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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_GENHD_H
#define _LINUX_GENHD_H
* genhd.h Copyright (C) 1992 Drew Eckhardt
* Generic hard disk header file by
* Drew Eckhardt
* <>
#include <linux/types.h>
#include <linux/kdev_t.h>
#include <linux/rcupdate.h>
#include <linux/slab.h>
#include <linux/percpu-refcount.h>
#include <linux/uuid.h>
#include <linux/blk_types.h>
#include <asm/local.h>
#define dev_to_disk(device) container_of((device), struct gendisk, part0.__dev)
#define dev_to_part(device) container_of((device), struct hd_struct, __dev)
#define disk_to_dev(disk) (&(disk)->part0.__dev)
#define part_to_dev(part) (&((part)->__dev))
extern struct device_type part_type;
extern struct class block_class;
#define DISK_MAX_PARTS 256
#define DISK_NAME_LEN 32
#include <linux/major.h>
#include <linux/device.h>
#include <linux/smp.h>
#include <linux/string.h>
#include <linux/fs.h>
#include <linux/workqueue.h>
* Enough for the string representation of any kind of UUID plus NULL.
* EFI UUID is 36 characters. MSDOS UUID is 11 characters.
struct partition_meta_info {
struct hd_struct {
sector_t start_sect;
* nr_sects is protected by sequence counter. One might extend a
* partition while IO is happening to it and update of nr_sects
* can be non-atomic on 32bit machines with 64bit sector_t.
sector_t nr_sects;
#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
seqcount_t nr_sects_seq;
unsigned long stamp;
struct disk_stats __percpu *dkstats;
struct percpu_ref ref;
sector_t alignment_offset;
unsigned int discard_alignment;
struct device __dev;
struct kobject *holder_dir;
int policy, partno;
struct partition_meta_info *info;
int make_it_fail;
struct rcu_work rcu_work;
* DOC: genhd capability flags
* ``GENHD_FL_REMOVABLE`` (0x0001): indicates that the block device
* gives access to removable media.
* When set, the device remains present even when media is not
* inserted.
* Must not be set for devices which are removed entirely when the
* media is removed.
* ``GENHD_FL_CD`` (0x0008): the block device is a CD-ROM-style
* device.
* Affects responses to the ``CDROM_GET_CAPABILITY`` ioctl.
* ``GENHD_FL_UP`` (0x0010): indicates that the block device is "up",
* with a similar meaning to network interfaces.
* ``GENHD_FL_SUPPRESS_PARTITION_INFO`` (0x0020): don't include
* partition information in ``/proc/partitions`` or in the output of
* printk_all_partitions().
* Used for the null block device and some MMC devices.
* ``GENHD_FL_EXT_DEVT`` (0x0040): the driver supports extended
* dynamic ``dev_t``, i.e. it wants extended device numbers
* This affects the maximum number of partitions.
* ``GENHD_FL_NATIVE_CAPACITY`` (0x0080): based on information in the
* partition table, the device's capacity has been extended to its
* native capacity; i.e. the device has hidden capacity used by one
* of the partitions (this is a flag used so that native capacity is
* only ever unlocked once).
* ``GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE`` (0x0100): event polling is
* blocked whenever a writer holds an exclusive lock.
* ``GENHD_FL_NO_PART_SCAN`` (0x0200): partition scanning is disabled.
* Used for loop devices in their default settings and some MMC
* devices.
* ``GENHD_FL_HIDDEN`` (0x0400): the block device is hidden; it
* doesn't produce events, doesn't appear in sysfs, and doesn't have
* an associated ``bdev``.
* Used for multipath devices.
#define GENHD_FL_REMOVABLE 0x0001
/* 2 is unused (used to be GENHD_FL_DRIVERFS) */
/* 4 is unused (used to be GENHD_FL_MEDIA_CHANGE_NOTIFY) */
#define GENHD_FL_CD 0x0008
#define GENHD_FL_UP 0x0010
#define GENHD_FL_EXT_DEVT 0x0040
#define GENHD_FL_NO_PART_SCAN 0x0200
#define GENHD_FL_HIDDEN 0x0400
enum {
DISK_EVENT_MEDIA_CHANGE = 1 << 0, /* media changed */
DISK_EVENT_EJECT_REQUEST = 1 << 1, /* eject requested */
enum {
/* Poll even if events_poll_msecs is unset */
/* Forward events to udev */
struct disk_part_tbl {
struct rcu_head rcu_head;
int len;
struct hd_struct __rcu *last_lookup;
struct hd_struct __rcu *part[];
struct disk_events;
struct badblocks;
struct blk_integrity {
const struct blk_integrity_profile *profile;
unsigned char flags;
unsigned char tuple_size;
unsigned char interval_exp;
unsigned char tag_size;
struct gendisk {
/* major, first_minor and minors are input parameters only,
* don't use directly. Use disk_devt() and disk_max_parts().
int major; /* major number of driver */
int first_minor;
int minors; /* maximum number of minors, =1 for
* disks that can't be partitioned. */
char disk_name[DISK_NAME_LEN]; /* name of major driver */
unsigned short events; /* supported events */
unsigned short event_flags; /* flags related to event processing */
/* Array of pointers to partitions indexed by partno.
