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/genhd.h>
12 #include <linux/kdev_t.h>
13 #include <linux/kernel.h>
14 #include <linux/blkdev.h>
15 #include <linux/backing-dev.h>
16 #include <linux/init.h>
17 #include <linux/spinlock.h>
18 #include <linux/proc_fs.h>
19 #include <linux/seq_file.h>
20 #include <linux/slab.h>
21 #include <linux/kmod.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>
29 #include "blk-rq-qos.h"
31 static struct kobject *block_depr;
34 * Unique, monotonically increasing sequential number associated with block
35 * devices instances (i.e. incremented each time a device is attached).
36 * Associating uevents with block devices in userspace is difficult and racy:
37 * the uevent netlink socket is lossy, and on slow and overloaded systems has
38 * a very high latency.
39 * Block devices do not have exclusive owners in userspace, any process can set
40 * one up (e.g. loop devices). Moreover, device names can be reused (e.g. loop0
41 * can be reused again and again).
42 * A userspace process setting up a block device and watching for its events
43 * cannot thus reliably tell whether an event relates to the device it just set
44 * up or another earlier instance with the same name.
45 * This sequential number allows userspace processes to solve this problem, and
46 * uniquely associate an uevent to the lifetime to a device.
48 static atomic64_t diskseq;
50 /* for extended dynamic devt allocation, currently only one major is used */
51 #define NR_EXT_DEVT (1 << MINORBITS)
52 static DEFINE_IDA(ext_devt_ida);
54 void set_capacity(struct gendisk *disk, sector_t sectors)
56 struct block_device *bdev = disk->part0;
58 spin_lock(&bdev->bd_size_lock);
59 i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT);
60 spin_unlock(&bdev->bd_size_lock);
62 EXPORT_SYMBOL(set_capacity);
65 * Set disk capacity and notify if the size is not currently zero and will not
66 * be set to zero. Returns true if a uevent was sent, otherwise false.
68 bool set_capacity_and_notify(struct gendisk *disk, sector_t size)
70 sector_t capacity = get_capacity(disk);
71 char *envp[] = { "RESIZE=1", NULL };
73 set_capacity(disk, size);
76 * Only print a message and send a uevent if the gendisk is user visible
77 * and alive. This avoids spamming the log and udev when setting the
78 * initial capacity during probing.
80 if (size == capacity ||
82 (disk->flags & GENHD_FL_HIDDEN))
85 pr_info("%s: detected capacity change from %lld to %lld\n",
86 disk->disk_name, capacity, size);
89 * Historically we did not send a uevent for changes to/from an empty
92 if (!capacity || !size)
94 kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp);
97 EXPORT_SYMBOL_GPL(set_capacity_and_notify);
100 * Format the device name of the indicated block device into the supplied buffer
101 * and return a pointer to that same buffer for convenience.
103 * Note: do not use this in new code, use the %pg specifier to sprintf and
106 const char *bdevname(struct block_device *bdev, char *buf)
108 struct gendisk *hd = bdev->bd_disk;
109 int partno = bdev->bd_partno;
112 snprintf(buf, BDEVNAME_SIZE, "%s", hd->disk_name);
113 else if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
114 snprintf(buf, BDEVNAME_SIZE, "%sp%d", hd->disk_name, partno);
116 snprintf(buf, BDEVNAME_SIZE, "%s%d", hd->disk_name, partno);
120 EXPORT_SYMBOL(bdevname);
122 static void part_stat_read_all(struct block_device *part,
123 struct disk_stats *stat)
127 memset(stat, 0, sizeof(struct disk_stats));
128 for_each_possible_cpu(cpu) {
129 struct disk_stats *ptr = per_cpu_ptr(part->bd_stats, cpu);
132 for (group = 0; group < NR_STAT_GROUPS; group++) {
133 stat->nsecs[group] += ptr->nsecs[group];
134 stat->sectors[group] += ptr->sectors[group];
135 stat->ios[group] += ptr->ios[group];
136 stat->merges[group] += ptr->merges[group];
139 stat->io_ticks += ptr->io_ticks;
143 static unsigned int part_in_flight(struct block_device *part)
145 unsigned int inflight = 0;
148 for_each_possible_cpu(cpu) {
149 inflight += part_stat_local_read_cpu(part, in_flight[0], cpu) +
150 part_stat_local_read_cpu(part, in_flight[1], cpu);
152 if ((int)inflight < 0)
158 static void part_in_flight_rw(struct block_device *part,
159 unsigned int inflight[2])
165 for_each_possible_cpu(cpu) {
166 inflight[0] += part_stat_local_read_cpu(part, in_flight[0], cpu);
167 inflight[1] += part_stat_local_read_cpu(part, in_flight[1], cpu);
169 if ((int)inflight[0] < 0)
171 if ((int)inflight[1] < 0)
176 * Can be deleted altogether. Later.
