xref: /openbmc/linux/block/blk-mq-debugfs.c (revision 1c2dd16a)
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-tag.h"
25 
26 struct blk_mq_debugfs_attr {
27 	const char *name;
28 	umode_t mode;
29 	const struct file_operations *fops;
30 };
31 
32 static int blk_mq_debugfs_seq_open(struct inode *inode, struct file *file,
33 				   const struct seq_operations *ops)
34 {
35 	struct seq_file *m;
36 	int ret;
37 
38 	ret = seq_open(file, ops);
39 	if (!ret) {
40 		m = file->private_data;
41 		m->private = inode->i_private;
42 	}
43 	return ret;
44 }
45 
46 static int blk_flags_show(struct seq_file *m, const unsigned long flags,
47 			  const char *const *flag_name, int flag_name_count)
48 {
49 	bool sep = false;
50 	int i;
51 
52 	for (i = 0; i < sizeof(flags) * BITS_PER_BYTE; i++) {
53 		if (!(flags & BIT(i)))
54 			continue;
55 		if (sep)
56 			seq_puts(m, " ");
57 		sep = true;
58 		if (i < flag_name_count && flag_name[i])
59 			seq_puts(m, flag_name[i]);
60 		else
61 			seq_printf(m, "%d", i);
62 	}
63 	return 0;
64 }
65 
66 static const char *const blk_queue_flag_name[] = {
67 	[QUEUE_FLAG_QUEUED]	 = "QUEUED",
68 	[QUEUE_FLAG_STOPPED]	 = "STOPPED",
69 	[QUEUE_FLAG_SYNCFULL]	 = "SYNCFULL",
70 	[QUEUE_FLAG_ASYNCFULL]	 = "ASYNCFULL",
71 	[QUEUE_FLAG_DYING]	 = "DYING",
72 	[QUEUE_FLAG_BYPASS]	 = "BYPASS",
73 	[QUEUE_FLAG_BIDI]	 = "BIDI",
74 	[QUEUE_FLAG_NOMERGES]	 = "NOMERGES",
75 	[QUEUE_FLAG_SAME_COMP]	 = "SAME_COMP",
76 	[QUEUE_FLAG_FAIL_IO]	 = "FAIL_IO",
77 	[QUEUE_FLAG_STACKABLE]	 = "STACKABLE",
78 	[QUEUE_FLAG_NONROT]	 = "NONROT",
79 	[QUEUE_FLAG_IO_STAT]	 = "IO_STAT",
80 	[QUEUE_FLAG_DISCARD]	 = "DISCARD",
81 	[QUEUE_FLAG_NOXMERGES]	 = "NOXMERGES",
82 	[QUEUE_FLAG_ADD_RANDOM]	 = "ADD_RANDOM",
83 	[QUEUE_FLAG_SECERASE]	 = "SECERASE",
84 	[QUEUE_FLAG_SAME_FORCE]	 = "SAME_FORCE",
85 	[QUEUE_FLAG_DEAD]	 = "DEAD",
86 	[QUEUE_FLAG_INIT_DONE]	 = "INIT_DONE",
87 	[QUEUE_FLAG_NO_SG_MERGE] = "NO_SG_MERGE",
88 	[QUEUE_FLAG_POLL]	 = "POLL",
89 	[QUEUE_FLAG_WC]		 = "WC",
90 	[QUEUE_FLAG_FUA]	 = "FUA",
91 	[QUEUE_FLAG_FLUSH_NQ]	 = "FLUSH_NQ",
92 	[QUEUE_FLAG_DAX]	 = "DAX",
93 	[QUEUE_FLAG_STATS]	 = "STATS",
94 	[QUEUE_FLAG_POLL_STATS]	 = "POLL_STATS",
95 	[QUEUE_FLAG_REGISTERED]	 = "REGISTERED",
96 };
97 
98 static int blk_queue_flags_show(struct seq_file *m, void *v)
99 {
100 	struct request_queue *q = m->private;
101 
102 	blk_flags_show(m, q->queue_flags, blk_queue_flag_name,
103 		       ARRAY_SIZE(blk_queue_flag_name));
104 	seq_puts(m, "\n");
105 	return 0;
106 }
107 
108 static ssize_t blk_queue_flags_store(struct file *file, const char __user *ubuf,
109 				     size_t len, loff_t *offp)
110 {
111 	struct request_queue *q = file_inode(file)->i_private;
112 	char op[16] = { }, *s;
113 
114 	len = min(len, sizeof(op) - 1);
115 	if (copy_from_user(op, ubuf, len))
116 		return -EFAULT;
117 	s = op;
118 	strsep(&s, " \t\n"); /* strip trailing whitespace */
119 	if (strcmp(op, "run") == 0) {
120 		blk_mq_run_hw_queues(q, true);
121 	} else if (strcmp(op, "start") == 0) {
122 		blk_mq_start_stopped_hw_queues(q, true);
123 	} else {
124 		pr_err("%s: unsupported operation %s. Use either 'run' or 'start'\n",
125 		       __func__, op);
126 		return -EINVAL;
127 	}
128 	return len;
129 }
130 
131 static int blk_queue_flags_open(struct inode *inode, struct file *file)
132 {
133 	return single_open(file, blk_queue_flags_show, inode->i_private);
134 }
135 
136 static const struct file_operations blk_queue_flags_fops = {
