1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Functions related to sysfs handling
4 */
5#include <linux/kernel.h>
6#include <linux/slab.h>
7#include <linux/module.h>
8#include <linux/bio.h>
9#include <linux/blkdev.h>
10#include <linux/backing-dev.h>
11#include <linux/blktrace_api.h>
12#include <linux/debugfs.h>
13
14#include "blk.h"
15#include "blk-mq.h"
16#include "blk-mq-debugfs.h"
17#include "blk-mq-sched.h"
18#include "blk-rq-qos.h"
19#include "blk-wbt.h"
20#include "blk-cgroup.h"
21#include "blk-throttle.h"
22
23struct queue_sysfs_entry {
24 struct attribute attr;
25 ssize_t (*show)(struct request_queue *, char *);
26 ssize_t (*store)(struct request_queue *, const char *, size_t);
27};
28
29static ssize_t
30queue_var_show(unsigned long var, char *page)
31{
32 return sprintf(buf: page, fmt: "%lu\n", var);
33}
34
35static ssize_t
36queue_var_store(unsigned long *var, const char *page, size_t count)
37{
38 int err;
39 unsigned long v;
40
41 err = kstrtoul(s: page, base: 10, res: &v);
42 if (err || v > UINT_MAX)
43 return -EINVAL;
44
45 *var = v;
46
47 return count;
48}
49
50static ssize_t queue_requests_show(struct request_queue *q, char *page)
51{
52 return queue_var_show(var: q->nr_requests, page);
53}
54
55static ssize_t
56queue_requests_store(struct request_queue *q, const char *page, size_t count)
57{
58 unsigned long nr;
59 int ret, err;
60
61 if (!queue_is_mq(q))
62 return -EINVAL;
63
64 ret = queue_var_store(var: &nr, page, count);
65 if (ret < 0)
66 return ret;
67
68 if (nr < BLKDEV_MIN_RQ)
69 nr = BLKDEV_MIN_RQ;
70
71 err = blk_mq_update_nr_requests(q, nr);
72 if (err)
73 return err;
74
75 return ret;
76}
77
78static ssize_t queue_ra_show(struct request_queue *q, char *page)
79{
80 unsigned long ra_kb;
81
82 if (!q->disk)
83 return -EINVAL;
84 ra_kb = q->disk->bdi->ra_pages << (PAGE_SHIFT - 10);
85 return queue_var_show(var: ra_kb, page);
86}
87
88static ssize_t
89queue_ra_store(struct request_queue *q, const char *page, size_t count)
90{
91 unsigned long ra_kb;
92 ssize_t ret;
93
94 if (!q->disk)
95 return -EINVAL;
96 ret = queue_var_store(var: &ra_kb, page, count);
97 if (ret < 0)
98 return ret;
99 q->disk->bdi->ra_pages = ra_kb >> (PAGE_SHIFT - 10);
100 return ret;
101}
102
103static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
104{
105 int max_sectors_kb = queue_max_sectors(q) >> 1;
106
107 return queue_var_show(var: max_sectors_kb, page);
108}
109
110static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
111{
112 return queue_var_show(var: queue_max_segments(q), page);
113}
114
115static ssize_t queue_max_discard_segments_show(struct request_queue *q,
116 char *page)
117{
118 return queue_var_show(var: queue_max_discard_segments(q), page);
119}
120
121static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
122{
123 return queue_var_show(var: q->limits.max_integrity_segments, page);
124}
125
126static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
127{
128 return queue_var_show(var: queue_max_segment_size(q), page);
129}
130
131static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
132{
133 return queue_var_show(var: queue_logical_block_size(q), page);
134}
135
136static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
137{
138 return queue_var_show(var: queue_physical_block_size(q), page);
139}
140
141static ssize_t queue_chunk_sectors_show(struct request_queue *q, char *page)
142{
143 return queue_var_show(var: q->limits.chunk_sectors, page);
144}
145
146static ssize_t queue_io_min_show(struct request_queue *q, char *page)
147{
148 return queue_var_show(var: queue_io_min(q), page);
149}
150
151static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
152{
153 return queue_var_show(var: queue_io_opt(q), page);
