diff options
Diffstat (limited to '')
| -rw-r--r-- | block/genhd.c | 1461 |
1 files changed, 1461 insertions, 0 deletions
diff --git a/block/genhd.c b/block/genhd.c new file mode 100644 index 0000000000..f9b81be6c7 --- /dev/null +++ b/block/genhd.c @@ -0,0 +1,1461 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * gendisk handling + * + * Portions Copyright (C) 2020 Christoph Hellwig + */ + +#include <linux/module.h> +#include <linux/ctype.h> +#include <linux/fs.h> +#include <linux/kdev_t.h> +#include <linux/kernel.h> +#include <linux/blkdev.h> +#include <linux/backing-dev.h> +#include <linux/init.h> +#include <linux/spinlock.h> +#include <linux/proc_fs.h> +#include <linux/seq_file.h> +#include <linux/slab.h> +#include <linux/kmod.h> +#include <linux/major.h> +#include <linux/mutex.h> +#include <linux/idr.h> +#include <linux/log2.h> +#include <linux/pm_runtime.h> +#include <linux/badblocks.h> +#include <linux/part_stat.h> +#include <linux/blktrace_api.h> + +#include "blk-throttle.h" +#include "blk.h" +#include "blk-mq-sched.h" +#include "blk-rq-qos.h" +#include "blk-cgroup.h" + +static struct kobject *block_depr; + +/* + * Unique, monotonically increasing sequential number associated with block + * devices instances (i.e. incremented each time a device is attached). + * Associating uevents with block devices in userspace is difficult and racy: + * the uevent netlink socket is lossy, and on slow and overloaded systems has + * a very high latency. + * Block devices do not have exclusive owners in userspace, any process can set + * one up (e.g. loop devices). Moreover, device names can be reused (e.g. loop0 + * can be reused again and again). + * A userspace process setting up a block device and watching for its events + * cannot thus reliably tell whether an event relates to the device it just set + * up or another earlier instance with the same name. + * This sequential number allows userspace processes to solve this problem, and + * uniquely associate an uevent to the lifetime to a device. + */ +static atomic64_t diskseq; + +/* for extended dynamic devt allocation, currently only one major is used */ +#define NR_EXT_DEVT (1 << MINORBITS) +static DEFINE_IDA(ext_devt_ida); + +void set_capacity(struct gendisk *disk, sector_t sectors) +{ + bdev_set_nr_sectors(disk->part0, sectors); +} +EXPORT_SYMBOL(set_capacity); + +/* + * Set disk capacity and notify if the size is not currently zero and will not + * be set to zero. Returns true if a uevent was sent, otherwise false. + */ +bool set_capacity_and_notify(struct gendisk *disk, sector_t size) +{ + sector_t capacity = get_capacity(disk); + char *envp[] = { "RESIZE=1", NULL }; + + set_capacity(disk, size); + + /* + * Only print a message and send a uevent if the gendisk is user visible + * and alive. This avoids spamming the log and udev when setting the + * initial capacity during probing. + */ + if (size == capacity || + !disk_live(disk) || + (disk->flags & GENHD_FL_HIDDEN)) + return false; + + pr_info("%s: detected capacity change from %lld to %lld\n", + disk->disk_name, capacity, size); + + /* + * Historically we did not send a uevent for changes to/from an empty + * device. + */ + if (!capacity || !size) + return false; + kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp); + return true; +} +EXPORT_SYMBOL_GPL(set_capacity_and_notify); + +static void part_stat_read_all(struct block_device *part, + struct disk_stats *stat) +{ + int cpu; + + memset(stat, 0, sizeof(struct disk_stats)); + for_each_possible_cpu(cpu) { + struct disk_stats *ptr = per_cpu_ptr(part->bd_stats, cpu); + int group; + + for (group = 0; group < NR_STAT_GROUPS; group++) { + stat->nsecs[group] += ptr->nsecs[group]; + stat->sectors[group] += ptr->sectors[group]; + stat->ios[group] += ptr->ios[group]; + stat->merges[group] += ptr->merges[group]; + } + + stat->io_ticks += ptr->io_ticks; + } +} + +static unsigned int part_in_flight(struct block_device *part) +{ + unsigned int inflight = 0; + int cpu; + + for_each_possible_cpu(cpu) { + inflight += part_stat_local_read_cpu(part, in_flight[0], cpu) + + part_stat_local_read_cpu(part, in_flight[1], cpu); + } + if ((int)inflight < 0) + inflight = 0; + + return inflight; +} + +static void part_in_flight_rw(struct block_device *part, + unsigned int inflight[2]) +{ + int cpu; + + inflight[0] = 0; + inflight[1] = 0; + for_each_possible_cpu(cpu) { + inflight[0] += part_stat_local_read_cpu(part, in_flight[0], cpu); + inflight[1] += part_stat_local_read_cpu(part, in_flight[1], cpu); + } + if ((int)inflight[0] < 0) + inflight[0] = 0; + if ((int)inflight[1] < 0) + inflight[1] = 0; +} + +/* + * Can be deleted altogether. Later. + * + */ +#define BLKDEV_MAJOR_HASH_SIZE 255 +static struct blk_major_name { + struct blk_major_name *next; + int major; + char name[16]; +#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD + void (*probe)(dev_t devt); +#endif +} *major_names[BLKDEV_MAJOR_HASH_SIZE]; +static DEFINE_MUTEX(major_names_lock); +static DEFINE_SPINLOCK(major_names_spinlock); + +/* index in the above - for now: assume no multimajor ranges */ +static inline int major_to_index(unsigned major) +{ + return major % BLKDEV_MAJOR_HASH_SIZE; +} + +#ifdef CONFIG_PROC_FS +void blkdev_show(struct seq_file *seqf, off_t offset) +{ + struct blk_major_name *dp; + + spin_lock(&major_names_spinlock); + for (dp = major_names[major_to_index(offset)]; dp; dp = dp->next) + if (dp->major == offset) + seq_printf(seqf, "%3d %s\n", dp->major, dp->name); + spin_unlock(&major_names_spinlock); +} +#endif /* CONFIG_PROC_FS */ + +/** + * __register_blkdev - register a new block device + * + * @major: the requested major device number [1..BLKDEV_MAJOR_MAX-1]. If + * @major = 0, try to allocate any unused major number. + * @name: the name of the new block device as a zero terminated string + * @probe: pre-devtmpfs / pre-udev callback used to create disks when their + * pre-created device node is accessed. When a probe call uses + * add_disk() and it fails the driver must cleanup resources. This + * interface may soon be removed. + * + * The @name must be unique within the system. + * + * The return value depends on the @major input parameter: + * + * - if a major device number was requested in range [1..BLKDEV_MAJOR_MAX-1] + * then the function returns zero on success, or a negative error code + * - if any unused major number was requested with @major = 0 parameter + * then the return value is the allocated major number in range + * [1..BLKDEV_MAJOR_MAX-1] or a negative error code otherwise + * + * See Documentation/admin-guide/devices.txt for the list of allocated + * major numbers. + * + * Use register_blkdev instead for any new code. + */ +int __register_blkdev(unsigned int major, const char *name, + void (*probe)(dev_t devt)) +{ + struct blk_major_name **n, *p; + int index, ret = 0; + + mutex_lock(&major_names_lock); + + /* temporary */ + if (major == 0) { + for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) { + if (major_names[index] == NULL) + break; + } + + if (index == 0) { + printk("%s: failed to get major for %s\n", + __func__, name); + ret = -EBUSY; + goto out; + } + major = index; + ret = major; + } + + if (major >= BLKDEV_MAJOR_MAX) { + pr_err("%s: major requested (%u) is greater than the maximum (%u) for %s\n", + __func__, major, BLKDEV_MAJOR_MAX-1, name); + + ret = -EINVAL; + goto out; + } + + p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL); + if (p == NULL) { + ret = -ENOMEM; + goto out; + } + + p->major = major; +#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD + p->probe = probe; +#endif + strscpy(p->name, name, sizeof(p->name)); + p->next = NULL; + index = major_to_index(major); + + spin_lock(&major_names_spinlock); + for (n = &major_names[index]; *n; n = &(*n)->next) { + if ((*n)->major == major) + break; + } + if (!*n) + *n = p; + else + ret = -EBUSY; + spin_unlock(&major_names_spinlock); + + if (ret < 0) { + printk("register_blkdev: cannot get major %u for %s\n", + major, name); + kfree(p); + } +out: + mutex_unlock(&major_names_lock); + return ret; +} +EXPORT_SYMBOL(__register_blkdev); + +void unregister_blkdev(unsigned int major, const char *name) +{ + struct blk_major_name **n; + struct blk_major_name *p = NULL; + int index = major_to_index(major); + + mutex_lock(&major_names_lock); + spin_lock(&major_names_spinlock); + for (n = &major_names[index]; *n; n = &(*n)->next) + if ((*n)->major == major) + break; + if (!*n || strcmp((*n)->name, name)) { + WARN_ON(1); + } else { + p = *n; + *n = p->next; + } + spin_unlock(&major_names_spinlock); + mutex_unlock(&major_names_lock); + kfree(p); +} + +EXPORT_SYMBOL(unregister_blkdev); + +int blk_alloc_ext_minor(void) +{ + int idx; + + idx = ida_alloc_range(&ext_devt_ida, 0, NR_EXT_DEVT - 1, GFP_KERNEL); + if (idx == -ENOSPC) + return -EBUSY; + return idx; +} + +void blk_free_ext_minor(unsigned int minor) +{ + ida_free(&ext_devt_ida, minor); +} + +void disk_uevent(struct gendisk *disk, enum kobject_action action) +{ + struct block_device *part; + unsigned long idx; + + rcu_read_lock(); + xa_for_each(&disk->part_tbl, idx, part) { + if (bdev_is_partition(part) && !bdev_nr_sectors(part)) + continue; + if (!kobject_get_unless_zero(&part->bd_device.kobj)) + continue; + + rcu_read_unlock(); + kobject_uevent(bdev_kobj(part), action); + put_device(&part->bd_device); + rcu_read_lock(); + } + rcu_read_unlock(); +} +EXPORT_SYMBOL_GPL(disk_uevent); + +int disk_scan_partitions(struct gendisk *disk, blk_mode_t mode) +{ + struct block_device *bdev; + int ret = 0; + + if (disk->flags & (GENHD_FL_NO_PART | GENHD_FL_HIDDEN)) + return -EINVAL; + if (test_bit(GD_SUPPRESS_PART_SCAN, &disk->state)) + return -EINVAL; + if (disk->open_partitions) + return -EBUSY; + + /* + * If the device is opened exclusively by current thread already, it's + * safe to scan partitons, otherwise, use bd_prepare_to_claim() to + * synchronize with other exclusive openers and other partition + * scanners. + */ + if (!