137 	.open		= blk_queue_flags_open,
138 	.read		= seq_read,
139 	.llseek		= seq_lseek,
140 	.release	= single_release,
141 	.write		= blk_queue_flags_store,
142 };
143 
144 static void print_stat(struct seq_file *m, struct blk_rq_stat *stat)
145 {
146 	if (stat->nr_samples) {
147 		seq_printf(m, "samples=%d, mean=%lld, min=%llu, max=%llu",
148 			   stat->nr_samples, stat->mean, stat->min, stat->max);
149 	} else {
150 		seq_puts(m, "samples=0");
151 	}
152 }
153 
154 static int queue_poll_stat_show(struct seq_file *m, void *v)
155 {
156 	struct request_queue *q = m->private;
157 	int bucket;
158 
159 	for (bucket = 0; bucket < BLK_MQ_POLL_STATS_BKTS/2; bucket++) {
160 		seq_printf(m, "read  (%d Bytes): ", 1 << (9+bucket));
161 		print_stat(m, &q->poll_stat[2*bucket]);
162 		seq_puts(m, "\n");
163 
164 		seq_printf(m, "write (%d Bytes): ",  1 << (9+bucket));
165 		print_stat(m, &q->poll_stat[2*bucket+1]);
166 		seq_puts(m, "\n");
167 	}
168 	return 0;
169 }
170 
171 static int queue_poll_stat_open(struct inode *inode, struct file *file)
172 {
173 	return single_open(file, queue_poll_stat_show, inode->i_private);
174 }
175 
176 static const struct file_operations queue_poll_stat_fops = {
177 	.open		= queue_poll_stat_open,
178 	.read		= seq_read,
179 	.llseek		= seq_lseek,
180 	.release	= single_release,
181 };
182 
183 static const char *const hctx_state_name[] = {
184 	[BLK_MQ_S_STOPPED]	 = "STOPPED",
185 	[BLK_MQ_S_TAG_ACTIVE]	 = "TAG_ACTIVE",
186 	[BLK_MQ_S_SCHED_RESTART] = "SCHED_RESTART",
187 	[BLK_MQ_S_TAG_WAITING]	 = "TAG_WAITING",
188 
189 };
190 static int hctx_state_show(struct seq_file *m, void *v)
191 {
192 	struct blk_mq_hw_ctx *hctx = m->private;
193 
194 	blk_flags_show(m, hctx->state, hctx_state_name,
195 		       ARRAY_SIZE(hctx_state_name));
196 	seq_puts(m, "\n");
197 	return 0;
198 }
199 
200 static int hctx_state_open(struct inode *inode, struct file *file)
201 {
202 	return single_open(file, hctx_state_show, inode->i_private);
203 }
204 
205 static const struct file_operations hctx_state_fops = {
206 	.open		= hctx_state_open,
207 	.read		= seq_read,
208 	.llseek		= seq_lseek,
209 	.release	= single_release,
210 };
211 
212 static const char *const alloc_policy_name[] = {
213 	[BLK_TAG_ALLOC_FIFO]	= "fifo",
214 	[BLK_TAG_ALLOC_RR]	= "rr",
215 };
216 
217 static const char *const hctx_flag_name[] = {
218 	[ilog2(BLK_MQ_F_SHOULD_MERGE)]	= "SHOULD_MERGE",
219 	[ilog2(BLK_MQ_F_TAG_SHARED)]	= "TAG_SHARED",
220 	[ilog2(BLK_MQ_F_SG_MERGE)]	= "SG_MERGE",
221 	[ilog2(BLK_MQ_F_BLOCKING)]	= "BLOCKING",
222 	[ilog2(BLK_MQ_F_NO_SCHED)]	= "NO_SCHED",
223 };
224 
225 static int hctx_flags_show(struct seq_file *m, void *v)
226 {
227 	struct blk_mq_hw_ctx *hctx = m->private;
228 	const int alloc_policy = BLK_MQ_FLAG_TO_ALLOC_POLICY(hctx->flags);
229 
230 	seq_puts(m, "alloc_policy=");
231 	if (alloc_policy < ARRAY_SIZE(alloc_policy_name) &&
232 	    alloc_policy_name[alloc_policy])
233 		seq_puts(m, alloc_policy_name[alloc_policy]);
234 	else
235 		seq_printf(m, "%d", alloc_policy);
236 	seq_puts(m, " ");
237 	blk_flags_show(m,
238 		       hctx->flags ^ BLK_ALLOC_POLICY_TO_MQ_FLAG(alloc_policy),
239 		       hctx_flag_name, ARRAY_SIZE(hctx_flag_name));
240 	seq_puts(m, "\n");
241 	return 0;
242 }
243 
244 static int hctx_flags_open(struct inode *inode, struct file *file)
245 {
246 	return single_open(file, hctx_flags_show, inode->i_private);
247 }
248 
249 static const struct file_operations hctx_flags_fops = {
