1 // SPDX-License-Identifier: GPL-2.0
5 * Portions Copyright (C) 2020 Christoph Hellwig
8 #include <linux/module.h>
9 #include <linux/ctype.h>
11 #include <linux/kdev_t.h>
12 #include <linux/kernel.h>
13 #include <linux/blkdev.h>
14 #include <linux/backing-dev.h>
15 #include <linux/init.h>
16 #include <linux/spinlock.h>
17 #include <linux/proc_fs.h>
18 #include <linux/seq_file.h>
19 #include <linux/slab.h>
20 #include <linux/kmod.h>
21 #include <linux/major.h>
22 #include <linux/mutex.h>
23 #include <linux/idr.h>
24 #include <linux/log2.h>
25 #include <linux/pm_runtime.h>
26 #include <linux/badblocks.h>
27 #include <linux/part_stat.h>
28 #include "blk-throttle.h"
31 #include "blk-mq-sched.h"
32 #include "blk-rq-qos.h"
33 #include "blk-cgroup.h"
35 static struct kobject *block_depr;
38 * Unique, monotonically increasing sequential number associated with block
39 * devices instances (i.e. incremented each time a device is attached).
40 * Associating uevents with block devices in userspace is difficult and racy:
41 * the uevent netlink socket is lossy, and on slow and overloaded systems has
42 * a very high latency.
43 * Block devices do not have exclusive owners in userspace, any process can set
44 * one up (e.g. loop devices). Moreover, device names can be reused (e.g. loop0
45 * can be reused again and again).
46 * A userspace process setting up a block device and watching for its events
47 * cannot thus reliably tell whether an event relates to the device it just set
48 * up or another earlier instance with the same name.
49 * This sequential number allows userspace processes to solve this problem, and
50 * uniquely associate an uevent to the lifetime to a device.
52 static atomic64_t diskseq;
54 /* for extended dynamic devt allocation, currently only one major is used */
55 #define NR_EXT_DEVT (1 << MINORBITS)
56 static DEFINE_IDA(ext_devt_ida);
58 void set_capacity(struct gendisk *disk, sector_t sectors)
60 struct block_device *bdev = disk->part0;
62 spin_lock(&bdev->bd_size_lock);
63 i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT);
64 bdev->bd_nr_sectors = sectors;
65 spin_unlock(&bdev->bd_size_lock);
67 EXPORT_SYMBOL(set_capacity);
70 * Set disk capacity and notify if the size is not currently zero and will not
71 * be set to zero. Returns true if a uevent was sent, otherwise false.
73 bool set_capacity_and_notify(struct gendisk *disk, sector_t size)
75 sector_t capacity = get_capacity(disk);
76 char *envp[] = { "RESIZE=1", NULL };
78 set_capacity(disk, size);
81 * Only print a message and send a uevent if the gendisk is user visible
82 * and alive. This avoids spamming the log and udev when setting the
83 * initial capacity during probing.
85 if (size == capacity ||
87 (disk->flags & GENHD_FL_HIDDEN))
90 pr_info("%s: detected capacity change from %lld to %lld\n",
91 disk->disk_name, capacity, size);
94 * Historically we did not send a uevent for changes to/from an empty
97 if (!capacity || !size)
99 kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp);
102 EXPORT_SYMBOL_GPL(set_capacity_and_notify);
104 static void part_stat_read_all(struct block_device *part,
105 struct disk_stats *stat)
109 memset(stat, 0, sizeof(struct disk_stats));
110 for_each_possible_cpu(cpu) {
111 struct disk_stats *ptr = per_cpu_ptr(part->bd_stats, cpu);
114 for (group = 0; group < NR_STAT_GROUPS; group++) {
115 stat->nsecs[group] += ptr->nsecs[group];
116 stat->sectors[group] += ptr->sectors[group];
117 stat->ios[group] += ptr->ios[group];
118 stat->merges[group] += ptr->merges[group];
121 stat->io_ticks += ptr->io_ticks;
125 static unsigned int part_in_flight(struct block_device *part)
127 unsigned int inflight = 0;
130 for_each_possible_cpu(cpu) {
131 inflight += part_stat_local_read_cpu(part, in_flight[0], cpu) +
132 part_stat_local_read_cpu(part, in_flight[1], cpu);
134 if ((int)inflight < 0)
140 static void part_in_flight_rw(struct block_device *part,
141 unsigned int inflight[2])
147 for_each_possible_cpu(cpu) {
148 inflight[0] += part_stat_local_read_cpu(part, in_flight[0], cpu);
149 inflight[1] += part_stat_local_read_cpu(part, in_flight[1], cpu);
151 if ((int)inflight[0] < 0)
153 if ((int)inflight[1] < 0)
158 * Can be deleted altogether. Later.
161 #define BLKDEV_MAJOR_HASH_SIZE 255
162 static struct blk_major_name {
163 struct blk_major_name *next;
166 #ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD
167 void (*probe)(dev_t devt);
169 } *major_names[BLKDEV_MAJOR_HASH_SIZE];
170 static DEFINE_MUTEX(major_names_lock);
171 static DEFINE_SPINLOCK(major_names_spinlock);
173 /* index in the above - for now: assume no multimajor ranges */
174 static inline int major_to_index(unsigned major)
176 return major % BLKDEV_MAJOR_HASH_SIZE;
179 #ifdef CONFIG_PROC_FS
180 void blkdev_show(struct seq_file *seqf, off_t offset)
182 struct blk_major_name *dp;
184 spin_lock(&major_names_spinlock);
185 for (dp = major_names[major_to_index(offset)]; dp; dp = dp->next)
186 if (dp->major == offset)
187 seq_printf(seqf, "%3d %s\n", dp->major, dp->name);
188 spin_unlock(&major_names_spinlock);
190 #endif /* CONFIG_PROC_FS */
193 * __register_blkdev - register a new block device
195 * @major: the requested major device number [1..BLKDEV_MAJOR_MAX-1]. If
196 * @major = 0, try to allocate any unused major number.
