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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 
 17 struct queue_sysfs_entry {
 18         struct attribute attr;
 19         ssize_t (*show)(struct request_queue *, char *);
 20         ssize_t (*store)(struct request_queue *, const char *, size_t);
 21 };
 22 
 23 static ssize_t
 24 queue_var_show(unsigned long var, char *page)
 25 {
 26         return sprintf(page, "%lu\n", var);
 27 }
 28 
 29 static ssize_t
 30 queue_var_store(unsigned long *var, const char *page, size_t count)
 31 {
 32         int err;
 33         unsigned long v;
 34 
 35         err = kstrtoul(page, 10, &v);
 36         if (err || v > UINT_MAX)
 37                 return -EINVAL;
 38 
 39         *var = v;
 40 
 41         return count;
 42 }
 43 
 44 static ssize_t queue_requests_show(struct request_queue *q, char *page)
 45 {
 46         return queue_var_show(q->nr_requests, (page));
 47 }
 48 
 49 static ssize_t
 50 queue_requests_store(struct request_queue *q, const char *page, size_t count)
 51 {
 52         unsigned long nr;
 53         int ret, err;
 54 
 55         if (!q->request_fn && !q->mq_ops)
 56                 return -EINVAL;
 57 
 58         ret = queue_var_store(&nr, page, count);
 59         if (ret < 0)
 60                 return ret;
 61 
 62         if (nr < BLKDEV_MIN_RQ)
 63                 nr = BLKDEV_MIN_RQ;
 64 
 65         if (q->request_fn)
 66                 err = blk_update_nr_requests(q, nr);
 67         else
 68                 err = blk_mq_update_nr_requests(q, nr);
 69 
 70         if (err)
 71                 return err;
 72 
 73         return ret;
 74 }
 75 
 76 static ssize_t queue_ra_show(struct request_queue *q, char *page)
 77 {
 78         unsigned long ra_kb = q->backing_dev_info.ra_pages <<
 79                                         (PAGE_SHIFT - 10);
 80 
 81         return queue_var_show(ra_kb, (page));
 82 }
 83 
 84 static ssize_t
 85 queue_ra_store(struct request_queue *q, const char *page, size_t count)
 86 {
 87         unsigned long ra_kb;
 88         ssize_t ret = queue_var_store(&ra_kb, page, count);
 89 
 90         if (ret < 0)
 91                 return ret;
 92 
 93         q->backing_dev_info.ra_pages = ra_kb >> (PAGE_SHIFT - 10);
 94 
 95         return ret;
 96 }
 97 
 98 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
 99 {
100         int max_sectors_kb = queue_max_sectors(q) >> 1;
101 
102         return queue_var_show(max_sectors_kb, (page));
103 }
104 
105 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
106 {
107         return queue_var_show(queue_max_segments(q), (page));
108 }
109 
110 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
111 {
112         return queue_var_show(q->limits.max_integrity_segments, (page));
113 }
114 
115 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
116 {
117         if (blk_queue_cluster(q))
118                 return queue_var_show(queue_max_segment_size(q), (page));
119 
120         return queue_var_show(PAGE_SIZE, (page));
121 }
122 
123 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
124 {
125         return queue_var_show(queue_logical_block_size(q), page);
126 }
127 
128 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
129 {
130         return queue_var_show(queue_physical_block_size(q), page);
131 }
132 
133 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
134 {
135         return queue_var_show(queue_io_min(q), page);
136 }
137 
138 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
139 {
140         return queue_var_show(queue_io_opt(q), page);
141 }
142 
143 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
144 {
145         return queue_var_show(q->limits.discard_granularity, page);
146 }
147 
148 static ssize_t queue_discard_max_hw_show(struct request_queue *q, char *page)
149 {
150 
151         return sprintf(page, "%llu\n",
152                 (unsigned long long)q->limits.max_hw_discard_sectors << 9);
153 }
154 
155 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
156 {
157         return sprintf(page, "%llu\n",
158                        (unsigned long long)q->limits.max_discard_sectors << 9);
159 }
160 
161 static ssize_t queue_discard_max_store(struct request_queue *q,
162                                        const char *page, size_t count)
163 {
164         unsigned long max_discard;
165         ssize_t ret = queue_var_store(&max_discard, page, count);
166 
167         if (ret < 0)
168                 return ret;
169 
170         if (max_discard & (q->limits.discard_granularity - 1))
171                 return -EINVAL;
172 
173         max_discard >>= 9;
174         if (max_discard > UINT_MAX)
175                 return -EINVAL;
176 
177         if (max_discard > q->limits.max_hw_discard_sectors)
178                 max_discard = q->limits.max_hw_discard_sectors;
179 
180         q->limits.max_discard_sectors = max_discard;
181         return ret;
182 }
183 
184 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
185 {
186         return queue_var_show(queue_discard_zeroes_data(q), page);
187 }
188 
189 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
190 {
191         return sprintf(page, "%llu\n",
192                 (unsigned long long)q->limits.max_write_same_sectors << 9);