(mode & BLK_OPEN_EXCL)) { + ret = bd_prepare_to_claim(disk->part0, disk_scan_partitions, + NULL); + if (ret) + return ret; + } + + set_bit(GD_NEED_PART_SCAN, &disk->state); + bdev = blkdev_get_by_dev(disk_devt(disk), mode & ~BLK_OPEN_EXCL, NULL, + NULL); + if (IS_ERR(bdev)) + ret = PTR_ERR(bdev); + else + blkdev_put(bdev, NULL); + + /* + * If blkdev_get_by_dev() failed early, GD_NEED_PART_SCAN is still set, + * and this will cause that re-assemble partitioned raid device will + * creat partition for underlying disk. + */ + clear_bit(GD_NEED_PART_SCAN, &disk->state); + if (!(mode & BLK_OPEN_EXCL)) + bd_abort_claiming(disk->part0, disk_scan_partitions); + return ret; +} + +/** + * device_add_disk - add disk information to kernel list + * @parent: parent device for the disk + * @disk: per-device partitioning information + * @groups: Additional per-device sysfs groups + * + * This function registers the partitioning information in @disk + * with the kernel. + */ +int __must_check device_add_disk(struct device *parent, struct gendisk *disk, + const struct attribute_group **groups) + +{ + struct device *ddev = disk_to_dev(disk); + int ret; + + /* Only makes sense for bio-based to set ->poll_bio */ + if (queue_is_mq(disk->queue) && disk->fops->poll_bio) + return -EINVAL; + + /* + * The disk queue should now be all set with enough information about + * the device for the elevator code to pick an adequate default + * elevator if one is needed, that is, for devices requesting queue + * registration. + */ + elevator_init_mq(disk->queue); + + /* Mark bdev as having a submit_bio, if needed */ + disk->part0->bd_has_submit_bio = disk->fops->submit_bio != NULL; + + /* + * If the driver provides an explicit major number it also must provide + * the number of minors numbers supported, and those will be used to + * setup the gendisk. + * Otherwise just allocate the device numbers for both the whole device + * and all partitions from the extended dev_t space. + */ + ret = -EINVAL; + if (disk->major) { + if (WARN_ON(!disk->minors)) + goto out_exit_elevator; + + if (disk->minors > DISK_MAX_PARTS) { + pr_err("block: can't allocate more than %d partitions\n", + DISK_MAX_PARTS); + disk->minors = DISK_MAX_PARTS; + } + if (disk->first_minor > MINORMASK || + disk->minors > MINORMASK + 1 || + disk->first_minor + disk->minors > MINORMASK + 1) + goto out_exit_elevator; + } else { + if (WARN_ON(disk->minors)) + goto out_exit_elevator; + + ret = blk_alloc_ext_minor(); + if (ret < 0) + goto out_exit_elevator; + disk->major = BLOCK_EXT_MAJOR; + disk->first_minor = ret; + } + + /* delay uevents, until we scanned partition table */ + dev_set_uevent_suppress(ddev, 1); + + ddev->parent = parent; + ddev->groups = groups; + dev_set_name(ddev, "%s", disk->disk_name); + if (!(disk->flags & GENHD_FL_HIDDEN)) + ddev->devt = MKDEV(disk->major, disk->first_minor); + ret = device_add(ddev); + if (ret) + goto out_free_ext_minor; + + ret = disk_alloc_events(disk); + if (ret) + goto out_device_del; + + ret = sysfs_create_link(block_depr, &ddev->kobj, + kobject_name(&ddev->kobj)); + if (ret) + goto out_device_del; + + /* + * avoid probable deadlock caused by allocating memory with + * GFP_KERNEL in runtime_resume callback of its all ancestor + * devices + */ + pm_runtime_set_memalloc_noio(ddev, true); + + disk->part0->bd_holder_dir = + kobject_create_and_add("holders", &ddev->kobj); + if (!disk->part0->bd_holder_dir) { + ret = -ENOMEM; + goto out_del_block_link; + } + disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj); + if (!disk->slave_dir) { + ret = -ENOMEM; + goto out_put_holder_dir; + } + + ret = blk_register_queue(disk); + if (ret) + goto out_put_slave_dir; + + if (!(disk->flags & GENHD_FL_HIDDEN)) { + ret = bdi_register(disk->bdi, "%u:%u", + disk->major, disk->first_minor); + if (ret) + goto out_unregister_queue; + bdi_set_owner(disk->bdi, ddev); + ret = sysfs_create_link(&ddev->kobj, + &disk->bdi->dev->kobj, "bdi"); + if (ret) + goto out_unregister_bdi; + + /* Make sure the first partition scan will be proceed */ + if (get_capacity(disk) && !