179 #define BLKDEV_MAJOR_HASH_SIZE 255
180 static struct blk_major_name {
181 struct blk_major_name *next;
184 void (*probe)(dev_t devt);
185 } *major_names[BLKDEV_MAJOR_HASH_SIZE];
186 static DEFINE_MUTEX(major_names_lock);
187 static DEFINE_SPINLOCK(major_names_spinlock);
189 /* index in the above - for now: assume no multimajor ranges */
190 static inline int major_to_index(unsigned major)
192 return major % BLKDEV_MAJOR_HASH_SIZE;
195 #ifdef CONFIG_PROC_FS
196 void blkdev_show(struct seq_file *seqf, off_t offset)
198 struct blk_major_name *dp;
200 spin_lock(&major_names_spinlock);
201 for (dp = major_names[major_to_index(offset)]; dp; dp = dp->next)
202 if (dp->major == offset)
203 seq_printf(seqf, "%3d %s\n", dp->major, dp->name);
204 spin_unlock(&major_names_spinlock);
206 #endif /* CONFIG_PROC_FS */
209 * __register_blkdev - register a new block device
211 * @major: the requested major device number [1..BLKDEV_MAJOR_MAX-1]. If
212 * @major = 0, try to allocate any unused major number.
213 * @name: the name of the new block device as a zero terminated string
214 * @probe: allback that is called on access to any minor number of @major
216 * The @name must be unique within the system.
218 * The return value depends on the @major input parameter:
220 * - if a major device number was requested in range [1..BLKDEV_MAJOR_MAX-1]
221 * then the function returns zero on success, or a negative error code
222 * - if any unused major number was requested with @major = 0 parameter
223 * then the return value is the allocated major number in range
224 * [1..BLKDEV_MAJOR_MAX-1] or a negative error code otherwise
226 * See Documentation/admin-guide/devices.txt for the list of allocated
229 * Use register_blkdev instead for any new code.
231 int __register_blkdev(unsigned int major, const char *name,
232 void (*probe)(dev_t devt))
234 struct blk_major_name **n, *p;
237 mutex_lock(&major_names_lock);
241 for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) {
242 if (major_names[index] == NULL)
247 printk("%s: failed to get major for %s\n",
256 if (major >= BLKDEV_MAJOR_MAX) {
257 pr_err("%s: major requested (%u) is greater than the maximum (%u) for %s\n",
258 __func__, major, BLKDEV_MAJOR_MAX-1, name);
264 p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL);
272 strlcpy(p->name, name, sizeof(p->name));
274 index = major_to_index(major);
276 spin_lock(&major_names_spinlock);
277 for (n = &major_names[index]; *n; n = &(*n)->next) {
278 if ((*n)->major == major)
285 spin_unlock(&major_names_spinlock);
288 printk("register_blkdev: cannot get major %u for %s\n",
293 mutex_unlock(&major_names_lock);
296 EXPORT_SYMBOL(__register_blkdev);
298 void unregister_blkdev(unsigned int major, const char *name)
300 struct blk_major_name **n;
301 struct blk_major_name *p = NULL;
302 int index = major_to_index(major);
304 mutex_lock(&major_names_lock);
305 spin_lock(&major_names_spinlock);
306 for (n = &major_names[index]; *n; n = &(*n)->next)
307 if ((*n)->major == major)
309 if (!*n || strcmp((*n)->name, name)) {
315 spin_unlock(&major_names_spinlock);
316 mutex_unlock(&major_names_lock);
320 EXPORT_SYMBOL(unregister_blkdev);
322 int blk_alloc_ext_minor(void)
326 idx = ida_alloc_range(&ext_devt_ida, 0, NR_EXT_DEVT, GFP_KERNEL);
332 void blk_free_ext_minor(unsigned int minor)
334 ida_free(&ext_devt_ida, minor);
337 static char *bdevt_str(dev_t devt, char *buf)
339 if (MAJOR(devt) <= 0xff && MINOR(devt) <= 0xff) {
340 char tbuf[BDEVT_SIZE];
341 snprintf(tbuf, BDEVT_SIZE, "%02x%02x", MAJOR(devt), MINOR(devt));
342 snprintf(buf, BDEVT_SIZE, "%-9s", tbuf);
344 snprintf(buf, BDEVT_SIZE, "%03x:%05x", MAJOR(devt), MINOR(devt));
349 void disk_uevent(struct gendisk *disk, enum kobject_action action)
351 struct block_device *part;
355 xa_for_each(&disk->part_tbl, idx, part) {
356 if (bdev_is_partition(part) && !bdev_nr_sectors(part))
358 if (!kobject_get_unless_zero(&part->bd_device.kobj))
362 kobject_uevent(bdev_kobj(part), action);
363 put_device(&part->bd_device);
368 EXPORT_SYMBOL_GPL(disk_uevent);
370 static void disk_scan_partitions(struct gendisk *disk)
372 struct block_device *bdev;
374 if (!get_capacity(disk) || !disk_part_scan_enabled(disk))
377 set_bit(GD_NEED_PART_SCAN, &disk->state);
378 bdev = blkdev_get_by_dev(disk_devt(disk), FMODE_READ, NULL);
380 blkdev_put(bdev, FMODE_READ);
384 * device_add_disk - add disk information to kernel list
385 * @parent: parent device for the disk
386 * @disk: per-device partitioning information
387 * @groups: Additional per-device sysfs groups
389 * This function registers the partitioning information in @disk
392 int device_add_disk(struct device *parent, struct gendisk *disk,
393 const struct attribute_group **groups)
396 struct device *ddev = disk_to_dev(disk);
400 * The disk queue should now be all set with enough information about
401 * the device for the elevator code to pick an adequate default
402 * elevator if one is needed, that is, for devices requesting queue
405 elevator_init_mq(disk->queue);
408 * If the driver provides an explicit major number it also must provide
409 * the number of minors numbers supported, and those will be used to
411 * Otherwise just allocate the device numbers for both the whole device
412 * and all partitions from the extended dev_t space.