193 }
194 
195 
196 static ssize_t
197 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
198 {
199         unsigned long max_sectors_kb,
200                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
201                         page_kb = 1 << (PAGE_SHIFT - 10);
202         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
203 
204         if (ret < 0)
205                 return ret;
206 
207         max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb, (unsigned long)
208                                          q->limits.max_dev_sectors >> 1);
209 
210         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
211                 return -EINVAL;
212 
213         spin_lock_irq(q->queue_lock);
214         q->limits.max_sectors = max_sectors_kb << 1;
215         spin_unlock_irq(q->queue_lock);
216 
217         return ret;
218 }
219 
220 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
221 {
222         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
223 
224         return queue_var_show(max_hw_sectors_kb, (page));
225 }
226 
227 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
228 static ssize_t                                                          \
229 queue_show_##name(struct request_queue *q, char *page)                  \
230 {                                                                       \
231         int bit;                                                        \
232         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
233         return queue_var_show(neg ? !bit : bit, page);                  \
234 }                                                                       \
235 static ssize_t                                                          \
236 queue_store_##name(struct request_queue *q, const char *page, size_t count) \
237 {                                                                       \
238         unsigned long val;                                              \
239         ssize_t ret;                                                    \
240         ret = queue_var_store(&val, page, count);                       \
241         if (ret < 0)                                                    \
242                  return ret;                                            \
243         if (neg)                                                        \
244                 val = !val;                                             \
245                                                                         \
246         spin_lock_irq(q->queue_lock);                                   \
247         if (val)                                                        \
248                 queue_flag_set(QUEUE_FLAG_##flag, q);                   \
249         else                                                            \
250                 queue_flag_clear(QUEUE_FLAG_##flag, q);                 \
251         spin_unlock_irq(q->queue_lock);                                 \
252         return ret;                                                     \
253 }
254 
255 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
256 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
257 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
258 #undef QUEUE_SYSFS_BIT_FNS
259 
260 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
261 {
262         return queue_var_show((blk_queue_nomerges(q) << 1) |
263                                blk_queue_noxmerges(q), page);
264 }
265 
266 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
267                                     size_t count)
268 {
269         unsigned long nm;
270         ssize_t ret = queue_var_store(&nm, page, count);
271 
272         if (ret < 0)
273                 return ret;
274 
275         spin_lock_irq(q->queue_lock);
276         queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
277         queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
278         if (nm == 2)
279                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
280         else if (nm)
281                 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
282         spin_unlock_irq(q->queue_lock);
283 
284         return ret;
285 }
286 
287 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
288 {
289         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
290         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
291 
292         return queue_var_show(set << force, page);
293 }
294 
295 static ssize_t
296 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
297 {
298         ssize_t ret = -EINVAL;
299 #ifdef CONFIG_SMP
300         unsigned long val;
301 
302         ret = queue_var_store(&val, page, count);
303         if (ret < 0)
304                 return ret;
305 
306         spin_lock_irq(q->queue_lock);
307         if (val == 2) {
308                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
309                 queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
310         } else if (val == 1) {
311                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
312                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
313         } else if (val == 0) {