197 * @name: the name of the new block device as a zero terminated string
198 * @probe: pre-devtmpfs / pre-udev callback used to create disks when their
199 * pre-created device node is accessed. When a probe call uses
200 * add_disk() and it fails the driver must cleanup resources. This
201 * interface may soon be removed.
203 * The @name must be unique within the system.
205 * The return value depends on the @major input parameter:
207 * - if a major device number was requested in range [1..BLKDEV_MAJOR_MAX-1]
208 * then the function returns zero on success, or a negative error code
209 * - if any unused major number was requested with @major = 0 parameter
210 * then the return value is the allocated major number in range
211 * [1..BLKDEV_MAJOR_MAX-1] or a negative error code otherwise
213 * See Documentation/admin-guide/devices.txt for the list of allocated
216 * Use register_blkdev instead for any new code.
218 int __register_blkdev(unsigned int major, const char *name,
219 void (*probe)(dev_t devt))
221 struct blk_major_name **n, *p;
224 mutex_lock(&major_names_lock);
228 for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) {
229 if (major_names[index] == NULL)
234 printk("%s: failed to get major for %s\n",
243 if (major >= BLKDEV_MAJOR_MAX) {
244 pr_err("%s: major requested (%u) is greater than the maximum (%u) for %s\n",
245 __func__, major, BLKDEV_MAJOR_MAX-1, name);
251 p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL);
258 #ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD
261 strlcpy(p->name, name, sizeof(p->name));
263 index = major_to_index(major);
265 spin_lock(&major_names_spinlock);
266 for (n = &major_names[index]; *n; n = &(*n)->next) {
267 if ((*n)->major == major)
274 spin_unlock(&major_names_spinlock);
277 printk("register_blkdev: cannot get major %u for %s\n",
282 mutex_unlock(&major_names_lock);
285 EXPORT_SYMBOL(__register_blkdev);
287 void unregister_blkdev(unsigned int major, const char *name)
289 struct blk_major_name **n;
290 struct blk_major_name *p = NULL;
291 int index = major_to_index(major);
293 mutex_lock(&major_names_lock);
294 spin_lock(&major_names_spinlock);
295 for (n = &major_names[index]; *n; n = &(*n)->next)
296 if ((*n)->major == major)
298 if (!*n || strcmp((*n)->name, name)) {
304 spin_unlock(&major_names_spinlock);
305 mutex_unlock(&major_names_lock);
309 EXPORT_SYMBOL(unregister_blkdev);
311 int blk_alloc_ext_minor(void)
315 idx = ida_alloc_range(&ext_devt_ida, 0, NR_EXT_DEVT - 1, GFP_KERNEL);
321 void blk_free_ext_minor(unsigned int minor)
323 ida_free(&ext_devt_ida, minor);
326 static char *bdevt_str(dev_t devt, char *buf)
328 if (MAJOR(devt) <= 0xff && MINOR(devt) <= 0xff) {
329 char tbuf[BDEVT_SIZE];
330 snprintf(tbuf, BDEVT_SIZE, "%02x%02x", MAJOR(devt), MINOR(devt));
331 snprintf(buf, BDEVT_SIZE, "%-9s", tbuf);
333 snprintf(buf, BDEVT_SIZE, "%03x:%05x", MAJOR(devt), MINOR(devt));
338 void disk_uevent(struct gendisk *disk, enum kobject_action action)
340 struct block_device *part;
344 xa_for_each(&disk->part_tbl, idx, part) {
345 if (bdev_is_partition(part) && !bdev_nr_sectors(part))
347 if (!kobject_get_unless_zero(&part->bd_device.kobj))
351 kobject_uevent(bdev_kobj(part), action);
352 put_device(&part->bd_device);
357 EXPORT_SYMBOL_GPL(disk_uevent);
359 int disk_scan_partitions(struct gendisk *disk, fmode_t mode)
361 struct block_device *bdev;
364 if (disk->flags & (GENHD_FL_NO_PART | GENHD_FL_HIDDEN))
366 if (test_bit(GD_SUPPRESS_PART_SCAN, &disk->state))
368 if (disk->open_partitions)
371 set_bit(GD_NEED_PART_SCAN, &disk->state);
373 * If the device is opened exclusively by current thread already, it's
374 * safe to scan partitons, otherwise, use bd_prepare_to_claim() to
375 * synchronize with other exclusive openers and other partition
378 if (!(mode & FMODE_EXCL)) {
379 ret = bd_prepare_to_claim(disk->part0, disk_scan_partitions);
384 bdev = blkdev_get_by_dev(disk_devt(disk), mode & ~FMODE_EXCL, NULL);
388 blkdev_put(bdev, mode);
390 if (!(mode & FMODE_EXCL))
391 bd_abort_claiming(disk->part0, disk_scan_partitions);
396 * device_add_disk - add disk information to kernel list
397 * @parent: parent device for the disk
398 * @disk: per-device partitioning information
399 * @groups: Additional per-device sysfs groups
401 * This function registers the partitioning information in @disk
404 int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
405 const struct attribute_group **groups)
408 struct device *ddev = disk_to_dev(disk);
411 /* Only makes sense for bio-based to set ->poll_bio */
412 if (queue_is_mq(disk->queue) && disk->fops->poll_bio)
416 * The disk queue should now be all set with enough information about
417 * the device for the elevator code to pick an adequate default
418 * elevator if one is needed, that is, for devices requesting queue
421 elevator_init_mq(disk->queue);
424 * If the driver provides an explicit major number it also must provide
425 * the number of minors numbers supported, and those will be used to
427 * Otherwise just allocate the device numbers for both the whole device
428 * and all partitions from the extended dev_t space.