250 	.open		= hctx_flags_open,
251 	.read		= seq_read,
252 	.llseek		= seq_lseek,
253 	.release	= single_release,
254 };
255 
256 static const char *const op_name[] = {
257 	[REQ_OP_READ]		= "READ",
258 	[REQ_OP_WRITE]		= "WRITE",
259 	[REQ_OP_FLUSH]		= "FLUSH",
260 	[REQ_OP_DISCARD]	= "DISCARD",
261 	[REQ_OP_ZONE_REPORT]	= "ZONE_REPORT",
262 	[REQ_OP_SECURE_ERASE]	= "SECURE_ERASE",
263 	[REQ_OP_ZONE_RESET]	= "ZONE_RESET",
264 	[REQ_OP_WRITE_SAME]	= "WRITE_SAME",
265 	[REQ_OP_WRITE_ZEROES]	= "WRITE_ZEROES",
266 	[REQ_OP_SCSI_IN]	= "SCSI_IN",
267 	[REQ_OP_SCSI_OUT]	= "SCSI_OUT",
268 	[REQ_OP_DRV_IN]		= "DRV_IN",
269 	[REQ_OP_DRV_OUT]	= "DRV_OUT",
270 };
271 
272 static const char *const cmd_flag_name[] = {
273 	[__REQ_FAILFAST_DEV]		= "FAILFAST_DEV",
274 	[__REQ_FAILFAST_TRANSPORT]	= "FAILFAST_TRANSPORT",
275 	[__REQ_FAILFAST_DRIVER]		= "FAILFAST_DRIVER",
276 	[__REQ_SYNC]			= "SYNC",
277 	[__REQ_META]			= "META",
278 	[__REQ_PRIO]			= "PRIO",
279 	[__REQ_NOMERGE]			= "NOMERGE",
280 	[__REQ_IDLE]			= "IDLE",
281 	[__REQ_INTEGRITY]		= "INTEGRITY",
282 	[__REQ_FUA]			= "FUA",
283 	[__REQ_PREFLUSH]		= "PREFLUSH",
284 	[__REQ_RAHEAD]			= "RAHEAD",
285 	[__REQ_BACKGROUND]		= "BACKGROUND",
286 	[__REQ_NR_BITS]			= "NR_BITS",
287 };
288 
289 static const char *const rqf_name[] = {
290 	[ilog2((__force u32)RQF_SORTED)]		= "SORTED",
291 	[ilog2((__force u32)RQF_STARTED)]		= "STARTED",
292 	[ilog2((__force u32)RQF_QUEUED)]		= "QUEUED",
293 	[ilog2((__force u32)RQF_SOFTBARRIER)]		= "SOFTBARRIER",
294 	[ilog2((__force u32)RQF_FLUSH_SEQ)]		= "FLUSH_SEQ",
295 	[ilog2((__force u32)RQF_MIXED_MERGE)]		= "MIXED_MERGE",
296 	[ilog2((__force u32)RQF_MQ_INFLIGHT)]		= "MQ_INFLIGHT",
297 	[ilog2((__force u32)RQF_DONTPREP)]		= "DONTPREP",
298 	[ilog2((__force u32)RQF_PREEMPT)]		= "PREEMPT",
299 	[ilog2((__force u32)RQF_COPY_USER)]		= "COPY_USER",
300 	[ilog2((__force u32)RQF_FAILED)]		= "FAILED",
301 	[ilog2((__force u32)RQF_QUIET)]			= "QUIET",
302 	[ilog2((__force u32)RQF_ELVPRIV)]		= "ELVPRIV",
303 	[ilog2((__force u32)RQF_IO_STAT)]		= "IO_STAT",
304 	[ilog2((__force u32)RQF_ALLOCED)]		= "ALLOCED",
305 	[ilog2((__force u32)RQF_PM)]			= "PM",
306 	[ilog2((__force u32)RQF_HASHED)]		= "HASHED",
307 	[ilog2((__force u32)RQF_STATS)]			= "STATS",
308 	[ilog2((__force u32)RQF_SPECIAL_PAYLOAD)]	= "SPECIAL_PAYLOAD",
309 };
310 
311 static int blk_mq_debugfs_rq_show(struct seq_file *m, void *v)
312 {
313 	struct request *rq = list_entry_rq(v);
314 	const struct blk_mq_ops *const mq_ops = rq->q->mq_ops;
315 	const unsigned int op = rq->cmd_flags & REQ_OP_MASK;
316 
317 	seq_printf(m, "%p {.op=", rq);
318 	if (op < ARRAY_SIZE(op_name) && op_name[op])
319 		seq_printf(m, "%s", op_name[op]);
320 	else
321 		seq_printf(m, "%d", op);
322 	seq_puts(m, ", .cmd_flags=");
323 	blk_flags_show(m, rq->cmd_flags & ~REQ_OP_MASK, cmd_flag_name,
324 		       ARRAY_SIZE(cmd_flag_name));
325 	seq_puts(m, ", .rq_flags=");
326 	blk_flags_show(m, (__force unsigned int)rq->rq_flags, rqf_name,
327 		       ARRAY_SIZE(rqf_name));
328 	seq_printf(m, ", .tag=%d, .internal_tag=%d", rq->tag,
329 		   rq->internal_tag);
330 	if (mq_ops->show_rq)
331 		mq_ops->show_rq(m, rq);
332 	seq_puts(m, "}\n");
333 	return 0;
334 }
335 
336 static void *hctx_dispatch_start(struct seq_file *m, loff_t *pos)
337 	__acquires(&hctx->lock)
338 {
339 	struct blk_mq_hw_ctx *hctx = m->private;
340 
341 	spin_lock(&hctx->lock);
342 	return seq_list_start(&hctx->dispatch, *pos);
343 }
344 
