1 // SPDX-License-Identifier: GPL-2.0
3 * Functions related to sysfs handling
5 #include <linux/kernel.h>
6 #include <linux/slab.h>
7 #include <linux/module.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>
17 #include "blk-mq-debugfs.h"
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);
27 queue_var_show(unsigned long var, char *page)
29 return sprintf(page, "%lu\n", var);
33 queue_var_store(unsigned long *var, const char *page, size_t count)
38 err = kstrtoul(page, 10, &v);
39 if (err || v > UINT_MAX)
47 static ssize_t queue_var_store64(s64 *var, const char *page)
52 err = kstrtos64(page, 10, &v);
60 static ssize_t queue_requests_show(struct request_queue *q, char *page)
62 return queue_var_show(q->nr_requests, (page));
66 queue_requests_store(struct request_queue *q, const char *page, size_t count)
74 ret = queue_var_store(&nr, page, count);
78 if (nr < BLKDEV_MIN_RQ)
81 err = blk_mq_update_nr_requests(q, nr);
88 static ssize_t queue_ra_show(struct request_queue *q, char *page)
90 unsigned long ra_kb = q->backing_dev_info->ra_pages <<
93 return queue_var_show(ra_kb, (page));
97 queue_ra_store(struct request_queue *q, const char *page, size_t count)
100 ssize_t ret = queue_var_store(&ra_kb, page, count);
105 q->backing_dev_info->ra_pages = ra_kb >> (PAGE_SHIFT - 10);
110 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
112 int max_sectors_kb = queue_max_sectors(q) >> 1;
114 return queue_var_show(max_sectors_kb, (page));
117 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
119 return queue_var_show(queue_max_segments(q), (page));
122 static ssize_t queue_max_discard_segments_show(struct request_queue *q,
125 return queue_var_show(queue_max_discard_segments(q), (page));
128 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
130 return queue_var_show(q->limits.max_integrity_segments, (page));
133 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
135 return queue_var_show(queue_max_segment_size(q), (page));
138 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
140 return queue_var_show(queue_logical_block_size(q), page);
143 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
145 return queue_var_show(queue_physical_block_size(q), page);
148 static ssize_t queue_chunk_sectors_show(struct request_queue *q, char *page)
150 return queue_var_show(q->limits.chunk_sectors, page);
153 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
155 return queue_var_show(queue_io_min(q), page);
158 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
160 return queue_var_show(queue_io_opt(q), page);
163 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
165 return queue_var_show(q->limits.discard_granularity, page);
168 static ssize_t queue_discard_max_hw_show(struct request_queue *q, char *page)
171 return sprintf(page, "%llu\n",
172 (unsigned long long)q->limits.max_hw_discard_sectors << 9);
175 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
177 return sprintf(page, "%llu\n",
178 (unsigned long long)q->limits.max_discard_sectors << 9);
181 static ssize_t queue_discard_max_store(struct request_queue *q,
182 const char *page, size_t count)
184 unsigned long max_discard;
185 ssize_t ret = queue_var_store(&max_discard, page, count);
190 if (max_discard & (q->limits.discard_granularity - 1))
194 if (max_discard > UINT_MAX)
197 if (max_discard > q->limits.max_hw_discard_sectors)
198 max_discard = q->limits.max_hw_discard_sectors;
200 q->limits.max_discard_sectors = max_discard;
204 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
206 return queue_var_show(0, page);
209 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
211 return sprintf(page, "%llu\n",
212 (unsigned long long)q->limits.max_write_same_sectors << 9);
215 static ssize_t queue_write_zeroes_max_show(struct request_queue *q, char *page)
217 return sprintf(page, "%llu\n",
218 (unsigned long long)q->limits.max_write_zeroes_sectors << 9);
222 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
224 unsigned long max_sectors_kb,
225 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
226 page_kb = 1 << (PAGE_SHIFT - 10);
227 ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
232 max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb, (unsigned long)
233 q->limits.max_dev_sectors >> 1);
235 if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
238 spin_lock_irq(&q->queue_lock);