432 if (WARN_ON(!disk->minors))
433 goto out_exit_elevator;
435 if (disk->minors > DISK_MAX_PARTS) {
436 pr_err("block: can't allocate more than %d partitions\n",
438 disk->minors = DISK_MAX_PARTS;
440 if (disk->first_minor + disk->minors > MINORMASK + 1)
441 goto out_exit_elevator;
443 if (WARN_ON(disk->minors))
444 goto out_exit_elevator;
446 ret = blk_alloc_ext_minor();
448 goto out_exit_elevator;
449 disk->major = BLOCK_EXT_MAJOR;
450 disk->first_minor = ret;
453 /* delay uevents, until we scanned partition table */
454 dev_set_uevent_suppress(ddev, 1);
456 ddev->parent = parent;
457 ddev->groups = groups;
458 dev_set_name(ddev, "%s", disk->disk_name);
459 if (!(disk->flags & GENHD_FL_HIDDEN))
460 ddev->devt = MKDEV(disk->major, disk->first_minor);
461 ret = device_add(ddev);
463 goto out_free_ext_minor;
465 ret = disk_alloc_events(disk);
469 ret = sysfs_create_link(block_depr, &ddev->kobj,
470 kobject_name(&ddev->kobj));
475 * avoid probable deadlock caused by allocating memory with
476 * GFP_KERNEL in runtime_resume callback of its all ancestor
479 pm_runtime_set_memalloc_noio(ddev, true);
481 ret = blk_integrity_add(disk);
483 goto out_del_block_link;
485 disk->part0->bd_holder_dir =
486 kobject_create_and_add("holders", &ddev->kobj);
487 if (!disk->part0->bd_holder_dir) {
489 goto out_del_integrity;
491 disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
492 if (!disk->slave_dir) {
494 goto out_put_holder_dir;
497 ret = blk_register_queue(disk);
499 goto out_put_slave_dir;
501 if (!(disk->flags & GENHD_FL_HIDDEN)) {
502 ret = bdi_register(disk->bdi, "%u:%u",
503 disk->major, disk->first_minor);
505 goto out_unregister_queue;
506 bdi_set_owner(disk->bdi, ddev);
507 ret = sysfs_create_link(&ddev->kobj,
508 &disk->bdi->dev->kobj, "bdi");
510 goto out_unregister_bdi;
512 /* Make sure the first partition scan will be proceed */
513 if (get_capacity(disk) && !(disk->flags & GENHD_FL_NO_PART) &&
514 !test_bit(GD_SUPPRESS_PART_SCAN, &disk->state))
515 set_bit(GD_NEED_PART_SCAN, &disk->state);
517 bdev_add(disk->part0, ddev->devt);
518 if (get_capacity(disk))
519 disk_scan_partitions(disk, FMODE_READ);
522 * Announce the disk and partitions after all partitions are
523 * created. (for hidden disks uevents remain suppressed forever)
525 dev_set_uevent_suppress(ddev, 0);
526 disk_uevent(disk, KOBJ_ADD);
529 * Even if the block_device for a hidden gendisk is not
530 * registered, it needs to have a valid bd_dev so that the
531 * freeing of the dynamic major works.
533 disk->part0->bd_dev = MKDEV(disk->major, disk->first_minor);
536 disk_update_readahead(disk);
537 disk_add_events(disk);
538 set_bit(GD_ADDED, &disk->state);
542 if (!(disk->flags & GENHD_FL_HIDDEN))
543 bdi_unregister(disk->bdi);
544 out_unregister_queue:
545 blk_unregister_queue(disk);
546 rq_qos_exit(disk->queue);
548 kobject_put(disk->slave_dir);
549 disk->slave_dir = NULL;
551 kobject_put(disk->part0->bd_holder_dir);
553 blk_integrity_del(disk);
555 sysfs_remove_link(block_depr, dev_name(ddev));
559 if (disk->major == BLOCK_EXT_MAJOR)
560 blk_free_ext_minor(disk->first_minor);
562 if (disk->queue->elevator)
563 elevator_exit(disk->queue);
566 EXPORT_SYMBOL(device_add_disk);
569 * blk_mark_disk_dead - mark a disk as dead
570 * @disk: disk to mark as dead
572 * Mark as disk as dead (e.g. surprise removed) and don't accept any new I/O
575 void blk_mark_disk_dead(struct gendisk *disk)
577 set_bit(GD_DEAD, &disk->state);
578 blk_queue_start_drain(disk->queue);
581 * Stop buffered writers from dirtying pages that can't be written out.