345 static void *hctx_dispatch_next(struct seq_file *m, void *v, loff_t *pos)
346 {
347 	struct blk_mq_hw_ctx *hctx = m->private;
348 
349 	return seq_list_next(v, &hctx->dispatch, pos);
350 }
351 
352 static void hctx_dispatch_stop(struct seq_file *m, void *v)
353 	__releases(&hctx->lock)
354 {
355 	struct blk_mq_hw_ctx *hctx = m->private;
356 
357 	spin_unlock(&hctx->lock);
358 }
359 
360 static const struct seq_operations hctx_dispatch_seq_ops = {
361 	.start	= hctx_dispatch_start,
362 	.next	= hctx_dispatch_next,
363 	.stop	= hctx_dispatch_stop,
364 	.show	= blk_mq_debugfs_rq_show,
365 };
366 
367 static int hctx_dispatch_open(struct inode *inode, struct file *file)
368 {
369 	return blk_mq_debugfs_seq_open(inode, file, &hctx_dispatch_seq_ops);
370 }
371 
372 static const struct file_operations hctx_dispatch_fops = {
373 	.open		= hctx_dispatch_open,
374 	.read		= seq_read,
375 	.llseek		= seq_lseek,
376 	.release	= seq_release,
377 };
378 
379 static int hctx_ctx_map_show(struct seq_file *m, void *v)
380 {
381 	struct blk_mq_hw_ctx *hctx = m->private;
382 
383 	sbitmap_bitmap_show(&hctx->ctx_map, m);
384 	return 0;
385 }
386 
387 static int hctx_ctx_map_open(struct inode *inode, struct file *file)
388 {
389 	return single_open(file, hctx_ctx_map_show, inode->i_private);
390 }
391 
392 static const struct file_operations hctx_ctx_map_fops = {
393 	.open		= hctx_ctx_map_open,
394 	.read		= seq_read,
395 	.llseek		= seq_lseek,
396 	.release	= single_release,
397 };
398 
399 static void blk_mq_debugfs_tags_show(struct seq_file *m,
400 				     struct blk_mq_tags *tags)
401 {
402 	seq_printf(m, "nr_tags=%u\n", tags->nr_tags);
403 	seq_printf(m, "nr_reserved_tags=%u\n", tags->nr_reserved_tags);
404 	seq_printf(m, "active_queues=%d\n",
405 		   atomic_read(&tags->active_queues));
406 
407 	seq_puts(m, "\nbitmap_tags:\n");
408 	sbitmap_queue_show(&tags->bitmap_tags, m);
409 
410 	if (tags->nr_reserved_tags) {
411 		seq_puts(m, "\nbreserved_tags:\n");
412 		sbitmap_queue_show(&tags->breserved_tags, m);
413 	}
414 }
415 
416 static int hctx_tags_show(struct seq_file *m, void *v)
417 {
418 	struct blk_mq_hw_ctx *hctx = m->private;
419 	struct request_queue *q = hctx->queue;
420 	int res;
421 
422 	res = mutex_lock_interruptible(&q->sysfs_lock);
423 	if (res)
424 		goto out;
425 	if (hctx->tags)
426 		blk_mq_debugfs_tags_show(m, hctx->tags);
427 	mutex_unlock(&q->sysfs_lock);
428 
429 out:
430 	return res;
431 }
432 
433 static int hctx_tags_open(struct inode *inode, struct file *file)
434 {
435 	return single_open(file, hctx_tags_show, inode->i_private);
436 }
437 
438 static const struct file_operations hctx_tags_fops = {
439 	.open		= hctx_tags_open,
440 	.read		= seq_read,
441 	.llseek		= seq_lseek,
442 	.release	= single_release,
443 };
444 
445 static int hctx_tags_bitmap_show(struct seq_file *m, void *v)
446 {
447 	struct blk_mq_hw_ctx *hctx = m->private;
448 	struct request_queue *q = hctx->queue;
449 	int res;
450 
451 	res = mutex_lock_interruptible(&q->sysfs_lock);
452 	if (res)
453 		goto out;
454 	if (hctx->tags)
455 		sbitmap_bitmap_show(&hctx->tags->bitmap_tags.sb, m);
456 	mutex_unlock(&q->sysfs_lock);
457 
458 out:
459 	return res;
460 }
461 
462 static int hctx_tags_bitmap_open(struct inode *inode, struct file *file)
463 {
464 	return single_open(file, hctx_tags_bitmap_show, inode->i_private);
465 }
466 
467 static const struct file_operations hctx_tags_bitmap_fops = {
468 	.open		= hctx_tags_bitmap_open,