239 q->limits.max_sectors = max_sectors_kb << 1;
240 q->backing_dev_info->io_pages = max_sectors_kb >> (PAGE_SHIFT - 10);
241 spin_unlock_irq(&q->queue_lock);
246 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
248 int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
250 return queue_var_show(max_hw_sectors_kb, (page));
253 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg) \
255 queue_show_##name(struct request_queue *q, char *page) \
258 bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags); \
259 return queue_var_show(neg ? !bit : bit, page); \
262 queue_store_##name(struct request_queue *q, const char *page, size_t count) \
266 ret = queue_var_store(&val, page, count); \
273 blk_queue_flag_set(QUEUE_FLAG_##flag, q); \
275 blk_queue_flag_clear(QUEUE_FLAG_##flag, q); \
279 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
280 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
281 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
282 #undef QUEUE_SYSFS_BIT_FNS
284 static ssize_t queue_zoned_show(struct request_queue *q, char *page)
286 switch (blk_queue_zoned_model(q)) {
288 return sprintf(page, "host-aware\n");
290 return sprintf(page, "host-managed\n");
292 return sprintf(page, "none\n");
296 static ssize_t queue_nr_zones_show(struct request_queue *q, char *page)
298 return queue_var_show(blk_queue_nr_zones(q), page);
301 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
303 return queue_var_show((blk_queue_nomerges(q) << 1) |
304 blk_queue_noxmerges(q), page);
307 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
311 ssize_t ret = queue_var_store(&nm, page, count);
316 blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
317 blk_queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
319 blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q);
321 blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
326 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
328 bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
329 bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
331 return queue_var_show(set << force, page);
335 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
337 ssize_t ret = -EINVAL;
341 ret = queue_var_store(&val, page, count);
346 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
347 blk_queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
348 } else if (val == 1) {
349 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
350 blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
351 } else if (val == 0) {
352 blk_queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
353 blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
359 static ssize_t queue_poll_delay_show(struct request_queue *q, char *page)
363 if (q->poll_nsec == -1)
366 val = q->poll_nsec / 1000;
368 return sprintf(page, "%d\n", val);
371 static ssize_t queue_poll_delay_store(struct request_queue *q, const char *page,
376 if (!q->mq_ops || !q->mq_ops->poll)
379 err = kstrtoint(page, 10, &val);
386 q->poll_nsec = val * 1000;
391 static ssize_t queue_poll_show(struct request_queue *q, char *page)
393 return queue_var_show(test_bit(QUEUE_FLAG_POLL, &q->queue_flags), page);
396 static ssize_t queue_poll_store(struct request_queue *q, const char *page,
399 unsigned long poll_on;
402 if (!q->tag_set || q->tag_set->nr_maps <= HCTX_TYPE_POLL ||
403 !q->tag_set->map[HCTX_TYPE_POLL].nr_queues)
406 ret = queue_var_store(&poll_on, page, count);
411 blk_queue_flag_set(QUEUE_FLAG_POLL, q);
413 blk_queue_flag_clear(QUEUE_FLAG_POLL, q);
418 static ssize_t queue_io_timeout_show(struct request_queue *q, char *page)
420 return sprintf(page, "%u\n", jiffies_to_msecs(q->rq_timeout));
423 static ssize_t queue_io_timeout_store(struct request_queue *q, const char *page,
429 err = kstrtou32(page, 10, &val);
433 blk_queue_rq_timeout(q, msecs_to_jiffies(val));
438 static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
443 return sprintf(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000));
446 static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
453 ret = queue_var_store64(&val, page);
459 rqos = wbt_rq_qos(q);
467 val = wbt_default_latency_nsec(q);
471 if (wbt_get_min_lat(q) == val)
475 * Ensure that the queue is idled, in case the latency update
476 * ends up either enabling or disabling wbt completely. We can't
477 * have IO inflight if that happens.
