xref: /linux/block/blk-mq-debugfs.c (revision b58b13f156c00c2457035b7071eaaac105fe6836) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2017 Facebook
4  */
5 
6 #include <linux/kernel.h>
7 #include <linux/blkdev.h>
8 #include <linux/debugfs.h>
9 
10 #include "blk.h"
11 #include "blk-mq.h"
12 #include "blk-mq-debugfs.h"
13 #include "blk-mq-sched.h"
14 #include "blk-rq-qos.h"
15 
16 static int queue_poll_stat_show(void *data, struct seq_file *m)
17 {
18 	return 0;
19 }
20 
21 static void *queue_requeue_list_start(struct seq_file *m, loff_t *pos)
22 	__acquires(&q->requeue_lock)
23 {
24 	struct request_queue *q = m->private;
25 
26 	spin_lock_irq(&q->requeue_lock);
27 	return seq_list_start(&q->requeue_list, *pos);
28 }
29 
30 static void *queue_requeue_list_next(struct seq_file *m, void *v, loff_t *pos)
31 {
32 	struct request_queue *q = m->private;
33 
34 	return seq_list_next(v, &q->requeue_list, pos);
35 }
36 
37 static void queue_requeue_list_stop(struct seq_file *m, void *v)
38 	__releases(&q->requeue_lock)
39 {
40 	struct request_queue *q = m->private;
41 
42 	spin_unlock_irq(&q->requeue_lock);
43 }
44 
45 static const struct seq_operations queue_requeue_list_seq_ops = {
46 	.start	= queue_requeue_list_start,
47 	.next	= queue_requeue_list_next,
48 	.stop	= queue_requeue_list_stop,
49 	.show	= blk_mq_debugfs_rq_show,
50 };
51 
52 static int blk_flags_show(struct seq_file *m, const unsigned long flags,
53 			  const char *const *flag_name, int flag_name_count)
54 {
55 	bool sep = false;
56 	int i;
57 
58 	for (i = 0; i < sizeof(flags) * BITS_PER_BYTE; i++) {
59 		if (!(flags & BIT(i)))
60 			continue;
61 		if (sep)
62 			seq_puts(m, "|");
63 		sep = true;
64 		if (i < flag_name_count && flag_name[i])
65 			seq_puts(m, flag_name[i]);
66 		else
67 			seq_printf(m, "%d", i);
68 	}
69 	return 0;
70 }
71 
72 static int queue_pm_only_show(void *data, struct seq_file *m)
73 {
74 	struct request_queue *q = data;
75 
76 	seq_printf(m, "%d\n", atomic_read(&q->pm_only));
77 	return 0;
78 }
79 
80 #define QUEUE_FLAG_NAME(name) [QUEUE_FLAG_##name] = #name
81 static const char *const blk_queue_flag_name[] = {
82 	QUEUE_FLAG_NAME(STOPPED),
83 	QUEUE_FLAG_NAME(DYING),
84 	QUEUE_FLAG_NAME(NOMERGES),
85 	QUEUE_FLAG_NAME(SAME_COMP),
86 	QUEUE_FLAG_NAME(FAIL_IO),
87 	QUEUE_FLAG_NAME(NONROT),
88 	QUEUE_FLAG_NAME(IO_STAT),
89 	QUEUE_FLAG_NAME(NOXMERGES),
90 	QUEUE_FLAG_NAME(ADD_RANDOM),
91 	QUEUE_FLAG_NAME(SYNCHRONOUS),
92 	QUEUE_FLAG_NAME(SAME_FORCE),
93 	QUEUE_FLAG_NAME(INIT_DONE),
94 	QUEUE_FLAG_NAME(STABLE_WRITES),
95 	QUEUE_FLAG_NAME(POLL),
96 	QUEUE_FLAG_NAME(WC),
97 	QUEUE_FLAG_NAME(FUA),
98 	QUEUE_FLAG_NAME(DAX),
99 	QUEUE_FLAG_NAME(STATS),
100 	QUEUE_FLAG_NAME(REGISTERED),
101 	QUEUE_FLAG_NAME(QUIESCED),
102 	QUEUE_FLAG_NAME(PCI_P2PDMA),
103 	QUEUE_FLAG_NAME(ZONE_RESETALL),
104 	QUEUE_FLAG_NAME(RQ_ALLOC_TIME),
105 	QUEUE_FLAG_NAME(HCTX_ACTIVE),
106 	QUEUE_FLAG_NAME(NOWAIT),
107 	QUEUE_FLAG_NAME(SQ_SCHED),
108 	QUEUE_FLAG_NAME(SKIP_TAGSET_QUIESCE),
109 };
110 #undef QUEUE_FLAG_NAME
111 
112 static int queue_state_show(void *data, struct seq_file *m)
113 {
114 	struct request_queue *q = data;
115 
116 	blk_flags_show(m, q->queue_flags, blk_queue_flag_name,
117 		       ARRAY_SIZE(blk_queue_flag_name));
118 	seq_puts(m, "\n");
119 	return 0;
120 }
121 
122 static ssize_t queue_state_write(void *data, const char __user *buf,
123 				 size_t count, loff_t *ppos)
124 {
125 	struct request_queue *q = data;
126 	char opbuf[16] = { }, *op;
127 
128 	/*
129 	 * The "state" attribute is removed when the queue is removed.  Don't
130 	 * allow setting the state on a dying queue to avoid a use-after-free.
