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>
30 static struct kobject *block_depr;
32 DECLARE_RWSEM(bdev_lookup_sem);
34 /* for extended dynamic devt allocation, currently only one major is used */
35 #define NR_EXT_DEVT (1 << MINORBITS)
36 static DEFINE_IDA(ext_devt_ida);
38 static void disk_check_events(struct disk_events *ev,
39 unsigned int *clearing_ptr);
40 static void disk_alloc_events(struct gendisk *disk);
41 static void disk_add_events(struct gendisk *disk);
42 static void disk_del_events(struct gendisk *disk);
43 static void disk_release_events(struct gendisk *disk);
45 void set_capacity(struct gendisk *disk, sector_t sectors)
47 struct block_device *bdev = disk->part0;
49 spin_lock(&bdev->bd_size_lock);
50 i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT);
51 spin_unlock(&bdev->bd_size_lock);
53 EXPORT_SYMBOL(set_capacity);
56 * Set disk capacity and notify if the size is not currently zero and will not
57 * be set to zero. Returns true if a uevent was sent, otherwise false.
59 bool set_capacity_and_notify(struct gendisk *disk, sector_t size)
61 sector_t capacity = get_capacity(disk);
62 char *envp[] = { "RESIZE=1", NULL };
64 set_capacity(disk, size);
67 * Only print a message and send a uevent if the gendisk is user visible
68 * and alive. This avoids spamming the log and udev when setting the
69 * initial capacity during probing.
71 if (size == capacity ||
72 (disk->flags & (GENHD_FL_UP | GENHD_FL_HIDDEN)) != GENHD_FL_UP)
75 pr_info("%s: detected capacity change from %lld to %lld\n",
76 disk->disk_name, capacity, size);
79 * Historically we did not send a uevent for changes to/from an empty
82 if (!capacity || !size)
84 kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp);
87 EXPORT_SYMBOL_GPL(set_capacity_and_notify);
90 * Format the device name of the indicated disk into the supplied buffer and
91 * return a pointer to that same buffer for convenience.
93 char *disk_name(struct gendisk *hd, int partno, char *buf)
96 snprintf(buf, BDEVNAME_SIZE, "%s", hd->disk_name);
97 else if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
98 snprintf(buf, BDEVNAME_SIZE, "%sp%d", hd->disk_name, partno);
100 snprintf(buf, BDEVNAME_SIZE, "%s%d", hd->disk_name, partno);
105 const char *bdevname(struct block_device *bdev, char *buf)
107 return disk_name(bdev->bd_disk, bdev->bd_partno, buf);
109 EXPORT_SYMBOL(bdevname);
111 static void part_stat_read_all(struct block_device *part,
112 struct disk_stats *stat)
116 memset(stat, 0, sizeof(struct disk_stats));
117 for_each_possible_cpu(cpu) {
118 struct disk_stats *ptr = per_cpu_ptr(part->bd_stats, cpu);
121 for (group = 0; group < NR_STAT_GROUPS; group++) {
122 stat->nsecs[group] += ptr->nsecs[group];
123 stat->sectors[group] += ptr->sectors[group];
124 stat->ios[group] += ptr->ios[group];
125 stat->merges[group] += ptr->merges[group];
128 stat->io_ticks += ptr->io_ticks;
132 static unsigned int part_in_flight(struct block_device *part)
134 unsigned int inflight = 0;
137 for_each_possible_cpu(cpu) {
138 inflight += part_stat_local_read_cpu(part, in_flight[0], cpu) +
139 part_stat_local_read_cpu(part, in_flight[1], cpu);
141 if ((int)inflight < 0)
147 static void part_in_flight_rw(struct block_device *part,
148 unsigned int inflight[2])
154 for_each_possible_cpu(cpu) {
155 inflight[0] += part_stat_local_read_cpu(part, in_flight[0], cpu);
156 inflight[1] += part_stat_local_read_cpu(part, in_flight[1], cpu);
158 if ((int)inflight[0] < 0)
160 if ((int)inflight[1] < 0)
165 * disk_part_iter_init - initialize partition iterator
166 * @piter: iterator to initialize
167 * @disk: disk to iterate over
168 * @flags: DISK_PITER_* flags
170 * Initialize @piter so that it iterates over partitions of @disk.
175 void disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk,
180 if (flags & (DISK_PITER_INCL_PART0 | DISK_PITER_INCL_EMPTY_PART0))
184 piter->flags = flags;
188 * disk_part_iter_next - proceed iterator to the next partition and return it
189 * @piter: iterator of interest
191 * Proceed @piter to the next partition and return it.
196 struct block_device *disk_part_iter_next(struct disk_part_iter *piter)
198 struct block_device *part;
201 /* put the last partition */
202 disk_part_iter_exit(piter);
205 xa_for_each_start(&piter->disk->part_tbl, idx, part, piter->idx) {
206 if (!bdev_nr_sectors(part) &&
207 !(piter->flags & DISK_PITER_INCL_EMPTY) &&
208 !(piter->flags & DISK_PITER_INCL_EMPTY_PART0 &&
212 piter->part = bdgrab(part);
215 piter->idx = idx + 1;
224 * disk_part_iter_exit - finish up partition iteration
225 * @piter: iter of interest
227 * Called when iteration is over. Cleans up @piter.
232 void disk_part_iter_exit(struct disk_part_iter *piter)
240 * Can be deleted altogether. Later.
243 #define BLKDEV_MAJOR_HASH_SIZE 255
244 static struct blk_major_name {
245 struct blk_major_name *next;
248 void (*probe)(dev_t devt);
249 } *major_names[BLKDEV_MAJOR_HASH_SIZE];
250 static DEFINE_MUTEX(major_names_lock);
252 /* index in the above - for now: assume no multimajor ranges */
253 static inline int major_to_index(unsigned major)
255 return major % BLKDEV_MAJOR_HASH_SIZE;
258 #ifdef CONFIG_PROC_FS
259 void blkdev_show(struct seq_file *seqf, off_t offset)
261 struct blk_major_name *dp;
263 mutex_lock(&major_names_lock);
264 for (dp = major_names[major_to_index(offset)]; dp; dp = dp->next)
265 if (dp->major == offset)
266 seq_printf(seqf, "%3d %s\n", dp->major, dp->name);
267 mutex_unlock(&major_names_lock);
269 #endif /* CONFIG_PROC_FS */
272 * __register_blkdev - register a new block device
274 * @major: the requested major device number [1..BLKDEV_MAJOR_MAX-1]. If
275 * @major = 0, try to allocate any unused major number.
276 * @name: the name of the new block device as a zero terminated string
277 * @probe: allback that is called on access to any minor number of @major
279 * The @name must be unique within the system.