314                 queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
315                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
316         }
317         spin_unlock_irq(q->queue_lock);
318 #endif
319         return ret;
320 }
321 
322 static ssize_t queue_poll_show(struct request_queue *q, char *page)
323 {
324         return queue_var_show(test_bit(QUEUE_FLAG_POLL, &q->queue_flags), page);
325 }
326 
327 static ssize_t queue_poll_store(struct request_queue *q, const char *page,
328                                 size_t count)
329 {
330         unsigned long poll_on;
331         ssize_t ret;
332 
333         if (!q->mq_ops || !q->mq_ops->poll)
334                 return -EINVAL;
335 
336         ret = queue_var_store(&poll_on, page, count);
337         if (ret < 0)
338                 return ret;
339 
340         spin_lock_irq(q->queue_lock);
341         if (poll_on)
342                 queue_flag_set(QUEUE_FLAG_POLL, q);
343         else
344                 queue_flag_clear(QUEUE_FLAG_POLL, q);
345         spin_unlock_irq(q->queue_lock);
346 
347         return ret;
348 }
349 
350 static ssize_t queue_wc_show(struct request_queue *q, char *page)
351 {
352         if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
353                 return sprintf(page, "write back\n");
354 
355         return sprintf(page, "write through\n");
356 }
357 
358 static ssize_t queue_wc_store(struct request_queue *q, const char *page,
359                               size_t count)
360 {
361         int set = -1;
362 
363         if (!strncmp(page, "write back", 10))
364                 set = 1;
365         else if (!strncmp(page, "write through", 13) ||
366                  !strncmp(page, "none", 4))
367                 set = 0;
368 
369         if (set == -1)
370                 return -EINVAL;
371 
372         spin_lock_irq(q->queue_lock);
373         if (set)
374                 queue_flag_set(QUEUE_FLAG_WC, q);
375         else
376                 queue_flag_clear(QUEUE_FLAG_WC, q);
377         spin_unlock_irq(q->queue_lock);
378 
379         return count;
380 }
381 
382 static struct queue_sysfs_entry queue_requests_entry = {
383         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
384         .show = queue_requests_show,
385         .store = queue_requests_store,
386 };
387 
388 static struct queue_sysfs_entry queue_ra_entry = {
389         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
390         .show = queue_ra_show,
391         .store = queue_ra_store,
392 };
393 
394 static struct queue_sysfs_entry queue_max_sectors_entry = {
395         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
396         .show = queue_max_sectors_show,
397         .store = queue_max_sectors_store,
398 };
399 
400 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
401         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
402         .show = queue_max_hw_sectors_show,
403 };
404 
405 static struct queue_sysfs_entry queue_max_segments_entry = {
406         .attr = {.name = "max_segments", .mode = S_IRUGO },
407         .show = queue_max_segments_show,
408 };
409 
410 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
411         .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
412         .show = queue_max_integrity_segments_show,
413 };
414 
415 static struct queue_sysfs_entry queue_max_segment_size_entry = {
416         .attr = {.name = "max_segment_size", .mode = S_IRUGO },
417         .show = queue_max_segment_size_show,
418 };
419 
420 static struct queue_sysfs_entry queue_iosched_entry = {
421         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
422         .show = elv_iosched_show,
423         .store = elv_iosched_store,
424 };
425 
426 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
427         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
428         .show = queue_logical_block_size_show,
429 };
430 
431 static struct queue_sysfs_entry queue_logical_block_size_entry = {
432         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
433         .show = queue_logical_block_size_show,
434 };
435 
436 static struct queue_sysfs_entry queue_physical_block_size_entry = {
437         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
438         .show = queue_physical_block_size_show,
439 };
440 
441 static struct queue_sysfs_entry queue_io_min_entry = {
442         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
443         .show = queue_io_min_show,
444 };
445 
446 static struct queue_sysfs_entry queue_io_opt_entry = {
447         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
448         .show = queue_io_opt_show,
449 };
450 
451 static struct queue_sysfs_entry queue_discard_granularity_entry = {
452         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
453         .show = queue_discard_granularity_show,
454 };
455 
456 static struct queue_sysfs_entry queue_discard_max_hw_entry = {
457         .attr = {.name = "discard_max_hw_bytes", .mode = S_IRUGO },
458         .show = queue_discard_max_hw_show,
459 };
460 
461 static struct queue_sysfs_entry queue_discard_max_entry = {
462         .attr = {.name = "discard_max_bytes", .mode = S_IRUGO | S_IWUSR },
463         .show = queue_discard_max_show,