131 	 */
132 	if (blk_queue_dying(q))
133 		return -ENOENT;
134 
135 	if (count >= sizeof(opbuf)) {
136 		pr_err("%s: operation too long\n", __func__);
137 		goto inval;
138 	}
139 
140 	if (copy_from_user(opbuf, buf, count))
141 		return -EFAULT;
142 	op = strstrip(opbuf);
143 	if (strcmp(op, "run") == 0) {
144 		blk_mq_run_hw_queues(q, true);
145 	} else if (strcmp(op, "start") == 0) {
146 		blk_mq_start_stopped_hw_queues(q, true);
147 	} else if (strcmp(op, "kick") == 0) {
148 		blk_mq_kick_requeue_list(q);
149 	} else {
150 		pr_err("%s: unsupported operation '%s'\n", __func__, op);
151 inval:
152 		pr_err("%s: use 'run', 'start' or 'kick'\n", __func__);
153 		return -EINVAL;
154 	}
155 	return count;
156 }
157 
158 static const struct blk_mq_debugfs_attr blk_mq_debugfs_queue_attrs[] = {
159 	{ "poll_stat", 0400, queue_poll_stat_show },
160 	{ "requeue_list", 0400, .seq_ops = &queue_requeue_list_seq_ops },
161 	{ "pm_only", 0600, queue_pm_only_show, NULL },
162 	{ "state", 0600, queue_state_show, queue_state_write },
163 	{ "zone_wlock", 0400, queue_zone_wlock_show, NULL },
164 	{ },
165 };
166 
167 #define HCTX_STATE_NAME(name) [BLK_MQ_S_##name] = #name
168 static const char *const hctx_state_name[] = {
169 	HCTX_STATE_NAME(STOPPED),
170 	HCTX_STATE_NAME(TAG_ACTIVE),
171 	HCTX_STATE_NAME(SCHED_RESTART),
172 	HCTX_STATE_NAME(INACTIVE),
173 };
174 #undef HCTX_STATE_NAME
175 
176 static int hctx_state_show(void *data, struct seq_file *m)
177 {
178 	struct blk_mq_hw_ctx *hctx = data;
179 
180 	blk_flags_show(m, hctx->state, hctx_state_name,
181 		       ARRAY_SIZE(hctx_state_name));
182 	seq_puts(m, "\n");
183 	return 0;
184 }
185 
186 #define BLK_TAG_ALLOC_NAME(name) [BLK_TAG_ALLOC_##name] = #name
187 static const char *const alloc_policy_name[] = {
188 	BLK_TAG_ALLOC_NAME(FIFO),
189 	BLK_TAG_ALLOC_NAME(RR),
190 };
191 #undef BLK_TAG_ALLOC_NAME
192 
193 #define HCTX_FLAG_NAME(name) [ilog2(BLK_MQ_F_##name)] = #name
194 static const char *const hctx_flag_name[] = {
195 	HCTX_FLAG_NAME(SHOULD_MERGE),
196 	HCTX_FLAG_NAME(TAG_QUEUE_SHARED),
197 	HCTX_FLAG_NAME(BLOCKING),
198 	HCTX_FLAG_NAME(NO_SCHED),
199 	HCTX_FLAG_NAME(STACKING),
200 	HCTX_FLAG_NAME(TAG_HCTX_SHARED),
201 };
202 #undef HCTX_FLAG_NAME
203 
204 static int hctx_flags_show(void *data, struct seq_file *m)
205 {
206 	struct blk_mq_hw_ctx *hctx = data;
207 	const int alloc_policy = BLK_MQ_FLAG_TO_ALLOC_POLICY(hctx->flags);
208 
209 	seq_puts(m, "alloc_policy=");
210 	if (alloc_policy < ARRAY_SIZE(alloc_policy_name) &&
211 	    alloc_policy_name[alloc_policy])
212 		seq_puts(m, alloc_policy_name[alloc_policy]);
213 	else
214 		seq_printf(m, "%d", alloc_policy);
215 	seq_puts(m, " ");
216 	blk_flags_show(m,
217 		       hctx->flags ^ BLK_ALLOC_POLICY_TO_MQ_FLAG(alloc_policy),
218 		       hctx_flag_name, ARRAY_SIZE(hctx_flag_name));
219 	seq_puts(m, "\n");
220 	return 0;
221 }
222 
223 #define CMD_FLAG_NAME(name) [__REQ_##name] = #name
224 static const char *const cmd_flag_name[] = {