281 * The return value depends on the @major input parameter:
283 * - if a major device number was requested in range [1..BLKDEV_MAJOR_MAX-1]
284 * then the function returns zero on success, or a negative error code
285 * - if any unused major number was requested with @major = 0 parameter
286 * then the return value is the allocated major number in range
287 * [1..BLKDEV_MAJOR_MAX-1] or a negative error code otherwise
289 * See Documentation/admin-guide/devices.txt for the list of allocated
292 * Use register_blkdev instead for any new code.
294 int __register_blkdev(unsigned int major, const char *name,
295 void (*probe)(dev_t devt))
297 struct blk_major_name **n, *p;
300 mutex_lock(&major_names_lock);
304 for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) {
305 if (major_names[index] == NULL)
310 printk("%s: failed to get major for %s\n",
319 if (major >= BLKDEV_MAJOR_MAX) {
320 pr_err("%s: major requested (%u) is greater than the maximum (%u) for %s\n",
321 __func__, major, BLKDEV_MAJOR_MAX-1, name);
327 p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL);
335 strlcpy(p->name, name, sizeof(p->name));
337 index = major_to_index(major);
339 for (n = &major_names[index]; *n; n = &(*n)->next) {
340 if ((*n)->major == major)
349 printk("register_blkdev: cannot get major %u for %s\n",
354 mutex_unlock(&major_names_lock);
357 EXPORT_SYMBOL(__register_blkdev);
359 void unregister_blkdev(unsigned int major, const char *name)
361 struct blk_major_name **n;
362 struct blk_major_name *p = NULL;
363 int index = major_to_index(major);
365 mutex_lock(&major_names_lock);
366 for (n = &major_names[index]; *n; n = &(*n)->next)
367 if ((*n)->major == major)
369 if (!*n || strcmp((*n)->name, name)) {
375 mutex_unlock(&major_names_lock);
379 EXPORT_SYMBOL(unregister_blkdev);
382 * blk_mangle_minor - scatter minor numbers apart
383 * @minor: minor number to mangle
385 * Scatter consecutively allocated @minor number apart if MANGLE_DEVT
386 * is enabled. Mangling twice gives the original value.
394 static int blk_mangle_minor(int minor)
396 #ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
399 for (i = 0; i < MINORBITS / 2; i++) {
400 int low = minor & (1 << i);
401 int high = minor & (1 << (MINORBITS - 1 - i));
402 int distance = MINORBITS - 1 - 2 * i;
404 minor ^= low | high; /* clear both bits */
405 low <<= distance; /* swap the positions */
407 minor |= low | high; /* and set */
414 * blk_alloc_devt - allocate a dev_t for a block device
415 * @bdev: block device to allocate dev_t for
416 * @devt: out parameter for resulting dev_t
418 * Allocate a dev_t for block device.
421 * 0 on success, allocated dev_t is returned in *@devt. -errno on
427 int blk_alloc_devt(struct block_device *bdev, dev_t *devt)
429 struct gendisk *disk = bdev->bd_disk;
432 /* in consecutive minor range? */
433 if (bdev->bd_partno < disk->minors) {
434 *devt = MKDEV(disk->major, disk->first_minor + bdev->bd_partno);
438 idx = ida_alloc_range(&ext_devt_ida, 0, NR_EXT_DEVT, GFP_KERNEL);
440 return idx == -ENOSPC ? -EBUSY : idx;
442 *devt = MKDEV(BLOCK_EXT_MAJOR, blk_mangle_minor(idx));
447 * blk_free_devt - free a dev_t
448 * @devt: dev_t to free
450 * Free @devt which was allocated using blk_alloc_devt().
455 void blk_free_devt(dev_t devt)
457 if (MAJOR(devt) == BLOCK_EXT_MAJOR)
458 ida_free(&ext_devt_ida, blk_mangle_minor(MINOR(devt)));
461 static char *bdevt_str(dev_t devt, char *buf)
463 if (MAJOR(devt) <= 0xff && MINOR(devt) <= 0xff) {
464 char tbuf[BDEVT_SIZE];
465 snprintf(tbuf, BDEVT_SIZE, "%02x%02x", MAJOR(devt), MINOR(devt));
466 snprintf(buf, BDEVT_SIZE, "%-9s", tbuf);
468 snprintf(buf, BDEVT_SIZE, "%03x:%05x", MAJOR(devt), MINOR(devt));
473 void disk_uevent(struct gendisk *disk, enum kobject_action action)
475 struct disk_part_iter piter;
476 struct block_device *part;
478 disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY_PART0);
479 while ((part = disk_part_iter_next(&piter)))
480 kobject_uevent(bdev_kobj(part), action);
481 disk_part_iter_exit(&piter);
483 EXPORT_SYMBOL_GPL(disk_uevent);
485 static void disk_scan_partitions(struct gendisk *disk)
487 struct block_device *bdev;
489 if (!get_capacity(disk) || !disk_part_scan_enabled(disk))
492 set_bit(GD_NEED_PART_SCAN, &disk->state);
493 bdev = blkdev_get_by_dev(disk_devt(disk), FMODE_READ, NULL);
495 blkdev_put(bdev, FMODE_READ);
498 static void register_disk(struct device *parent, struct gendisk *disk,
499 const struct attribute_group **groups)
501 struct device *ddev = disk_to_dev(disk);
504 ddev->parent = parent;
506 dev_set_name(ddev, "%s", disk->disk_name);
508 /* delay uevents, until we scanned partition table */
509 dev_set_uevent_suppress(ddev, 1);
512 WARN_ON(ddev->groups);
513 ddev->groups = groups;
515 if (device_add(ddev))
517 if (!sysfs_deprecated) {
518 err = sysfs_create_link(block_depr, &ddev->kobj,
519 kobject_name(&ddev->kobj));
527 * avoid probable deadlock caused by allocating memory with
528 * GFP_KERNEL in runtime_resume callback of its all ancestor
531 pm_runtime_set_memalloc_noio(ddev, true);
533 disk->part0->bd_holder_dir =
534 kobject_create_and_add("holders", &ddev->kobj);
535 disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
537 if (disk->flags & GENHD_FL_HIDDEN) {
538 dev_set_uevent_suppress(ddev, 0);
542 disk_scan_partitions(disk);
544 /* announce the disk and partitions after all partitions are created */
545 dev_set_uevent_suppress(ddev, 0);
546 disk_uevent(disk, KOBJ_ADD);
548 if (disk->queue->backing_dev_info->dev) {
549 err = sysfs_create_link(&ddev->kobj,
550 &disk->queue->backing_dev_info->dev->kobj,
557 * __device_add_disk - add disk information to kernel list
558 * @parent: parent device for the disk
559 * @disk: per-device partitioning information
560 * @groups: Additional per-device sysfs groups
561 * @register_queue: register the queue if set to true
563 * This function registers the partitioning information in @disk
566 * FIXME: error handling
568 static void __device_add_disk(struct device *parent, struct gendisk *disk,
569 const struct attribute_group **groups,
576 * The disk queue should now be all set with enough information about
577 * the device for the elevator code to pick an adequate default
578 * elevator if one is needed, that is, for devices requesting queue
582 elevator_init_mq(disk->queue);
584 /* minors == 0 indicates to use ext devt from part0 and should
585 * be accompanied with EXT_DEVT flag. Make sure all
586 * parameters make sense.
