GNU Linux-libre 5.10.219-gnu1
[releases.git] / block / blk-sysfs.c
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/blk-mq.h>
13 #include <linux/blk-cgroup.h>
14 #include <linux/debugfs.h>
15
16 #include "blk.h"
17 #include "blk-mq.h"
18 #include "blk-mq-debugfs.h"
19 #include "blk-wbt.h"
20
21 struct queue_sysfs_entry {
22         struct attribute attr;
23         ssize_t (*show)(struct request_queue *, char *);
24         ssize_t (*store)(struct request_queue *, const char *, size_t);
25 };
26
27 static ssize_t
28 queue_var_show(unsigned long var, char *page)
29 {
30         return sprintf(page, "%lu\n", var);
31 }
32
33 static ssize_t
34 queue_var_store(unsigned long *var, const char *page, size_t count)
35 {
36         int err;
37         unsigned long v;
38
39         err = kstrtoul(page, 10, &v);
40         if (err || v > UINT_MAX)
41                 return -EINVAL;
42
43         *var = v;
44
45         return count;
46 }
47
48 static ssize_t queue_var_store64(s64 *var, const char *page)
49 {
50         int err;
51         s64 v;
52
53         err = kstrtos64(page, 10, &v);
54         if (err < 0)
55                 return err;
56
57         *var = v;
58         return 0;
59 }
60
61 static ssize_t queue_requests_show(struct request_queue *q, char *page)
62 {
63         return queue_var_show(q->nr_requests, (page));
64 }
65
66 static ssize_t
67 queue_requests_store(struct request_queue *q, const char *page, size_t count)
68 {
69         unsigned long nr;
70         int ret, err;
71
72         if (!queue_is_mq(q))
73                 return -EINVAL;
74
75         ret = queue_var_store(&nr, page, count);
76         if (ret < 0)
77                 return ret;
78
79         if (nr < BLKDEV_MIN_RQ)
80                 nr = BLKDEV_MIN_RQ;
81
82         err = blk_mq_update_nr_requests(q, nr);
83         if (err)
84                 return err;
85
86         return ret;
87 }
88
89 static ssize_t queue_ra_show(struct request_queue *q, char *page)
90 {
91         unsigned long ra_kb = q->backing_dev_info->ra_pages <<
92                                         (PAGE_SHIFT - 10);
93
94         return queue_var_show(ra_kb, (page));
95 }
96
97 static ssize_t
98 queue_ra_store(struct request_queue *q, const char *page, size_t count)
99 {
100         unsigned long ra_kb;
101         ssize_t ret = queue_var_store(&ra_kb, page, count);
102
103         if (ret < 0)
104                 return ret;
105
106         q->backing_dev_info->ra_pages = ra_kb >> (PAGE_SHIFT - 10);
107
108         return ret;
109 }
110
111 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
112 {
113         int max_sectors_kb = queue_max_sectors(q) >> 1;
114
115         return queue_var_show(max_sectors_kb, (page));
116 }
117
118 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
119 {
120         return queue_var_show(queue_max_segments(q), (page));
121 }
122
123 static ssize_t queue_max_discard_segments_show(struct request_queue *q,
124                 char *page)
125 {
126         return queue_var_show(queue_max_discard_segments(q), (page));
127 }
128
129 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
130 {
131         return queue_var_show(q->limits.max_integrity_segments, (page));
132 }
133
134 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
135 {
136         return queue_var_show(queue_max_segment_size(q), (page));
137 }
138
139 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
140 {
141         return queue_var_show(queue_logical_block_size(q), page);
142 }
143
144 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
145 {
146         return queue_var_show(queue_physical_block_size(q), page);
147 }
148
149 static ssize_t queue_chunk_sectors_show(struct request_queue *q, char *page)
150 {
151         return queue_var_show(q->limits.chunk_sectors, page);
152 }
153
154 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
155 {
156         return queue_var_show(queue_io_min(q), page);
157 }
158
159 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
160 {
161         return queue_var_show(queue_io_opt(q), page);
162 }
163
164 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
165 {
166         return queue_var_show(q->limits.discard_granularity, page);
167 }
168
169 static ssize_t queue_discard_max_hw_show(struct request_queue *q, char *page)