154}
155
156static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
157{
158 return queue_var_show(var: q->limits.discard_granularity, page);
159}
160
161static ssize_t queue_discard_max_hw_show(struct request_queue *q, char *page)
162{
163
164 return sprintf(buf: page, fmt: "%llu\n",
165 (unsigned long long)q->limits.max_hw_discard_sectors << 9);
166}
167
168static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
169{
170 return sprintf(buf: page, fmt: "%llu\n",
171 (unsigned long long)q->limits.max_discard_sectors << 9);
172}
173
174static ssize_t queue_discard_max_store(struct request_queue *q,
175 const char *page, size_t count)
176{
177 unsigned long max_discard_bytes;
178 struct queue_limits lim;
179 ssize_t ret;
180 int err;
181
182 ret = queue_var_store(var: &max_discard_bytes, page, count);
183 if (ret < 0)
184 return ret;
185
186 if (max_discard_bytes & (q->limits.discard_granularity - 1))
187 return -EINVAL;
188
189 if ((max_discard_bytes >> SECTOR_SHIFT) > UINT_MAX)
190 return -EINVAL;
191
192 blk_mq_freeze_queue(q);
193 lim = queue_limits_start_update(q);
194 lim.max_user_discard_sectors = max_discard_bytes >> SECTOR_SHIFT;
195 err = queue_limits_commit_update(q, lim: &lim);
196 blk_mq_unfreeze_queue(q);
197
198 if (err)
199 return err;
200 return ret;
201}
202
203static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
204{
205 return queue_var_show(var: 0, page);
206}
207
208static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
209{
210 return queue_var_show(var: 0, page);
211}
212
213static ssize_t queue_write_zeroes_max_show(struct request_queue *q, char *page)
214{
215 return sprintf(buf: page, fmt: "%llu\n",
216 (unsigned long long)q->limits.max_write_zeroes_sectors << 9);
217}
218
219static ssize_t queue_zone_write_granularity_show(struct request_queue *q,
220 char *page)
221{
222 return queue_var_show(var: queue_zone_write_granularity(q), page);
223}
224
225static ssize_t queue_zone_append_max_show(struct request_queue *q, char *page)
226{
227 unsigned long long max_sectors = q->limits.max_zone_append_sectors;
228
229 return sprintf(buf: page, fmt: "%llu\n", max_sectors << SECTOR_SHIFT);
230}
231
232static ssize_t
233queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
234{
235 unsigned long max_sectors_kb;
236 struct queue_limits lim;
237 ssize_t ret;
238 int err;
239
240 ret = queue_var_store(var: &max_sectors_kb, page, count);
241 if (ret < 0)
242 return ret;
243
244 blk_mq_freeze_queue(q);
245 lim = queue_limits_start_update(q);
246 lim.max_user_sectors = max_sectors_kb << 1;
247 err = queue_limits_commit_update(q, lim: &lim);
248 blk_mq_unfreeze_queue(q);
249 if (err)
250 return err;
251 return ret;
252}
253
254static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
255{
256 int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
257
258 return queue_var_show(var: max_hw_sectors_kb, page);
259}
260
261static ssize_t queue_virt_boundary_mask_show(struct request_queue *q, char *page)
262{
263 return queue_var_show(var: q->limits.virt_boundary_mask, page);
264}
265
266static ssize_t queue_dma_alignment_show(struct request_queue *q, char *page)
267{
268 return queue_var_show(var: queue_dma_alignment(q), page);
269}
270
271#define QUEUE_SYSFS_BIT_FNS(name, flag, neg) \
272static ssize_t \
273queue_##name##_show(struct request_queue *q, char *page) \
274{ \
275 int bit; \
276 bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags); \
277 return queue_var_show(neg ? !bit : bit, page); \
278} \
279static ssize_t \
280queue_##name##_store(struct request_queue *q, const char *page, size_t count) \
281{ \
282 unsigned long val; \
283 ssize_t ret; \
284 ret = queue_var_store(&val, page, count); \