588 WARN_ON(disk->minors && !(disk->major || disk->first_minor));
589 WARN_ON(!disk->minors &&
590 !(disk->flags & (GENHD_FL_EXT_DEVT | GENHD_FL_HIDDEN)));
592 disk->flags |= GENHD_FL_UP;
594 retval = blk_alloc_devt(disk->part0, &devt);
599 disk->major = MAJOR(devt);
600 disk->first_minor = MINOR(devt);
602 disk_alloc_events(disk);
604 if (disk->flags & GENHD_FL_HIDDEN) {
606 * Don't let hidden disks show up in /proc/partitions,
607 * and don't bother scanning for partitions either.
609 disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO;
610 disk->flags |= GENHD_FL_NO_PART_SCAN;
612 struct backing_dev_info *bdi = disk->queue->backing_dev_info;
613 struct device *dev = disk_to_dev(disk);
616 /* Register BDI before referencing it from bdev */
618 ret = bdi_register(bdi, "%u:%u", MAJOR(devt), MINOR(devt));
620 bdi_set_owner(bdi, dev);
621 bdev_add(disk->part0, devt);
623 register_disk(parent, disk, groups);
625 blk_register_queue(disk);
628 * Take an extra ref on queue which will be put on disk_release()
629 * so that it sticks around as long as @disk is there.
631 WARN_ON_ONCE(!blk_get_queue(disk->queue));
633 disk_add_events(disk);
634 blk_integrity_add(disk);
637 void device_add_disk(struct device *parent, struct gendisk *disk,
638 const struct attribute_group **groups)
641 __device_add_disk(parent, disk, groups, true);
643 EXPORT_SYMBOL(device_add_disk);
645 void device_add_disk_no_queue_reg(struct device *parent, struct gendisk *disk)
647 __device_add_disk(parent, disk, NULL, false);
649 EXPORT_SYMBOL(device_add_disk_no_queue_reg);
651 static void invalidate_partition(struct block_device *bdev)
654 __invalidate_device(bdev, true);
657 * Unhash the bdev inode for this device so that it can't be looked
658 * up any more even if openers still hold references to it.
660 remove_inode_hash(bdev->bd_inode);
664 * del_gendisk - remove the gendisk
665 * @disk: the struct gendisk to remove
667 * Removes the gendisk and all its associated resources. This deletes the
668 * partitions associated with the gendisk, and unregisters the associated
671 * This is the counter to the respective __device_add_disk() call.
673 * The final removal of the struct gendisk happens when its refcount reaches 0
674 * with put_disk(), which should be called after del_gendisk(), if
675 * __device_add_disk() was used.
677 * Drivers exist which depend on the release of the gendisk to be synchronous,
678 * it should not be deferred.
682 void del_gendisk(struct gendisk *disk)
684 struct disk_part_iter piter;
685 struct block_device *part;
689 if (WARN_ON_ONCE(!disk->queue))
692 blk_integrity_del(disk);
693 disk_del_events(disk);
696 * Block lookups of the disk until all bdevs are unhashed and the
697 * disk is marked as dead (GENHD_FL_UP cleared).
699 down_write(&bdev_lookup_sem);
701 /* invalidate stuff */
702 disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
703 while ((part = disk_part_iter_next(&piter))) {
704 invalidate_partition(part);
705 delete_partition(part);
707 disk_part_iter_exit(&piter);
709 invalidate_partition(disk->part0);
710 set_capacity(disk, 0);
711 disk->flags &= ~GENHD_FL_UP;
712 up_write(&bdev_lookup_sem);
714 if (!(disk->flags & GENHD_FL_HIDDEN)) {
715 sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
718 * Unregister bdi before releasing device numbers (as they can
719 * get reused and we'd get clashes in sysfs).
721 bdi_unregister(disk->queue->backing_dev_info);
724 blk_unregister_queue(disk);
726 kobject_put(disk->part0->bd_holder_dir);
727 kobject_put(disk->slave_dir);
729 part_stat_set_all(disk->part0, 0);
730 disk->part0->bd_stamp = 0;
731 if (!sysfs_deprecated)
732 sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
733 pm_runtime_set_memalloc_noio(disk_to_dev(disk), false);
734 device_del(disk_to_dev(disk));
736 EXPORT_SYMBOL(del_gendisk);
738 /* sysfs access to bad-blocks list. */
739 static ssize_t disk_badblocks_show(struct device *dev,
740 struct device_attribute *attr,
743 struct gendisk *disk = dev_to_disk(dev);
746 return sprintf(page, "\n");
748 return badblocks_show(disk->bb, page, 0);
751 static ssize_t disk_badblocks_store(struct device *dev,
752 struct device_attribute *attr,
753 const char *page, size_t len)
755 struct gendisk *disk = dev_to_disk(dev);
760 return badblocks_store(disk->bb, page, len, 0);
763 void blk_request_module(dev_t devt)
765 unsigned int major = MAJOR(devt);
766 struct blk_major_name **n;
768 mutex_lock(&major_names_lock);
769 for (n = &major_names[major_to_index(major)]; *n; n = &(*n)->next) {
770 if ((*n)->major == major && (*n)->probe) {
772 mutex_unlock(&major_names_lock);
776 mutex_unlock(&major_names_lock);
778 if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0)
779 /* Make old-style 2.4 aliases work */
780 request_module("block-major-%d", MAJOR(devt));
784 * bdget_disk - do bdget() by gendisk and partition number
785 * @disk: gendisk of interest
786 * @partno: partition number
788 * Find partition @partno from @disk, do bdget() on it.
794 * Resulting block_device on success, NULL on failure.