469 	.read		= seq_read,
470 	.llseek		= seq_lseek,
471 	.release	= single_release,
472 };
473 
474 static int hctx_sched_tags_show(struct seq_file *m, void *v)
475 {
476 	struct blk_mq_hw_ctx *hctx = m->private;
477 	struct request_queue *q = hctx->queue;
478 	int res;
479 
480 	res = mutex_lock_interruptible(&q->sysfs_lock);
481 	if (res)
482 		goto out;
483 	if (hctx->sched_tags)
484 		blk_mq_debugfs_tags_show(m, hctx->sched_tags);
485 	mutex_unlock(&q->sysfs_lock);
486 
487 out:
488 	return res;
489 }
490 
491 static int hctx_sched_tags_open(struct inode *inode, struct file *file)
492 {
493 	return single_open(file, hctx_sched_tags_show, inode->i_private);
494 }
495 
496 static const struct file_operations hctx_sched_tags_fops = {
497 	.open		= hctx_sched_tags_open,
498 	.read		= seq_read,
499 	.llseek		= seq_lseek,
500 	.release	= single_release,
501 };
502 
503 static int hctx_sched_tags_bitmap_show(struct seq_file *m, void *v)
504 {
505 	struct blk_mq_hw_ctx *hctx = m->private;
506 	struct request_queue *q = hctx->queue;
507 	int res;
508 
509 	res = mutex_lock_interruptible(&q->sysfs_lock);
510 	if (res)
511 		goto out;
512 	if (hctx->sched_tags)
513 		sbitmap_bitmap_show(&hctx->sched_tags->bitmap_tags.sb, m);
514 	mutex_unlock(&q->sysfs_lock);
515 
516 out:
517 	return res;
518 }
519 
520 static int hctx_sched_tags_bitmap_open(struct inode *inode, struct file *file)
521 {
522 	return single_open(file, hctx_sched_tags_bitmap_show, inode->i_private);
523 }
524 
525 static const struct file_operations hctx_sched_tags_bitmap_fops = {
526 	.open		= hctx_sched_tags_bitmap_open,
527 	.read		= seq_read,
528 	.llseek		= seq_lseek,
529 	.release	= single_release,
530 };
531 
532 static int hctx_io_poll_show(struct seq_file *m, void *v)
533 {
534 	struct blk_mq_hw_ctx *hctx = m->private;
535 
536 	seq_printf(m, "considered=%lu\n", hctx->poll_considered);
537 	seq_printf(m, "invoked=%lu\n", hctx->poll_invoked);
538 	seq_printf(m, "success=%lu\n", hctx->poll_success);
539 	return 0;
540 }
541 
542 static int hctx_io_poll_open(struct inode *inode, struct file *file)
543 {
544 	return single_open(file, hctx_io_poll_show, inode->i_private);
545 }
546 
547 static ssize_t hctx_io_poll_write(struct file *file, const char __user *buf,
548 				  size_t count, loff_t *ppos)
549 {
550 	struct seq_file *m = file->private_data;
551 	struct blk_mq_hw_ctx *hctx = m->private;
552 
553 	hctx->poll_considered = hctx->poll_invoked = hctx->poll_success = 0;
554 	return count;
555 }
556 
557 static const struct file_operations hctx_io_poll_fops = {
558 	.open		= hctx_io_poll_open,
559 	.read		= seq_read,
560 	.write		= hctx_io_poll_write,
561 	.llseek		= seq_lseek,
562 	.release	= single_release,
563 };
564 
565 static int hctx_dispatched_show(struct seq_file *m, void *v)
566 {
567 	struct blk_mq_hw_ctx *hctx = m->private;
568 	int i;
569 
570 	seq_printf(m, "%8u\t%lu\n", 0U, hctx->dispatched[0]);
571 
572 	for (i = 1; i < BLK_MQ_MAX_DISPATCH_ORDER - 1; i++) {
573 		unsigned int d = 1U << (i - 1);
574 
575 		seq_printf(m, "%8u\t%lu\n", d, hctx->dispatched[i]);
576 	}
577 
578 	seq_printf(m, "%8u+\t%lu\n", 1U << (i - 1), hctx->dispatched[i]);
579 	return 0;
580 }
581 
582 static int hctx_dispatched_open(struct inode *inode, struct file *file)
583 {
584 	return single_open(file, hctx_dispatched_show, inode->i_private);
585 }
586 
587 static ssize_t hctx_dispatched_write(struct file *file, const char __user *buf,
588 				     size_t count, loff_t *ppos)