415 if (WARN_ON(!disk->minors))
418 if (disk->minors > DISK_MAX_PARTS) {
419 pr_err("block: can't allocate more than %d partitions\n",
421 disk->minors = DISK_MAX_PARTS;
423 if (disk->first_minor + disk->minors > MINORMASK + 1)
426 if (WARN_ON(disk->minors))
429 ret = blk_alloc_ext_minor();
432 disk->major = BLOCK_EXT_MAJOR;
433 disk->first_minor = ret;
434 disk->flags |= GENHD_FL_EXT_DEVT;
437 /* delay uevents, until we scanned partition table */
438 dev_set_uevent_suppress(ddev, 1);
440 ddev->parent = parent;
441 ddev->groups = groups;
442 dev_set_name(ddev, "%s", disk->disk_name);
443 if (!(disk->flags & GENHD_FL_HIDDEN))
444 ddev->devt = MKDEV(disk->major, disk->first_minor);
445 ret = device_add(ddev);
447 goto out_free_ext_minor;
449 ret = disk_alloc_events(disk);
453 if (!sysfs_deprecated) {
454 ret = sysfs_create_link(block_depr, &ddev->kobj,
455 kobject_name(&ddev->kobj));
461 * avoid probable deadlock caused by allocating memory with
462 * GFP_KERNEL in runtime_resume callback of its all ancestor
465 pm_runtime_set_memalloc_noio(ddev, true);
467 ret = blk_integrity_add(disk);
469 goto out_del_block_link;
471 disk->part0->bd_holder_dir =
472 kobject_create_and_add("holders", &ddev->kobj);
473 if (!disk->part0->bd_holder_dir) {
475 goto out_del_integrity;
477 disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
478 if (!disk->slave_dir) {
480 goto out_put_holder_dir;
483 ret = bd_register_pending_holders(disk);
485 goto out_put_slave_dir;
487 ret = blk_register_queue(disk);
489 goto out_put_slave_dir;
491 if (disk->flags & GENHD_FL_HIDDEN) {
493 * Don't let hidden disks show up in /proc/partitions,
494 * and don't bother scanning for partitions either.
496 disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO;
497 disk->flags |= GENHD_FL_NO_PART_SCAN;
499 ret = bdi_register(disk->bdi, "%u:%u",
500 disk->major, disk->first_minor);
502 goto out_unregister_queue;
503 bdi_set_owner(disk->bdi, ddev);
504 ret = sysfs_create_link(&ddev->kobj,
505 &disk->bdi->dev->kobj, "bdi");
507 goto out_unregister_bdi;
509 bdev_add(disk->part0, ddev->devt);
510 disk_scan_partitions(disk);
513 * Announce the disk and partitions after all partitions are
514 * created. (for hidden disks uevents remain suppressed forever)
516 dev_set_uevent_suppress(ddev, 0);
517 disk_uevent(disk, KOBJ_ADD);
520 disk_update_readahead(disk);
521 disk_add_events(disk);
525 if (!(disk->flags & GENHD_FL_HIDDEN))
526 bdi_unregister(disk->bdi);
527 out_unregister_queue:
528 blk_unregister_queue(disk);
530 kobject_put(disk->slave_dir);
532 kobject_put(disk->part0->bd_holder_dir);
534 blk_integrity_del(disk);
536 if (!sysfs_deprecated)
537 sysfs_remove_link(block_depr, dev_name(ddev));
541 if (disk->major == BLOCK_EXT_MAJOR)
542 blk_free_ext_minor(disk->first_minor);
543 return WARN_ON_ONCE(ret); /* keep until all callers handle errors */
545 EXPORT_SYMBOL(device_add_disk);
548 * del_gendisk - remove the gendisk
549 * @disk: the struct gendisk to remove
551 * Removes the gendisk and all its associated resources. This deletes the
552 * partitions associated with the gendisk, and unregisters the associated
555 * This is the counter to the respective __device_add_disk() call.