285 if (ret < 0) \
286 return ret; \
287 if (neg) \
288 val = !val; \
289 \
290 if (val) \
291 blk_queue_flag_set(QUEUE_FLAG_##flag, q); \
292 else \
293 blk_queue_flag_clear(QUEUE_FLAG_##flag, q); \
294 return ret; \
295}
296
297QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
298QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
299QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
300QUEUE_SYSFS_BIT_FNS(stable_writes, STABLE_WRITES, 0);
301#undef QUEUE_SYSFS_BIT_FNS
302
303static ssize_t queue_zoned_show(struct request_queue *q, char *page)
304{
305 if (blk_queue_is_zoned(q))
306 return sprintf(buf: page, fmt: "host-managed\n");
307 return sprintf(buf: page, fmt: "none\n");
308}
309
310static ssize_t queue_nr_zones_show(struct request_queue *q, char *page)
311{
312 return queue_var_show(var: disk_nr_zones(disk: q->disk), page);
313}
314
315static ssize_t queue_max_open_zones_show(struct request_queue *q, char *page)
316{
317 return queue_var_show(var: bdev_max_open_zones(bdev: q->disk->part0), page);
318}
319
320static ssize_t queue_max_active_zones_show(struct request_queue *q, char *page)
321{
322 return queue_var_show(var: bdev_max_active_zones(bdev: q->disk->part0), page);
323}
324
325static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
326{
327 return queue_var_show(var: (blk_queue_nomerges(q) << 1) |
328 blk_queue_noxmerges(q), page);
329}
330
331static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
332 size_t count)
333{
334 unsigned long nm;
335 ssize_t ret = queue_var_store(var: &nm, page, count);
336
337 if (ret < 0)
338 return ret;
339
340 blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
341 blk_queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
342 if (nm == 2)
343 blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q);
344 else if (nm)
345 blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
346
347 return ret;
348}
349
350static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
351{
352 bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
353 bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
354
355 return queue_var_show(var: set << force, page);
356}
357
358static ssize_t
359queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
360{
361 ssize_t ret = -EINVAL;
362#ifdef CONFIG_SMP
363 unsigned long val;
364
365 ret = queue_var_store(var: &val, page, count);
366 if (ret < 0)
367 return ret;
368
369 if (val == 2) {
370 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
371 blk_queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
372 } else if (val == 1) {
373 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
374 blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
375 } else if (val == 0) {
376 blk_queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
377 blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
378 }
379#endif
380 return ret;
381}
382
383static ssize_t queue_poll_delay_show(struct request_queue *q, char *page)
384{
385 return sprintf(buf: page, fmt: "%d\n", -1);
386}
387
388static ssize_t queue_poll_delay_store(struct request_queue *q, const char *page,
389 size_t count)
390{
391 return count;
392}
393
394static ssize_t queue_poll_show(struct request_queue *q, char *page)
395{
396 return queue_var_show(test_bit(QUEUE_FLAG_POLL, &q->queue_flags), page);
397}
398
399static ssize_t queue_poll_store(struct request_queue *q, const char *page,
400 size_t count)
401{
402 if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
403 return -EINVAL;
404 pr_info_ratelimited("writes to the poll attribute are ignored.\n");
405 pr_info_ratelimited("please use driver specific parameters instead.\n");
406 return count;
407}
408