479 blk_mq_freeze_queue(q);
480 blk_mq_quiesce_queue(q);
482 wbt_set_min_lat(q, val);
483 wbt_update_limits(q);
485 blk_mq_unquiesce_queue(q);
486 blk_mq_unfreeze_queue(q);
491 static ssize_t queue_wc_show(struct request_queue *q, char *page)
493 if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
494 return sprintf(page, "write back\n");
496 return sprintf(page, "write through\n");
499 static ssize_t queue_wc_store(struct request_queue *q, const char *page,
504 if (!strncmp(page, "write back", 10))
506 else if (!strncmp(page, "write through", 13) ||
507 !strncmp(page, "none", 4))
514 blk_queue_flag_set(QUEUE_FLAG_WC, q);
516 blk_queue_flag_clear(QUEUE_FLAG_WC, q);
521 static ssize_t queue_fua_show(struct request_queue *q, char *page)
523 return sprintf(page, "%u\n", test_bit(QUEUE_FLAG_FUA, &q->queue_flags));
526 static ssize_t queue_dax_show(struct request_queue *q, char *page)
528 return queue_var_show(blk_queue_dax(q), page);
531 static struct queue_sysfs_entry queue_requests_entry = {
532 .attr = {.name = "nr_requests", .mode = 0644 },
533 .show = queue_requests_show,
534 .store = queue_requests_store,
537 static struct queue_sysfs_entry queue_ra_entry = {
538 .attr = {.name = "read_ahead_kb", .mode = 0644 },
539 .show = queue_ra_show,
540 .store = queue_ra_store,
543 static struct queue_sysfs_entry queue_max_sectors_entry = {
544 .attr = {.name = "max_sectors_kb", .mode = 0644 },
545 .show = queue_max_sectors_show,
546 .store = queue_max_sectors_store,
549 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
550 .attr = {.name = "max_hw_sectors_kb", .mode = 0444 },
551 .show = queue_max_hw_sectors_show,
554 static struct queue_sysfs_entry queue_max_segments_entry = {
555 .attr = {.name = "max_segments", .mode = 0444 },
556 .show = queue_max_segments_show,
559 static struct queue_sysfs_entry queue_max_discard_segments_entry = {
560 .attr = {.name = "max_discard_segments", .mode = 0444 },
561 .show = queue_max_discard_segments_show,
564 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
565 .attr = {.name = "max_integrity_segments", .mode = 0444 },
566 .show = queue_max_integrity_segments_show,
569 static struct queue_sysfs_entry queue_max_segment_size_entry = {
570 .attr = {.name = "max_segment_size", .mode = 0444 },
571 .show = queue_max_segment_size_show,
574 static struct queue_sysfs_entry queue_iosched_entry = {
575 .attr = {.name = "scheduler", .mode = 0644 },
576 .show = elv_iosched_show,
577 .store = elv_iosched_store,
580 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
581 .attr = {.name = "hw_sector_size", .mode = 0444 },
582 .show = queue_logical_block_size_show,
585 static struct queue_sysfs_entry queue_logical_block_size_entry = {
586 .attr = {.name = "logical_block_size", .mode = 0444 },
587 .show = queue_logical_block_size_show,
590 static struct queue_sysfs_entry queue_physical_block_size_entry = {
591 .attr = {.name = "physical_block_size", .mode = 0444 },
592 .show = queue_physical_block_size_show,
595 static struct queue_sysfs_entry queue_chunk_sectors_entry = {
596 .attr = {.name = "chunk_sectors", .mode = 0444 },
597 .show = queue_chunk_sectors_show,
600 static struct queue_sysfs_entry queue_io_min_entry = {
601 .attr = {.name = "minimum_io_size", .mode = 0444 },
602 .show = queue_io_min_show,
605 static struct queue_sysfs_entry queue_io_opt_entry = {
606 .attr = {.name = "optimal_io_size", .mode = 0444 },
607 .show = queue_io_opt_show,