557 * The final removal of the struct gendisk happens when its refcount reaches 0
558 * with put_disk(), which should be called after del_gendisk(), if
559 * __device_add_disk() was used.
561 * Drivers exist which depend on the release of the gendisk to be synchronous,
562 * it should not be deferred.
566 void del_gendisk(struct gendisk *disk)
568 struct request_queue *q = disk->queue;
572 if (WARN_ON_ONCE(!disk_live(disk) && !(disk->flags & GENHD_FL_HIDDEN)))
575 blk_integrity_del(disk);
576 disk_del_events(disk);
578 mutex_lock(&disk->open_mutex);
579 remove_inode_hash(disk->part0->bd_inode);
580 blk_drop_partitions(disk);
581 mutex_unlock(&disk->open_mutex);
583 fsync_bdev(disk->part0);
584 __invalidate_device(disk->part0, true);
589 set_bit(GD_DEAD, &disk->state);
590 set_capacity(disk, 0);
593 * Prevent new I/O from crossing bio_queue_enter().
595 blk_queue_start_drain(q);
597 if (!(disk->flags & GENHD_FL_HIDDEN)) {
598 sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
601 * Unregister bdi before releasing device numbers (as they can
602 * get reused and we'd get clashes in sysfs).
604 bdi_unregister(disk->bdi);
607 blk_unregister_queue(disk);
609 kobject_put(disk->part0->bd_holder_dir);
610 kobject_put(disk->slave_dir);
612 part_stat_set_all(disk->part0, 0);
613 disk->part0->bd_stamp = 0;
614 if (!sysfs_deprecated)
615 sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
616 pm_runtime_set_memalloc_noio(disk_to_dev(disk), false);
617 device_del(disk_to_dev(disk));
619 blk_mq_freeze_queue_wait(q);
623 blk_flush_integrity();
625 * Allow using passthrough request again after the queue is torn down.
627 blk_queue_flag_clear(QUEUE_FLAG_INIT_DONE, q);
628 __blk_mq_unfreeze_queue(q, true);
631 EXPORT_SYMBOL(del_gendisk);
633 /* sysfs access to bad-blocks list. */
634 static ssize_t disk_badblocks_show(struct device *dev,
635 struct device_attribute *attr,
638 struct gendisk *disk = dev_to_disk(dev);
641 return sprintf(page, "\n");
643 return badblocks_show(disk->bb, page, 0);
646 static ssize_t disk_badblocks_store(struct device *dev,
647 struct device_attribute *attr,
648 const char *page, size_t len)
650 struct gendisk *disk = dev_to_disk(dev);
655 return badblocks_store(disk->bb, page, len, 0);
658 void blk_request_module(dev_t devt)
660 unsigned int major = MAJOR(devt);
661 struct blk_major_name **n;
663 mutex_lock(&major_names_lock);
664 for (n = &major_names[major_to_index(major)]; *n; n = &(*n)->next) {
665 if ((*n)->major == major && (*n)->probe) {
667 mutex_unlock(&major_names_lock);
671 mutex_unlock(&major_names_lock);
673 if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0)
674 /* Make old-style 2.4 aliases work */
675 request_module("block-major-%d", MAJOR(devt));
679 * print a full list of all partitions - intended for places where the root
680 * filesystem can't be mounted and thus to give the victim some idea of what
683 void __init printk_all_partitions(void)
685 struct class_dev_iter iter;
688 class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
689 while ((dev = class_dev_iter_next(&iter))) {
690 struct gendisk *disk = dev_to_disk(dev);
691 struct block_device *part;
692 char devt_buf[BDEVT_SIZE];
696 * Don't show empty devices or things that have been
699 if (get_capacity(disk) == 0 ||
700 (disk->flags & GENHD_FL_SUPPRESS_PARTITION_INFO))
704 * Note, unlike /proc/partitions, I am showing the numbers in
705 * hex - the same format as the root= option takes.