583 set_capacity_and_notify(disk, 0);
585 EXPORT_SYMBOL_GPL(blk_mark_disk_dead);
588 * del_gendisk - remove the gendisk
589 * @disk: the struct gendisk to remove
591 * Removes the gendisk and all its associated resources. This deletes the
592 * partitions associated with the gendisk, and unregisters the associated
595 * This is the counter to the respective __device_add_disk() call.
597 * The final removal of the struct gendisk happens when its refcount reaches 0
598 * with put_disk(), which should be called after del_gendisk(), if
599 * __device_add_disk() was used.
601 * Drivers exist which depend on the release of the gendisk to be synchronous,
602 * it should not be deferred.
606 void del_gendisk(struct gendisk *disk)
608 struct request_queue *q = disk->queue;
612 if (WARN_ON_ONCE(!disk_live(disk) && !(disk->flags & GENHD_FL_HIDDEN)))
615 blk_integrity_del(disk);
616 disk_del_events(disk);
618 mutex_lock(&disk->open_mutex);
619 remove_inode_hash(disk->part0->bd_inode);
620 blk_drop_partitions(disk);
621 mutex_unlock(&disk->open_mutex);
623 fsync_bdev(disk->part0);
624 __invalidate_device(disk->part0, true);
629 set_bit(GD_DEAD, &disk->state);
630 if (test_bit(GD_OWNS_QUEUE, &disk->state))
631 blk_queue_flag_set(QUEUE_FLAG_DYING, q);
632 set_capacity(disk, 0);
635 * Prevent new I/O from crossing bio_queue_enter().
637 blk_queue_start_drain(q);
639 if (!(disk->flags & GENHD_FL_HIDDEN)) {
640 sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
643 * Unregister bdi before releasing device numbers (as they can
644 * get reused and we'd get clashes in sysfs).
646 bdi_unregister(disk->bdi);
649 blk_unregister_queue(disk);
651 kobject_put(disk->part0->bd_holder_dir);
652 kobject_put(disk->slave_dir);
653 disk->slave_dir = NULL;
655 part_stat_set_all(disk->part0, 0);
656 disk->part0->bd_stamp = 0;
657 sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
658 pm_runtime_set_memalloc_noio(disk_to_dev(disk), false);
659 device_del(disk_to_dev(disk));
661 blk_mq_freeze_queue_wait(q);
663 blk_throtl_cancel_bios(disk);
666 blk_flush_integrity();
669 blk_mq_cancel_work_sync(q);
671 blk_mq_quiesce_queue(q);
673 mutex_lock(&q->sysfs_lock);
675 mutex_unlock(&q->sysfs_lock);
678 blk_mq_unquiesce_queue(q);
681 * If the disk does not own the queue, allow using passthrough requests
682 * again. Else leave the queue frozen to fail all I/O.
684 if (!test_bit(GD_OWNS_QUEUE, &disk->state)) {
685 blk_queue_flag_clear(QUEUE_FLAG_INIT_DONE, q);
686 __blk_mq_unfreeze_queue(q, true);
689 blk_mq_exit_queue(q);
692 EXPORT_SYMBOL(del_gendisk);
695 * invalidate_disk - invalidate the disk
696 * @disk: the struct gendisk to invalidate
698 * A helper to invalidates the disk. It will clean the disk's associated
699 * buffer/page caches and reset its internal states so that the disk
700 * can be reused by the drivers.
704 void invalidate_disk(struct gendisk *disk)
706 struct block_device *bdev = disk->part0;
708 invalidate_bdev(bdev);
709 bdev->bd_inode->i_mapping->wb_err = 0;
710 set_capacity(disk, 0);
712 EXPORT_SYMBOL(invalidate_disk);
714 /* sysfs access to bad-blocks list. */
715 static ssize_t disk_badblocks_show(struct device *dev,
716 struct device_attribute *attr,
719 struct gendisk *disk = dev_to_disk(dev);
722 return sprintf(page, "\n");
724 return badblocks_show(disk->bb, page, 0);
727 static ssize_t disk_badblocks_store(struct device *dev,
728 struct device_attribute *attr,
729 const char *page, size_t len)
731 struct gendisk *disk = dev_to_disk(dev);
736 return badblocks_store(disk->bb, page, len, 0);
739 #ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD
740 void blk_request_module(dev_t devt)
742 unsigned int major = MAJOR(devt);
743 struct blk_major_name **n;
745 mutex_lock(&major_names_lock);
746 for (n = &major_names[major_to_index(major)]; *n; n = &(*n)->next) {
747 if ((*n)->major == major && (*n)->probe) {
749 mutex_unlock(&major_names_lock);
753 mutex_unlock(&major_names_lock);
755 if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0)
756 /* Make old-style 2.4 aliases work */
757 request_module("block-major-%d", MAJOR(devt));
759 #endif /* CONFIG_BLOCK_LEGACY_AUTOLOAD */
762 * print a full list of all partitions - intended for places where the root
763 * filesystem can't be mounted and thus to give the victim some idea of what
766 void __init printk_all_partitions(void)
768 struct class_dev_iter iter;
771 class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
772 while ((dev = class_dev_iter_next(&iter))) {
773 struct gendisk *disk = dev_to_disk(dev);
774 struct block_device *part;
775 char devt_buf[BDEVT_SIZE];
779 * Don't show empty devices or things that have been
782 if (get_capacity(disk) == 0 || (disk->flags & GENHD_FL_HIDDEN))
786 * Note, unlike /proc/partitions, I am showing the numbers in
787 * hex - the same format as the root= option takes.