170 {
171
172         return sprintf(page, "%llu\n",
173                 (unsigned long long)q->limits.max_hw_discard_sectors << 9);
174 }
175
176 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
177 {
178         return sprintf(page, "%llu\n",
179                        (unsigned long long)q->limits.max_discard_sectors << 9);
180 }
181
182 static ssize_t queue_discard_max_store(struct request_queue *q,
183                                        const char *page, size_t count)
184 {
185         unsigned long max_discard;
186         ssize_t ret = queue_var_store(&max_discard, page, count);
187
188         if (ret < 0)
189                 return ret;
190
191         if (max_discard & (q->limits.discard_granularity - 1))
192                 return -EINVAL;
193
194         max_discard >>= 9;
195         if (max_discard > UINT_MAX)
196                 return -EINVAL;
197
198         if (max_discard > q->limits.max_hw_discard_sectors)
199                 max_discard = q->limits.max_hw_discard_sectors;
200
201         q->limits.max_discard_sectors = max_discard;
202         return ret;
203 }
204
205 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
206 {
207         return queue_var_show(0, page);
208 }
209
210 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
211 {
212         return sprintf(page, "%llu\n",
213                 (unsigned long long)q->limits.max_write_same_sectors << 9);
214 }
215
216 static ssize_t queue_write_zeroes_max_show(struct request_queue *q, char *page)
217 {
218         return sprintf(page, "%llu\n",
219                 (unsigned long long)q->limits.max_write_zeroes_sectors << 9);
220 }
221
222 static ssize_t queue_zone_write_granularity_show(struct request_queue *q,
223                                                  char *page)
224 {
225         return queue_var_show(queue_zone_write_granularity(q), page);
226 }
227
228 static ssize_t queue_zone_append_max_show(struct request_queue *q, char *page)
229 {
230         unsigned long long max_sectors = q->limits.max_zone_append_sectors;
231
232         return sprintf(page, "%llu\n", max_sectors << SECTOR_SHIFT);
233 }
234
235 static ssize_t
236 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
237 {
238         unsigned long max_sectors_kb,
239                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
240                         page_kb = 1 << (PAGE_SHIFT - 10);
241         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
242
243         if (ret < 0)
244                 return ret;
245
246         max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb, (unsigned long)
247                                          q->limits.max_dev_sectors >> 1);
248
249         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
250                 return -EINVAL;
251
252         spin_lock_irq(&q->queue_lock);
253         q->limits.max_sectors = max_sectors_kb << 1;
254         q->backing_dev_info->io_pages = max_sectors_kb >> (PAGE_SHIFT - 10);
255         spin_unlock_irq(&q->queue_lock);
256
257         return ret;
258 }
259
260 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
261 {
262         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
263
264         return queue_var_show(max_hw_sectors_kb, (page));
265 }
266
267 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
268 static ssize_t                                                          \
269 queue_##name##_show(struct request_queue *q, char *page)                \
270 {                                                                       \
271         int bit;                                                        \
272         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
273         return queue_var_show(neg ? !bit : bit, page);                  \
274 }                                                                       \
275 static ssize_t                                                          \
276 queue_##name##_store(struct request_queue *q, const char *page, size_t count) \
277 {                                                                       \
278         unsigned long val;                                              \
279         ssize_t ret;                                                    \
280         ret = queue_var_store(&val, page, count);                       \