708 xa_for_each(&disk->part_tbl, idx, part) {
709 if (!bdev_nr_sectors(part))
711 printk("%s%s %10llu %pg %s",
712 bdev_is_partition(part) ? " " : "",
713 bdevt_str(part->bd_dev, devt_buf),
714 bdev_nr_sectors(part) >> 1, part,
716 part->bd_meta_info->uuid : "");
717 if (bdev_is_partition(part))
719 else if (dev->parent && dev->parent->driver)
720 printk(" driver: %s\n",
721 dev->parent->driver->name);
723 printk(" (driver?)\n");
727 class_dev_iter_exit(&iter);
730 #ifdef CONFIG_PROC_FS
732 static void *disk_seqf_start(struct seq_file *seqf, loff_t *pos)
735 struct class_dev_iter *iter;
738 iter = kmalloc(sizeof(*iter), GFP_KERNEL);
740 return ERR_PTR(-ENOMEM);
742 seqf->private = iter;
743 class_dev_iter_init(iter, &block_class, NULL, &disk_type);
745 dev = class_dev_iter_next(iter);
750 return dev_to_disk(dev);
753 static void *disk_seqf_next(struct seq_file *seqf, void *v, loff_t *pos)
758 dev = class_dev_iter_next(seqf->private);
760 return dev_to_disk(dev);
765 static void disk_seqf_stop(struct seq_file *seqf, void *v)
767 struct class_dev_iter *iter = seqf->private;
769 /* stop is called even after start failed :-( */
771 class_dev_iter_exit(iter);
773 seqf->private = NULL;
777 static void *show_partition_start(struct seq_file *seqf, loff_t *pos)
781 p = disk_seqf_start(seqf, pos);
782 if (!IS_ERR_OR_NULL(p) && !*pos)
783 seq_puts(seqf, "major minor #blocks name\n\n");
787 static int show_partition(struct seq_file *seqf, void *v)
789 struct gendisk *sgp = v;
790 struct block_device *part;
793 /* Don't show non-partitionable removeable devices or empty devices */
794 if (!get_capacity(sgp) || (!disk_max_parts(sgp) &&
795 (sgp->flags & GENHD_FL_REMOVABLE)))
797 if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)
801 xa_for_each(&sgp->part_tbl, idx, part) {
802 if (!bdev_nr_sectors(part))
804 seq_printf(seqf, "%4d %7d %10llu %pg\n",
805 MAJOR(part->bd_dev), MINOR(part->bd_dev),
806 bdev_nr_sectors(part) >> 1, part);
812 static const struct seq_operations partitions_op = {
813 .start = show_partition_start,
814 .next = disk_seqf_next,
815 .stop = disk_seqf_stop,
816 .show = show_partition
820 static int __init genhd_device_init(void)
824 block_class.dev_kobj = sysfs_dev_block_kobj;
825 error = class_register(&block_class);
830 register_blkdev(BLOCK_EXT_MAJOR, "blkext");
832 /* create top-level block dir */
833 if (!sysfs_deprecated)
834 block_depr = kobject_create_and_add("block", NULL);
838 subsys_initcall(genhd_device_init);
840 static ssize_t disk_range_show(struct device *dev,
841 struct device_attribute *attr, char *buf)
843 struct gendisk *disk = dev_to_disk(dev);
845 return sprintf(buf, "%d\n", disk->minors);
848 static ssize_t disk_ext_range_show(struct device *dev,
849 struct device_attribute *attr, char *buf)
851 struct gendisk *disk = dev_to_disk(dev);
853 return sprintf(buf, "%d\n", disk_max_parts(disk));
856 static ssize_t disk_removable_show(struct device *dev,
857 struct device_attribute *attr, char *buf)
859 struct gendisk *disk = dev_to_disk(dev);
861 return sprintf(buf, "%d\n",
862 (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0));
865 static ssize_t disk_hidden_show(struct device *dev,
866 struct device_attribute *attr, char *buf)
868 struct gendisk *disk = dev_to_disk(dev);
870 return sprintf(buf, "%d\n",
871 (disk->flags & GENHD_FL_HIDDEN ? 1 : 0));
874 static ssize_t disk_ro_show(struct device *dev,
875 struct device_attribute *attr, char *buf)
877 struct gendisk *disk = dev_to_disk(dev);
879 return sprintf(buf, "%d\n", get_disk_ro(disk) ? 1 : 0);
882 ssize_t part_size_show(struct device *dev,
883 struct device_attribute *attr, char *buf)
885 return sprintf(buf, "%llu\n", bdev_nr_sectors(dev_to_bdev(dev)));
888 ssize_t part_stat_show(struct device *dev,
889 struct device_attribute *attr, char *buf)
891 struct block_device *bdev = dev_to_bdev(dev);
892 struct request_queue *q = bdev->bd_disk->queue;
893 struct disk_stats stat;
894 unsigned int inflight;
896 part_stat_read_all(bdev, &stat);
898 inflight = blk_mq_in_flight(q, bdev);
900 inflight = part_in_flight(bdev);
903 "%8lu %8lu %8llu %8u "
904 "%8lu %8lu %8llu %8u "
906 "%8lu %8lu %8llu %8u "
910 stat.merges[STAT_READ],
911 (unsigned long long)stat.sectors[STAT_READ],
912 (unsigned int)div_u64(stat.nsecs[STAT_READ], NSEC_PER_MSEC),
913 stat.ios[STAT_WRITE],
914 stat.merges[STAT_WRITE],
915 (unsigned long long)stat.sectors[STAT_WRITE],
916 (unsigned int)div_u64(stat.nsecs[STAT_WRITE], NSEC_PER_MSEC),
918 jiffies_to_msecs(stat.io_ticks),