790 xa_for_each(&disk->part_tbl, idx, part) {
791 if (!bdev_nr_sectors(part))
793 printk("%s%s %10llu %pg %s",
794 bdev_is_partition(part) ? " " : "",
795 bdevt_str(part->bd_dev, devt_buf),
796 bdev_nr_sectors(part) >> 1, part,
798 part->bd_meta_info->uuid : "");
799 if (bdev_is_partition(part))
801 else if (dev->parent && dev->parent->driver)
802 printk(" driver: %s\n",
803 dev->parent->driver->name);
805 printk(" (driver?)\n");
809 class_dev_iter_exit(&iter);
812 #ifdef CONFIG_PROC_FS
814 static void *disk_seqf_start(struct seq_file *seqf, loff_t *pos)
817 struct class_dev_iter *iter;
820 iter = kmalloc(sizeof(*iter), GFP_KERNEL);
822 return ERR_PTR(-ENOMEM);
824 seqf->private = iter;
825 class_dev_iter_init(iter, &block_class, NULL, &disk_type);
827 dev = class_dev_iter_next(iter);
832 return dev_to_disk(dev);
835 static void *disk_seqf_next(struct seq_file *seqf, void *v, loff_t *pos)
840 dev = class_dev_iter_next(seqf->private);
842 return dev_to_disk(dev);
847 static void disk_seqf_stop(struct seq_file *seqf, void *v)
849 struct class_dev_iter *iter = seqf->private;
851 /* stop is called even after start failed :-( */
853 class_dev_iter_exit(iter);
855 seqf->private = NULL;
859 static void *show_partition_start(struct seq_file *seqf, loff_t *pos)
863 p = disk_seqf_start(seqf, pos);
864 if (!IS_ERR_OR_NULL(p) && !*pos)
865 seq_puts(seqf, "major minor #blocks name\n\n");
869 static int show_partition(struct seq_file *seqf, void *v)
871 struct gendisk *sgp = v;
872 struct block_device *part;
875 if (!get_capacity(sgp) || (sgp->flags & GENHD_FL_HIDDEN))
879 xa_for_each(&sgp->part_tbl, idx, part) {
880 if (!bdev_nr_sectors(part))
882 seq_printf(seqf, "%4d %7d %10llu %pg\n",
883 MAJOR(part->bd_dev), MINOR(part->bd_dev),
884 bdev_nr_sectors(part) >> 1, part);
890 static const struct seq_operations partitions_op = {
891 .start = show_partition_start,
892 .next = disk_seqf_next,
893 .stop = disk_seqf_stop,
894 .show = show_partition
898 static int __init genhd_device_init(void)
902 block_class.dev_kobj = sysfs_dev_block_kobj;
903 error = class_register(&block_class);
908 register_blkdev(BLOCK_EXT_MAJOR, "blkext");
910 /* create top-level block dir */
911 block_depr = kobject_create_and_add("block", NULL);
915 subsys_initcall(genhd_device_init);
917 static ssize_t disk_range_show(struct device *dev,
918 struct device_attribute *attr, char *buf)
920 struct gendisk *disk = dev_to_disk(dev);
922 return sprintf(buf, "%d\n", disk->minors);
925 static ssize_t disk_ext_range_show(struct device *dev,
926 struct device_attribute *attr, char *buf)
928 struct gendisk *disk = dev_to_disk(dev);
930 return sprintf(buf, "%d\n",
931 (disk->flags & GENHD_FL_NO_PART) ? 1 : DISK_MAX_PARTS);
934 static ssize_t disk_removable_show(struct device *dev,
935 struct device_attribute *attr, char *buf)
937 struct gendisk *disk = dev_to_disk(dev);
939 return sprintf(buf, "%d\n",
940 (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0));
943 static ssize_t disk_hidden_show(struct device *dev,
944 struct device_attribute *attr, char *buf)
946 struct gendisk *disk = dev_to_disk(dev);
948 return sprintf(buf, "%d\n",
949 (disk->flags & GENHD_FL_HIDDEN ? 1 : 0));
952 static ssize_t disk_ro_show(struct device *dev,
953 struct device_attribute *attr, char *buf)
955 struct gendisk *disk = dev_to_disk(dev);
957 return sprintf(buf, "%d\n", get_disk_ro(disk) ? 1 : 0);
960 ssize_t part_size_show(struct device *dev,
961 struct device_attribute *attr, char *buf)
963 return sprintf(buf, "%llu\n", bdev_nr_sectors(dev_to_bdev(dev)));
966 ssize_t part_stat_show(struct device *dev,
967 struct device_attribute *attr, char *buf)
969 struct block_device *bdev = dev_to_bdev(dev);
970 struct request_queue *q = bdev_get_queue(bdev);
971 struct disk_stats stat;
972 unsigned int inflight;
975 inflight = blk_mq_in_flight(q, bdev);
977 inflight = part_in_flight(bdev);
981 update_io_ticks(bdev, jiffies, true);
984 part_stat_read_all(bdev, &stat);
986 "%8lu %8lu %8llu %8u "
987 "%8lu %8lu %8llu %8u "
989 "%8lu %8lu %8llu %8u "
993 stat.merges[STAT_READ],
994 (unsigned long long)stat.sectors[STAT_READ],
995 (unsigned int)div_u64(stat.nsecs[STAT_READ], NSEC_PER_MSEC),
996 stat.ios[STAT_WRITE],
997 stat.merges[STAT_WRITE],
998 (unsigned long long)stat.sectors[STAT_WRITE],
999 (unsigned int)div_u64(stat.nsecs[STAT_WRITE], NSEC_PER_MSEC),
1001 jiffies_to_msecs(stat.io_ticks),
1002 (unsigned int)div_u64(stat.nsecs[STAT_READ] +
1003 stat.nsecs[STAT_WRITE] +
1004 stat.nsecs[STAT_DISCARD] +