796 struct block_device *bdget_disk(struct gendisk *disk, int partno)
798 struct block_device *bdev = NULL;
801 bdev = xa_load(&disk->part_tbl, partno);
802 if (bdev && !bdgrab(bdev))
810 * print a full list of all partitions - intended for places where the root
811 * filesystem can't be mounted and thus to give the victim some idea of what
814 void __init printk_all_partitions(void)
816 struct class_dev_iter iter;
819 class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
820 while ((dev = class_dev_iter_next(&iter))) {
821 struct gendisk *disk = dev_to_disk(dev);
822 struct disk_part_iter piter;
823 struct block_device *part;
824 char name_buf[BDEVNAME_SIZE];
825 char devt_buf[BDEVT_SIZE];
828 * Don't show empty devices or things that have been
831 if (get_capacity(disk) == 0 ||
832 (disk->flags & GENHD_FL_SUPPRESS_PARTITION_INFO))
836 * Note, unlike /proc/partitions, I am showing the
837 * numbers in hex - the same format as the root=
840 disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
841 while ((part = disk_part_iter_next(&piter))) {
842 bool is_part0 = part == disk->part0;
844 printk("%s%s %10llu %s %s", is_part0 ? "" : " ",
845 bdevt_str(part->bd_dev, devt_buf),
846 bdev_nr_sectors(part) >> 1,
847 disk_name(disk, part->bd_partno, name_buf),
849 part->bd_meta_info->uuid : "");
851 if (dev->parent && dev->parent->driver)
852 printk(" driver: %s\n",
853 dev->parent->driver->name);
855 printk(" (driver?)\n");
859 disk_part_iter_exit(&piter);
861 class_dev_iter_exit(&iter);
864 #ifdef CONFIG_PROC_FS
866 static void *disk_seqf_start(struct seq_file *seqf, loff_t *pos)
869 struct class_dev_iter *iter;
872 iter = kmalloc(sizeof(*iter), GFP_KERNEL);
874 return ERR_PTR(-ENOMEM);
876 seqf->private = iter;
877 class_dev_iter_init(iter, &block_class, NULL, &disk_type);
879 dev = class_dev_iter_next(iter);
884 return dev_to_disk(dev);
887 static void *disk_seqf_next(struct seq_file *seqf, void *v, loff_t *pos)
892 dev = class_dev_iter_next(seqf->private);
894 return dev_to_disk(dev);
899 static void disk_seqf_stop(struct seq_file *seqf, void *v)
901 struct class_dev_iter *iter = seqf->private;
903 /* stop is called even after start failed :-( */
905 class_dev_iter_exit(iter);
907 seqf->private = NULL;
911 static void *show_partition_start(struct seq_file *seqf, loff_t *pos)
915 p = disk_seqf_start(seqf, pos);
916 if (!IS_ERR_OR_NULL(p) && !*pos)
917 seq_puts(seqf, "major minor #blocks name\n\n");
921 static int show_partition(struct seq_file *seqf, void *v)
923 struct gendisk *sgp = v;
924 struct disk_part_iter piter;
925 struct block_device *part;
926 char buf[BDEVNAME_SIZE];
928 /* Don't show non-partitionable removeable devices or empty devices */
929 if (!get_capacity(sgp) || (!disk_max_parts(sgp) &&
930 (sgp->flags & GENHD_FL_REMOVABLE)))
932 if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)
935 /* show the full disk and all non-0 size partitions of it */
936 disk_part_iter_init(&piter, sgp, DISK_PITER_INCL_PART0);
937 while ((part = disk_part_iter_next(&piter)))
938 seq_printf(seqf, "%4d %7d %10llu %s\n",
939 MAJOR(part->bd_dev), MINOR(part->bd_dev),
940 bdev_nr_sectors(part) >> 1,
941 disk_name(sgp, part->bd_partno, buf));
942 disk_part_iter_exit(&piter);
947 static const struct seq_operations partitions_op = {
948 .start = show_partition_start,
949 .next = disk_seqf_next,
950 .stop = disk_seqf_stop,
951 .show = show_partition
955 static int __init genhd_device_init(void)
959 block_class.dev_kobj = sysfs_dev_block_kobj;
960 error = class_register(&block_class);
965 register_blkdev(BLOCK_EXT_MAJOR, "blkext");
967 /* create top-level block dir */
968 if (!sysfs_deprecated)
969 block_depr = kobject_create_and_add("block", NULL);
973 subsys_initcall(genhd_device_init);
975 static ssize_t disk_range_show(struct device *dev,
976 struct device_attribute *attr, char *buf)
978 struct gendisk *disk = dev_to_disk(dev);
980 return sprintf(buf, "%d\n", disk->minors);
983 static ssize_t disk_ext_range_show(struct device *dev,
984 struct device_attribute *attr, char *buf)
986 struct gendisk *disk = dev_to_disk(dev);
988 return sprintf(buf, "%d\n", disk_max_parts(disk));
991 static ssize_t disk_removable_show(struct device *dev,
992 struct device_attribute *attr, char *buf)
994 struct gendisk *disk = dev_to_disk(dev);
996 return sprintf(buf, "%d\n",
997 (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0));
1000 static ssize_t disk_hidden_show(struct device *dev,
1001 struct device_attribute *attr, char *buf)
1003 struct gendisk *disk = dev_to_disk(dev);
1005 return sprintf(buf, "%d\n",
1006 (disk->flags & GENHD_FL_HIDDEN ? 1 : 0));
1009 static ssize_t disk_ro_show(struct device *dev,
1010 struct device_attribute *attr, char *buf)
1012 struct gendisk *disk = dev_to_disk(dev);
1014 return sprintf(buf, "%d\n", get_disk_ro(disk) ? 1 : 0);
1017 ssize_t part_size_show(struct device *dev,
1018 struct device_attribute *attr, char *buf)
1020 return sprintf(buf, "%llu\n", bdev_nr_sectors(dev_to_bdev(dev)));
1023 ssize_t part_stat_show(struct device *dev,
1024 struct device_attribute *attr, char *buf)
1026 struct block_device *bdev = dev_to_bdev(dev);
1027 struct request_queue *q = bdev->bd_disk->queue;
1028 struct disk_stats stat;
1029 unsigned int inflight;
1031 part_stat_read_all(bdev, &stat);
1033 inflight = blk_mq_in_flight(q, bdev);
1035 inflight = part_in_flight(bdev);
1038 "%8lu %8lu %8llu %8u "
1039 "%8lu %8lu %8llu %8u "
1041 "%8lu %8lu %8llu %8u "
1044 stat.ios[STAT_READ],
1045 stat.merges[STAT_READ],
1046 (unsigned long long)stat.sectors[STAT_READ],
