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/debugfs.h>
16 #include "blk-mq-debugfs.h"
17 #include "blk-mq-sched.h"
18 #include "blk-rq-qos.h"
20 #include "blk-cgroup.h"
21 #include "blk-throttle.h"
23 struct queue_sysfs_entry {
24 struct attribute attr;
25 ssize_t (*show)(struct request_queue *, char *);
26 ssize_t (*store)(struct request_queue *, const char *, size_t);
30 queue_var_show(unsigned long var, char *page)
32 return sprintf(page, "%lu\n", var);
36 queue_var_store(unsigned long *var, const char *page, size_t count)
41 err = kstrtoul(page, 10, &v);
42 if (err || v > UINT_MAX)
50 static ssize_t queue_requests_show(struct request_queue *q, char *page)
52 return queue_var_show(q->nr_requests, page);
56 queue_requests_store(struct request_queue *q, const char *page, size_t count)
64 ret = queue_var_store(&nr, page, count);
68 if (nr < BLKDEV_MIN_RQ)
71 err = blk_mq_update_nr_requests(q, nr);
78 static ssize_t queue_ra_show(struct request_queue *q, char *page)
84 ra_kb = q->disk->bdi->ra_pages << (PAGE_SHIFT - 10);
85 return queue_var_show(ra_kb, page);
89 queue_ra_store(struct request_queue *q, const char *page, size_t count)
96 ret = queue_var_store(&ra_kb, page, count);
99 q->disk->bdi->ra_pages = ra_kb >> (PAGE_SHIFT - 10);
103 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
105 int max_sectors_kb = queue_max_sectors(q) >> 1;
107 return queue_var_show(max_sectors_kb, page);
110 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
112 return queue_var_show(queue_max_segments(q), page);
115 static ssize_t queue_max_discard_segments_show(struct request_queue *q,
118 return queue_var_show(queue_max_discard_segments(q), page);
121 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
123 return queue_var_show(q->limits.max_integrity_segments, page);
126 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
128 return queue_var_show(queue_max_segment_size(q), page);
131 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
133 return queue_var_show(queue_logical_block_size(q), page);
136 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
138 return queue_var_show(queue_physical_block_size(q), page);
141 static ssize_t queue_chunk_sectors_show(struct request_queue *q, char *page)
143 return queue_var_show(q->limits.chunk_sectors, page);
146 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
148 return queue_var_show(queue_io_min(q), page);
151 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
153 return queue_var_show(queue_io_opt(q), page);
156 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
158 return queue_var_show(q->limits.discard_granularity, page);
161 static ssize_t queue_discard_max_hw_show(struct request_queue *q, char *page)
164 return sprintf(page, "%llu\n",
165 (unsigned long long)q->limits.max_hw_discard_sectors << 9);
168 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
170 return sprintf(page, "%llu\n",
171 (unsigned long long)q->limits.max_discard_sectors << 9);
174 static ssize_t queue_discard_max_store(struct request_queue *q,
175 const char *page, size_t count)
177 unsigned long max_discard;
178 ssize_t ret = queue_var_store(&max_discard, page, count);
183 if (max_discard & (q->limits.discard_granularity - 1))
187 if (max_discard > UINT_MAX)
190 if (max_discard > q->limits.max_hw_discard_sectors)
191 max_discard = q->limits.max_hw_discard_sectors;
193 q->limits.max_discard_sectors = max_discard;
197 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
199 return queue_var_show(0, page);
202 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
204 return queue_var_show(0, page);