(disk->flags & GENHD_FL_NO_PART) && + !test_bit(GD_SUPPRESS_PART_SCAN, &disk->state)) + set_bit(GD_NEED_PART_SCAN, &disk->state); + + bdev_add(disk->part0, ddev->devt); + if (get_capacity(disk)) + disk_scan_partitions(disk, BLK_OPEN_READ); + + /* + * Announce the disk and partitions after all partitions are + * created. (for hidden disks uevents remain suppressed forever) + */ + dev_set_uevent_suppress(ddev, 0); + disk_uevent(disk, KOBJ_ADD); + } else { + /* + * Even if the block_device for a hidden gendisk is not + * registered, it needs to have a valid bd_dev so that the + * freeing of the dynamic major works. + */ + disk->part0->bd_dev = MKDEV(disk->major, disk->first_minor); + } + + disk_update_readahead(disk); + disk_add_events(disk); + set_bit(GD_ADDED, &disk->state); + return 0; + +out_unregister_bdi: + if (!(disk->flags & GENHD_FL_HIDDEN)) + bdi_unregister(disk->bdi); +out_unregister_queue: + blk_unregister_queue(disk); + rq_qos_exit(disk->queue); +out_put_slave_dir: + kobject_put(disk->slave_dir); + disk->slave_dir = NULL; +out_put_holder_dir: + kobject_put(disk->part0->bd_holder_dir); +out_del_block_link: + sysfs_remove_link(block_depr, dev_name(ddev)); + pm_runtime_set_memalloc_noio(ddev, false); +out_device_del: + device_del(ddev); +out_free_ext_minor: + if (disk->major == BLOCK_EXT_MAJOR) + blk_free_ext_minor(disk->first_minor); +out_exit_elevator: + if (disk->queue->elevator) + elevator_exit(disk->queue); + return ret; +} +EXPORT_SYMBOL(device_add_disk); + +static void blk_report_disk_dead(struct gendisk *disk, bool surprise) +{ + struct block_device *bdev; + unsigned long idx; + + rcu_read_lock(); + xa_for_each(&disk->part_tbl, idx, bdev) { + if (!kobject_get_unless_zero(&bdev->bd_device.kobj)) + continue; + rcu_read_unlock(); + + bdev_mark_dead(bdev, surprise); + + put_device(&bdev->bd_device); + rcu_read_lock(); + } + rcu_read_unlock(); +} + +static void __blk_mark_disk_dead(struct gendisk *disk) +{ + /* + * Fail any new I/O. + */ + if (test_and_set_bit(GD_DEAD, &disk->state)) + return; + + if (test_bit(GD_OWNS_QUEUE, &disk->state)) + blk_queue_flag_set(QUEUE_FLAG_DYING, disk->queue); + + /* + * Stop buffered writers from dirtying pages that can't be written out. + */ + set_capacity(disk, 0); + + /* + * Prevent new I/O from crossing bio_queue_enter(). + */ + blk_queue_start_drain(disk->queue); +} + +/** + * blk_mark_disk_dead - mark a disk as dead + * @disk: disk to mark as dead + * + * Mark as disk as dead (e.g. surprise removed) and don't accept any new I/O + * to this disk. + */ +void blk_mark_disk_dead(struct gendisk *disk) +{ + __blk_mark_disk_dead(disk); + blk_report_disk_dead(disk, true); +} +EXPORT_SYMBOL_GPL(blk_mark_disk_dead); + +/** + * del_gendisk - remove the gendisk + * @disk: the struct gendisk to remove + * + * Removes the gendisk and all its associated resources. This deletes the + * partitions associated with the gendisk, and unregisters the associated + * request_queue. + * + * This is the counter to the respective __device_add_disk() call. + * + * The final removal of the struct gendisk happens when its refcount reaches 0 + * with put_disk(), which should be called after del_gendisk(), if + * __device_add_disk() was used. + * + * Drivers exist which depend on the release of the gendisk to be synchronous, + * it should not be deferred. + * + * Context: can sleep + */ +void del_gendisk(struct gendisk *disk) +{ + struct request_queue *q = disk->queue; + struct block_device *part; + unsigned long idx; + + might_sleep(); + + if (WARN_ON_ONCE(!disk_live(disk) && !(disk->flags & GENHD_FL_HIDDEN))) + return; + + disk_del_events(disk); + + /* + * Prevent new openers by unlinked the bdev inode. + */ + mutex_lock(&disk->open_mutex); + xa_for_each(&disk->part_tbl, idx, part) + remove_inode_hash(part->bd_inode); + mutex_unlock(&disk->open_mutex); + + /* + * Tell the file system to write back all dirty data and shut down if + * it hasn't been notified earlier. + */ + if (!test_bit(GD_DEAD, &disk->state)) + blk_report_disk_dead(disk, false); + __blk_mark_disk_dead(disk); + + /* + * Drop all partitions now that the disk is marked dead. + */ + mutex_lock(&disk->open_mutex); + xa_for_each_start(&disk->part_tbl, idx, part, 1) + drop_partition(part); + mutex_unlock(&disk->open_mutex); + + if (!