919 (unsigned int)div_u64(stat.nsecs[STAT_READ] +
920 stat.nsecs[STAT_WRITE] +
921 stat.nsecs[STAT_DISCARD] +
922 stat.nsecs[STAT_FLUSH],
924 stat.ios[STAT_DISCARD],
925 stat.merges[STAT_DISCARD],
926 (unsigned long long)stat.sectors[STAT_DISCARD],
927 (unsigned int)div_u64(stat.nsecs[STAT_DISCARD], NSEC_PER_MSEC),
928 stat.ios[STAT_FLUSH],
929 (unsigned int)div_u64(stat.nsecs[STAT_FLUSH], NSEC_PER_MSEC));
932 ssize_t part_inflight_show(struct device *dev, struct device_attribute *attr,
935 struct block_device *bdev = dev_to_bdev(dev);
936 struct request_queue *q = bdev->bd_disk->queue;
937 unsigned int inflight[2];
940 blk_mq_in_flight_rw(q, bdev, inflight);
942 part_in_flight_rw(bdev, inflight);
944 return sprintf(buf, "%8u %8u\n", inflight[0], inflight[1]);
947 static ssize_t disk_capability_show(struct device *dev,
948 struct device_attribute *attr, char *buf)
950 struct gendisk *disk = dev_to_disk(dev);
952 return sprintf(buf, "%x\n", disk->flags);
955 static ssize_t disk_alignment_offset_show(struct device *dev,
956 struct device_attribute *attr,
959 struct gendisk *disk = dev_to_disk(dev);
961 return sprintf(buf, "%d\n", queue_alignment_offset(disk->queue));
964 static ssize_t disk_discard_alignment_show(struct device *dev,
965 struct device_attribute *attr,
968 struct gendisk *disk = dev_to_disk(dev);
970 return sprintf(buf, "%d\n", queue_discard_alignment(disk->queue));
973 static ssize_t diskseq_show(struct device *dev,
974 struct device_attribute *attr, char *buf)
976 struct gendisk *disk = dev_to_disk(dev);
978 return sprintf(buf, "%llu\n", disk->diskseq);
981 static DEVICE_ATTR(range, 0444, disk_range_show, NULL);
982 static DEVICE_ATTR(ext_range, 0444, disk_ext_range_show, NULL);
983 static DEVICE_ATTR(removable, 0444, disk_removable_show, NULL);
984 static DEVICE_ATTR(hidden, 0444, disk_hidden_show, NULL);
985 static DEVICE_ATTR(ro, 0444, disk_ro_show, NULL);
986 static DEVICE_ATTR(size, 0444, part_size_show, NULL);
987 static DEVICE_ATTR(alignment_offset, 0444, disk_alignment_offset_show, NULL);
988 static DEVICE_ATTR(discard_alignment, 0444, disk_discard_alignment_show, NULL);
989 static DEVICE_ATTR(capability, 0444, disk_capability_show, NULL);
990 static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);
991 static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);
992 static DEVICE_ATTR(badblocks, 0644, disk_badblocks_show, disk_badblocks_store);
993 static DEVICE_ATTR(diskseq, 0444, diskseq_show, NULL);
995 #ifdef CONFIG_FAIL_MAKE_REQUEST
996 ssize_t part_fail_show(struct device *dev,
997 struct device_attribute *attr, char *buf)
999 return sprintf(buf, "%d\n", dev_to_bdev(dev)->bd_make_it_fail);
1002 ssize_t part_fail_store(struct device *dev,
1003 struct device_attribute *attr,
1004 const char *buf, size_t count)
1008 if (count > 0 && sscanf(buf, "%d", &i) > 0)
1009 dev_to_bdev(dev)->bd_make_it_fail = i;
1014 static struct device_attribute dev_attr_fail =
1015 __ATTR(make-it-fail, 0644, part_fail_show, part_fail_store);
1016 #endif /* CONFIG_FAIL_MAKE_REQUEST */
1018 #ifdef CONFIG_FAIL_IO_TIMEOUT
1019 static struct device_attribute dev_attr_fail_timeout =
1020 __ATTR(io-timeout-fail, 0644, part_timeout_show, part_timeout_store);
1023 static struct attribute *disk_attrs[] = {
1024 &dev_attr_range.attr,
1025 &dev_attr_ext_range.attr,
1026 &dev_attr_removable.attr,
1027 &dev_attr_hidden.attr,
1029 &dev_attr_size.attr,
1030 &dev_attr_alignment_offset.attr,
1031 &dev_attr_discard_alignment.attr,
1032 &dev_attr_capability.attr,
1033 &dev_attr_stat.attr,
1034 &dev_attr_inflight.attr,
1035 &dev_attr_badblocks.attr,
1036 &dev_attr_events.attr,
1037 &dev_attr_events_async.attr,
1038 &dev_attr_events_poll_msecs.attr,
1039 &dev_attr_diskseq.attr,
1040 #ifdef CONFIG_FAIL_MAKE_REQUEST
1041 &dev_attr_fail.attr,
1043 #ifdef CONFIG_FAIL_IO_TIMEOUT
1044 &dev_attr_fail_timeout.attr,
1049 static umode_t disk_visible(struct kobject *kobj, struct attribute *a, int n)
1051 struct device *dev = container_of(kobj, typeof(*dev), kobj);
1052 struct gendisk *disk = dev_to_disk(dev);
1054 if (a == &dev_attr_badblocks.attr && !disk->bb)
1059 static struct attribute_group disk_attr_group = {
1060 .attrs = disk_attrs,
1061 .is_visible = disk_visible,
1064 static const struct attribute_group *disk_attr_groups[] = {
1070 * disk_release - releases all allocated resources of the gendisk
1071 * @dev: the device representing this disk
1073 * This function releases all allocated resources of the gendisk.