225 	CMD_FLAG_NAME(FAILFAST_DEV),
226 	CMD_FLAG_NAME(FAILFAST_TRANSPORT),
227 	CMD_FLAG_NAME(FAILFAST_DRIVER),
228 	CMD_FLAG_NAME(SYNC),
229 	CMD_FLAG_NAME(META),
230 	CMD_FLAG_NAME(PRIO),
231 	CMD_FLAG_NAME(NOMERGE),
232 	CMD_FLAG_NAME(IDLE),
233 	CMD_FLAG_NAME(INTEGRITY),
234 	CMD_FLAG_NAME(FUA),
235 	CMD_FLAG_NAME(PREFLUSH),
236 	CMD_FLAG_NAME(RAHEAD),
237 	CMD_FLAG_NAME(BACKGROUND),
238 	CMD_FLAG_NAME(NOWAIT),
239 	CMD_FLAG_NAME(NOUNMAP),
240 	CMD_FLAG_NAME(POLLED),
241 };
242 #undef CMD_FLAG_NAME
243 
244 #define RQF_NAME(name) [ilog2((__force u32)RQF_##name)] = #name
245 static const char *const rqf_name[] = {
246 	RQF_NAME(STARTED),
247 	RQF_NAME(FLUSH_SEQ),
248 	RQF_NAME(MIXED_MERGE),
249 	RQF_NAME(DONTPREP),
250 	RQF_NAME(SCHED_TAGS),
251 	RQF_NAME(USE_SCHED),
252 	RQF_NAME(FAILED),
253 	RQF_NAME(QUIET),
254 	RQF_NAME(IO_STAT),
255 	RQF_NAME(PM),
256 	RQF_NAME(HASHED),
257 	RQF_NAME(STATS),
258 	RQF_NAME(SPECIAL_PAYLOAD),
259 	RQF_NAME(ZONE_WRITE_LOCKED),
260 	RQF_NAME(TIMED_OUT),
261 	RQF_NAME(RESV),
262 };
263 #undef RQF_NAME
264 
265 static const char *const blk_mq_rq_state_name_array[] = {
266 	[MQ_RQ_IDLE]		= "idle",
267 	[MQ_RQ_IN_FLIGHT]	= "in_flight",
268 	[MQ_RQ_COMPLETE]	= "complete",
269 };
270 
271 static const char *blk_mq_rq_state_name(enum mq_rq_state rq_state)
272 {
273 	if (WARN_ON_ONCE((unsigned int)rq_state >=
274 			 ARRAY_SIZE(blk_mq_rq_state_name_array)))
275 		return "(?)";
276 	return blk_mq_rq_state_name_array[rq_state];
277 }
278 
279 int __blk_mq_debugfs_rq_show(struct seq_file *m, struct request *rq)
280 {
281 	const struct blk_mq_ops *const mq_ops = rq->q->mq_ops;
282 	const enum req_op op = req_op(rq);
283 	const char *op_str = blk_op_str(op);
284 
285 	seq_printf(m, "%p {.op=", rq);
286 	if (strcmp(op_str, "UNKNOWN") == 0)
287 		seq_printf(m, "%u", op);
288 	else
289 		seq_printf(m, "%s", op_str);
290 	seq_puts(m, ", .cmd_flags=");
291 	blk_flags_show(m, (__force unsigned int)(rq->cmd_flags & ~REQ_OP_MASK),
292 		       cmd_flag_name, ARRAY_SIZE(cmd_flag_name));
293 	seq_puts(m, ", .rq_flags=");
294 	blk_flags_show(m, (__force unsigned int)rq->rq_flags, rqf_name,
295 		       ARRAY_SIZE(rqf_name));
296 	seq_printf(m, ", .state=%s", blk_mq_rq_state_name(blk_mq_rq_state(rq)));
297 	seq_printf(m, ", .tag=%d, .internal_tag=%d", rq->tag,
298 		   rq->internal_tag);
299 	if (mq_ops->show_rq)
300 		mq_ops->show_rq(m, rq);
301 	seq_puts(m, "}\n");
302 	return 0;
303 }
304 EXPORT_SYMBOL_GPL(__blk_mq_debugfs_rq_show);
305 
306 int blk_mq_debugfs_rq_show(struct seq_file *m, void *v)
307 {
308 	return __blk_mq_debugfs_rq_show(m, list_entry_rq(v));
309 }
310 EXPORT_SYMBOL_GPL(blk_mq_debugfs_rq_show);
311 
312 static void *hctx_dispatch_start(struct seq_file *m, loff_t *pos)
313 	__acquires(&hctx->lock)
314 {
315 	struct blk_mq_hw_ctx *hctx = m->private;
316 
317 	spin_lock(&hctx->lock);
318 	return seq_list_start(&hctx->dispatch, *pos);
319 }
320 
321 static void *hctx_dispatch_next(struct seq_file *m, void *v, loff_t *pos)
322 {
