xref: /openbmc/linux/block/blk-sysfs.c (revision f7d84fa7)
1 /*
2  * Functions related to sysfs handling
3  */
4 #include <linux/kernel.h>
5 #include <linux/slab.h>
6 #include <linux/module.h>
7 #include <linux/bio.h>
8 #include <linux/blkdev.h>
9 #include <linux/backing-dev.h>
10 #include <linux/blktrace_api.h>
11 #include <linux/blk-mq.h>
12 #include <linux/blk-cgroup.h>
13 
14 #include "blk.h"
15 #include "blk-mq.h"
16 #include "blk-mq-debugfs.h"
17 #include "blk-wbt.h"
18 
19 struct queue_sysfs_entry {
20 	struct attribute attr;
21 	ssize_t (*show)(struct request_queue *, char *);
22 	ssize_t (*store)(struct request_queue *, const char *, size_t);
23 };
24 
25 static ssize_t
26 queue_var_show(unsigned long var, char *page)
27 {
28 	return sprintf(page, "%lu\n", var);
29 }
30 
31 static ssize_t
32 queue_var_store(unsigned long *var, const char *page, size_t count)
33 {
34 	int err;
35 	unsigned long v;
36 
37 	err = kstrtoul(page, 10, &v);
38 	if (err || v > UINT_MAX)
39 		return -EINVAL;
40 
41 	*var = v;
42 
43 	return count;
44 }
45 
46 static ssize_t queue_var_store64(s64 *var, const char *page)
47 {
48 	int err;
49 	s64 v;
50 
51 	err = kstrtos64(page, 10, &v);
52 	if (err < 0)
53 		return err;
54 
55 	*var = v;
56 	return 0;
57 }
58 
59 static ssize_t queue_requests_show(struct request_queue *q, char *page)
60 {
61 	return queue_var_show(q->nr_requests, (page));
62 }
63 
64 static ssize_t
65 queue_requests_store(struct request_queue *q, const char *page, size_t count)
66 {
67 	unsigned long nr;
68 	int ret, err;
69 
70 	if (!q->request_fn && !q->mq_ops)
71 		return -EINVAL;
72 
73 	ret = queue_var_store(&nr, page, count);
74 	if (ret < 0)
75 		return ret;
76 
77 	if (nr < BLKDEV_MIN_RQ)
78 		nr = BLKDEV_MIN_RQ;
79 
80 	if (q->request_fn)
81 		err = blk_update_nr_requests(q, nr);
82 	else
83 		err = blk_mq_update_nr_requests(q, nr);
84 
85 	if (err)
86 		return err;
87 
88 	return ret;
89 }
90 
91 static ssize_t queue_ra_show(struct request_queue *q, char *page)
92 {
93 	unsigned long ra_kb = q->backing_dev_info->ra_pages <<
94 					(PAGE_SHIFT - 10);
95 
96 	return queue_var_show(ra_kb, (page));
97 }
98 
99 static ssize_t
100 queue_ra_store(struct request_queue *q, const char *page, size_t count)
101 {
102 	unsigned long ra_kb;
103 	ssize_t ret = queue_var_store(&ra_kb, page, count);
104 
105 	if (ret < 0)
106 		return ret;
107 
108 	q->backing_dev_info->ra_pages = ra_kb >> (PAGE_SHIFT - 10);
109 
110 	return ret;
111 }
112 
113 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
114 {
115 	int max_sectors_kb = queue_max_sectors(q) >> 1;
116 
117 	return queue_var_show(max_sectors_kb, (page));
118 }
119 
120 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
121 {
122 	return queue_var_show(queue_max_segments(q), (page));
123 }
124 
125 static ssize_t queue_max_discard_segments_show(struct request_queue *q,
126 		char *page)
127 {
128 	return queue_var_show(queue_max_discard_segments(q), (page));
129 }
130 
131 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
132 {
133 	return queue_var_show(q->limits.max_integrity_segments, (page));
134 }
135 
136 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
137 {
138 	if (blk_queue_cluster(q))
139 		return queue_var_show(queue_max_segment_size(q), (page));
140 
141 	return queue_var_show(PAGE_SIZE, (page));
142 }
143 
144 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
145 {
146 	return queue_var_show(queue_logical_block_size(q), page);
147 }
148 
149 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
150 {
151 	return queue_var_show(queue_physical_block_size(q), page);
152 }
153 
154 static ssize_t queue_chunk_sectors_show(struct request_queue *q, char *page)
155 {
156 	return queue_var_show(q->limits.chunk_sectors, page);
157 }
158 
159 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