610 static struct queue_sysfs_entry queue_discard_granularity_entry = {
611 .attr = {.name = "discard_granularity", .mode = 0444 },
612 .show = queue_discard_granularity_show,
615 static struct queue_sysfs_entry queue_discard_max_hw_entry = {
616 .attr = {.name = "discard_max_hw_bytes", .mode = 0444 },
617 .show = queue_discard_max_hw_show,
620 static struct queue_sysfs_entry queue_discard_max_entry = {
621 .attr = {.name = "discard_max_bytes", .mode = 0644 },
622 .show = queue_discard_max_show,
623 .store = queue_discard_max_store,
626 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
627 .attr = {.name = "discard_zeroes_data", .mode = 0444 },
628 .show = queue_discard_zeroes_data_show,
631 static struct queue_sysfs_entry queue_write_same_max_entry = {
632 .attr = {.name = "write_same_max_bytes", .mode = 0444 },
633 .show = queue_write_same_max_show,
636 static struct queue_sysfs_entry queue_write_zeroes_max_entry = {
637 .attr = {.name = "write_zeroes_max_bytes", .mode = 0444 },
638 .show = queue_write_zeroes_max_show,
641 static struct queue_sysfs_entry queue_nonrot_entry = {
642 .attr = {.name = "rotational", .mode = 0644 },
643 .show = queue_show_nonrot,
644 .store = queue_store_nonrot,
647 static struct queue_sysfs_entry queue_zoned_entry = {
648 .attr = {.name = "zoned", .mode = 0444 },
649 .show = queue_zoned_show,
652 static struct queue_sysfs_entry queue_nr_zones_entry = {
653 .attr = {.name = "nr_zones", .mode = 0444 },
654 .show = queue_nr_zones_show,
657 static struct queue_sysfs_entry queue_nomerges_entry = {
658 .attr = {.name = "nomerges", .mode = 0644 },
659 .show = queue_nomerges_show,
660 .store = queue_nomerges_store,
663 static struct queue_sysfs_entry queue_rq_affinity_entry = {
664 .attr = {.name = "rq_affinity", .mode = 0644 },
665 .show = queue_rq_affinity_show,
666 .store = queue_rq_affinity_store,
669 static struct queue_sysfs_entry queue_iostats_entry = {
670 .attr = {.name = "iostats", .mode = 0644 },
671 .show = queue_show_iostats,
672 .store = queue_store_iostats,
675 static struct queue_sysfs_entry queue_random_entry = {
676 .attr = {.name = "add_random", .mode = 0644 },
677 .show = queue_show_random,
678 .store = queue_store_random,
681 static struct queue_sysfs_entry queue_poll_entry = {
682 .attr = {.name = "io_poll", .mode = 0644 },
683 .show = queue_poll_show,
684 .store = queue_poll_store,
687 static struct queue_sysfs_entry queue_poll_delay_entry = {
688 .attr = {.name = "io_poll_delay", .mode = 0644 },
689 .show = queue_poll_delay_show,
690 .store = queue_poll_delay_store,
693 static struct queue_sysfs_entry queue_wc_entry = {
694 .attr = {.name = "write_cache", .mode = 0644 },
695 .show = queue_wc_show,
696 .store = queue_wc_store,
699 static struct queue_sysfs_entry queue_fua_entry = {
700 .attr = {.name = "fua", .mode = 0444 },
701 .show = queue_fua_show,
704 static struct queue_sysfs_entry queue_dax_entry = {
705 .attr = {.name = "dax", .mode = 0444 },
706 .show = queue_dax_show,
709 static struct queue_sysfs_entry queue_io_timeout_entry = {
710 .attr = {.name = "io_timeout", .mode = 0644 },
711 .show = queue_io_timeout_show,
712 .store = queue_io_timeout_store,
715 static struct queue_sysfs_entry queue_wb_lat_entry = {
716 .attr = {.name = "wbt_lat_usec", .mode = 0644 },
717 .show = queue_wb_lat_show,
718 .store = queue_wb_lat_store,
721 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
722 static struct queue_sysfs_entry throtl_sample_time_entry = {