207 static ssize_t queue_write_zeroes_max_show(struct request_queue *q, char *page)
209 return sprintf(page, "%llu\n",
210 (unsigned long long)q->limits.max_write_zeroes_sectors << 9);
213 static ssize_t queue_zone_write_granularity_show(struct request_queue *q,
216 return queue_var_show(queue_zone_write_granularity(q), page);
219 static ssize_t queue_zone_append_max_show(struct request_queue *q, char *page)
221 unsigned long long max_sectors = q->limits.max_zone_append_sectors;
223 return sprintf(page, "%llu\n", max_sectors << SECTOR_SHIFT);
227 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
230 unsigned int 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(&var, page, count);
238 max_sectors_kb = (unsigned int)var;
239 max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb,
240 q->limits.max_dev_sectors >> 1);
241 if (max_sectors_kb == 0) {
242 q->limits.max_user_sectors = 0;
243 max_sectors_kb = min(max_hw_sectors_kb,
244 BLK_DEF_MAX_SECTORS >> 1);
246 if (max_sectors_kb > max_hw_sectors_kb ||
247 max_sectors_kb < page_kb)
249 q->limits.max_user_sectors = max_sectors_kb << 1;
252 spin_lock_irq(&q->queue_lock);
253 q->limits.max_sectors = max_sectors_kb << 1;
255 q->disk->bdi->io_pages = max_sectors_kb >> (PAGE_SHIFT - 10);
256 spin_unlock_irq(&q->queue_lock);
261 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
263 int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
265 return queue_var_show(max_hw_sectors_kb, page);
268 static ssize_t queue_virt_boundary_mask_show(struct request_queue *q, char *page)
270 return queue_var_show(q->limits.virt_boundary_mask, page);
273 static ssize_t queue_dma_alignment_show(struct request_queue *q, char *page)
275 return queue_var_show(queue_dma_alignment(q), page);
278 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg) \
280 queue_##name##_show(struct request_queue *q, char *page) \
283 bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags); \
284 return queue_var_show(neg ? !bit : bit, page); \
287 queue_##name##_store(struct request_queue *q, const char *page, size_t count) \
291 ret = queue_var_store(&val, page, count); \
298 blk_queue_flag_set(QUEUE_FLAG_##flag, q); \
300 blk_queue_flag_clear(QUEUE_FLAG_##flag, q); \
304 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
305 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
306 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
307 QUEUE_SYSFS_BIT_FNS(stable_writes, STABLE_WRITES, 0);
308 #undef QUEUE_SYSFS_BIT_FNS
310 static ssize_t queue_zoned_show(struct request_queue *q, char *page)
312 switch (blk_queue_zoned_model(q)) {
314 return sprintf(page, "host-aware\n");
316 return sprintf(page, "host-managed\n");
318 return sprintf(page, "none\n");
322 static ssize_t queue_nr_zones_show(struct request_queue *q, char *page)
324 return queue_var_show(disk_nr_zones(q->disk), page);
327 static ssize_t queue_max_open_zones_show(struct request_queue *q, char *page)
329 return queue_var_show(bdev_max_open_zones(q->disk->part0), page);
332 static ssize_t queue_max_active_zones_show(struct request_queue *q, char *page)
334 return queue_var_show(bdev_max_active_zones(q->disk->part0), page);
337 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
339 return queue_var_show((blk_queue_nomerges(q) << 1) |
340 blk_queue_noxmerges(q), page);
343 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
347 ssize_t ret = queue_var_store(&nm, page, count);
352 blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
353 blk_queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
355 blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q);