1075 * Drivers which used __device_add_disk() have a gendisk with a request_queue
1076 * assigned. Since the request_queue sits on top of the gendisk for these
1077 * drivers we also call blk_put_queue() for them, and we expect the
1078 * request_queue refcount to reach 0 at this point, and so the request_queue
1079 * will also be freed prior to the disk.
1081 * Context: can sleep
1083 static void disk_release(struct device *dev)
1085 struct gendisk *disk = dev_to_disk(dev);
1088 WARN_ON_ONCE(disk_live(disk));
1090 blk_mq_cancel_work_sync(disk->queue);
1092 disk_release_events(disk);
1093 kfree(disk->random);
1094 xa_destroy(&disk->part_tbl);
1095 disk->queue->disk = NULL;
1096 blk_put_queue(disk->queue);
1097 iput(disk->part0->bd_inode); /* frees the disk */
1100 static int block_uevent(struct device *dev, struct kobj_uevent_env *env)
1102 struct gendisk *disk = dev_to_disk(dev);
1104 return add_uevent_var(env, "DISKSEQ=%llu", disk->diskseq);
1107 struct class block_class = {
1109 .dev_uevent = block_uevent,
1112 static char *block_devnode(struct device *dev, umode_t *mode,
1113 kuid_t *uid, kgid_t *gid)
1115 struct gendisk *disk = dev_to_disk(dev);
1117 if (disk->fops->devnode)
1118 return disk->fops->devnode(disk, mode);
1122 const struct device_type disk_type = {
1124 .groups = disk_attr_groups,
1125 .release = disk_release,
1126 .devnode = block_devnode,
1129 #ifdef CONFIG_PROC_FS
1131 * aggregate disk stat collector. Uses the same stats that the sysfs
1132 * entries do, above, but makes them available through one seq_file.
1134 * The output looks suspiciously like /proc/partitions with a bunch of
1137 static int diskstats_show(struct seq_file *seqf, void *v)
1139 struct gendisk *gp = v;
1140 struct block_device *hd;
1141 unsigned int inflight;
1142 struct disk_stats stat;
1146 if (&disk_to_dev(gp)->kobj.entry == block_class.devices.next)
1147 seq_puts(seqf, "major minor name"
1148 " rio rmerge rsect ruse wio wmerge "
1149 "wsect wuse running use aveq"
1154 xa_for_each(&gp->part_tbl, idx, hd) {
1155 if (bdev_is_partition(hd) && !bdev_nr_sectors(hd))
1157 part_stat_read_all(hd, &stat);
1158 if (queue_is_mq(gp->queue))
1159 inflight = blk_mq_in_flight(gp->queue, hd);
1161 inflight = part_in_flight(hd);
1163 seq_printf(seqf, "%4d %7d %pg "
1170 MAJOR(hd->bd_dev), MINOR(hd->bd_dev), hd,
1171 stat.ios[STAT_READ],
1172 stat.merges[STAT_READ],
1173 stat.sectors[STAT_READ],
1174 (unsigned int)div_u64(stat.nsecs[STAT_READ],
1176 stat.ios[STAT_WRITE],
1177 stat.merges[STAT_WRITE],
1178 stat.sectors[STAT_WRITE],
1179 (unsigned int)div_u64(stat.nsecs[STAT_WRITE],
1182 jiffies_to_msecs(stat.io_ticks),
1183 (unsigned int)div_u64(stat.nsecs[STAT_READ] +
1184 stat.nsecs[STAT_WRITE] +
1185 stat.nsecs[STAT_DISCARD] +
1186 stat.nsecs[STAT_FLUSH],
1188 stat.ios[STAT_DISCARD],
1189 stat.merges[STAT_DISCARD],
1190 stat.sectors[STAT_DISCARD],
1191 (unsigned int)div_u64(stat.nsecs[STAT_DISCARD],
1193 stat.ios[STAT_FLUSH],
1194 (unsigned int)div_u64(stat.nsecs[STAT_FLUSH],
1203 static const struct seq_operations diskstats_op = {
1204 .start = disk_seqf_start,
1205 .next = disk_seqf_next,
1206 .stop = disk_seqf_stop,
1207 .show = diskstats_show
1210 static int __init proc_genhd_init(void)
1212 proc_create_seq("diskstats", 0, NULL, &diskstats_op);
1213 proc_create_seq("partitions", 0, NULL, &partitions_op);
1216 module_init(proc_genhd_init);
1217 #endif /* CONFIG_PROC_FS */
1219 dev_t part_devt(struct gendisk *disk, u8 partno)
1221 struct block_device *part;
1225 part = xa_load(&disk->part_tbl, partno);
1227 devt = part->bd_dev;
1233 dev_t blk_lookup_devt(const char *name, int partno)
1235 dev_t devt = MKDEV(0, 0);
1236 struct class_dev_iter iter;
1239 class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
1240 while ((dev = class_dev_iter_next(&iter))) {
1241 struct gendisk *disk = dev_to_disk(dev);
1243 if (strcmp(dev_name(dev), name))
1246 if (partno < disk->minors) {
1247 /* We need to return the right devno, even
1248 * if the partition doesn't exist yet.