323 	struct blk_mq_hw_ctx *hctx = m->private;
324 
325 	return seq_list_next(v, &hctx->dispatch, pos);
326 }
327 
328 static void hctx_dispatch_stop(struct seq_file *m, void *v)
329 	__releases(&hctx->lock)
330 {
331 	struct blk_mq_hw_ctx *hctx = m->private;
332 
333 	spin_unlock(&hctx->lock);
334 }
335 
336 static const struct seq_operations hctx_dispatch_seq_ops = {
337 	.start	= hctx_dispatch_start,
338 	.next	= hctx_dispatch_next,
339 	.stop	= hctx_dispatch_stop,
340 	.show	= blk_mq_debugfs_rq_show,
341 };
342 
343 struct show_busy_params {
344 	struct seq_file		*m;
345 	struct blk_mq_hw_ctx	*hctx;
346 };
347 
348 /*
349  * Note: the state of a request may change while this function is in progress,
350  * e.g. due to a concurrent blk_mq_finish_request() call. Returns true to
351  * keep iterating requests.
352  */
353 static bool hctx_show_busy_rq(struct request *rq, void *data)
354 {
355 	const struct show_busy_params *params = data;
356 
357 	if (rq->mq_hctx == params->hctx)
358 		__blk_mq_debugfs_rq_show(params->m, rq);
359 
360 	return true;
361 }
362 
363 static int hctx_busy_show(void *data, struct seq_file *m)
364 {
365 	struct blk_mq_hw_ctx *hctx = data;
366 	struct show_busy_params params = { .m = m, .hctx = hctx };
367 
368 	blk_mq_tagset_busy_iter(hctx->queue->tag_set, hctx_show_busy_rq,
369 				&params);
370 
371 	return 0;
372 }
373 
374 static const char *const hctx_types[] = {
375 	[HCTX_TYPE_DEFAULT]	= "default",
376 	[HCTX_TYPE_READ]	= "read",
377 	[HCTX_TYPE_POLL]	= "poll",
378 };
379 
380 static int hctx_type_show(void *data, struct seq_file *m)
381 {
382 	struct blk_mq_hw_ctx *hctx = data;
383 
384 	BUILD_BUG_ON(ARRAY_SIZE(hctx_types) != HCTX_MAX_TYPES);
385 	seq_printf(m, "%s\n", hctx_types[hctx->type]);
386 	return 0;
387 }
388 
389 static int hctx_ctx_map_show(void *data, struct seq_file *m)
390 {
391 	struct blk_mq_hw_ctx *hctx = data;
392 
393 	sbitmap_bitmap_show(&hctx->ctx_map, m);
394 	return 0;
395 }
396 
397 static void blk_mq_debugfs_tags_show(struct seq_file *m,
398 				     struct blk_mq_tags *tags)
399 {
400 	seq_printf(m, "nr_tags=%u\n", tags->nr_tags);
401 	seq_printf(m, "nr_reserved_tags=%u\n", tags->nr_reserved_tags);
402 	seq_printf(m, "active_queues=%d\n",
403 		   READ_ONCE(tags->active_queues));
404 
405 	seq_puts(m, "\nbitmap_tags:\n");
406 	sbitmap_queue_show(&tags->bitmap_tags, m);
407 
408 	if (tags->nr_reserved_tags) {
409 		seq_puts(m, "\nbreserved_tags:\n");
410 		sbitmap_queue_show(&tags->breserved_tags, m);
411 	}
412 }
413 
414 static int hctx_tags_show(void *data, struct seq_file *m)
415 {
416 	struct blk_mq_hw_ctx *hctx = data;
417 	struct request_queue *q = hctx->queue;
418 	int res;
419 
420 	res = mutex_lock_interruptible(&q->sysfs_lock);
421 	if (res)
422 		goto out;
423 	if (hctx->tags)
424 		blk_mq_debugfs_tags_show(m, hctx->tags);
425 	mutex_unlock(&q->sysfs_lock);
426 
427 out:
428 	return res;
429 }
430 
431 static int hctx_tags_bitmap_show(void *data, struct seq_file *m)
432 {
433 	struct blk_mq_hw_ctx *hctx = data;