464         .store = queue_discard_max_store,
465 };
466 
467 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
468         .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
469         .show = queue_discard_zeroes_data_show,
470 };
471 
472 static struct queue_sysfs_entry queue_write_same_max_entry = {
473         .attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
474         .show = queue_write_same_max_show,
475 };
476 
477 static struct queue_sysfs_entry queue_nonrot_entry = {
478         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
479         .show = queue_show_nonrot,
480         .store = queue_store_nonrot,
481 };
482 
483 static struct queue_sysfs_entry queue_nomerges_entry = {
484         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
485         .show = queue_nomerges_show,
486         .store = queue_nomerges_store,
487 };
488 
489 static struct queue_sysfs_entry queue_rq_affinity_entry = {
490         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
491         .show = queue_rq_affinity_show,
492         .store = queue_rq_affinity_store,
493 };
494 
495 static struct queue_sysfs_entry queue_iostats_entry = {
496         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
497         .show = queue_show_iostats,
498         .store = queue_store_iostats,
499 };
500 
501 static struct queue_sysfs_entry queue_random_entry = {
502         .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
503         .show = queue_show_random,
504         .store = queue_store_random,
505 };
506 
507 static struct queue_sysfs_entry queue_poll_entry = {
508         .attr = {.name = "io_poll", .mode = S_IRUGO | S_IWUSR },
509         .show = queue_poll_show,
510         .store = queue_poll_store,
511 };
512 
513 static struct queue_sysfs_entry queue_wc_entry = {
514         .attr = {.name = "write_cache", .mode = S_IRUGO | S_IWUSR },
515         .show = queue_wc_show,
516         .store = queue_wc_store,
517 };
518 
519 static struct attribute *default_attrs[] = {
520         &queue_requests_entry.attr,
521         &queue_ra_entry.attr,
522         &queue_max_hw_sectors_entry.attr,
523         &queue_max_sectors_entry.attr,
524         &queue_max_segments_entry.attr,
525         &queue_max_integrity_segments_entry.attr,
526         &queue_max_segment_size_entry.attr,
527         &queue_iosched_entry.attr,
528         &queue_hw_sector_size_entry.attr,
529         &queue_logical_block_size_entry.attr,
530         &queue_physical_block_size_entry.attr,
531         &queue_io_min_entry.attr,
532         &queue_io_opt_entry.attr,
533         &queue_discard_granularity_entry.attr,
534         &queue_discard_max_entry.attr,
535         &queue_discard_max_hw_entry.attr,
536         &queue_discard_zeroes_data_entry.attr,
537         &queue_write_same_max_entry.attr,
538         &queue_nonrot_entry.attr,
539         &queue_nomerges_entry.attr,
540         &queue_rq_affinity_entry.attr,
541         &queue_iostats_entry.attr,
542         &queue_random_entry.attr,
543         &queue_poll_entry.attr,
544         &queue_wc_entry.attr,
545         NULL,
546 };
547 
548 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
549 
550 static ssize_t
551 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
552 {
553         struct queue_sysfs_entry *entry = to_queue(attr);
554         struct request_queue *q =
555                 container_of(kobj, struct request_queue, kobj);
556         ssize_t res;
557 
558         if (!entry->show)
559                 return -EIO;
560         mutex_lock(&q->sysfs_lock);
561         if (blk_queue_dying(q)) {
562                 mutex_unlock(&q->sysfs_lock);
563                 return -ENOENT;
564         }
565         res = entry->show(q, page);
566         mutex_unlock(&q->sysfs_lock);
567         return res;
568 }
569 
570 static ssize_t
571 queue_attr_store(struct kobject *kobj, struct attribute *attr,
572                     const char *page, size_t length)
573 {
574         struct queue_sysfs_entry *entry = to_queue(attr);
575         struct request_queue *q;
576         ssize_t res;
577 
578         if (!entry->store)
579                 return -EIO;
580 
581         q = container_of(kobj, struct request_queue, kobj);
582         mutex_lock(&q->sysfs_lock);
583         if (blk_queue_dying(q)) {
584                 mutex_unlock(&q->sysfs_lock);
585                 return -ENOENT;
586         }
587         res = entry->store(q, page, length);
588         mutex_unlock(&q->sysfs_lock);
589         return res;
590 }
591 
592 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
593 {
594         struct request_queue *q = container_of(rcu_head, struct request_queue,
595                                                rcu_head);
596         kmem_cache_free(blk_requestq_cachep, q);
597 }
598 
599 /**
600  * blk_release_queue: - release a &struct request_queue when it is no longer needed
601  * @kobj:    the kobj belonging to the request queue to be released
602  *
603  * Description:
604  *     blk_release_queue is the pair to blk_init_queue() or
605  *     blk_queue_make_request().  It should be called when a request queue is
606  *     being released; typically when a block device is being de-registered.