723 .attr = {.name = "throttle_sample_time", .mode = 0644 },
724 .show = blk_throtl_sample_time_show,
725 .store = blk_throtl_sample_time_store,
729 static struct attribute *default_attrs[] = {
730 &queue_requests_entry.attr,
731 &queue_ra_entry.attr,
732 &queue_max_hw_sectors_entry.attr,
733 &queue_max_sectors_entry.attr,
734 &queue_max_segments_entry.attr,
735 &queue_max_discard_segments_entry.attr,
736 &queue_max_integrity_segments_entry.attr,
737 &queue_max_segment_size_entry.attr,
738 &queue_iosched_entry.attr,
739 &queue_hw_sector_size_entry.attr,
740 &queue_logical_block_size_entry.attr,
741 &queue_physical_block_size_entry.attr,
742 &queue_chunk_sectors_entry.attr,
743 &queue_io_min_entry.attr,
744 &queue_io_opt_entry.attr,
745 &queue_discard_granularity_entry.attr,
746 &queue_discard_max_entry.attr,
747 &queue_discard_max_hw_entry.attr,
748 &queue_discard_zeroes_data_entry.attr,
749 &queue_write_same_max_entry.attr,
750 &queue_write_zeroes_max_entry.attr,
751 &queue_nonrot_entry.attr,
752 &queue_zoned_entry.attr,
753 &queue_nr_zones_entry.attr,
754 &queue_nomerges_entry.attr,
755 &queue_rq_affinity_entry.attr,
756 &queue_iostats_entry.attr,
757 &queue_random_entry.attr,
758 &queue_poll_entry.attr,
759 &queue_wc_entry.attr,
760 &queue_fua_entry.attr,
761 &queue_dax_entry.attr,
762 &queue_wb_lat_entry.attr,
763 &queue_poll_delay_entry.attr,
764 &queue_io_timeout_entry.attr,
765 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
766 &throtl_sample_time_entry.attr,
771 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
774 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
776 struct queue_sysfs_entry *entry = to_queue(attr);
777 struct request_queue *q =
778 container_of(kobj, struct request_queue, kobj);
783 mutex_lock(&q->sysfs_lock);
784 if (blk_queue_dying(q)) {
785 mutex_unlock(&q->sysfs_lock);
788 res = entry->show(q, page);
789 mutex_unlock(&q->sysfs_lock);
794 queue_attr_store(struct kobject *kobj, struct attribute *attr,
795 const char *page, size_t length)
797 struct queue_sysfs_entry *entry = to_queue(attr);
798 struct request_queue *q;
804 q = container_of(kobj, struct request_queue, kobj);
805 mutex_lock(&q->sysfs_lock);
806 if (blk_queue_dying(q)) {
807 mutex_unlock(&q->sysfs_lock);
810 res = entry->store(q, page, length);
811 mutex_unlock(&q->sysfs_lock);
815 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
817 struct request_queue *q = container_of(rcu_head, struct request_queue,
819 kmem_cache_free(blk_requestq_cachep, q);
823 * __blk_release_queue - release a request queue
824 * @work: pointer to the release_work member of the request queue to be released
827 * This function is called when a block device is being unregistered. The
828 * process of releasing a request queue starts with blk_cleanup_queue, which
829 * set the appropriate flags and then calls blk_put_queue, that decrements
830 * the reference counter of the request queue. Once the reference counter
831 * of the request queue reaches zero, blk_release_queue is called to release
832 * all allocated resources of the request queue.
834 static void __blk_release_queue(struct work_struct *work)
836 struct request_queue *q = container_of(work, typeof(*q), release_work);
838 if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags))
839 blk_stat_remove_callback(q, q->poll_cb);
840 blk_stat_free_callback(q->poll_cb);
842 if (!blk_queue_dead(q)) {
844 * Last reference was dropped without having called
845 * blk_cleanup_queue().