357 blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
362 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
364 bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
365 bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
367 return queue_var_show(set << force, page);
371 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
373 ssize_t ret = -EINVAL;
377 ret = queue_var_store(&val, page, count);
382 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
383 blk_queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
384 } else if (val == 1) {
385 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
386 blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
387 } else if (val == 0) {
388 blk_queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
389 blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
395 static ssize_t queue_poll_delay_show(struct request_queue *q, char *page)
397 return sprintf(page, "%d\n", -1);
400 static ssize_t queue_poll_delay_store(struct request_queue *q, const char *page,
406 static ssize_t queue_poll_show(struct request_queue *q, char *page)
408 return queue_var_show(test_bit(QUEUE_FLAG_POLL, &q->queue_flags), page);
411 static ssize_t queue_poll_store(struct request_queue *q, const char *page,
414 if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
416 pr_info_ratelimited("writes to the poll attribute are ignored.\n");
417 pr_info_ratelimited("please use driver specific parameters instead.\n");
421 static ssize_t queue_io_timeout_show(struct request_queue *q, char *page)
423 return sprintf(page, "%u\n", jiffies_to_msecs(q->rq_timeout));
426 static ssize_t queue_io_timeout_store(struct request_queue *q, const char *page,
432 err = kstrtou32(page, 10, &val);
436 blk_queue_rq_timeout(q, msecs_to_jiffies(val));
441 static ssize_t queue_wc_show(struct request_queue *q, char *page)
443 if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
444 return sprintf(page, "write back\n");
446 return sprintf(page, "write through\n");
449 static ssize_t queue_wc_store(struct request_queue *q, const char *page,
454 if (!strncmp(page, "write back", 10))
456 else if (!strncmp(page, "write through", 13) ||
457 !strncmp(page, "none", 4))
464 blk_queue_flag_set(QUEUE_FLAG_WC, q);
466 blk_queue_flag_clear(QUEUE_FLAG_WC, q);
471 static ssize_t queue_fua_show(struct request_queue *q, char *page)
473 return sprintf(page, "%u\n", test_bit(QUEUE_FLAG_FUA, &q->queue_flags));
476 static ssize_t queue_dax_show(struct request_queue *q, char *page)
478 return queue_var_show(blk_queue_dax(q), page);
481 #define QUEUE_RO_ENTRY(_prefix, _name) \
482 static struct queue_sysfs_entry _prefix##_entry = { \
483 .attr = { .name = _name, .mode = 0444 }, \
484 .show = _prefix##_show, \
487 #define QUEUE_RW_ENTRY(_prefix, _name) \
488 static struct queue_sysfs_entry _prefix##_entry = { \
489 .attr = { .name = _name, .mode = 0644 }, \
490 .show = _prefix##_show, \
491 .store = _prefix##_store, \
494 QUEUE_RW_ENTRY(queue_requests, "nr_requests");
495 QUEUE_RW_ENTRY(queue_ra, "read_ahead_kb");
496 QUEUE_RW_ENTRY(queue_max_sectors, "max_sectors_kb");
497 QUEUE_RO_ENTRY(queue_max_hw_sectors, "max_hw_sectors_kb");
498 QUEUE_RO_ENTRY(queue_max_segments, "max_segments");
499 QUEUE_RO_ENTRY(queue_max_integrity_segments, "max_integrity_segments");
500 QUEUE_RO_ENTRY(queue_max_segment_size, "max_segment_size");
501 QUEUE_RW_ENTRY(elv_iosched, "scheduler");
503 QUEUE_RO_ENTRY(queue_logical_block_size, "logical_block_size");
504 QUEUE_RO_ENTRY(queue_physical_block_size, "physical_block_size");
505 QUEUE_RO_ENTRY(queue_chunk_sectors, "chunk_sectors");