434 	struct request_queue *q = hctx->queue;
435 	int res;
436 
437 	res = mutex_lock_interruptible(&q->sysfs_lock);
438 	if (res)
439 		goto out;
440 	if (hctx->tags)
441 		sbitmap_bitmap_show(&hctx->tags->bitmap_tags.sb, m);
442 	mutex_unlock(&q->sysfs_lock);
443 
444 out:
445 	return res;
446 }
447 
448 static int hctx_sched_tags_show(void *data, struct seq_file *m)
449 {
450 	struct blk_mq_hw_ctx *hctx = data;
451 	struct request_queue *q = hctx->queue;
452 	int res;
453 
454 	res = mutex_lock_interruptible(&q->sysfs_lock);
455 	if (res)
456 		goto out;
457 	if (hctx->sched_tags)
458 		blk_mq_debugfs_tags_show(m, hctx->sched_tags);
459 	mutex_unlock(&q->sysfs_lock);
460 
461 out:
462 	return res;
463 }
464 
465 static int hctx_sched_tags_bitmap_show(void *data, struct seq_file *m)
466 {
467 	struct blk_mq_hw_ctx *hctx = data;
468 	struct request_queue *q = hctx->queue;
469 	int res;
470 
471 	res = mutex_lock_interruptible(&q->sysfs_lock);
472 	if (res)
473 		goto out;
474 	if (hctx->sched_tags)
475 		sbitmap_bitmap_show(&hctx->sched_tags->bitmap_tags.sb, m);
476 	mutex_unlock(&q->sysfs_lock);
477 
478 out:
479 	return res;
480 }
481 
482 static int hctx_active_show(void *data, struct seq_file *m)
483 {
484 	struct blk_mq_hw_ctx *hctx = data;
485 
486 	seq_printf(m, "%d\n", __blk_mq_active_requests(hctx));
487 	return 0;
488 }
489 
490 static int hctx_dispatch_busy_show(void *data, struct seq_file *m)
491 {
492 	struct blk_mq_hw_ctx *hctx = data;
493 
494 	seq_printf(m, "%u\n", hctx->dispatch_busy);
495 	return 0;
496 }
497 
498 #define CTX_RQ_SEQ_OPS(name, type)					\
499 static void *ctx_##name##_rq_list_start(struct seq_file *m, loff_t *pos) \
500 	__acquires(&ctx->lock)						\
501 {									\
502 	struct blk_mq_ctx *ctx = m->private;				\
503 									\
504 	spin_lock(&ctx->lock);						\
505 	return seq_list_start(&ctx->rq_lists[type], *pos);		\
506 }									\
507 									\
508 static void *ctx_##name##_rq_list_next(struct seq_file *m, void *v,	\
509 				     loff_t *pos)			\
510 {									\
511 	struct blk_mq_ctx *ctx = m->private;				\
512 									\
513 	return seq_list_next(v, &ctx->rq_lists[type], pos);		\
514 }									\
515 									\
516 static void ctx_##name##_rq_list_stop(struct seq_file *m, void *v)	\
517 	__releases(&ctx->lock)						\
518 {									\
519 	struct blk_mq_ctx *ctx = m->private;				\
520 									\
521 	spin_unlock(&ctx->lock);					\
522 }									\
523 									\
524 static const struct seq_operations ctx_##name##_rq_list_seq_ops = {	\
525 	.start	= ctx_##name##_rq_list_start,				\
526 	.next	= ctx_##name##_rq_list_next,				\
527 	.stop	= ctx_##name##_rq_list_stop,				\
528 	.show	= blk_mq_debugfs_rq_show,				\
529 }
530 
531 CTX_RQ_SEQ_OPS(default, HCTX_TYPE_DEFAULT);
532 CTX_RQ_SEQ_OPS(read, HCTX_TYPE_READ);
533 CTX_RQ_SEQ_OPS(poll, HCTX_TYPE_POLL);
534 
535 static int blk_mq_debugfs_show(struct seq_file *m, void *v)
536 {
537 	const struct blk_mq_debugfs_attr *attr = m->private;