847 WARN_ONCE(blk_queue_init_done(q),
848 "request queue %p has been registered but blk_cleanup_queue() has not been called for that queue\n",
853 WARN(blk_queue_root_blkg(q),
854 "request queue %p is being released but it has not yet been removed from the blkcg controller\n",
857 blk_free_queue_stats(q->stats);
859 blk_queue_free_zone_bitmaps(q);
864 blk_trace_shutdown(q);
867 blk_mq_debugfs_unregister(q);
869 bioset_exit(&q->bio_split);
871 ida_simple_remove(&blk_queue_ida, q->id);
872 call_rcu(&q->rcu_head, blk_free_queue_rcu);
875 static void blk_release_queue(struct kobject *kobj)
877 struct request_queue *q =
878 container_of(kobj, struct request_queue, kobj);
880 INIT_WORK(&q->release_work, __blk_release_queue);
881 schedule_work(&q->release_work);
884 static const struct sysfs_ops queue_sysfs_ops = {
885 .show = queue_attr_show,
886 .store = queue_attr_store,
889 struct kobj_type blk_queue_ktype = {
890 .sysfs_ops = &queue_sysfs_ops,
891 .default_attrs = default_attrs,
892 .release = blk_release_queue,
896 * blk_register_queue - register a block layer queue with sysfs
897 * @disk: Disk of which the request queue should be registered with sysfs.
899 int blk_register_queue(struct gendisk *disk)
902 struct device *dev = disk_to_dev(disk);
903 struct request_queue *q = disk->queue;
908 WARN_ONCE(test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags),
909 "%s is registering an already registered queue\n",
910 kobject_name(&dev->kobj));
911 blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q);
914 * SCSI probing may synchronously create and destroy a lot of
915 * request_queues for non-existent devices. Shutting down a fully
916 * functional queue takes measureable wallclock time as RCU grace
917 * periods are involved. To avoid excessive latency in these
918 * cases, a request_queue starts out in a degraded mode which is
919 * faster to shut down and is made fully functional here as
920 * request_queues for non-existent devices never get registered.
922 if (!blk_queue_init_done(q)) {
923 blk_queue_flag_set(QUEUE_FLAG_INIT_DONE, q);
924 percpu_ref_switch_to_percpu(&q->q_usage_counter);
927 ret = blk_trace_init_sysfs(dev);
931 /* Prevent changes through sysfs until registration is completed. */
932 mutex_lock(&q->sysfs_lock);
934 ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
936 blk_trace_remove_sysfs(dev);
940 if (queue_is_mq(q)) {
941 __blk_mq_register_dev(dev, q);
942 blk_mq_debugfs_register(q);
945 kobject_uevent(&q->kobj, KOBJ_ADD);
947 wbt_enable_default(q);
949 blk_throtl_register_queue(q);
952 ret = elv_register_queue(q);
954 mutex_unlock(&q->sysfs_lock);
955 kobject_uevent(&q->kobj, KOBJ_REMOVE);
956 kobject_del(&q->kobj);
957 blk_trace_remove_sysfs(dev);
958 kobject_put(&dev->kobj);
964 mutex_unlock(&q->sysfs_lock);
967 EXPORT_SYMBOL_GPL(blk_register_queue);
970 * blk_unregister_queue - counterpart of blk_register_queue()
971 * @disk: Disk of which the request queue should be unregistered from sysfs.
973 * Note: the caller is responsible for guaranteeing that this function is called
974 * after blk_register_queue() has finished.
976 void blk_unregister_queue(struct gendisk *disk)
978 struct request_queue *q = disk->queue;
983 /* Return early if disk->queue was never registered. */
984 if (!test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags))
988 * Since sysfs_remove_dir() prevents adding new directory entries
989 * before removal of existing entries starts, protect against
990 * concurrent elv_iosched_store() calls.
992 mutex_lock(&q->sysfs_lock);
994 blk_queue_flag_clear(QUEUE_FLAG_REGISTERED, q);
997 * Remove the sysfs attributes before unregistering the queue data
998 * structures that can be modified through sysfs.
1001 blk_mq_unregister_dev(disk_to_dev(disk), q);
1002 mutex_unlock(&q->sysfs_lock);
1004 kobject_uevent(&q->kobj, KOBJ_REMOVE);
1005 kobject_del(&q->kobj);
1006 blk_trace_remove_sysfs(disk_to_dev(disk));
1008 mutex_lock(&q->sysfs_lock);
1010 elv_unregister_queue(q);
1011 mutex_unlock(&q->sysfs_lock);
1013 kobject_put(&disk_to_dev(disk)->kobj);