607  *     Currently, its primary task it to free all the &struct request
608  *     structures that were allocated to the queue and the queue itself.
609  *
610  * Note:
611  *     The low level driver must have finished any outstanding requests first
612  *     via blk_cleanup_queue().
613  **/
614 static void blk_release_queue(struct kobject *kobj)
615 {
616         struct request_queue *q =
617                 container_of(kobj, struct request_queue, kobj);
618 
619         bdi_exit(&q->backing_dev_info);
620         blkcg_exit_queue(q);
621 
622         if (q->elevator) {
623                 spin_lock_irq(q->queue_lock);
624                 ioc_clear_queue(q);
625                 spin_unlock_irq(q->queue_lock);
626                 elevator_exit(q->elevator);
627         }
628 
629         blk_exit_rl(&q->root_rl);
630 
631         if (q->queue_tags)
632                 __blk_queue_free_tags(q);
633 
634         if (!q->mq_ops)
635                 blk_free_flush_queue(q->fq);
636         else
637                 blk_mq_release(q);
638 
639         blk_trace_shutdown(q);
640 
641         if (q->bio_split)
642                 bioset_free(q->bio_split);
643 
644         ida_simple_remove(&blk_queue_ida, q->id);
645         call_rcu(&q->rcu_head, blk_free_queue_rcu);
646 }
647 
648 static const struct sysfs_ops queue_sysfs_ops = {
649         .show   = queue_attr_show,
650         .store  = queue_attr_store,
651 };
652 
653 struct kobj_type blk_queue_ktype = {
654         .sysfs_ops      = &queue_sysfs_ops,
655         .default_attrs  = default_attrs,
656         .release        = blk_release_queue,
657 };
658 
659 int blk_register_queue(struct gendisk *disk)
660 {
661         int ret;
662         struct device *dev = disk_to_dev(disk);
663         struct request_queue *q = disk->queue;
664 
665         if (WARN_ON(!q))
666                 return -ENXIO;
667 
668         /*
669          * SCSI probing may synchronously create and destroy a lot of
670          * request_queues for non-existent devices.  Shutting down a fully
671          * functional queue takes measureable wallclock time as RCU grace
672          * periods are involved.  To avoid excessive latency in these
673          * cases, a request_queue starts out in a degraded mode which is
674          * faster to shut down and is made fully functional here as
675          * request_queues for non-existent devices never get registered.
676          */
677         if (!blk_queue_init_done(q)) {
678                 queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q);
679                 percpu_ref_switch_to_percpu(&q->q_usage_counter);
680                 blk_queue_bypass_end(q);
681         }
682 
683         ret = blk_trace_init_sysfs(dev);
684         if (ret)
685                 return ret;
686 
687         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
688         if (ret < 0) {
689                 blk_trace_remove_sysfs(dev);
690                 return ret;
691         }
692 
693         kobject_uevent(&q->kobj, KOBJ_ADD);
694 
695         if (q->mq_ops)
696                 blk_mq_register_disk(disk);
697 
698         if (!q->request_fn)
699                 return 0;
700 
701         ret = elv_register_queue(q);
702         if (ret) {
703                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
704                 kobject_del(&q->kobj);
705                 blk_trace_remove_sysfs(dev);
706                 kobject_put(&dev->kobj);
707                 return ret;
708         }
709 
710         return 0;
711 }
712 
713 void blk_unregister_queue(struct gendisk *disk)
714 {
715         struct request_queue *q = disk->queue;
716 
717         if (WARN_ON(!q))
718                 return;
719 
720         if (q->mq_ops)
721                 blk_mq_unregister_disk(disk);
722 
723         if (q->request_fn)
724                 elv_unregister_queue(q);
725 
726         kobject_uevent(&q->kobj, KOBJ_REMOVE);
727         kobject_del(&q->kobj);
728         blk_trace_remove_sysfs(disk_to_dev(disk));
729         kobject_put(&disk_to_dev(disk)->kobj);
730 }
731 

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