281         if (ret < 0)                                                    \
282                  return ret;                                            \
283         if (neg)                                                        \
284                 val = !val;                                             \
285                                                                         \
286         if (val)                                                        \
287                 blk_queue_flag_set(QUEUE_FLAG_##flag, q);               \
288         else                                                            \
289                 blk_queue_flag_clear(QUEUE_FLAG_##flag, q);             \
290         return ret;                                                     \
291 }
292
293 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
294 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
295 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
296 QUEUE_SYSFS_BIT_FNS(stable_writes, STABLE_WRITES, 0);
297 #undef QUEUE_SYSFS_BIT_FNS
298
299 static ssize_t queue_zoned_show(struct request_queue *q, char *page)
300 {
301         switch (blk_queue_zoned_model(q)) {
302         case BLK_ZONED_HA:
303                 return sprintf(page, "host-aware\n");
304         case BLK_ZONED_HM:
305                 return sprintf(page, "host-managed\n");
306         default:
307                 return sprintf(page, "none\n");
308         }
309 }
310
311 static ssize_t queue_nr_zones_show(struct request_queue *q, char *page)
312 {
313         return queue_var_show(blk_queue_nr_zones(q), page);
314 }
315
316 static ssize_t queue_max_open_zones_show(struct request_queue *q, char *page)
317 {
318         return queue_var_show(queue_max_open_zones(q), page);
319 }
320
321 static ssize_t queue_max_active_zones_show(struct request_queue *q, char *page)
322 {
323         return queue_var_show(queue_max_active_zones(q), page);
324 }
325
326 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
327 {
328         return queue_var_show((blk_queue_nomerges(q) << 1) |
329                                blk_queue_noxmerges(q), page);
330 }
331
332 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
333                                     size_t count)
334 {
335         unsigned long nm;
336         ssize_t ret = queue_var_store(&nm, page, count);
337
338         if (ret < 0)
339                 return ret;
340
341         blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
342         blk_queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
343         if (nm == 2)
344                 blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q);
345         else if (nm)
346                 blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
347
348         return ret;
349 }
350
351 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
352 {
353         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
354         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
355
356         return queue_var_show(set << force, page);
357 }
358
359 static ssize_t
360 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
361 {
362         ssize_t ret = -EINVAL;
363 #ifdef CONFIG_SMP
364         unsigned long val;
365
366         ret = queue_var_store(&val, page, count);
367         if (ret < 0)
368                 return ret;
369
370         if (val == 2) {
371                 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
372                 blk_queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
373         } else if (val == 1) {
374                 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
375                 blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
376         } else if (val == 0) {
377                 blk_queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
378                 blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
379         }
380 #endif
381         return ret;
382 }
383
384 static ssize_t queue_poll_delay_show(struct request_queue *q, char *page)
385 {
386         int val;
387
388         if (q->poll_nsec == BLK_MQ_POLL_CLASSIC)
389                 val = BLK_MQ_POLL_CLASSIC;
390         else
391                 val = q->poll_nsec / 1000;
392
393         return sprintf(page, "%d\n", val);