1250 devt = MKDEV(MAJOR(dev->devt),
1251 MINOR(dev->devt) + partno);
1253 devt = part_devt(disk, partno);
1258 class_dev_iter_exit(&iter);
1262 struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id,
1263 struct lock_class_key *lkclass)
1265 struct gendisk *disk;
1267 if (!blk_get_queue(q))
1270 disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);
1274 disk->bdi = bdi_alloc(node_id);
1278 disk->part0 = bdev_alloc(disk, 0);
1282 disk->node_id = node_id;
1283 mutex_init(&disk->open_mutex);
1284 xa_init(&disk->part_tbl);
1285 if (xa_insert(&disk->part_tbl, 0, disk->part0, GFP_KERNEL))
1286 goto out_destroy_part_tbl;
1288 rand_initialize_disk(disk);
1289 disk_to_dev(disk)->class = &block_class;
1290 disk_to_dev(disk)->type = &disk_type;
1291 device_initialize(disk_to_dev(disk));
1295 lockdep_init_map(&disk->lockdep_map, "(bio completion)", lkclass, 0);
1296 #ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
1297 INIT_LIST_HEAD(&disk->slave_bdevs);
1301 out_destroy_part_tbl:
1302 xa_destroy(&disk->part_tbl);
1303 disk->part0->bd_disk = NULL;
1304 iput(disk->part0->bd_inode);
1313 EXPORT_SYMBOL(__alloc_disk_node);
1315 struct gendisk *__blk_alloc_disk(int node, struct lock_class_key *lkclass)
1317 struct request_queue *q;
1318 struct gendisk *disk;
1320 q = blk_alloc_queue(node);
1324 disk = __alloc_disk_node(q, node, lkclass);
1326 blk_cleanup_queue(q);
1331 EXPORT_SYMBOL(__blk_alloc_disk);
1334 * put_disk - decrements the gendisk refcount
1335 * @disk: the struct gendisk to decrement the refcount for
1337 * This decrements the refcount for the struct gendisk. When this reaches 0
1338 * we'll have disk_release() called.
1340 * Context: Any context, but the last reference must not be dropped from
1343 void put_disk(struct gendisk *disk)
1346 put_device(disk_to_dev(disk));
1348 EXPORT_SYMBOL(put_disk);
1351 * blk_cleanup_disk - shutdown a gendisk allocated by blk_alloc_disk
1352 * @disk: gendisk to shutdown
1354 * Mark the queue hanging off @disk DYING, drain all pending requests, then mark
1355 * the queue DEAD, destroy and put it and the gendisk structure.
1357 * Context: can sleep
1359 void blk_cleanup_disk(struct gendisk *disk)
1361 blk_cleanup_queue(disk->queue);
1364 EXPORT_SYMBOL(blk_cleanup_disk);
1366 static void set_disk_ro_uevent(struct gendisk *gd, int ro)
1368 char event[] = "DISK_RO=1";
1369 char *envp[] = { event, NULL };
1373 kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp);
1377 * set_disk_ro - set a gendisk read-only
1378 * @disk: gendisk to operate on
1379 * @read_only: %true to set the disk read-only, %false set the disk read/write
1381 * This function is used to indicate whether a given disk device should have its
1382 * read-only flag set. set_disk_ro() is typically used by device drivers to
1383 * indicate whether the underlying physical device is write-protected.
1385 void set_disk_ro(struct gendisk *disk, bool read_only)
1388 if (test_and_set_bit(GD_READ_ONLY, &disk->state))
1391 if (!test_and_clear_bit(GD_READ_ONLY, &disk->state))
1394 set_disk_ro_uevent(disk, read_only);
1396 EXPORT_SYMBOL(set_disk_ro);
1398 int bdev_read_only(struct block_device *bdev)
1400 return bdev->bd_read_only || get_disk_ro(bdev->bd_disk);
1402 EXPORT_SYMBOL(bdev_read_only);
1404 void inc_diskseq(struct gendisk *disk)
1406 disk->diskseq = atomic64_inc_return(&diskseq);