160 {
161 	return queue_var_show(queue_io_min(q), page);
162 }
163 
164 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
165 {
166 	return queue_var_show(queue_io_opt(q), page);
167 }
168 
169 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
170 {
171 	return queue_var_show(q->limits.discard_granularity, page);
172 }
173 
174 static ssize_t queue_discard_max_hw_show(struct request_queue *q, char *page)
175 {
176 
177 	return sprintf(page, "%llu\n",
178 		(unsigned long long)q->limits.max_hw_discard_sectors << 9);
179 }
180 
181 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
182 {
183 	return sprintf(page, "%llu\n",
184 		       (unsigned long long)q->limits.max_discard_sectors << 9);
185 }
186 
187 static ssize_t queue_discard_max_store(struct request_queue *q,
188 				       const char *page, size_t count)
189 {
190 	unsigned long max_discard;
191 	ssize_t ret = queue_var_store(&max_discard, page, count);
192 
193 	if (ret < 0)
194 		return ret;
195 
196 	if (max_discard & (q->limits.discard_granularity - 1))
197 		return -EINVAL;
198 
199 	max_discard >>= 9;
200 	if (max_discard > UINT_MAX)
201 		return -EINVAL;
202 
203 	if (max_discard > q->limits.max_hw_discard_sectors)
204 		max_discard = q->limits.max_hw_discard_sectors;
205 
206 	q->limits.max_discard_sectors = max_discard;
207 	return ret;
208 }
209 
210 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
211 {
212 	return queue_var_show(0, page);
213 }
214 
215 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
216 {
217 	return sprintf(page, "%llu\n",
218 		(unsigned long long)q->limits.max_write_same_sectors << 9);
219 }
220 
221 static ssize_t queue_write_zeroes_max_show(struct request_queue *q, char *page)
222 {
223 	return sprintf(page, "%llu\n",
224 		(unsigned long long)q->limits.max_write_zeroes_sectors << 9);
225 }
226 
227 static ssize_t
228 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
229 {
230 	unsigned long max_sectors_kb,
231 		max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
232 			page_kb = 1 << (PAGE_SHIFT - 10);
233 	ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
234 
235 	if (ret < 0)
236 		return ret;
237 
238 	max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb, (unsigned long)
239 					 q->limits.max_dev_sectors >> 1);
240 
241 	if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
242 		return -EINVAL;
243 
244 	spin_lock_irq(q->queue_lock);
245 	q->limits.max_sectors = max_sectors_kb << 1;
246 	q->backing_dev_info->io_pages = max_sectors_kb >> (PAGE_SHIFT - 10);
247 	spin_unlock_irq(q->queue_lock);
248 
249 	return ret;
250 }
251 
252 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
253 {
254 	int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
255 
256 	return queue_var_show(max_hw_sectors_kb, (page));
257 }
258 
259 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)				\
260 static ssize_t								\
261 queue_show_##name(struct request_queue *q, char *page)			\
262 {									\
263 	int bit;							\
264 	bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);		\
265 	return queue_var_show(neg ? !bit : bit, page);			\
266 }									\
267 static ssize_t								\
268 queue_store_##name(struct request_queue *q, const char *page, size_t count) \
269 {									\
270 	unsigned long val;						\
271 	ssize_t ret;							\
272 	ret = queue_var_store(&val, page, count);			\
273 	if (ret < 0)							\
274 		 return ret;						\
275 	if (neg)							\
276 		val = !val;						\
277 									\
278 	spin_lock_irq(q->queue_lock);					\
279 	if (val)							\
280 		queue_flag_set(QUEUE_FLAG_##flag, q);			\
281 	else								\
282 		queue_flag_clear(QUEUE_FLAG_##flag, q);			\
283 	spin_unlock_irq(q->queue_lock);					\
284 	return ret;							\
285 }
286 
287 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
288 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