394 }
395
396 static ssize_t queue_poll_delay_store(struct request_queue *q, const char *page,
397                                 size_t count)
398 {
399         int err, val;
400
401         if (!q->mq_ops || !q->mq_ops->poll)
402                 return -EINVAL;
403
404         err = kstrtoint(page, 10, &val);
405         if (err < 0)
406                 return err;
407
408         if (val == BLK_MQ_POLL_CLASSIC)
409                 q->poll_nsec = BLK_MQ_POLL_CLASSIC;
410         else if (val >= 0)
411                 q->poll_nsec = val * 1000;
412         else
413                 return -EINVAL;
414
415         return count;
416 }
417
418 static ssize_t queue_poll_show(struct request_queue *q, char *page)
419 {
420         return queue_var_show(test_bit(QUEUE_FLAG_POLL, &q->queue_flags), page);
421 }
422
423 static ssize_t queue_poll_store(struct request_queue *q, const char *page,
424                                 size_t count)
425 {
426         unsigned long poll_on;
427         ssize_t ret;
428
429         if (!q->tag_set || q->tag_set->nr_maps <= HCTX_TYPE_POLL ||
430             !q->tag_set->map[HCTX_TYPE_POLL].nr_queues)
431                 return -EINVAL;
432
433         ret = queue_var_store(&poll_on, page, count);
434         if (ret < 0)
435                 return ret;
436
437         if (poll_on)
438                 blk_queue_flag_set(QUEUE_FLAG_POLL, q);
439         else
440                 blk_queue_flag_clear(QUEUE_FLAG_POLL, q);
441
442         return ret;
443 }
444
445 static ssize_t queue_io_timeout_show(struct request_queue *q, char *page)
446 {
447         return sprintf(page, "%u\n", jiffies_to_msecs(q->rq_timeout));
448 }
449
450 static ssize_t queue_io_timeout_store(struct request_queue *q, const char *page,
451                                   size_t count)
452 {
453         unsigned int val;
454         int err;
455
456         err = kstrtou32(page, 10, &val);
457         if (err || val == 0)
458                 return -EINVAL;
459
460         blk_queue_rq_timeout(q, msecs_to_jiffies(val));
461
462         return count;
463 }
464
465 static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
466 {
467         if (!wbt_rq_qos(q))
468                 return -EINVAL;
469
470         return sprintf(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000));
471 }
472
473 static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
474                                   size_t count)
475 {
476         struct rq_qos *rqos;
477         ssize_t ret;
478         s64 val;
479
480         ret = queue_var_store64(&val, page);
481         if (ret < 0)
482                 return ret;
483         if (val < -1)
484                 return -EINVAL;
485
486         rqos = wbt_rq_qos(q);
487         if (!rqos) {
488                 ret = wbt_init(q);
489                 if (ret)
490                         return ret;
491         }
492
493         if (val == -1)
494                 val = wbt_default_latency_nsec(q);
495         else if (val >= 0)
496                 val *= 1000ULL;
497
498         if (wbt_get_min_lat(q) == val)
499                 return count;
500
501         /*
502          * Ensure that the queue is idled, in case the latency update
503          * ends up either enabling or disabling wbt completely. We can't
504          * have IO inflight if that happens.
505          */
506         blk_mq_freeze_queue(q);
507         blk_mq_quiesce_queue(q);
508
509         wbt_set_min_lat(q, val);
510
511         blk_mq_unquiesce_queue(q);
512         blk_mq_unfreeze_queue(q);
513
514         return count;
515 }
516
517 static ssize_t queue_wc_show(struct request_queue *q, char *page)
518 {
519         if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
520                 return sprintf(page, "write back\n");
521
522         return sprintf(page, "write through\n");
523 }
524
525 static ssize_t queue_wc_store(struct request_queue *q, const char *page,
526                               size_t count)
527 {
528         int set = -1;
529
530         if (!strncmp(page, "write back", 10))
531                 set = 1;
532         else if (!strncmp(page, "write through", 13) ||
533                  !strncmp(page, "none", 4))
534                 set = 0;
535
536         if (set == -1)
537                 return -EINVAL;