* Protected with matching bdev lock but stat and other
* non-critical accesses use RCU. Always access through
* helpers.
struct disk_part_tbl __rcu *part_tbl;
struct hd_struct part0;
const struct block_device_operations *fops;
struct request_queue *queue;
void *private_data;
int flags;
struct rw_semaphore lookup_sem;
struct kobject *slave_dir;
struct timer_rand_state *random;
atomic_t sync_io; /* RAID */
struct disk_events *ev;
struct kobject integrity_kobj;
struct cdrom_device_info *cdi;
int node_id;
struct badblocks *bb;
struct lockdep_map lockdep_map;
#define disk_to_cdi(disk) ((disk)->cdi)
#define disk_to_cdi(disk) NULL
static inline struct gendisk *part_to_disk(struct hd_struct *part)
if (likely(part)) {
if (part->partno)
return dev_to_disk(part_to_dev(part)->parent);
return dev_to_disk(part_to_dev(part));
return NULL;
static inline int disk_max_parts(struct gendisk *disk)
if (disk->flags & GENHD_FL_EXT_DEVT)
return disk->minors;
static inline bool disk_part_scan_enabled(struct gendisk *disk)
return disk_max_parts(disk) > 1 &&
!(disk->flags & GENHD_FL_NO_PART_SCAN);
static inline dev_t disk_devt(struct gendisk *disk)
return MKDEV(disk->major, disk->first_minor);
static inline dev_t part_devt(struct hd_struct *part)
return part_to_dev(part)->devt;
extern struct hd_struct *__disk_get_part(struct gendisk *disk, int partno);
extern struct hd_struct *disk_get_part(struct gendisk *disk, int partno);
static inline void disk_put_part(struct hd_struct *part)
if (likely(part))
static inline void hd_sects_seq_init(struct hd_struct *p)
#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
* Smarter partition iterator without context limits.
#define DISK_PITER_REVERSE (1 << 0) /* iterate in the reverse direction */
#define DISK_PITER_INCL_EMPTY (1 << 1) /* include 0-sized parts */
#define DISK_PITER_INCL_PART0 (1 << 2) /* include partition 0 */
#define DISK_PITER_INCL_EMPTY_PART0 (1 << 3) /* include empty partition 0 */
struct disk_part_iter {
struct gendisk *disk;
struct hd_struct *part;
int idx;
unsigned int flags;
extern void disk_part_iter_init(struct disk_part_iter *piter,
struct gendisk *disk, unsigned int flags);
extern struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter);
extern void disk_part_iter_exit(struct disk_part_iter *piter);
extern bool disk_has_partitions(struct gendisk *disk);
/* block/genhd.c */
extern void device_add_disk(struct device *parent, struct gendisk *disk,
const struct attribute_group **groups);
static inline void add_disk(struct gendisk *disk)
device_add_disk(NULL, disk, NULL);
extern void device_add_disk_no_queue_reg(struct device *parent, struct gendisk *disk);
static inline void add_disk_no_queue_reg(struct gendisk *disk)
device_add_disk_no_queue_reg(NULL, disk);
extern void del_gendisk(struct gendisk *gp);
extern struct gendisk *get_gendisk(dev_t dev, int *partno);
extern struct block_device *bdget_disk(struct gendisk *disk, int partno);
extern void set_device_ro(struct block_device *bdev, int flag);
extern void set_disk_ro(struct gendisk *disk, int flag);
static inline int get_disk_ro(struct gendisk *disk)
return disk->part0.policy;
extern void disk_block_events(struct gendisk *disk);
extern void disk_unblock_events(struct gendisk *disk);
extern void disk_flush_events(struct gendisk *disk, unsigned int mask);
extern void set_capacity_revalidate_and_notify(struct gendisk *disk,
sector_t size, bool revalidate);
extern unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask);
/* drivers/char/random.c */
extern void add_disk_randomness(struct gendisk *disk) __latent_entropy;
extern void rand_initialize_disk(struct gendisk *disk);
static inline sector_t get_start_sect(struct block_device *bdev)
return bdev->bd_part->start_sect;
static inline sector_t get_capacity(struct gendisk *disk)
return disk->part0.nr_sects;
static inline void set_capacity(struct gendisk *disk, sector_t size)
disk->part0.nr_sects = size;
extern dev_t blk_lookup_devt(const char *name, int partno);
int bdev_disk_changed(struct block_device *bdev, bool invalidate);
int blk_add_partitions(struct gendisk *disk, struct block_device *bdev);
int blk_drop_partitions(struct block_device *bdev);
extern void printk_all_partitions(void);
extern struct gendisk *__alloc_disk_node(int minors, int node_id);
extern struct kobject *get_disk_and_module(struct gendisk *disk);
extern void put_disk(struct gendisk *disk);
extern void put_disk_and_module(struct gendisk *disk);
extern void blk_register_region(dev_t devt, unsigned long range,
struct module *module,
struct kobject *(*probe)(dev_t, int *, void *),
int (*lock)(dev_t, void *),
void *data);
extern void blk_unregister_region(dev_t devt, unsigned long range);
#define alloc_disk_node(minors, node_id) \
({ \
static struct lock_class_key __key; \
const char *__name; \
struct gendisk *__disk; \
__name = "(gendisk_completion)"#minors"("#node_id")"; \
__disk = __alloc_disk_node(minors, node_id); \
if (__disk) \
lockdep_init_map(&__disk->lockdep_map, __name, &__key, 0); \
__disk; \
#define alloc_disk(minors) alloc_disk_node(minors, NUMA_NO_NODE)
#else /* CONFIG_BLOCK */
static inline void printk_all_partitions(void) { }
static inline dev_t blk_lookup_devt(const char *name, int partno)
dev_t devt = MKDEV(0, 0);
return devt;
#endif /* CONFIG_BLOCK */
#endif /* _LINUX_GENHD_H */