(disk->flags & GENHD_FL_HIDDEN)) { + sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi"); + + /* + * Unregister bdi before releasing device numbers (as they can + * get reused and we'd get clashes in sysfs). + */ + bdi_unregister(disk->bdi); + } + + blk_unregister_queue(disk); + + kobject_put(disk->part0->bd_holder_dir); + kobject_put(disk->slave_dir); + disk->slave_dir = NULL; + + part_stat_set_all(disk->part0, 0); + disk->part0->bd_stamp = 0; + sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk))); + pm_runtime_set_memalloc_noio(disk_to_dev(disk), false); + device_del(disk_to_dev(disk)); + + blk_mq_freeze_queue_wait(q); + + blk_throtl_cancel_bios(disk); + + blk_sync_queue(q); + blk_flush_integrity(); + + if (queue_is_mq(q)) + blk_mq_cancel_work_sync(q); + + blk_mq_quiesce_queue(q); + if (q->elevator) { + mutex_lock(&q->sysfs_lock); + elevator_exit(q); + mutex_unlock(&q->sysfs_lock); + } + rq_qos_exit(q); + blk_mq_unquiesce_queue(q); + + /* + * If the disk does not own the queue, allow using passthrough requests + * again. Else leave the queue frozen to fail all I/O. + */ + if (!test_bit(GD_OWNS_QUEUE, &disk->state)) { + blk_queue_flag_clear(QUEUE_FLAG_INIT_DONE, q); + __blk_mq_unfreeze_queue(q, true); + } else { + if (queue_is_mq(q)) + blk_mq_exit_queue(q); + } +} +EXPORT_SYMBOL(del_gendisk); + +/** + * invalidate_disk - invalidate the disk + * @disk: the struct gendisk to invalidate + * + * A helper to invalidates the disk. It will clean the disk's associated + * buffer/page caches and reset its internal states so that the disk + * can be reused by the drivers. + * + * Context: can sleep + */ +void invalidate_disk(struct gendisk *disk) +{ + struct block_device *bdev = disk->part0; + + invalidate_bdev(bdev); + bdev->bd_inode->i_mapping->wb_err = 0; + set_capacity(disk, 0); +} +EXPORT_SYMBOL(invalidate_disk); + +/* sysfs access to bad-blocks list. */ +static ssize_t disk_badblocks_show(struct device *dev, + struct device_attribute *attr, + char *page) +{ + struct gendisk *disk = dev_to_disk(dev); + + if (!disk->bb) + return sprintf(page, "\n"); + + return badblocks_show(disk->bb, page, 0); +} + +static ssize_t disk_badblocks_store(struct device *dev, + struct device_attribute *attr, + const char *page, size_t len) +{ + struct gendisk *disk = dev_to_disk(dev); + + if (!disk->bb) + return -ENXIO; + + return badblocks_store(disk->bb, page, len, 0); +} + +#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD +void blk_request_module(dev_t devt) +{ + unsigned int major = MAJOR(devt); + struct blk_major_name **n; + + mutex_lock(&major_names_lock); + for (n = &major_names[major_to_index(major)]; *n; n = &(*n)->next) { + if ((*n)->major == major && (*n)->probe) { + (*n)->probe(devt); + mutex_unlock(&major_names_lock); + return; + } + } + mutex_unlock(&major_names_lock); + + if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0) + /* Make old-style 2.4 aliases work */ + request_module("block-major-%d", MAJOR(devt)); +} +#endif /* CONFIG_BLOCK_LEGACY_AUTOLOAD */ + +#ifdef CONFIG_PROC_FS +/* iterator */ +static void *disk_seqf_start(struct seq_file *seqf, loff_t *pos) +{ + loff_t skip = *pos; + struct class_dev_iter *iter; + struct device *dev; + + iter = kmalloc(sizeof(*iter), GFP_KERNEL); + if (!iter) + return ERR_PTR(-ENOMEM); + + seqf->private = iter; + class_dev_iter_init(iter, &block_class, NULL, &disk_type); + do { + dev = class_dev_iter_next(iter); + if (!dev) + return NULL; + } while (skip--); + + return dev_to_disk(dev); +} + +static void *disk_seqf_next(struct seq_file *seqf, void *v, loff_t *pos) +{ + struct device *dev; + + (*pos)++; + dev = class_dev_iter_next(seqf->private); + if (dev) + return dev_to_disk(dev); + + return NULL; +} + +static void disk_seqf_stop(struct seq_file *seqf, void *v) +{ + struct class_dev_iter *iter = seqf->private; + + /* stop is called even after start failed :-( */ + if (iter) { + class_dev_iter_exit(iter); + kfree(iter); + seqf->private = NULL; + } +} + +static void *show_partition_start(struct seq_file *seqf, loff_t *pos) +{ + void *p; + + p = disk_seqf_start(seqf, pos); + if (!IS_ERR_OR_NULL(p) && !*pos) + seq_puts(seqf, "major minor #blocks name\n\n"); + return p; +} + +static int show_partition(struct seq_file *seqf, void *v) +{ + struct gendisk *sgp = v; + struct block_device *part; + unsigned long idx; + + if (!get_capacity(sgp) || (sgp->flags & GENHD_FL_HIDDEN)) + return 0; + + rcu_read_lock(); + xa_for_each(&sgp->part_tbl, idx, part) { + if (!bdev_nr_sectors(part)) + continue; + seq_printf(seqf, "%4d %7d %10llu %pg\n", + MAJOR(part->bd_dev), MINOR(part->bd_dev), + bdev_nr_sectors(part) >> 1, part); + } + rcu_read_unlock(); + return 0; +} + +static const struct seq_operations partitions_op = { + .start = show_partition_start, + .next = disk_seqf_next, + .stop = disk_seqf_stop, + .show = show_partition +}; +#endif + +static int __init genhd_device_init(void) +{ + int error; + + error = class_register(&block_class); + if (unlikely(error)) + return error; + blk_dev_init(); + + register_blkdev(BLOCK_EXT_MAJOR, "blkext"); + + /* create top-level block dir */ + block_depr = kobject_create_and_add("block", NULL); + return 0; +} + +subsys_initcall(genhd_device_init); + +static ssize_t disk_range_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return sprintf(buf, "%d\n", disk->minors); +} + +static ssize_t disk_ext_range_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return sprintf(buf, "%d\n", + (disk->flags & GENHD_FL_NO_PART) ? 