538
539         if (set)
540                 blk_queue_flag_set(QUEUE_FLAG_WC, q);
541         else
542                 blk_queue_flag_clear(QUEUE_FLAG_WC, q);
543
544         return count;
545 }
546
547 static ssize_t queue_fua_show(struct request_queue *q, char *page)
548 {
549         return sprintf(page, "%u\n", test_bit(QUEUE_FLAG_FUA, &q->queue_flags));
550 }
551
552 static ssize_t queue_dax_show(struct request_queue *q, char *page)
553 {
554         return queue_var_show(blk_queue_dax(q), page);
555 }
556
557 #define QUEUE_RO_ENTRY(_prefix, _name)                  \
558 static struct queue_sysfs_entry _prefix##_entry = {     \
559         .attr   = { .name = _name, .mode = 0444 },      \
560         .show   = _prefix##_show,                       \
561 };
562
563 #define QUEUE_RW_ENTRY(_prefix, _name)                  \
564 static struct queue_sysfs_entry _prefix##_entry = {     \
565         .attr   = { .name = _name, .mode = 0644 },      \
566         .show   = _prefix##_show,                       \
567         .store  = _prefix##_store,                      \
568 };
569
570 QUEUE_RW_ENTRY(queue_requests, "nr_requests");
571 QUEUE_RW_ENTRY(queue_ra, "read_ahead_kb");
572 QUEUE_RW_ENTRY(queue_max_sectors, "max_sectors_kb");
573 QUEUE_RO_ENTRY(queue_max_hw_sectors, "max_hw_sectors_kb");
574 QUEUE_RO_ENTRY(queue_max_segments, "max_segments");
575 QUEUE_RO_ENTRY(queue_max_integrity_segments, "max_integrity_segments");
576 QUEUE_RO_ENTRY(queue_max_segment_size, "max_segment_size");
577 QUEUE_RW_ENTRY(elv_iosched, "scheduler");
578
579 QUEUE_RO_ENTRY(queue_logical_block_size, "logical_block_size");
580 QUEUE_RO_ENTRY(queue_physical_block_size, "physical_block_size");
581 QUEUE_RO_ENTRY(queue_chunk_sectors, "chunk_sectors");
582 QUEUE_RO_ENTRY(queue_io_min, "minimum_io_size");
583 QUEUE_RO_ENTRY(queue_io_opt, "optimal_io_size");
584
585 QUEUE_RO_ENTRY(queue_max_discard_segments, "max_discard_segments");
586 QUEUE_RO_ENTRY(queue_discard_granularity, "discard_granularity");
587 QUEUE_RO_ENTRY(queue_discard_max_hw, "discard_max_hw_bytes");
588 QUEUE_RW_ENTRY(queue_discard_max, "discard_max_bytes");
589 QUEUE_RO_ENTRY(queue_discard_zeroes_data, "discard_zeroes_data");
590
591 QUEUE_RO_ENTRY(queue_write_same_max, "write_same_max_bytes");
592 QUEUE_RO_ENTRY(queue_write_zeroes_max, "write_zeroes_max_bytes");
593 QUEUE_RO_ENTRY(queue_zone_append_max, "zone_append_max_bytes");
594 QUEUE_RO_ENTRY(queue_zone_write_granularity, "zone_write_granularity");
595
596 QUEUE_RO_ENTRY(queue_zoned, "zoned");
597 QUEUE_RO_ENTRY(queue_nr_zones, "nr_zones");
598 QUEUE_RO_ENTRY(queue_max_open_zones, "max_open_zones");
599 QUEUE_RO_ENTRY(queue_max_active_zones, "max_active_zones");
600
601 QUEUE_RW_ENTRY(queue_nomerges, "nomerges");
602 QUEUE_RW_ENTRY(queue_rq_affinity, "rq_affinity");
603 QUEUE_RW_ENTRY(queue_poll, "io_poll");
604 QUEUE_RW_ENTRY(queue_poll_delay, "io_poll_delay");
605 QUEUE_RW_ENTRY(queue_wc, "write_cache");
606 QUEUE_RO_ENTRY(queue_fua, "fua");
607 QUEUE_RO_ENTRY(queue_dax, "dax");
608 QUEUE_RW_ENTRY(queue_io_timeout, "io_timeout");
609 QUEUE_RW_ENTRY(queue_wb_lat, "wbt_lat_usec");
610
611 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
612 QUEUE_RW_ENTRY(blk_throtl_sample_time, "throttle_sample_time");
613 #endif
614
615 /* legacy alias for logical_block_size: */
616 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
617         .attr = {.name = "hw_sector_size", .mode = 0444 },
618         .show = queue_logical_block_size_show,
619 };
620
621 QUEUE_RW_ENTRY(queue_nonrot, "rotational");
622 QUEUE_RW_ENTRY(queue_iostats, "iostats");
623 QUEUE_RW_ENTRY(queue_random, "add_random");
624 QUEUE_RW_ENTRY(queue_stable_writes, "stable_writes");
625
626 static struct attribute *queue_attrs[] = {
627         &queue_requests_entry.attr,
628         &queue_ra_entry.attr,
629         &queue_max_hw_sectors_entry.attr,
630         &queue_max_sectors_entry.attr,
631         &queue_max_segments_entry.attr,
632         &queue_max_discard_segments_entry.attr,
633         &queue_max_integrity_segments_entry.attr,
634         &queue_max_segment_size_entry.attr,
635         &elv_iosched_entry.attr,
636         &queue_hw_sector_size_entry.attr,
637         &queue_logical_block_size_entry.attr,
638         &queue_physical_block_size_entry.attr,