289 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
290 #undef QUEUE_SYSFS_BIT_FNS
291 
292 static ssize_t queue_zoned_show(struct request_queue *q, char *page)
293 {
294 	switch (blk_queue_zoned_model(q)) {
295 	case BLK_ZONED_HA:
296 		return sprintf(page, "host-aware\n");
297 	case BLK_ZONED_HM:
298 		return sprintf(page, "host-managed\n");
299 	default:
300 		return sprintf(page, "none\n");
301 	}
302 }
303 
304 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
305 {
306 	return queue_var_show((blk_queue_nomerges(q) << 1) |
307 			       blk_queue_noxmerges(q), page);
308 }
309 
310 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
311 				    size_t count)
312 {
313 	unsigned long nm;
314 	ssize_t ret = queue_var_store(&nm, page, count);
315 
316 	if (ret < 0)
317 		return ret;
318 
319 	spin_lock_irq(q->queue_lock);
320 	queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
321 	queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
322 	if (nm == 2)
323 		queue_flag_set(QUEUE_FLAG_NOMERGES, q);
324 	else if (nm)
325 		queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
326 	spin_unlock_irq(q->queue_lock);
327 
328 	return ret;
329 }
330 
331 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
332 {
333 	bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
334 	bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
335 
336 	return queue_var_show(set << force, page);
337 }
338 
339 static ssize_t
340 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
341 {
342 	ssize_t ret = -EINVAL;
343 #ifdef CONFIG_SMP
344 	unsigned long val;
345 
346 	ret = queue_var_store(&val, page, count);
347 	if (ret < 0)
348 		return ret;
349 
350 	spin_lock_irq(q->queue_lock);
351 	if (val == 2) {
352 		queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
353 		queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
354 	} else if (val == 1) {
355 		queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
356 		queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
357 	} else if (val == 0) {
358 		queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
359 		queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
360 	}
361 	spin_unlock_irq(q->queue_lock);
362 #endif
363 	return ret;
364 }
365 
366 static ssize_t queue_poll_delay_show(struct request_queue *q, char *page)
367 {
368 	int val;
369 
370 	if (q->poll_nsec == -1)
371 		val = -1;
372 	else
373 		val = q->poll_nsec / 1000;
374 
375 	return sprintf(page, "%d\n", val);
376 }
377 
378 static ssize_t queue_poll_delay_store(struct request_queue *q, const char *page,
379 				size_t count)
380 {
381 	int err, val;
382 
383 	if (!q->mq_ops || !q->mq_ops->poll)
384 		return -EINVAL;
385 
386 	err = kstrtoint(page, 10, &val);
387 	if (err < 0)
388 		return err;
389 
390 	if (val == -1)
391 		q->poll_nsec = -1;
392 	else
393 		q->poll_nsec = val * 1000;
394 
395 	return count;
396 }
397 
398 static ssize_t queue_poll_show(struct request_queue *q, char *page)
399 {
400 	return queue_var_show(test_bit(QUEUE_FLAG_POLL, &q->queue_flags), page);
401 }
402 
403 static ssize_t queue_poll_store(struct request_queue *q, const char *page,
404 				size_t count)
405 {
406 	unsigned long poll_on;
407 	ssize_t ret;
408 
409 	if (!q->mq_ops || !q->mq_ops->poll)
410 		return -EINVAL;
411 
412 	ret = queue_var_store(&poll_on, page, count);
413 	if (ret < 0)
414 		return ret;
415 
416 	spin_lock_irq(q->queue_lock);
417 	if (poll_on)
418 		queue_flag_set(QUEUE_FLAG_POLL, q);
419 	else
420 		queue_flag_clear(QUEUE_FLAG_POLL, q);
421 	spin_unlock_irq(q->queue_lock);
422 
423 	return ret;
424 }
425 
426 static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
427 {
428 	if (!q->rq_wb)
429 		return -EINVAL;
430 
431 	return sprintf(page, "%llu\n", div_u64(q->rq_wb->min_lat_nsec, 1000));