1 : DISK_MAX_PARTS); +} + +static ssize_t disk_removable_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return sprintf(buf, "%d\n", + (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0)); +} + +static ssize_t disk_hidden_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return sprintf(buf, "%d\n", + (disk->flags & GENHD_FL_HIDDEN ? 1 : 0)); +} + +static ssize_t disk_ro_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return sprintf(buf, "%d\n", get_disk_ro(disk) ? 1 : 0); +} + +ssize_t part_size_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%llu\n", bdev_nr_sectors(dev_to_bdev(dev))); +} + +ssize_t part_stat_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct block_device *bdev = dev_to_bdev(dev); + struct request_queue *q = bdev_get_queue(bdev); + struct disk_stats stat; + unsigned int inflight; + + if (queue_is_mq(q)) + inflight = blk_mq_in_flight(q, bdev); + else + inflight = part_in_flight(bdev); + + if (inflight) { + part_stat_lock(); + update_io_ticks(bdev, jiffies, true); + part_stat_unlock(); + } + part_stat_read_all(bdev, &stat); + return sprintf(buf, + "%8lu %8lu %8llu %8u " + "%8lu %8lu %8llu %8u " + "%8u %8u %8u " + "%8lu %8lu %8llu %8u " + "%8lu %8u" + "\n", + stat.ios[STAT_READ], + stat.merges[STAT_READ], + (unsigned long long)stat.sectors[STAT_READ], + (unsigned int)div_u64(stat.nsecs[STAT_READ], NSEC_PER_MSEC), + stat.ios[STAT_WRITE], + stat.merges[STAT_WRITE], + (unsigned long long)stat.sectors[STAT_WRITE], + (unsigned int)div_u64(stat.nsecs[STAT_WRITE], NSEC_PER_MSEC), + inflight, + jiffies_to_msecs(stat.io_ticks), + (unsigned int)div_u64(stat.nsecs[STAT_READ] + + stat.nsecs[STAT_WRITE] + + stat.nsecs[STAT_DISCARD] + + stat.nsecs[STAT_FLUSH], + NSEC_PER_MSEC), + stat.ios[STAT_DISCARD], + stat.merges[STAT_DISCARD], + (unsigned long long)stat.sectors[STAT_DISCARD], + (unsigned int)div_u64(stat.nsecs[STAT_DISCARD], NSEC_PER_MSEC), + stat.ios[STAT_FLUSH], + (unsigned int)div_u64(stat.nsecs[STAT_FLUSH], NSEC_PER_MSEC)); +} + +ssize_t part_inflight_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct block_device *bdev = dev_to_bdev(dev); + struct request_queue *q = bdev_get_queue(bdev); + unsigned int inflight[2]; + + if (queue_is_mq(q)) + blk_mq_in_flight_rw(q, bdev, inflight); + else + part_in_flight_rw(bdev, inflight); + + return sprintf(buf, "%8u %8u\n", inflight[0], inflight[1]); +} + +static ssize_t disk_capability_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + dev_warn_once(dev, "the capability attribute has been deprecated.\n"); + return sprintf(buf, "0\n"); +} + +static ssize_t disk_alignment_offset_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return sprintf(buf, "%d\n", bdev_alignment_offset(disk->part0)); +} + +static ssize_t disk_discard_alignment_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return sprintf(buf, "%d\n", bdev_alignment_offset(disk->part0)); +} + +static ssize_t diskseq_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return sprintf(buf, "%llu\n", disk->diskseq); +} + +static DEVICE_ATTR(range, 0444, disk_range_show, NULL); +static DEVICE_ATTR(ext_range, 0444, disk_ext_range_show, NULL); +static DEVICE_ATTR(removable, 0444, disk_removable_show, NULL); +static DEVICE_ATTR(hidden, 0444, disk_hidden_show, NULL); +static DEVICE_ATTR(ro, 0444, disk_ro_show, NULL); +static DEVICE_ATTR(size, 0444, part_size_show, NULL); +static DEVICE_ATTR(alignment_offset, 0444, disk_alignment_offset_show, NULL); +static DEVICE_ATTR(discard_alignment, 0444, disk_discard_alignment_show, NULL); +static DEVICE_ATTR(capability, 0444, disk_capability_show, NULL); +static DEVICE_ATTR(stat, 0444, part_stat_show, NULL); +static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL); +static DEVICE_ATTR(badblocks, 0644, disk_badblocks_show, disk_badblocks_store); +static DEVICE_ATTR(diskseq, 0444, diskseq_show, NULL); + +#ifdef CONFIG_FAIL_MAKE_REQUEST +ssize_t part_fail_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", dev_to_bdev(dev)->bd_make_it_fail); +} + +ssize_t part_fail_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + int i; + + if (count > 0 && sscanf(buf, "%d", &i) > 0) + dev_to_bdev(dev)->bd_make_it_fail = i; + + return count; +} + +static struct device_attribute dev_attr_fail = + __ATTR(make-it-fail, 0644, part_fail_show, part_fail_store); +#endif /* CONFIG_FAIL_MAKE_REQUEST */ + +#ifdef CONFIG_FAIL_IO_TIMEOUT +static struct device_attribute dev_attr_fail_timeout = + __ATTR(io-timeout-fail, 0644, part_timeout_show, part_timeout_store); +#endif + +static struct attribute *disk_attrs[] = { + &dev_attr_range.attr, + &dev_attr_ext_range.attr, + &dev_attr_removable.attr, + &dev_attr_hidden.attr, + &dev_attr_ro.attr, + &dev_attr_size.attr, + &dev_attr_alignment_offset.attr, + &dev_attr_discard_alignment.attr, + &dev_attr_capability.attr, + &dev_attr_stat.attr, + &dev_attr_inflight.attr, + &dev_attr_badblocks.attr, + &dev_attr_events.attr, + &dev_attr_events_async.attr, + &dev_attr_events_poll_msecs.attr, + &dev_attr_diskseq.attr, +#ifdef CONFIG_FAIL_MAKE_REQUEST + &dev_attr_fail.attr, +#endif +#ifdef CONFIG_FAIL_IO_TIMEOUT + &dev_attr_fail_timeout.attr, +#endif + NULL +}; + +static umode_t disk_visible(struct kobject *kobj, struct attribute *a, int n) +{ + struct device *dev = container_of(kobj, typeof(*dev), kobj); + struct gendisk *disk = dev_to_disk(dev); + + if (a == &dev_attr_badblocks.attr && !disk->bb) + return 0; + return a->mode; +} + +static struct attribute_group disk_attr_group = { + .attrs = disk_attrs, + .is_visible = disk_visible, +}; + +static const struct attribute_group *disk_attr_groups[] = { + &disk_attr_group, +#ifdef CONFIG_BLK_DEV_IO_TRACE + &blk_trace_attr_group, +#endif +#ifdef CONFIG_BLK_DEV_INTEGRITY + &blk_integrity_attr_group, +#endif + NULL +}; + +/** + * disk_release - releases all allocated resources of the gendisk + * @dev: the device representing this disk + * + * This function releases all allocated resources of the gendisk. + * + * Drivers which used __device_add_disk() have a gendisk with a request_queue + * assigned. Since the request_queue sits on top of the gendisk for these + * drivers we also call blk_put_queue() for them, and we expect the + * request_queue refcount to reach 0 at this point, and so the request_queue + * will also be freed prior to the disk. + * + * Context: can sleep + */ +static void disk_release(struct device *dev) +{ + struct gendisk *disk = dev_to_disk(dev); + + might_sleep(); + WARN_ON_ONCE(disk_live(disk)); + + blk_trace_remove(disk->queue); + + /* + * To undo the all initialization from blk_mq_init_allocated_queue in + * case of a probe failure where add_disk is never called we have to + * call blk_mq_exit_queue here. We can't do this for the more common + * teardown case (yet) as the tagset can be gone by the time the disk + * is released once it was added. + */ + if (queue_is_mq(disk->queue) && + test_bit(GD_OWNS_QUEUE, &disk->state) && + !test_bit(GD_ADDED, &disk->state)) + blk_mq_exit_queue(disk->queue); + + blkcg_exit_disk(disk); + + bioset_exit(&disk->bio_split); + + disk_release_events(disk); + kfree(disk->random); + disk_free_zone_bitmaps(disk); + xa_destroy(&disk->part_tbl); + + disk->queue->disk = NULL; + blk_put_queue(disk->queue); + + if (test_bit(GD_ADDED, &disk->state) && disk->fops->free_disk) + disk->fops->free_disk(disk); + + iput(disk->part0->bd_inode); /* frees the disk */ +} + +static int block_uevent(const struct device *dev, struct kobj_uevent_env *env) +{ + const struct gendisk *disk = dev_to_disk(dev); + + return add_uevent_var(env, "DISKSEQ=%llu", disk->diskseq); +} + +struct class block_class = { + .name = "block", + .dev_uevent = block_uevent, +}; + +static char *block_devnode(const struct device *dev, umode_t *mode, + kuid_t *uid, kgid_t *gid) +{ + struct gendisk *disk = dev_to_disk(dev); + + if (disk->fops->devnode) + return disk->fops->devnode(disk, mode); + return NULL; +} + +const struct device_type disk_type = { + .name = "disk", + .groups = disk_attr_groups, + .release = disk_release, + .devnode = block_devnode, +}; + +#ifdef CONFIG_PROC_FS +/* + * aggregate disk stat collector. Uses the same stats that the sysfs + * entries do, above, but makes them available through one seq_file. + * + * The output looks suspiciously like /proc/partitions with a bunch of + * extra fields. + */ +static int diskstats_show(struct seq_file *seqf, void *v) +{ + struct gendisk *gp = v; + struct block_device *hd; + unsigned int inflight; + struct disk_stats stat; + unsigned long idx; + + /* + if (&disk_to_dev(gp)->kobj.entry == block_class.devices.next) + seq_puts(seqf, "major minor name" + " rio rmerge rsect ruse wio wmerge " + "wsect wuse running use aveq" + "\n\n"); + */ + + rcu_read_lock(); + xa_for_each(&gp->part_tbl, idx, hd) { + if (bdev_is_partition(hd) && !bdev_nr_sectors(hd)) + continue; + if (queue_is_mq(gp->queue)) + inflight = blk_mq_in_flight(gp->queue, hd); + else + inflight = part_in_flight(hd); + + if (inflight) { + part_stat_lock(); + update_io_ticks(hd, jiffies, true); + part_stat_unlock(); + } + part_stat_read_all(hd, &stat); + seq_printf(seqf, "%4d %7d %pg " + "%lu %lu %lu %u " + "%lu %lu %lu %u " + "%u %u %u " + "%lu %lu %lu %u " + "%lu %u" + "\n", + MAJOR(hd->bd_dev), MINOR(hd->bd_dev), hd, + stat.ios[STAT_READ], + stat.merges[STAT_READ], + stat.sectors[STAT_READ], + (unsigned