1047 (unsigned int)div_u64(stat.nsecs[STAT_READ], NSEC_PER_MSEC),
1048 stat.ios[STAT_WRITE],
1049 stat.merges[STAT_WRITE],
1050 (unsigned long long)stat.sectors[STAT_WRITE],
1051 (unsigned int)div_u64(stat.nsecs[STAT_WRITE], NSEC_PER_MSEC),
1053 jiffies_to_msecs(stat.io_ticks),
1054 (unsigned int)div_u64(stat.nsecs[STAT_READ] +
1055 stat.nsecs[STAT_WRITE] +
1056 stat.nsecs[STAT_DISCARD] +
1057 stat.nsecs[STAT_FLUSH],
1059 stat.ios[STAT_DISCARD],
1060 stat.merges[STAT_DISCARD],
1061 (unsigned long long)stat.sectors[STAT_DISCARD],
1062 (unsigned int)div_u64(stat.nsecs[STAT_DISCARD], NSEC_PER_MSEC),
1063 stat.ios[STAT_FLUSH],
1064 (unsigned int)div_u64(stat.nsecs[STAT_FLUSH], NSEC_PER_MSEC));
1067 ssize_t part_inflight_show(struct device *dev, struct device_attribute *attr,
1070 struct block_device *bdev = dev_to_bdev(dev);
1071 struct request_queue *q = bdev->bd_disk->queue;
1072 unsigned int inflight[2];
1075 blk_mq_in_flight_rw(q, bdev, inflight);
1077 part_in_flight_rw(bdev, inflight);
1079 return sprintf(buf, "%8u %8u\n", inflight[0], inflight[1]);
1082 static ssize_t disk_capability_show(struct device *dev,
1083 struct device_attribute *attr, char *buf)
1085 struct gendisk *disk = dev_to_disk(dev);
1087 return sprintf(buf, "%x\n", disk->flags);
1090 static ssize_t disk_alignment_offset_show(struct device *dev,
1091 struct device_attribute *attr,
1094 struct gendisk *disk = dev_to_disk(dev);
1096 return sprintf(buf, "%d\n", queue_alignment_offset(disk->queue));
1099 static ssize_t disk_discard_alignment_show(struct device *dev,
1100 struct device_attribute *attr,
1103 struct gendisk *disk = dev_to_disk(dev);
1105 return sprintf(buf, "%d\n", queue_discard_alignment(disk->queue));
1108 static DEVICE_ATTR(range, 0444, disk_range_show, NULL);
1109 static DEVICE_ATTR(ext_range, 0444, disk_ext_range_show, NULL);
1110 static DEVICE_ATTR(removable, 0444, disk_removable_show, NULL);
1111 static DEVICE_ATTR(hidden, 0444, disk_hidden_show, NULL);
1112 static DEVICE_ATTR(ro, 0444, disk_ro_show, NULL);
1113 static DEVICE_ATTR(size, 0444, part_size_show, NULL);
1114 static DEVICE_ATTR(alignment_offset, 0444, disk_alignment_offset_show, NULL);
1115 static DEVICE_ATTR(discard_alignment, 0444, disk_discard_alignment_show, NULL);
1116 static DEVICE_ATTR(capability, 0444, disk_capability_show, NULL);
1117 static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);
1118 static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);
1119 static DEVICE_ATTR(badblocks, 0644, disk_badblocks_show, disk_badblocks_store);
1121 #ifdef CONFIG_FAIL_MAKE_REQUEST
1122 ssize_t part_fail_show(struct device *dev,
1123 struct device_attribute *attr, char *buf)
1125 return sprintf(buf, "%d\n", dev_to_bdev(dev)->bd_make_it_fail);
1128 ssize_t part_fail_store(struct device *dev,
1129 struct device_attribute *attr,
1130 const char *buf, size_t count)
1134 if (count > 0 && sscanf(buf, "%d", &i) > 0)
1135 dev_to_bdev(dev)->bd_make_it_fail = i;
1140 static struct device_attribute dev_attr_fail =
1141 __ATTR(make-it-fail, 0644, part_fail_show, part_fail_store);
1142 #endif /* CONFIG_FAIL_MAKE_REQUEST */
1144 #ifdef CONFIG_FAIL_IO_TIMEOUT
1145 static struct device_attribute dev_attr_fail_timeout =
1146 __ATTR(io-timeout-fail, 0644, part_timeout_show, part_timeout_store);
1149 static struct attribute *disk_attrs[] = {
1150 &dev_attr_range.attr,
1151 &dev_attr_ext_range.attr,
1152 &dev_attr_removable.attr,
1153 &dev_attr_hidden.attr,
1155 &dev_attr_size.attr,
1156 &dev_attr_alignment_offset.attr,
1157 &dev_attr_discard_alignment.attr,
1158 &dev_attr_capability.attr,
1159 &dev_attr_stat.attr,
1160 &dev_attr_inflight.attr,
1161 &dev_attr_badblocks.attr,
1162 #ifdef CONFIG_FAIL_MAKE_REQUEST
1163 &dev_attr_fail.attr,
1165 #ifdef CONFIG_FAIL_IO_TIMEOUT
1166 &dev_attr_fail_timeout.attr,
1171 static umode_t disk_visible(struct kobject *kobj, struct attribute *a, int n)
1173 struct device *dev = container_of(kobj, typeof(*dev), kobj);
1174 struct gendisk *disk = dev_to_disk(dev);
1176 if (a == &dev_attr_badblocks.attr && !disk->bb)
1181 static struct attribute_group disk_attr_group = {
1182 .attrs = disk_attrs,
1183 .is_visible = disk_visible,
1186 static const struct attribute_group *disk_attr_groups[] = {
1192 * disk_release - releases all allocated resources of the gendisk
1193 * @dev: the device representing this disk
1195 * This function releases all allocated resources of the gendisk.
1197 * Drivers which used __device_add_disk() have a gendisk with a request_queue
1198 * assigned. Since the request_queue sits on top of the gendisk for these
1199 * drivers we also call blk_put_queue() for them, and we expect the
1200 * request_queue refcount to reach 0 at this point, and so the request_queue
1201 * will also be freed prior to the disk.
1203 * Context: can sleep
1205 static void disk_release(struct device *dev)
1207 struct gendisk *disk = dev_to_disk(dev);
1211 blk_free_devt(dev->devt);
1212 disk_release_events(disk);
1213 kfree(disk->random);
1214 xa_destroy(&disk->part_tbl);
1217 blk_put_queue(disk->queue);
1220 struct class block_class = {
1224 static char *block_devnode(struct device *dev, umode_t *mode,
1225 kuid_t *uid, kgid_t *gid)
1227 struct gendisk *disk = dev_to_disk(dev);
1229 if (disk->fops->devnode)
1230 return disk->fops->devnode(disk, mode);
1234 const struct device_type disk_type = {
1236 .groups = disk_attr_groups,
1237 .release = disk_release,
1238 .devnode = block_devnode,
1241 #ifdef CONFIG_PROC_FS
1243 * aggregate disk stat collector. Uses the same stats that the sysfs
1244 * entries do, above, but makes them available through one seq_file.
