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TOMOYO Linux Cross Reference
Linux/block/blk-sysfs.c

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

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