589 {
590 	struct seq_file *m = file->private_data;
591 	struct blk_mq_hw_ctx *hctx = m->private;
592 	int i;
593 
594 	for (i = 0; i < BLK_MQ_MAX_DISPATCH_ORDER; i++)
595 		hctx->dispatched[i] = 0;
596 	return count;
597 }
598 
599 static const struct file_operations hctx_dispatched_fops = {
600 	.open		= hctx_dispatched_open,
601 	.read		= seq_read,
602 	.write		= hctx_dispatched_write,
603 	.llseek		= seq_lseek,
604 	.release	= single_release,
605 };
606 
607 static int hctx_queued_show(struct seq_file *m, void *v)
608 {
609 	struct blk_mq_hw_ctx *hctx = m->private;
610 
611 	seq_printf(m, "%lu\n", hctx->queued);
612 	return 0;
613 }
614 
615 static int hctx_queued_open(struct inode *inode, struct file *file)
616 {
617 	return single_open(file, hctx_queued_show, inode->i_private);
618 }
619 
620 static ssize_t hctx_queued_write(struct file *file, const char __user *buf,
621 				 size_t count, loff_t *ppos)
622 {
623 	struct seq_file *m = file->private_data;
624 	struct blk_mq_hw_ctx *hctx = m->private;
625 
626 	hctx->queued = 0;
627 	return count;
628 }
629 
630 static const struct file_operations hctx_queued_fops = {
631 	.open		= hctx_queued_open,
632 	.read		= seq_read,
633 	.write		= hctx_queued_write,
634 	.llseek		= seq_lseek,
635 	.release	= single_release,
636 };
637 
638 static int hctx_run_show(struct seq_file *m, void *v)
639 {
640 	struct blk_mq_hw_ctx *hctx = m->private;
641 
642 	seq_printf(m, "%lu\n", hctx->run);
643 	return 0;
644 }
645 
646 static int hctx_run_open(struct inode *inode, struct file *file)
647 {
648 	return single_open(file, hctx_run_show, inode->i_private);
649 }
650 
651 static ssize_t hctx_run_write(struct file *file, const char __user *buf,
652 				 size_t count, loff_t *ppos)
653 {
654 	struct seq_file *m = file->private_data;
655 	struct blk_mq_hw_ctx *hctx = m->private;
656 
657 	hctx->run = 0;
658 	return count;
659 }
660 
661 static const struct file_operations hctx_run_fops = {
662 	.open		= hctx_run_open,
663 	.read		= seq_read,
664 	.write		= hctx_run_write,
665 	.llseek		= seq_lseek,
666 	.release	= single_release,
667 };
668 
669 static int hctx_active_show(struct seq_file *m, void *v)
670 {
671 	struct blk_mq_hw_ctx *hctx = m->private;
672 
673 	seq_printf(m, "%d\n", atomic_read(&hctx->nr_active));
674 	return 0;
675 }
676 
677 static int hctx_active_open(struct inode *inode, struct file *file)
678 {
679 	return single_open(file, hctx_active_show, inode->i_private);
680 }
681 
682 static const struct file_operations hctx_active_fops = {
683 	.open		= hctx_active_open,
684 	.read		= seq_read,
685 	.llseek		= seq_lseek,
686 	.release	= single_release,
687 };
688 
689 static void *ctx_rq_list_start(struct seq_file *m, loff_t *pos)
690 	__acquires(&ctx->lock)
691 {
692 	struct blk_mq_ctx *ctx = m->private;
693 
694 	spin_lock(&ctx->lock);
695 	return seq_list_start(&ctx->rq_list, *pos);
696 }
697 
698 static void *ctx_rq_list_next(struct seq_file *m, void *v, loff_t *pos)
699 {
700 	struct blk_mq_ctx *ctx = m->private;
701 
702 	return seq_list_next(v, &ctx->rq_list, pos);
703 }
704 
705 static void ctx_rq_list_stop(struct seq_file *m, void *v)
706 	__releases(&ctx->lock)
707 {
708 	struct blk_mq_ctx *ctx = m->private;
709 
710 	spin_unlock(&ctx->lock);
711 }
712 
713 static const struct seq_operations ctx_rq_list_seq_ops = {
714 	.start	= ctx_rq_list_start,
715 	.next	= ctx_rq_list_next,
716 	.stop	= ctx_rq_list_stop,
717 	.show	= blk_mq_debugfs_rq_show,
718 };