639         &queue_chunk_sectors_entry.attr,
640         &queue_io_min_entry.attr,
641         &queue_io_opt_entry.attr,
642         &queue_discard_granularity_entry.attr,
643         &queue_discard_max_entry.attr,
644         &queue_discard_max_hw_entry.attr,
645         &queue_discard_zeroes_data_entry.attr,
646         &queue_write_same_max_entry.attr,
647         &queue_write_zeroes_max_entry.attr,
648         &queue_zone_append_max_entry.attr,
649         &queue_zone_write_granularity_entry.attr,
650         &queue_nonrot_entry.attr,
651         &queue_zoned_entry.attr,
652         &queue_nr_zones_entry.attr,
653         &queue_max_open_zones_entry.attr,
654         &queue_max_active_zones_entry.attr,
655         &queue_nomerges_entry.attr,
656         &queue_rq_affinity_entry.attr,
657         &queue_iostats_entry.attr,
658         &queue_stable_writes_entry.attr,
659         &queue_random_entry.attr,
660         &queue_poll_entry.attr,
661         &queue_wc_entry.attr,
662         &queue_fua_entry.attr,
663         &queue_dax_entry.attr,
664         &queue_wb_lat_entry.attr,
665         &queue_poll_delay_entry.attr,
666         &queue_io_timeout_entry.attr,
667 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
668         &blk_throtl_sample_time_entry.attr,
669 #endif
670         NULL,
671 };
672
673 static umode_t queue_attr_visible(struct kobject *kobj, struct attribute *attr,
674                                 int n)
675 {
676         struct request_queue *q =
677                 container_of(kobj, struct request_queue, kobj);
678
679         if (attr == &queue_io_timeout_entry.attr &&
680                 (!q->mq_ops || !q->mq_ops->timeout))
681                         return 0;
682
683         if ((attr == &queue_max_open_zones_entry.attr ||
684              attr == &queue_max_active_zones_entry.attr) &&
685             !blk_queue_is_zoned(q))
686                 return 0;
687
688         return attr->mode;
689 }
690
691 static struct attribute_group queue_attr_group = {
692         .attrs = queue_attrs,
693         .is_visible = queue_attr_visible,
694 };
695
696
697 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
698
699 static ssize_t
700 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
701 {
702         struct queue_sysfs_entry *entry = to_queue(attr);
703         struct request_queue *q =
704                 container_of(kobj, struct request_queue, kobj);
705         ssize_t res;
706
707         if (!entry->show)
708                 return -EIO;
709         mutex_lock(&q->sysfs_lock);
710         res = entry->show(q, page);
711         mutex_unlock(&q->sysfs_lock);
712         return res;
713 }
714
715 static ssize_t
716 queue_attr_store(struct kobject *kobj, struct attribute *attr,
717                     const char *page, size_t length)
718 {
719         struct queue_sysfs_entry *entry = to_queue(attr);
720         struct request_queue *q;
721         ssize_t res;
722
723         if (!entry->store)
724                 return -EIO;
725
726         q = container_of(kobj, struct request_queue, kobj);
727         mutex_lock(&q->sysfs_lock);
728         res = entry->store(q, page, length);
729         mutex_unlock(&q->sysfs_lock);
730         return res;
731 }
732
733 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
734 {
735         struct request_queue *q = container_of(rcu_head, struct request_queue,
736                                                rcu_head);
737
738         percpu_ref_exit(&q->q_usage_counter);
739         kmem_cache_free(blk_requestq_cachep, q);
740 }
741
742 /* Unconfigure the I/O scheduler and dissociate from the cgroup controller. */
743 static void blk_exit_queue(struct request_queue *q)
744 {
745         /*
746          * Since the I/O scheduler exit code may access cgroup information,
747          * perform I/O scheduler exit before disassociating from the block
748          * cgroup controller.
749          */
750         if (q->elevator) {
751                 ioc_clear_queue(q);
752                 __elevator_exit(q, q->elevator);
753         }
754
755         /*
756          * Remove all references to @q from the block cgroup controller before
757          * restoring @q->queue_lock to avoid that restoring this pointer causes
758          * e.g. blkcg_print_blkgs() to crash.