506 QUEUE_RO_ENTRY(queue_io_min, "minimum_io_size");
507 QUEUE_RO_ENTRY(queue_io_opt, "optimal_io_size");
509 QUEUE_RO_ENTRY(queue_max_discard_segments, "max_discard_segments");
510 QUEUE_RO_ENTRY(queue_discard_granularity, "discard_granularity");
511 QUEUE_RO_ENTRY(queue_discard_max_hw, "discard_max_hw_bytes");
512 QUEUE_RW_ENTRY(queue_discard_max, "discard_max_bytes");
513 QUEUE_RO_ENTRY(queue_discard_zeroes_data, "discard_zeroes_data");
515 QUEUE_RO_ENTRY(queue_write_same_max, "write_same_max_bytes");
516 QUEUE_RO_ENTRY(queue_write_zeroes_max, "write_zeroes_max_bytes");
517 QUEUE_RO_ENTRY(queue_zone_append_max, "zone_append_max_bytes");
518 QUEUE_RO_ENTRY(queue_zone_write_granularity, "zone_write_granularity");
520 QUEUE_RO_ENTRY(queue_zoned, "zoned");
521 QUEUE_RO_ENTRY(queue_nr_zones, "nr_zones");
522 QUEUE_RO_ENTRY(queue_max_open_zones, "max_open_zones");
523 QUEUE_RO_ENTRY(queue_max_active_zones, "max_active_zones");
525 QUEUE_RW_ENTRY(queue_nomerges, "nomerges");
526 QUEUE_RW_ENTRY(queue_rq_affinity, "rq_affinity");
527 QUEUE_RW_ENTRY(queue_poll, "io_poll");
528 QUEUE_RW_ENTRY(queue_poll_delay, "io_poll_delay");
529 QUEUE_RW_ENTRY(queue_wc, "write_cache");
530 QUEUE_RO_ENTRY(queue_fua, "fua");
531 QUEUE_RO_ENTRY(queue_dax, "dax");
532 QUEUE_RW_ENTRY(queue_io_timeout, "io_timeout");
533 QUEUE_RO_ENTRY(queue_virt_boundary_mask, "virt_boundary_mask");
534 QUEUE_RO_ENTRY(queue_dma_alignment, "dma_alignment");
536 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
537 QUEUE_RW_ENTRY(blk_throtl_sample_time, "throttle_sample_time");
540 /* legacy alias for logical_block_size: */
541 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
542 .attr = {.name = "hw_sector_size", .mode = 0444 },
543 .show = queue_logical_block_size_show,
546 QUEUE_RW_ENTRY(queue_nonrot, "rotational");
547 QUEUE_RW_ENTRY(queue_iostats, "iostats");
548 QUEUE_RW_ENTRY(queue_random, "add_random");
549 QUEUE_RW_ENTRY(queue_stable_writes, "stable_writes");
551 #ifdef CONFIG_BLK_WBT
552 static ssize_t queue_var_store64(s64 *var, const char *page)
557 err = kstrtos64(page, 10, &v);
565 static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
571 return sprintf(page, "0\n");
573 return sprintf(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000));
576 static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
583 ret = queue_var_store64(&val, page);
589 rqos = wbt_rq_qos(q);
591 ret = wbt_init(q->disk);
597 val = wbt_default_latency_nsec(q);
601 if (wbt_get_min_lat(q) == val)
605 * Ensure that the queue is idled, in case the latency update
606 * ends up either enabling or disabling wbt completely. We can't
607 * have IO inflight if that happens.
609 blk_mq_freeze_queue(q);
610 blk_mq_quiesce_queue(q);
612 wbt_set_min_lat(q, val);
614 blk_mq_unquiesce_queue(q);
615 blk_mq_unfreeze_queue(q);
620 QUEUE_RW_ENTRY(queue_wb_lat, "wbt_lat_usec");
623 static struct attribute *queue_attrs[] = {
624 &queue_ra_entry.attr,
625 &queue_max_hw_sectors_entry.attr,
626 &queue_max_sectors_entry.attr,
627 &queue_max_segments_entry.attr,
628 &queue_max_discard_segments_entry.attr,
629 &queue_max_integrity_segments_entry.attr,
630 &queue_max_segment_size_entry.attr,
631 &queue_hw_sector_size_entry.attr,
632 &queue_logical_block_size_entry.attr,
633 &queue_physical_block_size_entry.attr,
634 &queue_chunk_sectors_entry.attr,
635 &queue_io_min_entry.attr,
636 &queue_io_opt_entry.attr,
637 &queue_discard_granularity_entry.attr,
638 &queue_discard_max_entry.attr,
639 &queue_discard_max_hw_entry.attr,
640 &queue_discard_zeroes_data_entry.attr,
641 &queue_write_same_max_entry.attr,