719 
720 static int ctx_rq_list_open(struct inode *inode, struct file *file)
721 {
722 	return blk_mq_debugfs_seq_open(inode, file, &ctx_rq_list_seq_ops);
723 }
724 
725 static const struct file_operations ctx_rq_list_fops = {
726 	.open		= ctx_rq_list_open,
727 	.read		= seq_read,
728 	.llseek		= seq_lseek,
729 	.release	= seq_release,
730 };
731 
732 static int ctx_dispatched_show(struct seq_file *m, void *v)
733 {
734 	struct blk_mq_ctx *ctx = m->private;
735 
736 	seq_printf(m, "%lu %lu\n", ctx->rq_dispatched[1], ctx->rq_dispatched[0]);
737 	return 0;
738 }
739 
740 static int ctx_dispatched_open(struct inode *inode, struct file *file)
741 {
742 	return single_open(file, ctx_dispatched_show, inode->i_private);
743 }
744 
745 static ssize_t ctx_dispatched_write(struct file *file, const char __user *buf,
746 				    size_t count, loff_t *ppos)
747 {
748 	struct seq_file *m = file->private_data;
749 	struct blk_mq_ctx *ctx = m->private;
750 
751 	ctx->rq_dispatched[0] = ctx->rq_dispatched[1] = 0;
752 	return count;
753 }
754 
755 static const struct file_operations ctx_dispatched_fops = {
756 	.open		= ctx_dispatched_open,
757 	.read		= seq_read,
758 	.write		= ctx_dispatched_write,
759 	.llseek		= seq_lseek,
760 	.release	= single_release,
761 };
762 
763 static int ctx_merged_show(struct seq_file *m, void *v)
764 {
765 	struct blk_mq_ctx *ctx = m->private;
766 
767 	seq_printf(m, "%lu\n", ctx->rq_merged);
768 	return 0;
769 }
770 
771 static int ctx_merged_open(struct inode *inode, struct file *file)
772 {
773 	return single_open(file, ctx_merged_show, inode->i_private);
774 }
775 
776 static ssize_t ctx_merged_write(struct file *file, const char __user *buf,
777 				    size_t count, loff_t *ppos)
778 {
779 	struct seq_file *m = file->private_data;
780 	struct blk_mq_ctx *ctx = m->private;
781 
782 	ctx->rq_merged = 0;
783 	return count;
784 }
785 
786 static const struct file_operations ctx_merged_fops = {
787 	.open		= ctx_merged_open,
788 	.read		= seq_read,
789 	.write		= ctx_merged_write,
790 	.llseek		= seq_lseek,
791 	.release	= single_release,
792 };
793 
794 static int ctx_completed_show(struct seq_file *m, void *v)
795 {
796 	struct blk_mq_ctx *ctx = m->private;
797 
798 	seq_printf(m, "%lu %lu\n", ctx->rq_completed[1], ctx->rq_completed[0]);
799 	return 0;
800 }
801 
802 static int ctx_completed_open(struct inode *inode, struct file *file)
803 {
804 	return single_open(file, ctx_completed_show, inode->i_private);
805 }
806 
807 static ssize_t ctx_completed_write(struct file *file, const char __user *buf,
808 				   size_t count, loff_t *ppos)
809 {
810 	struct seq_file *m = file->private_data;
811 	struct blk_mq_ctx *ctx = m->private;
812 
813 	ctx->rq_completed[0] = ctx->rq_completed[1] = 0;
814 	return count;
815 }
816 
817 static const struct file_operations ctx_completed_fops = {
818 	.open		= ctx_completed_open,
819 	.read		= seq_read,
820 	.write		= ctx_completed_write,
821 	.llseek		= seq_lseek,
822 	.release	= single_release,
823 };
824 
825 static const struct blk_mq_debugfs_attr blk_mq_debugfs_queue_attrs[] = {
826 	{"poll_stat", 0400, &queue_poll_stat_fops},
827 	{"state", 0600, &blk_queue_flags_fops},
828 	{},
829 };
830 
831 static const struct blk_mq_debugfs_attr blk_mq_debugfs_hctx_attrs[] = {
832 	{"state", 0400, &hctx_state_fops},
833 	{"flags", 0400, &hctx_flags_fops},
834 	{"dispatch", 0400, &hctx_dispatch_fops},
835 	{"ctx_map", 0400, &hctx_ctx_map_fops},
836 	{"tags", 0400, &hctx_tags_fops},