1246 * The output looks suspiciously like /proc/partitions with a bunch of
1249 static int diskstats_show(struct seq_file *seqf, void *v)
1251 struct gendisk *gp = v;
1252 struct disk_part_iter piter;
1253 struct block_device *hd;
1254 char buf[BDEVNAME_SIZE];
1255 unsigned int inflight;
1256 struct disk_stats stat;
1259 if (&disk_to_dev(gp)->kobj.entry == block_class.devices.next)
1260 seq_puts(seqf, "major minor name"
1261 " rio rmerge rsect ruse wio wmerge "
1262 "wsect wuse running use aveq"
1266 disk_part_iter_init(&piter, gp, DISK_PITER_INCL_EMPTY_PART0);
1267 while ((hd = disk_part_iter_next(&piter))) {
1268 part_stat_read_all(hd, &stat);
1269 if (queue_is_mq(gp->queue))
1270 inflight = blk_mq_in_flight(gp->queue, hd);
1272 inflight = part_in_flight(hd);
1274 seq_printf(seqf, "%4d %7d %s "
1281 MAJOR(hd->bd_dev), MINOR(hd->bd_dev),
1282 disk_name(gp, hd->bd_partno, buf),
1283 stat.ios[STAT_READ],
1284 stat.merges[STAT_READ],
1285 stat.sectors[STAT_READ],
1286 (unsigned int)div_u64(stat.nsecs[STAT_READ],
1288 stat.ios[STAT_WRITE],
1289 stat.merges[STAT_WRITE],
1290 stat.sectors[STAT_WRITE],
1291 (unsigned int)div_u64(stat.nsecs[STAT_WRITE],
1294 jiffies_to_msecs(stat.io_ticks),
1295 (unsigned int)div_u64(stat.nsecs[STAT_READ] +
1296 stat.nsecs[STAT_WRITE] +
1297 stat.nsecs[STAT_DISCARD] +
1298 stat.nsecs[STAT_FLUSH],
1300 stat.ios[STAT_DISCARD],
1301 stat.merges[STAT_DISCARD],
1302 stat.sectors[STAT_DISCARD],
1303 (unsigned int)div_u64(stat.nsecs[STAT_DISCARD],
1305 stat.ios[STAT_FLUSH],
1306 (unsigned int)div_u64(stat.nsecs[STAT_FLUSH],
1310 disk_part_iter_exit(&piter);
1315 static const struct seq_operations diskstats_op = {
1316 .start = disk_seqf_start,
1317 .next = disk_seqf_next,
1318 .stop = disk_seqf_stop,
1319 .show = diskstats_show
1322 static int __init proc_genhd_init(void)
1324 proc_create_seq("diskstats", 0, NULL, &diskstats_op);
1325 proc_create_seq("partitions", 0, NULL, &partitions_op);
1328 module_init(proc_genhd_init);
1329 #endif /* CONFIG_PROC_FS */
1331 dev_t blk_lookup_devt(const char *name, int partno)
1333 dev_t devt = MKDEV(0, 0);
1334 struct class_dev_iter iter;
1337 class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
1338 while ((dev = class_dev_iter_next(&iter))) {
1339 struct gendisk *disk = dev_to_disk(dev);
1340 struct block_device *part;
1342 if (strcmp(dev_name(dev), name))
1345 if (partno < disk->minors) {
1346 /* We need to return the right devno, even
1347 * if the partition doesn't exist yet.
1349 devt = MKDEV(MAJOR(dev->devt),
1350 MINOR(dev->devt) + partno);
1353 part = bdget_disk(disk, partno);
1355 devt = part->bd_dev;
1360 class_dev_iter_exit(&iter);
1364 struct gendisk *__alloc_disk_node(int minors, int node_id)
1366 struct gendisk *disk;
1368 if (minors > DISK_MAX_PARTS) {
1370 "block: can't allocate more than %d partitions\n",
1372 minors = DISK_MAX_PARTS;
1375 disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);
1379 disk->part0 = bdev_alloc(disk, 0);
1383 disk->node_id = node_id;
1384 xa_init(&disk->part_tbl);
1385 if (xa_insert(&disk->part_tbl, 0, disk->part0, GFP_KERNEL))
1386 goto out_destroy_part_tbl;
1388 disk->minors = minors;
1389 rand_initialize_disk(disk);
1390 disk_to_dev(disk)->class = &block_class;
1391 disk_to_dev(disk)->type = &disk_type;
1392 device_initialize(disk_to_dev(disk));
1395 out_destroy_part_tbl:
1396 xa_destroy(&disk->part_tbl);
1402 EXPORT_SYMBOL(__alloc_disk_node);
1405 * put_disk - decrements the gendisk refcount
1406 * @disk: the struct gendisk to decrement the refcount for
1408 * This decrements the refcount for the struct gendisk. When this reaches 0
1409 * we'll have disk_release() called.
1411 * Context: Any context, but the last reference must not be dropped from
1414 void put_disk(struct gendisk *disk)
1417 put_device(disk_to_dev(disk));
1419 EXPORT_SYMBOL(put_disk);
1421 static void set_disk_ro_uevent(struct gendisk *gd, int ro)
1423 char event[] = "DISK_RO=1";
1424 char *envp[] = { event, NULL };
1428 kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp);
1432 * set_disk_ro - set a gendisk read-only
1433 * @disk: gendisk to operate on
1434 * @read_only: %true to set the disk read-only, %false set the disk read/write
1436 * This function is used to indicate whether a given disk device should have its
1437 * read-only flag set. set_disk_ro() is typically used by device drivers to
1438 * indicate whether the underlying physical device is write-protected.
1440 void set_disk_ro(struct gendisk *disk, bool read_only)
1443 if (test_and_set_bit(GD_READ_ONLY, &disk->state))
1446 if (!test_and_clear_bit(GD_READ_ONLY, &disk->state))
1449 set_disk_ro_uevent(disk, read_only);
1451 EXPORT_SYMBOL(set_disk_ro);
1453 int bdev_read_only(struct block_device *bdev)
1455 return bdev->bd_read_only || get_disk_ro(bdev->bd_disk);
1457 EXPORT_SYMBOL(bdev_read_only);
1460 * Disk events - monitor disk events like media change and eject request.