642 &queue_write_zeroes_max_entry.attr,
643 &queue_zone_append_max_entry.attr,
644 &queue_zone_write_granularity_entry.attr,
645 &queue_nonrot_entry.attr,
646 &queue_zoned_entry.attr,
647 &queue_nr_zones_entry.attr,
648 &queue_max_open_zones_entry.attr,
649 &queue_max_active_zones_entry.attr,
650 &queue_nomerges_entry.attr,
651 &queue_iostats_entry.attr,
652 &queue_stable_writes_entry.attr,
653 &queue_random_entry.attr,
654 &queue_poll_entry.attr,
655 &queue_wc_entry.attr,
656 &queue_fua_entry.attr,
657 &queue_dax_entry.attr,
658 &queue_poll_delay_entry.attr,
659 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
660 &blk_throtl_sample_time_entry.attr,
662 &queue_virt_boundary_mask_entry.attr,
663 &queue_dma_alignment_entry.attr,
667 static struct attribute *blk_mq_queue_attrs[] = {
668 &queue_requests_entry.attr,
669 &elv_iosched_entry.attr,
670 &queue_rq_affinity_entry.attr,
671 &queue_io_timeout_entry.attr,
672 #ifdef CONFIG_BLK_WBT
673 &queue_wb_lat_entry.attr,
678 static umode_t queue_attr_visible(struct kobject *kobj, struct attribute *attr,
681 struct gendisk *disk = container_of(kobj, struct gendisk, queue_kobj);
682 struct request_queue *q = disk->queue;
684 if ((attr == &queue_max_open_zones_entry.attr ||
685 attr == &queue_max_active_zones_entry.attr) &&
686 !blk_queue_is_zoned(q))
692 static umode_t blk_mq_queue_attr_visible(struct kobject *kobj,
693 struct attribute *attr, int n)
695 struct gendisk *disk = container_of(kobj, struct gendisk, queue_kobj);
696 struct request_queue *q = disk->queue;
701 if (attr == &queue_io_timeout_entry.attr && !q->mq_ops->timeout)
707 static struct attribute_group queue_attr_group = {
708 .attrs = queue_attrs,
709 .is_visible = queue_attr_visible,
712 static struct attribute_group blk_mq_queue_attr_group = {
713 .attrs = blk_mq_queue_attrs,
714 .is_visible = blk_mq_queue_attr_visible,
717 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
720 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
722 struct queue_sysfs_entry *entry = to_queue(attr);
723 struct gendisk *disk = container_of(kobj, struct gendisk, queue_kobj);
724 struct request_queue *q = disk->queue;
729 mutex_lock(&q->sysfs_lock);
730 res = entry->show(q, page);
731 mutex_unlock(&q->sysfs_lock);
736 queue_attr_store(struct kobject *kobj, struct attribute *attr,
737 const char *page, size_t length)
739 struct queue_sysfs_entry *entry = to_queue(attr);
740 struct gendisk *disk = container_of(kobj, struct gendisk, queue_kobj);
741 struct request_queue *q = disk->queue;
747 mutex_lock(&q->sysfs_lock);
748 res = entry->store(q, page, length);
749 mutex_unlock(&q->sysfs_lock);
753 static const struct sysfs_ops queue_sysfs_ops = {
754 .show = queue_attr_show,
755 .store = queue_attr_store,
758 static const struct attribute_group *blk_queue_attr_groups[] = {
760 &blk_mq_queue_attr_group,
764 static void blk_queue_release(struct kobject *kobj)
766 /* nothing to do here, all data is associated with the parent gendisk */
769 static const struct kobj_type blk_queue_ktype = {
770 .default_groups = blk_queue_attr_groups,
771 .sysfs_ops = &queue_sysfs_ops,
772 .release = blk_queue_release,
775 static void blk_debugfs_remove(struct gendisk *disk)
777 struct request_queue *q = disk->queue;
779 mutex_lock(&q->debugfs_mutex);
780 blk_trace_shutdown(q);
781 debugfs_remove_recursive(q->debugfs_dir);
782 q->debugfs_dir = NULL;
783 q->sched_debugfs_dir = NULL;
784 q->rqos_debugfs_dir = NULL;
785 mutex_unlock(&q->debugfs_mutex);
789 * blk_register_queue - register a block layer queue with sysfs
790 * @disk: Disk of which the request queue should be registered with sysfs.