int)div_u64(stat.nsecs[STAT_READ], + NSEC_PER_MSEC), + stat.ios[STAT_WRITE], + stat.merges[STAT_WRITE], + stat.sectors[STAT_WRITE], + (unsigned int)div_u64(stat.nsecs[STAT_WRITE], + NSEC_PER_MSEC), + inflight, + jiffies_to_msecs(stat.io_ticks), + (unsigned int)div_u64(stat.nsecs[STAT_READ] + + stat.nsecs[STAT_WRITE] + + stat.nsecs[STAT_DISCARD] + + stat.nsecs[STAT_FLUSH], + NSEC_PER_MSEC), + stat.ios[STAT_DISCARD], + stat.merges[STAT_DISCARD], + stat.sectors[STAT_DISCARD], + (unsigned int)div_u64(stat.nsecs[STAT_DISCARD], + NSEC_PER_MSEC), + stat.ios[STAT_FLUSH], + (unsigned int)div_u64(stat.nsecs[STAT_FLUSH], + NSEC_PER_MSEC) + ); + } + rcu_read_unlock(); + + return 0; +} + +static const struct seq_operations diskstats_op = { + .start = disk_seqf_start, + .next = disk_seqf_next, + .stop = disk_seqf_stop, + .show = diskstats_show +}; + +static int __init proc_genhd_init(void) +{ + proc_create_seq("diskstats", 0, NULL, &diskstats_op); + proc_create_seq("partitions", 0, NULL, &partitions_op); + return 0; +} +module_init(proc_genhd_init); +#endif /* CONFIG_PROC_FS */ + +dev_t part_devt(struct gendisk *disk, u8 partno) +{ + struct block_device *part; + dev_t devt = 0; + + rcu_read_lock(); + part = xa_load(&disk->part_tbl, partno); + if (part) + devt = part->bd_dev; + rcu_read_unlock(); + + return devt; +} + +struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id, + struct lock_class_key *lkclass) +{ + struct gendisk *disk; + + disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id); + if (!disk) + return NULL; + + if (bioset_init(&disk->bio_split, BIO_POOL_SIZE, 0, 0)) + goto out_free_disk; + + disk->bdi = bdi_alloc(node_id); + if (!disk->bdi) + goto out_free_bioset; + + /* bdev_alloc() might need the queue, set before the first call */ + disk->queue = q; + + disk->part0 = bdev_alloc(disk, 0); + if (!disk->part0) + goto out_free_bdi; + + disk->node_id = node_id; + mutex_init(&disk->open_mutex); + xa_init(&disk->part_tbl); + if (xa_insert(&disk->part_tbl, 0, disk->part0, GFP_KERNEL)) + goto out_destroy_part_tbl; + + if (blkcg_init_disk(disk)) + goto out_erase_part0; + + rand_initialize_disk(disk); + disk_to_dev(disk)->class = &block_class; + disk_to_dev(disk)->type = &disk_type; + device_initialize(disk_to_dev(disk)); + inc_diskseq(disk); + q->disk = disk; + lockdep_init_map(&disk->lockdep_map, "(bio completion)", lkclass, 0); +#ifdef CONFIG_BLOCK_HOLDER_DEPRECATED + INIT_LIST_HEAD(&disk->slave_bdevs); +#endif + return disk; + +out_erase_part0: + xa_erase(&disk->part_tbl, 0); +out_destroy_part_tbl: + xa_destroy(&disk->part_tbl); + disk->part0->bd_disk = NULL; + iput(disk->part0->bd_inode); +out_free_bdi: + bdi_put(disk->bdi); +out_free_bioset: + bioset_exit(&disk->bio_split); +out_free_disk: + kfree(disk); + return NULL; +} + +struct gendisk *__blk_alloc_disk(int node, struct lock_class_key *lkclass) +{ + struct request_queue *q; + struct gendisk *disk; + + q = blk_alloc_queue(node); + if (!q) + return NULL; + + disk = __alloc_disk_node(q, node, lkclass); + if (!disk) { + blk_put_queue(q); + return NULL; + } + set_bit(GD_OWNS_QUEUE, &disk->state); + return disk; +} +EXPORT_SYMBOL(__blk_alloc_disk); + +/** + * put_disk - decrements the gendisk refcount + * @disk: the struct gendisk to decrement the refcount for + * + * This decrements the refcount for the struct gendisk. When this reaches 0 + * we'll have disk_release() called. + * + * Note: for blk-mq disk put_disk must be called before freeing the tag_set + * when handling probe errors (that is before add_disk() is called). + * + * Context: Any context, but the last reference must not be dropped from + * atomic context. + */ +void put_disk(struct gendisk *disk) +{ + if (disk) + put_device(disk_to_dev(disk)); +} +EXPORT_SYMBOL(put_disk); + +static void set_disk_ro_uevent(struct gendisk *gd, int ro) +{ + char event[] = "DISK_RO=1"; + char *envp[] = { event, NULL }; + + if (!ro) + event[8] = '0'; + kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp); +} + +/** + * set_disk_ro - set a gendisk read-only + * @disk: gendisk to operate on + * @read_only: %true to set the disk read-only, %false set the disk read/write + * + * This function is used to indicate whether a given disk device should have its + * read-only flag set. set_disk_ro() is typically used by device drivers to + * indicate whether the underlying physical device is write-protected. + */ +void set_disk_ro(struct gendisk *disk, bool read_only) +{ + if (read_only) { + if (test_and_set_bit(GD_READ_ONLY, &disk->state)) + return; + } else { + if (!test_and_clear_bit(GD_READ_ONLY, &disk->state)) + return; + } + set_disk_ro_uevent(disk, read_only); +} +EXPORT_SYMBOL(set_disk_ro); + +void inc_diskseq(struct gendisk *disk) +{ + disk->diskseq = atomic64_inc_return(&diskseq); +} |