugfs_dir = NULL;
909 }
910
911 static int blk_mq_debugfs_register_ctx(struct blk_mq_hw_ctx *hctx,
912                                        struct blk_mq_ctx *ctx)
913 {
914         struct dentry *ctx_dir;
915         char name[20];
916
917         snprintf(name, sizeof(name), "cpu%u", ctx->cpu);
918         ctx_dir = debugfs_create_dir(name, hctx->debugfs_dir);
919         if (!ctx_dir)
920                 return -ENOMEM;
921
922         if (!debugfs_create_files(ctx_dir, ctx, blk_mq_debugfs_ctx_attrs))
923                 return -ENOMEM;
924
925         return 0;
926 }
927
928 int blk_mq_debugfs_register_hctx(struct request_queue *q,
929                                  struct blk_mq_hw_ctx *hctx)
930 {
931         struct blk_mq_ctx *ctx;
932         char name[20];
933         int i;
934
935         if (!q->debugfs_dir)
936                 return -ENOENT;
937
938         snprintf(name, sizeof(name), "hctx%u", hctx->queue_num);
939         hctx->debugfs_dir = debugfs_create_dir(name, q->debugfs_dir);
940         if (!hctx->debugfs_dir)
941                 return -ENOMEM;
942
943         if (!debugfs_create_files(hctx->debugfs_dir, hctx,
944                                   blk_mq_debugfs_hctx_attrs))
945                 goto err;
946
947         hctx_for_each_ctx(hctx, ctx, i) {
948                 if (blk_mq_debugfs_register_ctx(hctx, ctx))
949                         goto err;
950         }
951
952         return 0;
953
954 err:
955         blk_mq_debugfs_unregister_hctx(hctx);
956         return -ENOMEM;
957 }
958
959 void blk_mq_debugfs_unregister_hctx(struct blk_mq_hw_ctx *hctx)
960 {
961         debugfs_remove_recursive(hctx->debugfs_dir);
962         hctx->sched_debugfs_dir = NULL;
963         hctx->debugfs_dir = NULL;
964 }
965
966 int blk_mq_debugfs_register_hctxs(struct request_queue *q)
967 {
968         struct blk_mq_hw_ctx *hctx;
969         int i;
970
971         queue_for_each_hw_ctx(q, hctx, i) {
972                 if (blk_mq_debugfs_register_hctx(q, hctx))
973                         return -ENOMEM;
974         }
975
976         return 0;
977 }
978
979 void blk_mq_debugfs_unregister_hctxs(struct request_queue *q)
980 {
981         struct blk_mq_hw_ctx *hctx;
982         int i;
983
984         queue_for_each_hw_ctx(q, hctx, i)
985                 blk_mq_debugfs_unregister_hctx(hctx);
986 }
987
988 int blk_mq_debugfs_register_sched(struct request_queue *q)
989 {
990         struct elevator_type *e = q->elevator->type;
991
992         if (!q->debugfs_dir)
993                 return -ENOENT;
994
995         if (!e->queue_debugfs_attrs)
996                 return 0;
997
998         q->sched_debugfs_dir = debugfs_create_dir("sched", q->debugfs_dir);
999         if (!q->sched_debugfs_dir)
1000                 return -ENOMEM;
1001
1002         if (!debugfs_create_files(q->sched_debugfs_dir, q,
1003                                   e->queue_debugfs_attrs))
1004                 goto err;
1005
1006         return 0;
1007
1008 err:
1009         blk_mq_debugfs_unregister_sched(q);
1010         return -ENOMEM;
1011 }
1012
1013 void blk_mq_debugfs_unregister_sched(struct request_queue *q)
1014 {
1015         debugfs_remove_recursive(q->sched_debugfs_dir);
1016         q->sched_debugfs_dir = NULL;
1017 }
1018
1019 void blk_mq_debugfs_unregister_rqos(struct rq_qos *rqos)
1020 {
1021         debugfs_remove_recursive(rqos->debugfs_dir);
1022         rqos->debugfs_dir = NULL;
1023 }
1024
1025 int blk_mq_debugfs_register_rqos(struct rq_qos *rqos)
1026 {
1027         struct request_queue *q = rqos->q;
1028         const char *dir_name = rq_qos_id_to_name(rqos->id);
1029
1030         if (!q->debugfs_dir)
1031                 return -ENOENT;
1032
1033         if (rqos->debugfs_dir || !rqos->ops->debugfs_attrs)
1034                 return 0;
1035
1036         if (!q->rqos_debugfs_dir) {
1037                 q->rqos_debugfs_dir = debugfs_create_dir("rqos",
1038                                                          q->debugfs_dir);
1039                 if (!q->rqos_debugfs_dir)
1040                         return -ENOMEM;
1041         }
1042
1043         rqos->debugfs_dir = debugfs_create_dir(dir_name,
1044                                                rqos->q->rqos_debugfs_dir);
1045         if (!rqos->debugfs_dir)
1046                 return -ENOMEM;
1047
1048         if (!debugfs_create_files(rqos->debugfs_dir, rqos,
1049                                   rqos->ops->debugfs_attrs))
1050                 goto err;
1051         return 0;
1052  err:
1053         blk_mq_debugfs_unregister_rqos(rqos);
1054         return -ENOMEM;
1055 }
1056
1057 void blk_mq_debugfs_unregister_queue_rqos(struct request_queue *q)
1058 {
1059         debugfs_remove_recursive(q->rqos_debugfs_dir);
1060         q->rqos_debugfs_dir = NULL;
1061 }
1062
1063 int blk_mq_debugfs_register_sched_hctx(struct request_queue *q,
1064                                        struct blk_mq_hw_ctx *hctx)
1065 {
1066         struct elevator_type *e = q->elevator->type;
1067
1068         if (!hctx->debugfs_dir)
1069                 return -ENOENT;
1070
1071         if (!e->hctx_debugfs_attrs)
1072                 return 0;
1073
1074         hctx->sched_debugfs_dir = debugfs_create_dir("sched",
1075                                                      hctx->debugfs_dir);
1076         if (!hctx->sched_debugfs_dir)
1077                 return -ENOMEM;
1078
1079         if (!debugfs_create_files(hctx->sched_debugfs_dir, hctx,
1080                                   e->hctx_debugfs_attrs))
1081                 return -ENOMEM;
1082
1083         return 0;
1084 }
1085
1086 void blk_mq_debugfs_unregister_sched_hctx(struct blk_mq_hw_ctx *hctx)
1087 {
1088         debugfs_remove_recursive(hctx->sched_debugfs_dir);
1089         hctx->sched_debugfs_dir = NULL;
1090 }