432 }
433 
434 static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
435 				  size_t count)
436 {
437 	struct rq_wb *rwb;
438 	ssize_t ret;
439 	s64 val;
440 
441 	ret = queue_var_store64(&val, page);
442 	if (ret < 0)
443 		return ret;
444 	if (val < -1)
445 		return -EINVAL;
446 
447 	rwb = q->rq_wb;
448 	if (!rwb) {
449 		ret = wbt_init(q);
450 		if (ret)
451 			return ret;
452 
453 		rwb = q->rq_wb;
454 		if (!rwb)
455 			return -EINVAL;
456 	}
457 
458 	if (val == -1)
459 		rwb->min_lat_nsec = wbt_default_latency_nsec(q);
460 	else if (val >= 0)
461 		rwb->min_lat_nsec = val * 1000ULL;
462 
463 	if (rwb->enable_state == WBT_STATE_ON_DEFAULT)
464 		rwb->enable_state = WBT_STATE_ON_MANUAL;
465 
466 	wbt_update_limits(rwb);
467 	return count;
468 }
469 
470 static ssize_t queue_wc_show(struct request_queue *q, char *page)
471 {
472 	if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
473 		return sprintf(page, "write back\n");
474 
475 	return sprintf(page, "write through\n");
476 }
477 
478 static ssize_t queue_wc_store(struct request_queue *q, const char *page,
479 			      size_t count)
480 {
481 	int set = -1;
482 
483 	if (!strncmp(page, "write back", 10))
484 		set = 1;
485 	else if (!strncmp(page, "write through", 13) ||
486 		 !strncmp(page, "none", 4))
487 		set = 0;
488 
489 	if (set == -1)
490 		return -EINVAL;
491 
492 	spin_lock_irq(q->queue_lock);
493 	if (set)
494 		queue_flag_set(QUEUE_FLAG_WC, q);
495 	else
496 		queue_flag_clear(QUEUE_FLAG_WC, q);
497 	spin_unlock_irq(q->queue_lock);
498 
499 	return count;
500 }
501 
502 static ssize_t queue_dax_show(struct request_queue *q, char *page)
503 {
504 	return queue_var_show(blk_queue_dax(q), page);
505 }
506 
507 static struct queue_sysfs_entry queue_requests_entry = {
508 	.attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
509 	.show = queue_requests_show,
510 	.store = queue_requests_store,
511 };
512 
513 static struct queue_sysfs_entry queue_ra_entry = {
514 	.attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
515 	.show = queue_ra_show,
516 	.store = queue_ra_store,
517 };
518 
519 static struct queue_sysfs_entry queue_max_sectors_entry = {
520 	.attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
521 	.show = queue_max_sectors_show,
522 	.store = queue_max_sectors_store,
523 };
524 
525 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
526 	.attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
527 	.show = queue_max_hw_sectors_show,
528 };
529 
530 static struct queue_sysfs_entry queue_max_segments_entry = {
531 	.attr = {.name = "max_segments", .mode = S_IRUGO },
532 	.show = queue_max_segments_show,
533 };
534 
535 static struct queue_sysfs_entry queue_max_discard_segments_entry = {
536 	.attr = {.name = "max_discard_segments", .mode = S_IRUGO },
537 	.show = queue_max_discard_segments_show,
538 };
539 
540 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
541 	.attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
542 	.show = queue_max_integrity_segments_show,
543 };
544 
545 static struct queue_sysfs_entry queue_max_segment_size_entry = {
546 	.attr = {.name = "max_segment_size", .mode = S_IRUGO },
547 	.show = queue_max_segment_size_show,
548 };
549 
550 static struct queue_sysfs_entry queue_iosched_entry = {
551 	.attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
552 	.show = elv_iosched_show,
553 	.store = elv_iosched_store,
554 };
555 
556 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
557 	.attr = {.name = "hw_sector_size", .mode = S_IRUGO },
558 	.show = queue_logical_block_size_show,
559 };
560 
561 static struct queue_sysfs_entry queue_logical_block_size_entry = {
562 	.attr = {.name = "logical_block_size", .mode = S_IRUGO },
563 	.show = queue_logical_block_size_show,
564 };
565 
566 static struct queue_sysfs_entry queue_physical_block_size_entry = {