1005 stat.nsecs[STAT_FLUSH],
1007 stat.ios[STAT_DISCARD],
1008 stat.merges[STAT_DISCARD],
1009 (unsigned long long)stat.sectors[STAT_DISCARD],
1010 (unsigned int)div_u64(stat.nsecs[STAT_DISCARD], NSEC_PER_MSEC),
1011 stat.ios[STAT_FLUSH],
1012 (unsigned int)div_u64(stat.nsecs[STAT_FLUSH], NSEC_PER_MSEC));
1015 ssize_t part_inflight_show(struct device *dev, struct device_attribute *attr,
1018 struct block_device *bdev = dev_to_bdev(dev);
1019 struct request_queue *q = bdev_get_queue(bdev);
1020 unsigned int inflight[2];
1023 blk_mq_in_flight_rw(q, bdev, inflight);
1025 part_in_flight_rw(bdev, inflight);
1027 return sprintf(buf, "%8u %8u\n", inflight[0], inflight[1]);
1030 static ssize_t disk_capability_show(struct device *dev,
1031 struct device_attribute *attr, char *buf)
1033 dev_warn_once(dev, "the capability attribute has been deprecated.\n");
1034 return sprintf(buf, "0\n");
1037 static ssize_t disk_alignment_offset_show(struct device *dev,
1038 struct device_attribute *attr,
1041 struct gendisk *disk = dev_to_disk(dev);
1043 return sprintf(buf, "%d\n", bdev_alignment_offset(disk->part0));
1046 static ssize_t disk_discard_alignment_show(struct device *dev,
1047 struct device_attribute *attr,
1050 struct gendisk *disk = dev_to_disk(dev);
1052 return sprintf(buf, "%d\n", bdev_alignment_offset(disk->part0));
1055 static ssize_t diskseq_show(struct device *dev,
1056 struct device_attribute *attr, char *buf)
1058 struct gendisk *disk = dev_to_disk(dev);
1060 return sprintf(buf, "%llu\n", disk->diskseq);
1063 static DEVICE_ATTR(range, 0444, disk_range_show, NULL);
1064 static DEVICE_ATTR(ext_range, 0444, disk_ext_range_show, NULL);
1065 static DEVICE_ATTR(removable, 0444, disk_removable_show, NULL);
1066 static DEVICE_ATTR(hidden, 0444, disk_hidden_show, NULL);
1067 static DEVICE_ATTR(ro, 0444, disk_ro_show, NULL);
1068 static DEVICE_ATTR(size, 0444, part_size_show, NULL);
1069 static DEVICE_ATTR(alignment_offset, 0444, disk_alignment_offset_show, NULL);
1070 static DEVICE_ATTR(discard_alignment, 0444, disk_discard_alignment_show, NULL);
1071 static DEVICE_ATTR(capability, 0444, disk_capability_show, NULL);
1072 static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);
1073 static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);
1074 static DEVICE_ATTR(badblocks, 0644, disk_badblocks_show, disk_badblocks_store);
1075 static DEVICE_ATTR(diskseq, 0444, diskseq_show, NULL);
1077 #ifdef CONFIG_FAIL_MAKE_REQUEST
1078 ssize_t part_fail_show(struct device *dev,
1079 struct device_attribute *attr, char *buf)
1081 return sprintf(buf, "%d\n", dev_to_bdev(dev)->bd_make_it_fail);
1084 ssize_t part_fail_store(struct device *dev,
1085 struct device_attribute *attr,
1086 const char *buf, size_t count)
1090 if (count > 0 && sscanf(buf, "%d", &i) > 0)
1091 dev_to_bdev(dev)->bd_make_it_fail = i;
1096 static struct device_attribute dev_attr_fail =
1097 __ATTR(make-it-fail, 0644, part_fail_show, part_fail_store);
1098 #endif /* CONFIG_FAIL_MAKE_REQUEST */
1100 #ifdef CONFIG_FAIL_IO_TIMEOUT
1101 static struct device_attribute dev_attr_fail_timeout =
1102 __ATTR(io-timeout-fail, 0644, part_timeout_show, part_timeout_store);
1105 static struct attribute *disk_attrs[] = {
1106 &dev_attr_range.attr,
1107 &dev_attr_ext_range.attr,
1108 &dev_attr_removable.attr,
1109 &dev_attr_hidden.attr,
1111 &dev_attr_size.attr,
1112 &dev_attr_alignment_offset.attr,
1113 &dev_attr_discard_alignment.attr,
1114 &dev_attr_capability.attr,
1115 &dev_attr_stat.attr,
1116 &dev_attr_inflight.attr,
1117 &dev_attr_badblocks.attr,
1118 &dev_attr_events.attr,
1119 &dev_attr_events_async.attr,
1120 &dev_attr_events_poll_msecs.attr,
1121 &dev_attr_diskseq.attr,
1122 #ifdef CONFIG_FAIL_MAKE_REQUEST
1123 &dev_attr_fail.attr,
1125 #ifdef CONFIG_FAIL_IO_TIMEOUT
1126 &dev_attr_fail_timeout.attr,
1131 static umode_t disk_visible(struct kobject *kobj, struct attribute *a, int n)
1133 struct device *dev = container_of(kobj, typeof(*dev), kobj);
1134 struct gendisk *disk = dev_to_disk(dev);
1136 if (a == &dev_attr_badblocks.attr && !disk->bb)
1141 static struct attribute_group disk_attr_group = {
1142 .attrs = disk_attrs,
1143 .is_visible = disk_visible,
1146 static const struct attribute_group *disk_attr_groups[] = {
1148 #ifdef CONFIG_BLK_DEV_IO_TRACE
1149 &blk_trace_attr_group,
1155 * disk_release - releases all allocated resources of the gendisk
1156 * @dev: the device representing this disk
1158 * This function releases all allocated resources of the gendisk.