538 	void *data = d_inode(m->file->f_path.dentry->d_parent)->i_private;
539 
540 	return attr->show(data, m);
541 }
542 
543 static ssize_t blk_mq_debugfs_write(struct file *file, const char __user *buf,
544 				    size_t count, loff_t *ppos)
545 {
546 	struct seq_file *m = file->private_data;
547 	const struct blk_mq_debugfs_attr *attr = m->private;
548 	void *data = d_inode(file->f_path.dentry->d_parent)->i_private;
549 
550 	/*
551 	 * Attributes that only implement .seq_ops are read-only and 'attr' is
552 	 * the same with 'data' in this case.
553 	 */
554 	if (attr == data || !attr->write)
555 		return -EPERM;
556 
557 	return attr->write(data, buf, count, ppos);
558 }
559 
560 static int blk_mq_debugfs_open(struct inode *inode, struct file *file)
561 {
562 	const struct blk_mq_debugfs_attr *attr = inode->i_private;
563 	void *data = d_inode(file->f_path.dentry->d_parent)->i_private;
564 	struct seq_file *m;
565 	int ret;
566 
567 	if (attr->seq_ops) {
568 		ret = seq_open(file, attr->seq_ops);
569 		if (!ret) {
570 			m = file->private_data;
571 			m->private = data;
572 		}
573 		return ret;
574 	}
575 
576 	if (WARN_ON_ONCE(!attr->show))
577 		return -EPERM;
578 
579 	return single_open(file, blk_mq_debugfs_show, inode->i_private);
580 }
581 
582 static int blk_mq_debugfs_release(struct inode *inode, struct file *file)
583 {
584 	const struct blk_mq_debugfs_attr *attr = inode->i_private;
585 
586 	if (attr->show)
587 		return single_release(inode, file);
588 
589 	return seq_release(inode, file);
590 }
591 
592 static const struct file_operations blk_mq_debugfs_fops = {
593 	.open		= blk_mq_debugfs_open,
594 	.read		= seq_read,
595 	.write		= blk_mq_debugfs_write,
596 	.llseek		= seq_lseek,
597 	.release	= blk_mq_debugfs_release,
598 };
599 
600 static const struct blk_mq_debugfs_attr blk_mq_debugfs_hctx_attrs[] = {
601 	{"state", 0400, hctx_state_show},
602 	{"flags", 0400, hctx_flags_show},
603 	{"dispatch", 0400, .seq_ops = &hctx_dispatch_seq_ops},
604 	{"busy", 0400, hctx_busy_show},
605 	{"ctx_map", 0400, hctx_ctx_map_show},
606 	{"tags", 0400, hctx_tags_show},
607 	{"tags_bitmap", 0400, hctx_tags_bitmap_show},
608 	{"sched_tags", 0400, hctx_sched_tags_show},
609 	{"sched_tags_bitmap", 0400, hctx_sched_tags_bitmap_show},
610 	{"active", 0400, hctx_active_show},
611 	{"dispatch_busy", 0400, hctx_dispatch_busy_show},
612 	{"type", 0400, hctx_type_show},
613 	{},
614 };
615 
616 static const struct blk_mq_debugfs_attr blk_mq_debugfs_ctx_attrs[] = {
617 	{"default_rq_list", 0400, .seq_ops = &ctx_default_rq_list_seq_ops},
618 	{"read_rq_list", 0400, .seq_ops = &ctx_read_rq_list_seq_ops},
619 	{"poll_rq_list", 0400, .seq_ops = &ctx_poll_rq_list_seq_ops},
620 	{},
621 };
622 
623 static void debugfs_create_files(struct dentry *parent, void *data,
624 				 const struct blk_mq_debugfs_attr *attr)
625 {
626 	if (IS_ERR_OR_NULL(parent))
627 		return;
628 
629 	d_inode(parent)->i_private = data;
630 
631 	for (; attr->name; attr++)
632 		debugfs_create_file(attr->name, attr->mode, parent,