409static ssize_t queue_io_timeout_show(struct request_queue *q, char *page)
410{
411 return sprintf(buf: page, fmt: "%u\n", jiffies_to_msecs(j: q->rq_timeout));
412}
413
414static ssize_t queue_io_timeout_store(struct request_queue *q, const char *page,
415 size_t count)
416{
417 unsigned int val;
418 int err;
419
420 err = kstrtou32(s: page, base: 10, res: &val);
421 if (err || val == 0)
422 return -EINVAL;
423
424 blk_queue_rq_timeout(q, msecs_to_jiffies(m: val));
425
426 return count;
427}
428
429static ssize_t queue_wc_show(struct request_queue *q, char *page)
430{
431 if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
432 return sprintf(buf: page, fmt: "write back\n");
433
434 return sprintf(buf: page, fmt: "write through\n");
435}
436
437static ssize_t queue_wc_store(struct request_queue *q, const char *page,
438 size_t count)
439{
440 if (!strncmp(page, "write back", 10)) {
441 if (!test_bit(QUEUE_FLAG_HW_WC, &q->queue_flags))
442 return -EINVAL;
443 blk_queue_flag_set(QUEUE_FLAG_WC, q);
444 } else if (!strncmp(page, "write through", 13) ||
445 !strncmp(page, "none", 4)) {
446 blk_queue_flag_clear(QUEUE_FLAG_WC, q);
447 } else {
448 return -EINVAL;
449 }
450
451 return count;
452}
453
454static ssize_t queue_fua_show(struct request_queue *q, char *page)
455{
456 return sprintf(buf: page, fmt: "%u\n", test_bit(QUEUE_FLAG_FUA, &q->queue_flags));
457}
458
459static ssize_t queue_dax_show(struct request_queue *q, char *page)
460{
461 return queue_var_show(blk_queue_dax(q), page);
462}
463
464#define QUEUE_RO_ENTRY(_prefix, _name) \
465static struct queue_sysfs_entry _prefix##_entry = { \
466 .attr = { .name = _name, .mode = 0444 }, \
467 .show = _prefix##_show, \
468};
469
470#define QUEUE_RW_ENTRY(_prefix, _name) \
471static struct queue_sysfs_entry _prefix##_entry = { \
472 .attr = { .name = _name, .mode = 0644 }, \
473 .show = _prefix##_show, \
474 .store = _prefix##_store, \
475};
476
477QUEUE_RW_ENTRY(queue_requests, "nr_requests");
478QUEUE_RW_ENTRY(queue_ra, "read_ahead_kb");
479QUEUE_RW_ENTRY(queue_max_sectors, "max_sectors_kb");
480QUEUE_RO_ENTRY(queue_max_hw_sectors, "max_hw_sectors_kb");
481QUEUE_RO_ENTRY(queue_max_segments, "max_segments");
482QUEUE_RO_ENTRY(queue_max_integrity_segments, "max_integrity_segments");
483QUEUE_RO_ENTRY(queue_max_segment_size, "max_segment_size");
484QUEUE_RW_ENTRY(elv_iosched, "scheduler");
485
486QUEUE_RO_ENTRY(queue_logical_block_size, "logical_block_size");
487QUEUE_RO_ENTRY(queue_physical_block_size, "physical_block_size");
488QUEUE_RO_ENTRY(queue_chunk_sectors, "chunk_sectors");
489QUEUE_RO_ENTRY(queue_io_min, "minimum_io_size");
490QUEUE_RO_ENTRY(queue_io_opt, "optimal_io_size");
491
492QUEUE_RO_ENTRY(queue_max_discard_segments, "max_discard_segments");
493QUEUE_RO_ENTRY(queue_discard_granularity, "discard_granularity");
494QUEUE_RO_ENTRY(queue_discard_max_hw, "discard_max_hw_bytes");
495QUEUE_RW_ENTRY(queue_discard_max, "discard_max_bytes");
496QUEUE_RO_ENTRY(queue_discard_zeroes_data, "discard_zeroes_data");
497
498QUEUE_RO_ENTRY(queue_write_same_max, "write_same_max_bytes");
499QUEUE_RO_ENTRY(queue_write_zeroes_max, "write_zeroes_max_bytes");
500QUEUE_RO_ENTRY(queue_zone_append_max, "zone_append_max_bytes");
501QUEUE_RO_ENTRY(queue_zone_write_granularity, "zone_write_granularity");
502
503QUEUE_RO_ENTRY(queue_zoned, "zoned");
504QUEUE_RO_ENTRY(queue_nr_zones, "nr_zones");
505QUEUE_RO_ENTRY(queue_max_open_zones, "max_open_zones");
506QUEUE_RO_ENTRY(queue_max_active_zones, "max_active_zones");
507
508QUEUE_RW_ENTRY(queue_nomerges, "nomerges");
509QUEUE_RW_ENTRY(queue_rq_affinity, "rq_affinity");
510QUEUE_RW_ENTRY(queue_poll, "io_poll");
511QUEUE_RW_ENTRY(queue_poll_delay, "io_poll_delay");
512QUEUE_RW_ENTRY(queue_wc, "write_cache");
