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

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

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