837 	{"tags_bitmap", 0400, &hctx_tags_bitmap_fops},
838 	{"sched_tags", 0400, &hctx_sched_tags_fops},
839 	{"sched_tags_bitmap", 0400, &hctx_sched_tags_bitmap_fops},
840 	{"io_poll", 0600, &hctx_io_poll_fops},
841 	{"dispatched", 0600, &hctx_dispatched_fops},
842 	{"queued", 0600, &hctx_queued_fops},
843 	{"run", 0600, &hctx_run_fops},
844 	{"active", 0400, &hctx_active_fops},
845 	{},
846 };
847 
848 static const struct blk_mq_debugfs_attr blk_mq_debugfs_ctx_attrs[] = {
849 	{"rq_list", 0400, &ctx_rq_list_fops},
850 	{"dispatched", 0600, &ctx_dispatched_fops},
851 	{"merged", 0600, &ctx_merged_fops},
852 	{"completed", 0600, &ctx_completed_fops},
853 	{},
854 };
855 
856 int blk_mq_debugfs_register(struct request_queue *q)
857 {
858 	if (!blk_debugfs_root)
859 		return -ENOENT;
860 
861 	q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
862 					    blk_debugfs_root);
863 	if (!q->debugfs_dir)
864 		goto err;
865 
866 	if (blk_mq_debugfs_register_mq(q))
867 		goto err;
868 
869 	return 0;
870 
871 err:
872 	blk_mq_debugfs_unregister(q);
873 	return -ENOMEM;
874 }
875 
876 void blk_mq_debugfs_unregister(struct request_queue *q)
877 {
878 	debugfs_remove_recursive(q->debugfs_dir);
879 	q->mq_debugfs_dir = NULL;
880 	q->debugfs_dir = NULL;
881 }
882 
883 static bool debugfs_create_files(struct dentry *parent, void *data,
884 				const struct blk_mq_debugfs_attr *attr)
885 {
886 	for (; attr->name; attr++) {
887 		if (!debugfs_create_file(attr->name, attr->mode, parent,
888 					 data, attr->fops))
889 			return false;
890 	}
891 	return true;
892 }
893 
894 static int blk_mq_debugfs_register_ctx(struct request_queue *q,
895 				       struct blk_mq_ctx *ctx,
896 				       struct dentry *hctx_dir)
897 {
898 	struct dentry *ctx_dir;
899 	char name[20];
900 
901 	snprintf(name, sizeof(name), "cpu%u", ctx->cpu);
902 	ctx_dir = debugfs_create_dir(name, hctx_dir);
903 	if (!ctx_dir)
904 		return -ENOMEM;
905 
906 	if (!debugfs_create_files(ctx_dir, ctx, blk_mq_debugfs_ctx_attrs))
907 		return -ENOMEM;
908 
909 	return 0;
910 }
911 
912 static int blk_mq_debugfs_register_hctx(struct request_queue *q,
913 					struct blk_mq_hw_ctx *hctx)
914 {
915 	struct blk_mq_ctx *ctx;
916 	struct dentry *hctx_dir;
917 	char name[20];
918 	int i;
919 
920 	snprintf(name, sizeof(name), "%u", hctx->queue_num);
921 	hctx_dir = debugfs_create_dir(name, q->mq_debugfs_dir);
922 	if (!hctx_dir)
923 		return -ENOMEM;
924 
925 	if (!debugfs_create_files(hctx_dir, hctx, blk_mq_debugfs_hctx_attrs))
926 		return -ENOMEM;
927 
928 	hctx_for_each_ctx(hctx, ctx, i) {
929 		if (blk_mq_debugfs_register_ctx(q, ctx, hctx_dir))
930 			return -ENOMEM;
931 	}
932 
933 	return 0;
934 }
935 
936 int blk_mq_debugfs_register_mq(struct request_queue *q)
937 {
938 	struct blk_mq_hw_ctx *hctx;
939 	int i;
940 
941 	if (!q->debugfs_dir)
942 		return -ENOENT;
943 
944 	q->mq_debugfs_dir = debugfs_create_dir("mq", q->debugfs_dir);
945 	if (!q->mq_debugfs_dir)
946 		goto err;
947 
948 	if (!debugfs_create_files(q->mq_debugfs_dir, q, blk_mq_debugfs_queue_attrs))
949 		goto err;
950 
951 	queue_for_each_hw_ctx(q, hctx, i) {
952 		if (blk_mq_debugfs_register_hctx(q, hctx))
953 			goto err;
954 	}
955 
956 	return 0;
957 
958 err:
959 	blk_mq_debugfs_unregister_mq(q);
960 	return -ENOMEM;
961 }
962 
963 void blk_mq_debugfs_unregister_mq(struct request_queue *q)
964 {
965 	debugfs_remove_recursive(q->mq_debugfs_dir);
966 	q->mq_debugfs_dir = NULL;
967 }
968