Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

Linux/block/blk-sysfs.c

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

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