633 				    (void *)attr, &blk_mq_debugfs_fops);
634 }
635 
636 void blk_mq_debugfs_register(struct request_queue *q)
637 {
638 	struct blk_mq_hw_ctx *hctx;
639 	unsigned long i;
640 
641 	debugfs_create_files(q->debugfs_dir, q, blk_mq_debugfs_queue_attrs);
642 
643 	/*
644 	 * blk_mq_init_sched() attempted to do this already, but q->debugfs_dir
645 	 * didn't exist yet (because we don't know what to name the directory
646 	 * until the queue is registered to a gendisk).
647 	 */
648 	if (q->elevator && !q->sched_debugfs_dir)
649 		blk_mq_debugfs_register_sched(q);
650 
651 	/* Similarly, blk_mq_init_hctx() couldn't do this previously. */
652 	queue_for_each_hw_ctx(q, hctx, i) {
653 		if (!hctx->debugfs_dir)
654 			blk_mq_debugfs_register_hctx(q, hctx);
655 		if (q->elevator && !hctx->sched_debugfs_dir)
656 			blk_mq_debugfs_register_sched_hctx(q, hctx);
657 	}
658 
659 	if (q->rq_qos) {
660 		struct rq_qos *rqos = q->rq_qos;
661 
662 		while (rqos) {
663 			blk_mq_debugfs_register_rqos(rqos);
664 			rqos = rqos->next;
665 		}
666 	}
667 }
668 
669 static void blk_mq_debugfs_register_ctx(struct blk_mq_hw_ctx *hctx,
670 					struct blk_mq_ctx *ctx)
671 {
672 	struct dentry *ctx_dir;
673 	char name[20];
674 
675 	snprintf(name, sizeof(name), "cpu%u", ctx->cpu);
676 	ctx_dir = debugfs_create_dir(name, hctx->debugfs_dir);
677 
678 	debugfs_create_files(ctx_dir, ctx, blk_mq_debugfs_ctx_attrs);
679 }
680 
681 void blk_mq_debugfs_register_hctx(struct request_queue *q,
682 				  struct blk_mq_hw_ctx *hctx)
683 {
684 	struct blk_mq_ctx *ctx;
685 	char name[20];
686 	int i;
687 
688 	if (!q->debugfs_dir)
689 		return;
690 
691 	snprintf(name, sizeof(name), "hctx%u", hctx->queue_num);
692 	hctx->debugfs_dir = debugfs_create_dir(name, q->debugfs_dir);
693 
694 	debugfs_create_files(hctx->debugfs_dir, hctx, blk_mq_debugfs_hctx_attrs);
695 
696 	hctx_for_each_ctx(hctx, ctx, i)
697 		blk_mq_debugfs_register_ctx(hctx, ctx);
698 }
699 
700 void blk_mq_debugfs_unregister_hctx(struct blk_mq_hw_ctx *hctx)
701 {
702 	if (!hctx->queue->debugfs_dir)
703 		return;
704 	debugfs_remove_recursive(hctx->debugfs_dir);
705 	hctx->sched_debugfs_dir = NULL;
706 	hctx->debugfs_dir = NULL;
707 }
708 
709 void blk_mq_debugfs_register_hctxs(struct request_queue *q)
710 {
711 	struct blk_mq_hw_ctx *hctx;
712 	unsigned long i;
713 
714 	queue_for_each_hw_ctx(q, hctx, i)
715 		blk_mq_debugfs_register_hctx(q, hctx);
716 }
717 
718 void blk_mq_debugfs_unregister_hctxs(struct request_queue *q)
719 {
720 	struct blk_mq_hw_ctx *hctx;
721 	unsigned long i;
722 
723 	queue_for_each_hw_ctx(q, hctx, i)
724 		blk_mq_debugfs_unregister_hctx(hctx);
725 }
726 
727 void blk_mq_debugfs_register_sched(struct request_queue *q)
728 {
729 	struct elevator_type *e = q->elevator->type;
730 
731 	lockdep_assert_held(&q->debugfs_mutex);
732 
733 	/*
734 	 * If the parent directory has not been created yet, return, we will be
735 	 * called again later on and the directory/files will be created then.