513QUEUE_RO_ENTRY(queue_fua, "fua");
514QUEUE_RO_ENTRY(queue_dax, "dax");
515QUEUE_RW_ENTRY(queue_io_timeout, "io_timeout");
516QUEUE_RO_ENTRY(queue_virt_boundary_mask, "virt_boundary_mask");
517QUEUE_RO_ENTRY(queue_dma_alignment, "dma_alignment");
518
519#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
520QUEUE_RW_ENTRY(blk_throtl_sample_time, "throttle_sample_time");
521#endif
522
523/* legacy alias for logical_block_size: */
524static struct queue_sysfs_entry queue_hw_sector_size_entry = {
525 .attr = {.name = "hw_sector_size", .mode = 0444 },
526 .show = queue_logical_block_size_show,
527};
528
529QUEUE_RW_ENTRY(queue_nonrot, "rotational");
530QUEUE_RW_ENTRY(queue_iostats, "iostats");
531QUEUE_RW_ENTRY(queue_random, "add_random");
532QUEUE_RW_ENTRY(queue_stable_writes, "stable_writes");
533
534#ifdef CONFIG_BLK_WBT
535static ssize_t queue_var_store64(s64 *var, const char *page)
536{
537 int err;
538 s64 v;
539
540 err = kstrtos64(s: page, base: 10, res: &v);
541 if (err < 0)
542 return err;
543
544 *var = v;
545 return 0;
546}
547
548static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
549{
550 if (!wbt_rq_qos(q))
551 return -EINVAL;
552
553 if (wbt_disabled(q))
554 return sprintf(buf: page, fmt: "0\n");
555
556 return sprintf(buf: page, fmt: "%llu\n", div_u64(dividend: wbt_get_min_lat(q), divisor: 1000));
557}
558
559static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
560 size_t count)
561{
562 struct rq_qos *rqos;
563 ssize_t ret;
564 s64 val;
565
566 ret = queue_var_store64(var: &val, page);
567 if (ret < 0)
568 return ret;
569 if (val < -1)
570 return -EINVAL;
571
572 rqos = wbt_rq_qos(q);
573 if (!rqos) {
574 ret = wbt_init(disk: q->disk);
575 if (ret)
576 return ret;
577 }
578
579 if (val == -1)
580 val = wbt_default_latency_nsec(q);
581 else if (val >= 0)
582 val *= 1000ULL;
583
584 if (wbt_get_min_lat(q) == val)
585 return count;
586
587 /*
588 * Ensure that the queue is idled, in case the latency update
589 * ends up either enabling or disabling wbt completely. We can't
590 * have IO inflight if that happens.
591 */
592 blk_mq_freeze_queue(q);
593 blk_mq_quiesce_queue(q);
594
595 wbt_set_min_lat(q, val);
596
597 blk_mq_unquiesce_queue(q);
598 blk_mq_unfreeze_queue(q);
599
600 return count;
601}
602
603QUEUE_RW_ENTRY(queue_wb_lat, "wbt_lat_usec");
604#endif
605
606/* Common attributes for bio-based and request-based queues. */
607static struct attribute *queue_attrs[] = {
608 &queue_ra_entry.attr,
609 &queue_max_hw_sectors_entry.attr,
610 &queue_max_sectors_entry.attr,
611 &queue_max_segments_entry.attr,
612 &queue_max_discard_segments_entry.attr,
613 &queue_max_integrity_segments_entry.attr,
614 &queue_max_segment_size_entry.attr,
615 &queue_hw_sector_size_entry.attr,
616 &queue_logical_block_size_entry.attr,
617 &queue_physical_block_size_entry.attr,
618 &queue_chunk_sectors_entry.attr,
619 &queue_io_min_entry.attr,
620 &queue_io_opt_entry.attr,
621 &queue_discard_granularity_entry.attr,
622 &queue_discard_max_entry.attr,
623 &queue_discard_max_hw_entry.attr,
624 &queue_discard_zeroes_data_entry.attr,
625 &queue_write_same_max_entry.attr,
626 &queue_write_zeroes_max_entry.attr,
627 &queue_zone_append_max_entry.attr,
628 &queue_zone_write_granularity_entry.attr,
629 &queue_nonrot_entry.attr,
630 &queue_zoned_entry.attr,
631 &queue_nr_zones_entry.attr,
632 &queue_max_open_zones_entry.attr,
633 &queue_max_active_zones_entry.attr,
634 &queue_nomerges_entry.attr,
635 &queue_iostats_entry.attr,
636 &queue_stable_writes_entry.attr,
637 &queue_random_entry.attr,
638 &queue_poll_entry.attr,
639 &queue_wc_entry.attr,
640 &queue_fua_entry.attr,
641 &queue_dax_entry.attr,
642 &queue_poll_delay_entry.attr,