1462 struct disk_events {
1463 struct list_head node; /* all disk_event's */
1464 struct gendisk *disk; /* the associated disk */
1467 struct mutex block_mutex; /* protects blocking */
1468 int block; /* event blocking depth */
1469 unsigned int pending; /* events already sent out */
1470 unsigned int clearing; /* events being cleared */
1472 long poll_msecs; /* interval, -1 for default */
1473 struct delayed_work dwork;
1476 static const char *disk_events_strs[] = {
1477 [ilog2(DISK_EVENT_MEDIA_CHANGE)] = "media_change",
1478 [ilog2(DISK_EVENT_EJECT_REQUEST)] = "eject_request",
1481 static char *disk_uevents[] = {
1482 [ilog2(DISK_EVENT_MEDIA_CHANGE)] = "DISK_MEDIA_CHANGE=1",
1483 [ilog2(DISK_EVENT_EJECT_REQUEST)] = "DISK_EJECT_REQUEST=1",
1486 /* list of all disk_events */
1487 static DEFINE_MUTEX(disk_events_mutex);
1488 static LIST_HEAD(disk_events);
1490 /* disable in-kernel polling by default */
1491 static unsigned long disk_events_dfl_poll_msecs;
1493 static unsigned long disk_events_poll_jiffies(struct gendisk *disk)
1495 struct disk_events *ev = disk->ev;
1496 long intv_msecs = 0;
1499 * If device-specific poll interval is set, always use it. If
1500 * the default is being used, poll if the POLL flag is set.
1502 if (ev->poll_msecs >= 0)
1503 intv_msecs = ev->poll_msecs;
1504 else if (disk->event_flags & DISK_EVENT_FLAG_POLL)
1505 intv_msecs = disk_events_dfl_poll_msecs;
1507 return msecs_to_jiffies(intv_msecs);
1511 * disk_block_events - block and flush disk event checking
1512 * @disk: disk to block events for
1514 * On return from this function, it is guaranteed that event checking
1515 * isn't in progress and won't happen until unblocked by
1516 * disk_unblock_events(). Events blocking is counted and the actual
1517 * unblocking happens after the matching number of unblocks are done.
1519 * Note that this intentionally does not block event checking from
1520 * disk_clear_events().
1525 void disk_block_events(struct gendisk *disk)
1527 struct disk_events *ev = disk->ev;
1528 unsigned long flags;
1535 * Outer mutex ensures that the first blocker completes canceling
1536 * the event work before further blockers are allowed to finish.
1538 mutex_lock(&ev->block_mutex);
1540 spin_lock_irqsave(&ev->lock, flags);
1541 cancel = !ev->block++;
1542 spin_unlock_irqrestore(&ev->lock, flags);
1545 cancel_delayed_work_sync(&disk->ev->dwork);
1547 mutex_unlock(&ev->block_mutex);
1550 static void __disk_unblock_events(struct gendisk *disk, bool check_now)
1552 struct disk_events *ev = disk->ev;
1554 unsigned long flags;
1556 spin_lock_irqsave(&ev->lock, flags);
1558 if (WARN_ON_ONCE(ev->block <= 0))
1564 intv = disk_events_poll_jiffies(disk);
1566 queue_delayed_work(system_freezable_power_efficient_wq,
1569 queue_delayed_work(system_freezable_power_efficient_wq,
1572 spin_unlock_irqrestore(&ev->lock, flags);
1576 * disk_unblock_events - unblock disk event checking
1577 * @disk: disk to unblock events for
1579 * Undo disk_block_events(). When the block count reaches zero, it
1580 * starts events polling if configured.
1583 * Don't care. Safe to call from irq context.
1585 void disk_unblock_events(struct gendisk *disk)
1588 __disk_unblock_events(disk, false);
1592 * disk_flush_events - schedule immediate event checking and flushing
1593 * @disk: disk to check and flush events for
1594 * @mask: events to flush
1596 * Schedule immediate event checking on @disk if not blocked. Events in
1597 * @mask are scheduled to be cleared from the driver. Note that this
1598 * doesn't clear the events from @disk->ev.
1601 * If @mask is non-zero must be called with bdev->bd_mutex held.
1603 void disk_flush_events(struct gendisk *disk, unsigned int mask)
1605 struct disk_events *ev = disk->ev;
1610 spin_lock_irq(&ev->lock);
1611 ev->clearing |= mask;
1613 mod_delayed_work(system_freezable_power_efficient_wq,
1615 spin_unlock_irq(&ev->lock);
1619 * disk_clear_events - synchronously check, clear and return pending events
1620 * @disk: disk to fetch and clear events from
1621 * @mask: mask of events to be fetched and cleared
1623 * Disk events are synchronously checked and pending events in @mask
1624 * are cleared and returned. This ignores the block count.
1629 static unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask)
1631 struct disk_events *ev = disk->ev;
1632 unsigned int pending;
1633 unsigned int clearing = mask;
1638 disk_block_events(disk);
1641 * store the union of mask and ev->clearing on the stack so that the
1642 * race with disk_flush_events does not cause ambiguity (ev->clearing
1643 * can still be modified even if events are blocked).
1645 spin_lock_irq(&ev->lock);
1646 clearing |= ev->clearing;
1648 spin_unlock_irq(&ev->lock);
1650 disk_check_events(ev, &clearing);
1652 * if ev->clearing is not 0, the disk_flush_events got called in the
1653 * middle of this function, so we want to run the workfn without delay.
1655 __disk_unblock_events(disk, ev->clearing ? true : false);
1657 /* then, fetch and clear pending events */
1658 spin_lock_irq(&ev->lock);
1659 pending = ev->pending & mask;
1660 ev->pending &= ~mask;
1661 spin_unlock_irq(&ev->lock);
1662 WARN_ON_ONCE(clearing & mask);
1668 * bdev_check_media_change - check if a removable media has been changed
1669 * @bdev: block device to check
1671 * Check whether a removable media has been changed, and attempt to free all
1672 * dentries and inodes and invalidates all block device page cache entries in
1675 * Returns %true if the block device changed, or %false if not.
1677 bool bdev_check_media_change(struct block_device *bdev)
1679 unsigned int events;
1681 events = disk_clear_events(bdev->bd_disk, DISK_EVENT_MEDIA_CHANGE |
1682 DISK_EVENT_EJECT_REQUEST);
1683 if (!(events & DISK_EVENT_MEDIA_CHANGE))
1686 if (__invalidate_device(bdev, true))
1687 pr_warn("VFS: busy inodes on changed media %s\n",
1688 bdev->bd_disk->disk_name);
1689 set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
1692 EXPORT_SYMBOL(bdev_check_media_change);
1695 * Separate this part out so that a different pointer for clearing_ptr can be
1696 * passed in for disk_clear_events.