736 	 */
737 	if (!q->debugfs_dir)
738 		return;
739 
740 	if (!e->queue_debugfs_attrs)
741 		return;
742 
743 	q->sched_debugfs_dir = debugfs_create_dir("sched", q->debugfs_dir);
744 
745 	debugfs_create_files(q->sched_debugfs_dir, q, e->queue_debugfs_attrs);
746 }
747 
748 void blk_mq_debugfs_unregister_sched(struct request_queue *q)
749 {
750 	lockdep_assert_held(&q->debugfs_mutex);
751 
752 	debugfs_remove_recursive(q->sched_debugfs_dir);
753 	q->sched_debugfs_dir = NULL;
754 }
755 
756 static const char *rq_qos_id_to_name(enum rq_qos_id id)
757 {
758 	switch (id) {
759 	case RQ_QOS_WBT:
760 		return "wbt";
761 	case RQ_QOS_LATENCY:
762 		return "latency";
763 	case RQ_QOS_COST:
764 		return "cost";
765 	}
766 	return "unknown";
767 }
768 
769 void blk_mq_debugfs_unregister_rqos(struct rq_qos *rqos)
770 {
771 	lockdep_assert_held(&rqos->disk->queue->debugfs_mutex);
772 
773 	if (!rqos->disk->queue->debugfs_dir)
774 		return;
775 	debugfs_remove_recursive(rqos->debugfs_dir);
776 	rqos->debugfs_dir = NULL;
777 }
778 
779 void blk_mq_debugfs_register_rqos(struct rq_qos *rqos)
780 {
781 	struct request_queue *q = rqos->disk->queue;
782 	const char *dir_name = rq_qos_id_to_name(rqos->id);
783 
784 	lockdep_assert_held(&q->debugfs_mutex);
785 
786 	if (rqos->debugfs_dir || !rqos->ops->debugfs_attrs)
787 		return;
788 
789 	if (!q->rqos_debugfs_dir)
790 		q->rqos_debugfs_dir = debugfs_create_dir("rqos",
791 							 q->debugfs_dir);
792 
793 	rqos->debugfs_dir = debugfs_create_dir(dir_name, q->rqos_debugfs_dir);
794 	debugfs_create_files(rqos->debugfs_dir, rqos, rqos->ops->debugfs_attrs);
795 }
796 
797 void blk_mq_debugfs_register_sched_hctx(struct request_queue *q,
798 					struct blk_mq_hw_ctx *hctx)
799 {
800 	struct elevator_type *e = q->elevator->type;
801 
802 	lockdep_assert_held(&q->debugfs_mutex);
803 
804 	/*
805 	 * If the parent debugfs directory has not been created yet, return;
806 	 * We will be called again later on with appropriate parent debugfs
807 	 * directory from blk_register_queue()
808 	 */
809 	if (!hctx->debugfs_dir)
810 		return;
811 
812 	if (!e->hctx_debugfs_attrs)
813 		return;
814 
815 	hctx->sched_debugfs_dir = debugfs_create_dir("sched",
816 						     hctx->debugfs_dir);
817 	debugfs_create_files(hctx->sched_debugfs_dir, hctx,
818 			     e->hctx_debugfs_attrs);
819 }
820 
821 void blk_mq_debugfs_unregister_sched_hctx(struct blk_mq_hw_ctx *hctx)
822 {
823 	lockdep_assert_held(&hctx->queue->debugfs_mutex);
824 
825 	if (!hctx->queue->debugfs_dir)
826 		return;
827 	debugfs_remove_recursive(hctx->sched_debugfs_dir);
828 	hctx->sched_debugfs_dir = NULL;
829 }
830