759          */
760         blkcg_exit_queue(q);
761
762         /*
763          * Since the cgroup code may dereference the @q->backing_dev_info
764          * pointer, only decrease its reference count after having removed the
765          * association with the block cgroup controller.
766          */
767         bdi_put(q->backing_dev_info);
768 }
769
770 /**
771  * blk_release_queue - releases all allocated resources of the request_queue
772  * @kobj: pointer to a kobject, whose container is a request_queue
773  *
774  * This function releases all allocated resources of the request queue.
775  *
776  * The struct request_queue refcount is incremented with blk_get_queue() and
777  * decremented with blk_put_queue(). Once the refcount reaches 0 this function
778  * is called.
779  *
780  * For drivers that have a request_queue on a gendisk and added with
781  * __device_add_disk() the refcount to request_queue will reach 0 with
782  * the last put_disk() called by the driver. For drivers which don't use
783  * __device_add_disk() this happens with blk_cleanup_queue().
784  *
785  * Drivers exist which depend on the release of the request_queue to be
786  * synchronous, it should not be deferred.
787  *
788  * Context: can sleep
789  */
790 static void blk_release_queue(struct kobject *kobj)
791 {
792         struct request_queue *q =
793                 container_of(kobj, struct request_queue, kobj);
794
795         might_sleep();
796
797         if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags))
798                 blk_stat_remove_callback(q, q->poll_cb);
799         blk_stat_free_callback(q->poll_cb);
800
801         blk_free_queue_stats(q->stats);
802
803         if (queue_is_mq(q)) {
804                 struct blk_mq_hw_ctx *hctx;
805                 int i;
806
807                 cancel_delayed_work_sync(&q->requeue_work);
808
809                 queue_for_each_hw_ctx(q, hctx, i)
810                         cancel_delayed_work_sync(&hctx->run_work);
811         }
812
813         blk_exit_queue(q);
814
815         blk_queue_free_zone_bitmaps(q);
816
817         if (queue_is_mq(q))
818                 blk_mq_release(q);
819
820         blk_trace_shutdown(q);
821         mutex_lock(&q->debugfs_mutex);
822         debugfs_remove_recursive(q->debugfs_dir);
823         mutex_unlock(&q->debugfs_mutex);
824
825         if (queue_is_mq(q))
826                 blk_mq_debugfs_unregister(q);
827
828         bioset_exit(&q->bio_split);
829
830         ida_simple_remove(&blk_queue_ida, q->id);
831         call_rcu(&q->rcu_head, blk_free_queue_rcu);
832 }
833
834 static const struct sysfs_ops queue_sysfs_ops = {
835         .show   = queue_attr_show,
836         .store  = queue_attr_store,
837 };
838
839 struct kobj_type blk_queue_ktype = {
840         .sysfs_ops      = &queue_sysfs_ops,
841         .release        = blk_release_queue,
842 };
843
844 /**
845  * blk_register_queue - register a block layer queue with sysfs
846  * @disk: Disk of which the request queue should be registered with sysfs.
847  */
848 int blk_register_queue(struct gendisk *disk)
849 {
850         int ret;
851         struct device *dev = disk_to_dev(disk);
852         struct request_queue *q = disk->queue;
853
854         if (WARN_ON(!q))
855                 return -ENXIO;
856
857         WARN_ONCE(blk_queue_registered(q),
858                   "%s is registering an already registered queue\n",
859                   kobject_name(&dev->kobj));
860
861         /*
862          * SCSI probing may synchronously create and destroy a lot of
863          * request_queues for non-existent devices.  Shutting down a fully
864          * functional queue takes measureable wallclock time as RCU grace
865          * periods are involved.  To avoid excessive latency in these
866          * cases, a request_queue starts out in a degraded mode which is
867          * faster to shut down and is made fully functional here as
868          * request_queues for non-existent devices never get registered.