643#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
644 &blk_throtl_sample_time_entry.attr,
645#endif
646 &queue_virt_boundary_mask_entry.attr,
647 &queue_dma_alignment_entry.attr,
648 NULL,
649};
650
651/* Request-based queue attributes that are not relevant for bio-based queues. */
652static struct attribute *blk_mq_queue_attrs[] = {
653 &queue_requests_entry.attr,
654 &elv_iosched_entry.attr,
655 &queue_rq_affinity_entry.attr,
656 &queue_io_timeout_entry.attr,
657#ifdef CONFIG_BLK_WBT
658 &queue_wb_lat_entry.attr,
659#endif
660 NULL,
661};
662
663static umode_t queue_attr_visible(struct kobject *kobj, struct attribute *attr,
664 int n)
665{
666 struct gendisk *disk = container_of(kobj, struct gendisk, queue_kobj);
667 struct request_queue *q = disk->queue;
668
669 if ((attr == &queue_max_open_zones_entry.attr ||
670 attr == &queue_max_active_zones_entry.attr) &&
671 !blk_queue_is_zoned(q))
672 return 0;
673
674 return attr->mode;
675}
676
677static umode_t blk_mq_queue_attr_visible(struct kobject *kobj,
678 struct attribute *attr, int n)
679{
680 struct gendisk *disk = container_of(kobj, struct gendisk, queue_kobj);
681 struct request_queue *q = disk->queue;
682
683 if (!queue_is_mq(q))
684 return 0;
685
686 if (attr == &queue_io_timeout_entry.attr && !q->mq_ops->timeout)
687 return 0;
688
689 return attr->mode;
690}
691
692static struct attribute_group queue_attr_group = {
693 .attrs = queue_attrs,
694 .is_visible = queue_attr_visible,
695};
696
697static struct attribute_group blk_mq_queue_attr_group = {
698 .attrs = blk_mq_queue_attrs,
699 .is_visible = blk_mq_queue_attr_visible,
700};
701
702#define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
703
704static ssize_t
705queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
706{
707 struct queue_sysfs_entry *entry = to_queue(attr);
708 struct gendisk *disk = container_of(kobj, struct gendisk, queue_kobj);
709 struct request_queue *q = disk->queue;
710 ssize_t res;
711
712 if (!entry->show)
713 return -EIO;
714 mutex_lock(&q->sysfs_lock);
715 res = entry->show(q, page);
716 mutex_unlock(lock: &q->sysfs_lock);
717 return res;
718}
719
720static ssize_t
721queue_attr_store(struct kobject *kobj, struct attribute *attr,
722 const char *page, size_t length)
723{
724 struct queue_sysfs_entry *entry = to_queue(attr);
725 struct gendisk *disk = container_of(kobj, struct gendisk, queue_kobj);
726 struct request_queue *q = disk->queue;
727 ssize_t res;
728
729 if (!entry->store)
730 return -EIO;
731
732 mutex_lock(&q->sysfs_lock);
733 res = entry->store(q, page, length);
734 mutex_unlock(lock: &q->sysfs_lock);
735 return res;
736}
737
738static const struct sysfs_ops queue_sysfs_ops = {
739 .show = queue_attr_show,
740 .store = queue_attr_store,
741};
742
743static const struct attribute_group *blk_queue_attr_groups[] = {
744 &queue_attr_group,
745 &blk_mq_queue_attr_group,
746 NULL
747};
748
749static void blk_queue_release(struct kobject *kobj)
750{
751 /* nothing to do here, all data is associated with the parent gendisk */
752}
753
754static const struct kobj_type blk_queue_ktype = {
755 .default_groups = blk_queue_attr_groups,
756 .sysfs_ops = &queue_sysfs_ops,
757 .release = blk_queue_release,
758};
759
760static void blk_debugfs_remove(struct gendisk *disk)
761{
762 struct request_queue *q = disk->queue;
763
764 mutex_lock(&q->debugfs_mutex);
765 blk_trace_shutdown(q);
766 debugfs_remove_recursive(dentry: q->debugfs_dir);
767 q->debugfs_dir = NULL;
768 q->sched_debugfs_dir = NULL;
769 q->rqos_debugfs_dir = NULL;
770 mutex_unlock(lock: &q->debugfs_mutex);
771}
772
773/**
774 * blk_register_queue - register a block layer queue with sysfs
775 * @disk: Disk of which the request queue should be registered with sysfs.