792 int blk_register_queue(struct gendisk *disk)
794 struct request_queue *q = disk->queue;
797 mutex_lock(&q->sysfs_dir_lock);
798 kobject_init(&disk->queue_kobj, &blk_queue_ktype);
799 ret = kobject_add(&disk->queue_kobj, &disk_to_dev(disk)->kobj, "queue");
801 goto out_put_queue_kobj;
803 if (queue_is_mq(q)) {
804 ret = blk_mq_sysfs_register(disk);
806 goto out_put_queue_kobj;
808 mutex_lock(&q->sysfs_lock);
810 mutex_lock(&q->debugfs_mutex);
811 q->debugfs_dir = debugfs_create_dir(disk->disk_name, blk_debugfs_root);
813 blk_mq_debugfs_register(q);
814 mutex_unlock(&q->debugfs_mutex);
816 ret = disk_register_independent_access_ranges(disk);
818 goto out_debugfs_remove;
821 ret = elv_register_queue(q, false);
823 goto out_unregister_ia_ranges;
826 ret = blk_crypto_sysfs_register(disk);
828 goto out_elv_unregister;
830 blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q);
831 wbt_enable_default(disk);
832 blk_throtl_register(disk);
834 /* Now everything is ready and send out KOBJ_ADD uevent */
835 kobject_uevent(&disk->queue_kobj, KOBJ_ADD);
837 kobject_uevent(&q->elevator->kobj, KOBJ_ADD);
838 mutex_unlock(&q->sysfs_lock);
839 mutex_unlock(&q->sysfs_dir_lock);
842 * SCSI probing may synchronously create and destroy a lot of
843 * request_queues for non-existent devices. Shutting down a fully
844 * functional queue takes measureable wallclock time as RCU grace
845 * periods are involved. To avoid excessive latency in these
846 * cases, a request_queue starts out in a degraded mode which is
847 * faster to shut down and is made fully functional here as
848 * request_queues for non-existent devices never get registered.
850 if (!blk_queue_init_done(q)) {
851 blk_queue_flag_set(QUEUE_FLAG_INIT_DONE, q);
852 percpu_ref_switch_to_percpu(&q->q_usage_counter);
858 elv_unregister_queue(q);
859 out_unregister_ia_ranges:
860 disk_unregister_independent_access_ranges(disk);
862 blk_debugfs_remove(disk);
863 mutex_unlock(&q->sysfs_lock);
865 kobject_put(&disk->queue_kobj);
866 mutex_unlock(&q->sysfs_dir_lock);
871 * blk_unregister_queue - counterpart of blk_register_queue()
872 * @disk: Disk of which the request queue should be unregistered from sysfs.
874 * Note: the caller is responsible for guaranteeing that this function is called
875 * after blk_register_queue() has finished.
877 void blk_unregister_queue(struct gendisk *disk)
879 struct request_queue *q = disk->queue;
884 /* Return early if disk->queue was never registered. */
885 if (!blk_queue_registered(q))
889 * Since sysfs_remove_dir() prevents adding new directory entries
890 * before removal of existing entries starts, protect against
891 * concurrent elv_iosched_store() calls.
893 mutex_lock(&q->sysfs_lock);
894 blk_queue_flag_clear(QUEUE_FLAG_REGISTERED, q);
895 mutex_unlock(&q->sysfs_lock);
897 mutex_lock(&q->sysfs_dir_lock);
899 * Remove the sysfs attributes before unregistering the queue data
900 * structures that can be modified through sysfs.
903 blk_mq_sysfs_unregister(disk);
904 blk_crypto_sysfs_unregister(disk);
906 mutex_lock(&q->sysfs_lock);
907 elv_unregister_queue(q);
908 disk_unregister_independent_access_ranges(disk);
909 mutex_unlock(&q->sysfs_lock);
911 /* Now that we've deleted all child objects, we can delete the queue. */
912 kobject_uevent(&disk->queue_kobj, KOBJ_REMOVE);
913 kobject_del(&disk->queue_kobj);
914 mutex_unlock(&q->sysfs_dir_lock);
916 blk_debugfs_remove(disk);