869          */
870         if (!blk_queue_init_done(q)) {
871                 blk_queue_flag_set(QUEUE_FLAG_INIT_DONE, q);
872                 percpu_ref_switch_to_percpu(&q->q_usage_counter);
873         }
874
875         blk_queue_update_readahead(q);
876
877         ret = blk_trace_init_sysfs(dev);
878         if (ret)
879                 return ret;
880
881         mutex_lock(&q->sysfs_dir_lock);
882
883         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
884         if (ret < 0) {
885                 blk_trace_remove_sysfs(dev);
886                 goto unlock;
887         }
888
889         ret = sysfs_create_group(&q->kobj, &queue_attr_group);
890         if (ret) {
891                 blk_trace_remove_sysfs(dev);
892                 kobject_del(&q->kobj);
893                 kobject_put(&dev->kobj);
894                 goto unlock;
895         }
896
897         mutex_lock(&q->debugfs_mutex);
898         q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
899                                             blk_debugfs_root);
900         mutex_unlock(&q->debugfs_mutex);
901
902         if (queue_is_mq(q)) {
903                 __blk_mq_register_dev(dev, q);
904                 blk_mq_debugfs_register(q);
905         }
906
907         mutex_lock(&q->sysfs_lock);
908         if (q->elevator) {
909                 ret = elv_register_queue(q, false);
910                 if (ret) {
911                         mutex_unlock(&q->sysfs_lock);
912                         mutex_unlock(&q->sysfs_dir_lock);
913                         kobject_del(&q->kobj);
914                         blk_trace_remove_sysfs(dev);
915                         kobject_put(&dev->kobj);
916                         return ret;
917                 }
918         }
919
920         blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q);
921         wbt_enable_default(q);
922         blk_throtl_register_queue(q);
923
924         /* Now everything is ready and send out KOBJ_ADD uevent */
925         kobject_uevent(&q->kobj, KOBJ_ADD);
926         if (q->elevator)
927                 kobject_uevent(&q->elevator->kobj, KOBJ_ADD);
928         mutex_unlock(&q->sysfs_lock);
929
930         ret = 0;
931 unlock:
932         mutex_unlock(&q->sysfs_dir_lock);
933         return ret;
934 }
935 EXPORT_SYMBOL_GPL(blk_register_queue);
936
937 /**
938  * blk_unregister_queue - counterpart of blk_register_queue()
939  * @disk: Disk of which the request queue should be unregistered from sysfs.
940  *
941  * Note: the caller is responsible for guaranteeing that this function is called
942  * after blk_register_queue() has finished.
943  */
944 void blk_unregister_queue(struct gendisk *disk)
945 {
946         struct request_queue *q = disk->queue;
947
948         if (WARN_ON(!q))
949                 return;
950
951         /* Return early if disk->queue was never registered. */
952         if (!blk_queue_registered(q))
953                 return;
954
955         /*
956          * Since sysfs_remove_dir() prevents adding new directory entries
957          * before removal of existing entries starts, protect against
958          * concurrent elv_iosched_store() calls.
959          */
960         mutex_lock(&q->sysfs_lock);
961         blk_queue_flag_clear(QUEUE_FLAG_REGISTERED, q);
962         mutex_unlock(&q->sysfs_lock);
963
964         mutex_lock(&q->sysfs_dir_lock);
965         /*
966          * Remove the sysfs attributes before unregistering the queue data
967          * structures that can be modified through sysfs.
968          */
969         if (queue_is_mq(q))
970                 blk_mq_unregister_dev(disk_to_dev(disk), q);
971         blk_trace_remove_sysfs(disk_to_dev(disk));
972
973         mutex_lock(&q->sysfs_lock);
974         if (q->elevator)
975                 elv_unregister_queue(q);
976         mutex_unlock(&q->sysfs_lock);
977
978         /* Now that we've deleted all child objects, we can delete the queue. */
979         kobject_uevent(&q->kobj, KOBJ_REMOVE);
980         kobject_del(&q->kobj);
981
982         mutex_unlock(&q->sysfs_dir_lock);
983
984         kobject_put(&disk_to_dev(disk)->kobj);
985 }