1160 * Drivers which used __device_add_disk() have a gendisk with a request_queue
1161 * assigned. Since the request_queue sits on top of the gendisk for these
1162 * drivers we also call blk_put_queue() for them, and we expect the
1163 * request_queue refcount to reach 0 at this point, and so the request_queue
1164 * will also be freed prior to the disk.
1166 * Context: can sleep
1168 static void disk_release(struct device *dev)
1170 struct gendisk *disk = dev_to_disk(dev);
1173 WARN_ON_ONCE(disk_live(disk));
1176 * To undo the all initialization from blk_mq_init_allocated_queue in
1177 * case of a probe failure where add_disk is never called we have to
1178 * call blk_mq_exit_queue here. We can't do this for the more common
1179 * teardown case (yet) as the tagset can be gone by the time the disk
1180 * is released once it was added.
1182 if (queue_is_mq(disk->queue) &&
1183 test_bit(GD_OWNS_QUEUE, &disk->state) &&
1184 !test_bit(GD_ADDED, &disk->state))
1185 blk_mq_exit_queue(disk->queue);
1187 blkcg_exit_disk(disk);
1189 bioset_exit(&disk->bio_split);
1191 disk_release_events(disk);
1192 kfree(disk->random);
1193 disk_free_zone_bitmaps(disk);
1194 xa_destroy(&disk->part_tbl);
1196 disk->queue->disk = NULL;
1197 blk_put_queue(disk->queue);
1199 if (test_bit(GD_ADDED, &disk->state) && disk->fops->free_disk)
1200 disk->fops->free_disk(disk);
1202 iput(disk->part0->bd_inode); /* frees the disk */
1205 static int block_uevent(const struct device *dev, struct kobj_uevent_env *env)
1207 const struct gendisk *disk = dev_to_disk(dev);
1209 return add_uevent_var(env, "DISKSEQ=%llu", disk->diskseq);
1212 struct class block_class = {
1214 .dev_uevent = block_uevent,
1217 static char *block_devnode(const struct device *dev, umode_t *mode,
1218 kuid_t *uid, kgid_t *gid)
1220 struct gendisk *disk = dev_to_disk(dev);
1222 if (disk->fops->devnode)
1223 return disk->fops->devnode(disk, mode);
1227 const struct device_type disk_type = {
1229 .groups = disk_attr_groups,
1230 .release = disk_release,
1231 .devnode = block_devnode,
1234 #ifdef CONFIG_PROC_FS
1236 * aggregate disk stat collector. Uses the same stats that the sysfs
1237 * entries do, above, but makes them available through one seq_file.
1239 * The output looks suspiciously like /proc/partitions with a bunch of
1242 static int diskstats_show(struct seq_file *seqf, void *v)
1244 struct gendisk *gp = v;
1245 struct block_device *hd;
1246 unsigned int inflight;
1247 struct disk_stats stat;
1251 if (&disk_to_dev(gp)->kobj.entry == block_class.devices.next)
1252 seq_puts(seqf, "major minor name"
1253 " rio rmerge rsect ruse wio wmerge "
1254 "wsect wuse running use aveq"
1259 xa_for_each(&gp->part_tbl, idx, hd) {
1260 if (bdev_is_partition(hd) && !bdev_nr_sectors(hd))
1262 if (queue_is_mq(gp->queue))
1263 inflight = blk_mq_in_flight(gp->queue, hd);
1265 inflight = part_in_flight(hd);
1269 update_io_ticks(hd, jiffies, true);
1272 part_stat_read_all(hd, &stat);
1273 seq_printf(seqf, "%4d %7d %pg "
1280 MAJOR(hd->bd_dev), MINOR(hd->bd_dev), hd,
1281 stat.ios[STAT_READ],
1282 stat.merges[STAT_READ],
1283 stat.sectors[STAT_READ],
1284 (unsigned int)div_u64(stat.nsecs[STAT_READ],
1286 stat.ios[STAT_WRITE],
1287 stat.merges[STAT_WRITE],
1288 stat.sectors[STAT_WRITE],
1289 (unsigned int)div_u64(stat.nsecs[STAT_WRITE],
1292 jiffies_to_msecs(stat.io_ticks),
1293 (unsigned int)div_u64(stat.nsecs[STAT_READ] +
1294 stat.nsecs[STAT_WRITE] +
1295 stat.nsecs[STAT_DISCARD] +
1296 stat.nsecs[STAT_FLUSH],
1298 stat.ios[STAT_DISCARD],
1299 stat.merges[STAT_DISCARD],
1300 stat.sectors[STAT_DISCARD],
1301 (unsigned int)div_u64(stat.nsecs[STAT_DISCARD],
1303 stat.ios[STAT_FLUSH],
1304 (unsigned int)div_u64(stat.nsecs[STAT_FLUSH],
1313 static const struct seq_operations diskstats_op = {
1314 .start = disk_seqf_start,
1315 .next = disk_seqf_next,
1316 .stop = disk_seqf_stop,
1317 .show = diskstats_show
1320 static int __init proc_genhd_init(void)