567 	.attr = {.name = "physical_block_size", .mode = S_IRUGO },
568 	.show = queue_physical_block_size_show,
569 };
570 
571 static struct queue_sysfs_entry queue_chunk_sectors_entry = {
572 	.attr = {.name = "chunk_sectors", .mode = S_IRUGO },
573 	.show = queue_chunk_sectors_show,
574 };
575 
576 static struct queue_sysfs_entry queue_io_min_entry = {
577 	.attr = {.name = "minimum_io_size", .mode = S_IRUGO },
578 	.show = queue_io_min_show,
579 };
580 
581 static struct queue_sysfs_entry queue_io_opt_entry = {
582 	.attr = {.name = "optimal_io_size", .mode = S_IRUGO },
583 	.show = queue_io_opt_show,
584 };
585 
586 static struct queue_sysfs_entry queue_discard_granularity_entry = {
587 	.attr = {.name = "discard_granularity", .mode = S_IRUGO },
588 	.show = queue_discard_granularity_show,
589 };
590 
591 static struct queue_sysfs_entry queue_discard_max_hw_entry = {
592 	.attr = {.name = "discard_max_hw_bytes", .mode = S_IRUGO },
593 	.show = queue_discard_max_hw_show,
594 };
595 
596 static struct queue_sysfs_entry queue_discard_max_entry = {
597 	.attr = {.name = "discard_max_bytes", .mode = S_IRUGO | S_IWUSR },
598 	.show = queue_discard_max_show,
599 	.store = queue_discard_max_store,
600 };
601 
602 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
603 	.attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
604 	.show = queue_discard_zeroes_data_show,
605 };
606 
607 static struct queue_sysfs_entry queue_write_same_max_entry = {
608 	.attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
609 	.show = queue_write_same_max_show,
610 };
611 
612 static struct queue_sysfs_entry queue_write_zeroes_max_entry = {
613 	.attr = {.name = "write_zeroes_max_bytes", .mode = S_IRUGO },
614 	.show = queue_write_zeroes_max_show,
615 };
616 
617 static struct queue_sysfs_entry queue_nonrot_entry = {
618 	.attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
619 	.show = queue_show_nonrot,
620 	.store = queue_store_nonrot,
621 };
622 
623 static struct queue_sysfs_entry queue_zoned_entry = {
624 	.attr = {.name = "zoned", .mode = S_IRUGO },
625 	.show = queue_zoned_show,
626 };
627 
628 static struct queue_sysfs_entry queue_nomerges_entry = {
629 	.attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
630 	.show = queue_nomerges_show,
631 	.store = queue_nomerges_store,
632 };
633 
634 static struct queue_sysfs_entry queue_rq_affinity_entry = {
635 	.attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
636 	.show = queue_rq_affinity_show,
637 	.store = queue_rq_affinity_store,
638 };
639 
640 static struct queue_sysfs_entry queue_iostats_entry = {
641 	.attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
642 	.show = queue_show_iostats,
643 	.store = queue_store_iostats,
644 };
645 
646 static struct queue_sysfs_entry queue_random_entry = {
647 	.attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
648 	.show = queue_show_random,
649 	.store = queue_store_random,
650 };
651 
652 static struct queue_sysfs_entry queue_poll_entry = {
653 	.attr = {.name = "io_poll", .mode = S_IRUGO | S_IWUSR },
654 	.show = queue_poll_show,
655 	.store = queue_poll_store,
656 };
657 
658 static struct queue_sysfs_entry queue_poll_delay_entry = {
659 	.attr = {.name = "io_poll_delay", .mode = S_IRUGO | S_IWUSR },
660 	.show = queue_poll_delay_show,
661 	.store = queue_poll_delay_store,
662 };
663 
664 static struct queue_sysfs_entry queue_wc_entry = {
665 	.attr = {.name = "write_cache", .mode = S_IRUGO | S_IWUSR },
666 	.show = queue_wc_show,
667 	.store = queue_wc_store,
668 };
669 
670 static struct queue_sysfs_entry queue_dax_entry = {
671 	.attr = {.name = "dax", .mode = S_IRUGO },
672 	.show = queue_dax_show,
673 };
674 
675 static struct queue_sysfs_entry queue_wb_lat_entry = {
676 	.attr = {.name = "wbt_lat_usec", .mode = S_IRUGO | S_IWUSR },