1698 static void disk_events_workfn(struct work_struct *work)
1700 struct delayed_work *dwork = to_delayed_work(work);
1701 struct disk_events *ev = container_of(dwork, struct disk_events, dwork);
1703 disk_check_events(ev, &ev->clearing);
1706 static void disk_check_events(struct disk_events *ev,
1707 unsigned int *clearing_ptr)
1709 struct gendisk *disk = ev->disk;
1710 char *envp[ARRAY_SIZE(disk_uevents) + 1] = { };
1711 unsigned int clearing = *clearing_ptr;
1712 unsigned int events;
1714 int nr_events = 0, i;
1717 events = disk->fops->check_events(disk, clearing);
1719 /* accumulate pending events and schedule next poll if necessary */
1720 spin_lock_irq(&ev->lock);
1722 events &= ~ev->pending;
1723 ev->pending |= events;
1724 *clearing_ptr &= ~clearing;
1726 intv = disk_events_poll_jiffies(disk);
1727 if (!ev->block && intv)
1728 queue_delayed_work(system_freezable_power_efficient_wq,
1731 spin_unlock_irq(&ev->lock);
1734 * Tell userland about new events. Only the events listed in
1735 * @disk->events are reported, and only if DISK_EVENT_FLAG_UEVENT
1736 * is set. Otherwise, events are processed internally but never
1737 * get reported to userland.
1739 for (i = 0; i < ARRAY_SIZE(disk_uevents); i++)
1740 if ((events & disk->events & (1 << i)) &&
1741 (disk->event_flags & DISK_EVENT_FLAG_UEVENT))
1742 envp[nr_events++] = disk_uevents[i];
1745 kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp);
1749 * A disk events enabled device has the following sysfs nodes under
1750 * its /sys/block/X/ directory.
1752 * events : list of all supported events
1753 * events_async : list of events which can be detected w/o polling
1754 * (always empty, only for backwards compatibility)
1755 * events_poll_msecs : polling interval, 0: disable, -1: system default
1757 static ssize_t __disk_events_show(unsigned int events, char *buf)
1759 const char *delim = "";
1763 for (i = 0; i < ARRAY_SIZE(disk_events_strs); i++)
1764 if (events & (1 << i)) {
1765 pos += sprintf(buf + pos, "%s%s",
1766 delim, disk_events_strs[i]);
1770 pos += sprintf(buf + pos, "\n");
1774 static ssize_t disk_events_show(struct device *dev,
1775 struct device_attribute *attr, char *buf)
1777 struct gendisk *disk = dev_to_disk(dev);
1779 if (!(disk->event_flags & DISK_EVENT_FLAG_UEVENT))
1782 return __disk_events_show(disk->events, buf);
1785 static ssize_t disk_events_async_show(struct device *dev,
1786 struct device_attribute *attr, char *buf)
1791 static ssize_t disk_events_poll_msecs_show(struct device *dev,
1792 struct device_attribute *attr,
1795 struct gendisk *disk = dev_to_disk(dev);
1798 return sprintf(buf, "-1\n");
1800 return sprintf(buf, "%ld\n", disk->ev->poll_msecs);
1803 static ssize_t disk_events_poll_msecs_store(struct device *dev,
1804 struct device_attribute *attr,
1805 const char *buf, size_t count)
1807 struct gendisk *disk = dev_to_disk(dev);
1810 if (!count || !sscanf(buf, "%ld", &intv))
1813 if (intv < 0 && intv != -1)
1819 disk_block_events(disk);
1820 disk->ev->poll_msecs = intv;
1821 __disk_unblock_events(disk, true);
1826 static const DEVICE_ATTR(events, 0444, disk_events_show, NULL);
1827 static const DEVICE_ATTR(events_async, 0444, disk_events_async_show, NULL);
1828 static const DEVICE_ATTR(events_poll_msecs, 0644,
1829 disk_events_poll_msecs_show,
1830 disk_events_poll_msecs_store);
1832 static const struct attribute *disk_events_attrs[] = {
1833 &dev_attr_events.attr,
1834 &dev_attr_events_async.attr,
1835 &dev_attr_events_poll_msecs.attr,
1840 * The default polling interval can be specified by the kernel
1841 * parameter block.events_dfl_poll_msecs which defaults to 0
1842 * (disable). This can also be modified runtime by writing to
1843 * /sys/module/block/parameters/events_dfl_poll_msecs.
1845 static int disk_events_set_dfl_poll_msecs(const char *val,
1846 const struct kernel_param *kp)
1848 struct disk_events *ev;
1851 ret = param_set_ulong(val, kp);
1855 mutex_lock(&disk_events_mutex);
1857 list_for_each_entry(ev, &disk_events, node)
1858 disk_flush_events(ev->disk, 0);
1860 mutex_unlock(&disk_events_mutex);
1865 static const struct kernel_param_ops disk_events_dfl_poll_msecs_param_ops = {
1866 .set = disk_events_set_dfl_poll_msecs,
1867 .get = param_get_ulong,
1870 #undef MODULE_PARAM_PREFIX
1871 #define MODULE_PARAM_PREFIX "block."
1873 module_param_cb(events_dfl_poll_msecs, &disk_events_dfl_poll_msecs_param_ops,
1874 &disk_events_dfl_poll_msecs, 0644);
1877 * disk_{alloc|add|del|release}_events - initialize and destroy disk_events.
1879 static void disk_alloc_events(struct gendisk *disk)
1881 struct disk_events *ev;
1883 if (!disk->fops->check_events || !disk->events)
1886 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
1888 pr_warn("%s: failed to initialize events\n", disk->disk_name);
1892 INIT_LIST_HEAD(&ev->node);
1894 spin_lock_init(&ev->lock);
1895 mutex_init(&ev->block_mutex);
1897 ev->poll_msecs = -1;
1898 INIT_DELAYED_WORK(&ev->dwork, disk_events_workfn);
1903 static void disk_add_events(struct gendisk *disk)
1905 /* FIXME: error handling */
1906 if (sysfs_create_files(&disk_to_dev(disk)->kobj, disk_events_attrs) < 0)
1907 pr_warn("%s: failed to create sysfs files for events\n",
1913 mutex_lock(&disk_events_mutex);
1914 list_add_tail(&disk->ev->node, &disk_events);
1915 mutex_unlock(&disk_events_mutex);
1918 * Block count is initialized to 1 and the following initial
1919 * unblock kicks it into action.
1921 __disk_unblock_events(disk, true);
1924 static void disk_del_events(struct gendisk *disk)
1927 disk_block_events(disk);
1929 mutex_lock(&disk_events_mutex);
1930 list_del_init(&disk->ev->node);
1931 mutex_unlock(&disk_events_mutex);
1934 sysfs_remove_files(&disk_to_dev(disk)->kobj, disk_events_attrs);
1937 static void disk_release_events(struct gendisk *disk)
1939 /* the block count should be 1 from disk_del_events() */
1940 WARN_ON_ONCE(disk->ev && disk->ev->block != 1);