1322 proc_create_seq("diskstats", 0, NULL, &diskstats_op);
1323 proc_create_seq("partitions", 0, NULL, &partitions_op);
1326 module_init(proc_genhd_init);
1327 #endif /* CONFIG_PROC_FS */
1329 dev_t part_devt(struct gendisk *disk, u8 partno)
1331 struct block_device *part;
1335 part = xa_load(&disk->part_tbl, partno);
1337 devt = part->bd_dev;
1343 dev_t blk_lookup_devt(const char *name, int partno)
1345 dev_t devt = MKDEV(0, 0);
1346 struct class_dev_iter iter;
1349 class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
1350 while ((dev = class_dev_iter_next(&iter))) {
1351 struct gendisk *disk = dev_to_disk(dev);
1353 if (strcmp(dev_name(dev), name))
1356 if (partno < disk->minors) {
1357 /* We need to return the right devno, even
1358 * if the partition doesn't exist yet.
1360 devt = MKDEV(MAJOR(dev->devt),
1361 MINOR(dev->devt) + partno);
1363 devt = part_devt(disk, partno);
1368 class_dev_iter_exit(&iter);
1372 struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id,
1373 struct lock_class_key *lkclass)
1375 struct gendisk *disk;
1377 disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);
1381 if (bioset_init(&disk->bio_split, BIO_POOL_SIZE, 0, 0))
1384 disk->bdi = bdi_alloc(node_id);
1386 goto out_free_bioset;
1388 /* bdev_alloc() might need the queue, set before the first call */
1391 disk->part0 = bdev_alloc(disk, 0);
1395 disk->node_id = node_id;
1396 mutex_init(&disk->open_mutex);
1397 xa_init(&disk->part_tbl);
1398 if (xa_insert(&disk->part_tbl, 0, disk->part0, GFP_KERNEL))
1399 goto out_destroy_part_tbl;
1401 if (blkcg_init_disk(disk))
1402 goto out_erase_part0;
1404 rand_initialize_disk(disk);
1405 disk_to_dev(disk)->class = &block_class;
1406 disk_to_dev(disk)->type = &disk_type;
1407 device_initialize(disk_to_dev(disk));
1410 lockdep_init_map(&disk->lockdep_map, "(bio completion)", lkclass, 0);
1411 #ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
1412 INIT_LIST_HEAD(&disk->slave_bdevs);
1417 xa_erase(&disk->part_tbl, 0);
1418 out_destroy_part_tbl:
1419 xa_destroy(&disk->part_tbl);
1420 disk->part0->bd_disk = NULL;
1421 iput(disk->part0->bd_inode);
1425 bioset_exit(&disk->bio_split);
1431 struct gendisk *__blk_alloc_disk(int node, struct lock_class_key *lkclass)
1433 struct request_queue *q;
1434 struct gendisk *disk;
1436 q = blk_alloc_queue(node);
1440 disk = __alloc_disk_node(q, node, lkclass);
1445 set_bit(GD_OWNS_QUEUE, &disk->state);
1448 EXPORT_SYMBOL(__blk_alloc_disk);
1451 * put_disk - decrements the gendisk refcount
1452 * @disk: the struct gendisk to decrement the refcount for
1454 * This decrements the refcount for the struct gendisk. When this reaches 0
1455 * we'll have disk_release() called.
1457 * Note: for blk-mq disk put_disk must be called before freeing the tag_set
1458 * when handling probe errors (that is before add_disk() is called).
1460 * Context: Any context, but the last reference must not be dropped from
1463 void put_disk(struct gendisk *disk)
1466 put_device(disk_to_dev(disk));
1468 EXPORT_SYMBOL(put_disk);
1470 static void set_disk_ro_uevent(struct gendisk *gd, int ro)
1472 char event[] = "DISK_RO=1";
1473 char *envp[] = { event, NULL };
1477 kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp);
1481 * set_disk_ro - set a gendisk read-only
1482 * @disk: gendisk to operate on
1483 * @read_only: %true to set the disk read-only, %false set the disk read/write
1485 * This function is used to indicate whether a given disk device should have its
1486 * read-only flag set. set_disk_ro() is typically used by device drivers to
1487 * indicate whether the underlying physical device is write-protected.
1489 void set_disk_ro(struct gendisk *disk, bool read_only)
1492 if (test_and_set_bit(GD_READ_ONLY, &disk->state))
1495 if (!test_and_clear_bit(GD_READ_ONLY, &disk->state))
1498 set_disk_ro_uevent(disk, read_only);
1500 EXPORT_SYMBOL(set_disk_ro);
1502 void inc_diskseq(struct gendisk *disk)
1504 disk->diskseq = atomic64_inc_return(&diskseq);