677 	.show = queue_wb_lat_show,
678 	.store = queue_wb_lat_store,
679 };
680 
681 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
682 static struct queue_sysfs_entry throtl_sample_time_entry = {
683 	.attr = {.name = "throttle_sample_time", .mode = S_IRUGO | S_IWUSR },
684 	.show = blk_throtl_sample_time_show,
685 	.store = blk_throtl_sample_time_store,
686 };
687 #endif
688 
689 static struct attribute *default_attrs[] = {
690 	&queue_requests_entry.attr,
691 	&queue_ra_entry.attr,
692 	&queue_max_hw_sectors_entry.attr,
693 	&queue_max_sectors_entry.attr,
694 	&queue_max_segments_entry.attr,
695 	&queue_max_discard_segments_entry.attr,
696 	&queue_max_integrity_segments_entry.attr,
697 	&queue_max_segment_size_entry.attr,
698 	&queue_iosched_entry.attr,
699 	&queue_hw_sector_size_entry.attr,
700 	&queue_logical_block_size_entry.attr,
701 	&queue_physical_block_size_entry.attr,
702 	&queue_chunk_sectors_entry.attr,
703 	&queue_io_min_entry.attr,
704 	&queue_io_opt_entry.attr,
705 	&queue_discard_granularity_entry.attr,
706 	&queue_discard_max_entry.attr,
707 	&queue_discard_max_hw_entry.attr,
708 	&queue_discard_zeroes_data_entry.attr,
709 	&queue_write_same_max_entry.attr,
710 	&queue_write_zeroes_max_entry.attr,
711 	&queue_nonrot_entry.attr,
712 	&queue_zoned_entry.attr,
713 	&queue_nomerges_entry.attr,
714 	&queue_rq_affinity_entry.attr,
715 	&queue_iostats_entry.attr,
716 	&queue_random_entry.attr,
717 	&queue_poll_entry.attr,
718 	&queue_wc_entry.attr,
719 	&queue_dax_entry.attr,
720 	&queue_wb_lat_entry.attr,
721 	&queue_poll_delay_entry.attr,
722 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
723 	&throtl_sample_time_entry.attr,
724 #endif
725 	NULL,
726 };
727 
728 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
729 
730 static ssize_t
731 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
732 {
733 	struct queue_sysfs_entry *entry = to_queue(attr);
734 	struct request_queue *q =
735 		container_of(kobj, struct request_queue, kobj);
736 	ssize_t res;
737 
738 	if (!entry->show)
739 		return -EIO;
740 	mutex_lock(&q->sysfs_lock);
741 	if (blk_queue_dying(q)) {
742 		mutex_unlock(&q->sysfs_lock);
743 		return -ENOENT;
744 	}
745 	res = entry->show(q, page);
746 	mutex_unlock(&q->sysfs_lock);
747 	return res;
748 }
749 
750 static ssize_t
751 queue_attr_store(struct kobject *kobj, struct attribute *attr,
752 		    const char *page, size_t length)
753 {
754 	struct queue_sysfs_entry *entry = to_queue(attr);
755 	struct request_queue *q;
756 	ssize_t res;
757 
758 	if (!entry->store)
759 		return -EIO;
760 
761 	q = container_of(kobj, struct request_queue, kobj);
762 	mutex_lock(&q->sysfs_lock);
763 	if (blk_queue_dying(q)) {
764 		mutex_unlock(&q->sysfs_lock);
765 		return -ENOENT;
766 	}
767 	res = entry->store(q, page, length);
768 	mutex_unlock(&q->sysfs_lock);
769 	return res;
770 }
771 
772 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
773 {
774 	struct request_queue *q = container_of(rcu_head, struct request_queue,
775 					       rcu_head);
776 	kmem_cache_free(blk_requestq_cachep, q);
777 }
778 
779 /**
780  * __blk_release_queue - release a request queue when it is no longer needed
781  * @work: pointer to the release_work member of the request queue to be released
782  *
783  * Description:
784  *     blk_release_queue is the counterpart of blk_init_queue(). It should be
785  *     called when a request queue is being released; typically when a block
786  *     device is being de-registered. Its primary task it to free the queue
787  *     itself.
788  *
789  * Notes:
790  *     The low level driver must have finished any outstanding requests first
791  *     via blk_cleanup_queue().
792  *
793  *     Although blk_release_queue() may be called with preemption disabled,
794  *     __blk_release_queue() may sleep.