776 */
777int blk_register_queue(struct gendisk *disk)
778{
779 struct request_queue *q = disk->queue;
780 int ret;
781
782 mutex_lock(&q->sysfs_dir_lock);
783 kobject_init(kobj: &disk->queue_kobj, ktype: &blk_queue_ktype);
784 ret = kobject_add(kobj: &disk->queue_kobj, parent: &disk_to_dev(disk)->kobj, fmt: "queue");
785 if (ret < 0)
786 goto out_put_queue_kobj;
787
788 if (queue_is_mq(q)) {
789 ret = blk_mq_sysfs_register(disk);
790 if (ret)
791 goto out_put_queue_kobj;
792 }
793 mutex_lock(&q->sysfs_lock);
794
795 mutex_lock(&q->debugfs_mutex);
796 q->debugfs_dir = debugfs_create_dir(name: disk->disk_name, parent: blk_debugfs_root);
797 if (queue_is_mq(q))
798 blk_mq_debugfs_register(q);
799 mutex_unlock(lock: &q->debugfs_mutex);
800
801 ret = disk_register_independent_access_ranges(disk);
802 if (ret)
803 goto out_debugfs_remove;
804
805 if (q->elevator) {
806 ret = elv_register_queue(q, uevent: false);
807 if (ret)
808 goto out_unregister_ia_ranges;
809 }
810
811 ret = blk_crypto_sysfs_register(disk);
812 if (ret)
813 goto out_elv_unregister;
814
815 blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q);
816 wbt_enable_default(disk);
817 blk_throtl_register(disk);
818
819 /* Now everything is ready and send out KOBJ_ADD uevent */
820 kobject_uevent(kobj: &disk->queue_kobj, action: KOBJ_ADD);
821 if (q->elevator)
822 kobject_uevent(kobj: &q->elevator->kobj, action: KOBJ_ADD);
823 mutex_unlock(lock: &q->sysfs_lock);
824 mutex_unlock(lock: &q->sysfs_dir_lock);
825
826 /*
827 * SCSI probing may synchronously create and destroy a lot of
828 * request_queues for non-existent devices. Shutting down a fully
829 * functional queue takes measureable wallclock time as RCU grace
830 * periods are involved. To avoid excessive latency in these
831 * cases, a request_queue starts out in a degraded mode which is
832 * faster to shut down and is made fully functional here as
833 * request_queues for non-existent devices never get registered.
834 */
835 if (!blk_queue_init_done(q)) {
836 blk_queue_flag_set(QUEUE_FLAG_INIT_DONE, q);
837 percpu_ref_switch_to_percpu(ref: &q->q_usage_counter);
838 }
839
840 return ret;
841
842out_elv_unregister:
843 elv_unregister_queue(q);
844out_unregister_ia_ranges:
845 disk_unregister_independent_access_ranges(disk);
846out_debugfs_remove:
847 blk_debugfs_remove(disk);
848 mutex_unlock(lock: &q->sysfs_lock);
849out_put_queue_kobj:
850 kobject_put(kobj: &disk->queue_kobj);
851 mutex_unlock(lock: &q->sysfs_dir_lock);
852 return ret;
853}
854
855/**
856 * blk_unregister_queue - counterpart of blk_register_queue()
857 * @disk: Disk of which the request queue should be unregistered from sysfs.
858 *
859 * Note: the caller is responsible for guaranteeing that this function is called
860 * after blk_register_queue() has finished.
861 */
862void blk_unregister_queue(struct gendisk *disk)
863{
864 struct request_queue *q = disk->queue;
865
866 if (WARN_ON(!q))
867 return;
868
869 /* Return early if disk->queue was never registered. */
870 if (!blk_queue_registered(q))
871 return;
872
873 /*
874 * Since sysfs_remove_dir() prevents adding new directory entries
875 * before removal of existing entries starts, protect against
876 * concurrent elv_iosched_store() calls.
877 */
878 mutex_lock(&q->sysfs_lock);
879 blk_queue_flag_clear(QUEUE_FLAG_REGISTERED, q);
880 mutex_unlock(lock: &q->sysfs_lock);
881
882 mutex_lock(&q->sysfs_dir_lock);
883 /*
884 * Remove the sysfs attributes before unregistering the queue data
885 * structures that can be modified through sysfs.
886 */
887 if (queue_is_mq(q))
888 blk_mq_sysfs_unregister(disk);
889 blk_crypto_sysfs_unregister(disk);
890
891 mutex_lock(&q->sysfs_lock);
892 elv_unregister_queue(q);
893 disk_unregister_independent_access_ranges(disk);
894 mutex_unlock(lock: &q->sysfs_lock);
895
896 /* Now that we've deleted all child objects, we can delete the queue. */
897 kobject_uevent(kobj: &disk->queue_kobj, action: KOBJ_REMOVE);
898 kobject_del(kobj: &disk->queue_kobj);
899 mutex_unlock(lock: &q->sysfs_dir_lock);
900
901 blk_debugfs_remove(disk);
902}
903

source code of linux/block/blk-sysfs.c