795  */
796 static void __blk_release_queue(struct work_struct *work)
797 {
798 	struct request_queue *q = container_of(work, typeof(*q), release_work);
799 
800 	if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags))
801 		blk_stat_remove_callback(q, q->poll_cb);
802 	blk_stat_free_callback(q->poll_cb);
803 	bdi_put(q->backing_dev_info);
804 	blkcg_exit_queue(q);
805 
806 	if (q->elevator) {
807 		ioc_clear_queue(q);
808 		elevator_exit(q, q->elevator);
809 	}
810 
811 	blk_free_queue_stats(q->stats);
812 
813 	blk_exit_rl(q, &q->root_rl);
814 
815 	if (q->queue_tags)
816 		__blk_queue_free_tags(q);
817 
818 	if (!q->mq_ops) {
819 		if (q->exit_rq_fn)
820 			q->exit_rq_fn(q, q->fq->flush_rq);
821 		blk_free_flush_queue(q->fq);
822 	} else {
823 		blk_mq_release(q);
824 	}
825 
826 	blk_trace_shutdown(q);
827 
828 	if (q->mq_ops)
829 		blk_mq_debugfs_unregister(q);
830 
831 	if (q->bio_split)
832 		bioset_free(q->bio_split);
833 
834 	ida_simple_remove(&blk_queue_ida, q->id);
835 	call_rcu(&q->rcu_head, blk_free_queue_rcu);
836 }
837 
838 static void blk_release_queue(struct kobject *kobj)
839 {
840 	struct request_queue *q =
841 		container_of(kobj, struct request_queue, kobj);
842 
843 	INIT_WORK(&q->release_work, __blk_release_queue);
844 	schedule_work(&q->release_work);
845 }
846 
847 static const struct sysfs_ops queue_sysfs_ops = {
848 	.show	= queue_attr_show,
849 	.store	= queue_attr_store,
850 };
851 
852 struct kobj_type blk_queue_ktype = {
853 	.sysfs_ops	= &queue_sysfs_ops,
854 	.default_attrs	= default_attrs,
855 	.release	= blk_release_queue,
856 };
857 
858 int blk_register_queue(struct gendisk *disk)
859 {
860 	int ret;
861 	struct device *dev = disk_to_dev(disk);
862 	struct request_queue *q = disk->queue;
863 
864 	if (WARN_ON(!q))
865 		return -ENXIO;
866 
867 	WARN_ONCE(test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags),
868 		  "%s is registering an already registered queue\n",
869 		  kobject_name(&dev->kobj));
870 	queue_flag_set_unlocked(QUEUE_FLAG_REGISTERED, q);
871 
872 	/*
873 	 * SCSI probing may synchronously create and destroy a lot of
874 	 * request_queues for non-existent devices.  Shutting down a fully
875 	 * functional queue takes measureable wallclock time as RCU grace
876 	 * periods are involved.  To avoid excessive latency in these
877 	 * cases, a request_queue starts out in a degraded mode which is
878 	 * faster to shut down and is made fully functional here as
879 	 * request_queues for non-existent devices never get registered.
880 	 */
881 	if (!blk_queue_init_done(q)) {
882 		queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q);
883 		percpu_ref_switch_to_percpu(&q->q_usage_counter);
884 		blk_queue_bypass_end(q);
885 	}
886 
887 	ret = blk_trace_init_sysfs(dev);
888 	if (ret)
889 		return ret;
890 
891 	/* Prevent changes through sysfs until registration is completed. */
892 	mutex_lock(&q->sysfs_lock);
893 
894 	ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
895 	if (ret < 0) {
896 		blk_trace_remove_sysfs(dev);
897 		goto unlock;
898 	}
899 
900 	if (q->mq_ops) {
901 		__blk_mq_register_dev(dev, q);
902 		blk_mq_debugfs_register(q);
903 	}
904 
905 	kobject_uevent(&q->kobj, KOBJ_ADD);
906 
907 	wbt_enable_default(q);
908 
909 	blk_throtl_register_queue(q);
910 
911 	if (q->request_fn || (q->mq_ops && q->elevator)) {
912 		ret = elv_register_queue(q);
913 		if (ret) {
914 			kobject_uevent(&q->kobj, KOBJ_REMOVE);
915 			kobject_del(&q->kobj);
916 			blk_trace_remove_sysfs(dev);
917 			kobject_put(&dev->kobj);
918 			goto unlock;
919 		}
920 	}
921 	ret = 0;
922 unlock:
923 	mutex_unlock(&q->sysfs_lock);
924 	return ret;
925 }
926 
927 void blk_unregister_queue(struct gendisk *disk)
928 {
929 	struct request_queue *q = disk->queue;
930 
931 	if (WARN_ON(!q))
932 		return;
933 
934 	queue_flag_clear_unlocked(QUEUE_FLAG_REGISTERED, q);
935 
936 	wbt_exit(q);
937 
938 
939 	if (q->mq_ops)
940 		blk_mq_unregister_dev(disk_to_dev(disk), q);
941 
942 	if (q->request_fn || (q->mq_ops && q->elevator))
943 		elv_unregister_queue(q);
944 
945 	kobject_uevent(&q->kobj, KOBJ_REMOVE);
946 	kobject_del(&q->kobj);
947 	blk_trace_remove_sysfs(disk_to_dev(disk));
948 	kobject_put(&disk_to_dev(disk)->kobj);
949 }
950