include/linux/genhd.h - kernel/common - Git at Google

 /* 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
  *
  *		<[email protected]>
  */

 #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 const struct device_type disk_type;
 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>

 #define PARTITION_META_INFO_VOLNAMELTH	64
 /*
  * Enough for the string representation of any kind of UUID plus NULL.
  * EFI UUID is 36 characters. MSDOS UUID is 11 characters.
  */
 #define PARTITION_META_INFO_UUIDLTH	(UUID_STRING_LEN + 1)

 struct partition_meta_info {
 	char uuid[PARTITION_META_INFO_UUIDLTH];
 	u8 volname[PARTITION_META_INFO_VOLNAMELTH];
 };

 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;
 #endif
 	unsigned long stamp;
 	struct disk_stats __percpu *dkstats;
 	struct percpu_ref ref;

 	struct device __dev;
 	struct kobject *holder_dir;
 	int policy, partno;
 	struct partition_meta_info *info;
 #ifdef CONFIG_FAIL_MAKE_REQUEST
 	int make_it_fail;
 #endif
 	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
  * (``BLOCK_EXT_MAJOR``).
  * 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``.
  * Implies ``GENHD_FL_SUPPRESS_PARTITION_INFO`` and
  * ``GENHD_FL_NO_PART_SCAN``.
  * 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_SUPPRESS_PARTITION_INFO	0x0020
 #define GENHD_FL_EXT_DEVT			0x0040
 #define GENHD_FL_NATIVE_CAPACITY		0x0080
 #define GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE	0x0100
 #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 */
 	DISK_EVENT_FLAG_POLL			= 1 << 0,
 	/* Forward events to udev */
 	DISK_EVENT_FLAG_UEVENT			= 1 << 1,
 };

 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;
 	unsigned long state;
 #define GD_NEED_PART_SCAN		0
 	struct rw_semaphore lookup_sem;
 	struct kobject *slave_dir;

 	struct timer_rand_state *random;
 	atomic_t sync_io;		/* RAID */
 	struct disk_events *ev;
 #ifdef  CONFIG_BLK_DEV_INTEGRITY
 	struct kobject integrity_kobj;
 #endif	/* CONFIG_BLK_DEV_INTEGRITY */
 #if IS_ENABLED(CONFIG_CDROM)
 	struct cdrom_device_info *cdi;
 #endif
 	int node_id;
 	struct badblocks *bb;
 	struct lockdep_map lockdep_map;
 };

 #if IS_REACHABLE(CONFIG_CDROM)
 #define disk_to_cdi(disk)	((disk)->cdi)
 #else
 #define disk_to_cdi(disk)	NULL
 #endif

 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);
 		else
 			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_MAX_PARTS;
 	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))
 		put_device(part_to_dev(part));
 }

 static inline void hd_sects_seq_init(struct hd_struct *p)
 {
 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
 	seqcount_init(&p->nr_sects_seq);
 #endif
 }

 /*
  * 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);
 bool set_capacity_revalidate_and_notify(struct gendisk *disk, sector_t size,
 		bool update_bdev);

 /* 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;
 }

 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 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)

 int register_blkdev(unsigned int major, const char *name);
 void unregister_blkdev(unsigned int major, const char *name);

 void revalidate_disk_size(struct gendisk *disk, bool verbose);
 bool bdev_check_media_change(struct block_device *bdev);
 int __invalidate_device(struct block_device *bdev, bool kill_dirty);
 void bd_set_nr_sectors(struct block_device *bdev, sector_t sectors);

 /* for drivers/char/raw.c: */
 int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long);
 long compat_blkdev_ioctl(struct file *, unsigned, unsigned long);

 #ifdef CONFIG_SYSFS
 int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk);
 void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk);
 #else
 static inline int bd_link_disk_holder(struct block_device *bdev,
 				      struct gendisk *disk)
 {
 	return 0;
 }
 static inline void bd_unlink_disk_holder(struct block_device *bdev,
 					 struct gendisk *disk)
 {
 }
 #endif /* CONFIG_SYSFS */

 #ifdef CONFIG_BLOCK
 void printk_all_partitions(void);
 dev_t blk_lookup_devt(const char *name, int partno);
 #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 */
	/* 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
	*
	* <[email protected]>
	*/

	#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 const struct device_type disk_type;
	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>

	#define PARTITION_META_INFO_VOLNAMELTH 64
	/*
	* Enough for the string representation of any kind of UUID plus NULL.
	* EFI UUID is 36 characters. MSDOS UUID is 11 characters.
	*/
	#define PARTITION_META_INFO_UUIDLTH (UUID_STRING_LEN + 1)

	struct partition_meta_info {
	char uuid[PARTITION_META_INFO_UUIDLTH];
	u8 volname[PARTITION_META_INFO_VOLNAMELTH];
	};

	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;
	#endif
	unsigned long stamp;
	struct disk_stats __percpu *dkstats;
	struct percpu_ref ref;

	struct device __dev;
	struct kobject *holder_dir;
	int policy, partno;
	struct partition_meta_info *info;
	#ifdef CONFIG_FAIL_MAKE_REQUEST
	int make_it_fail;
	#endif
	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
	* (``BLOCK_EXT_MAJOR``).
	* 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``.
	* Implies ``GENHD_FL_SUPPRESS_PARTITION_INFO`` and
	* ``GENHD_FL_NO_PART_SCAN``.
	* 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_SUPPRESS_PARTITION_INFO 0x0020
	#define GENHD_FL_EXT_DEVT 0x0040
	#define GENHD_FL_NATIVE_CAPACITY 0x0080
	#define GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE 0x0100
	#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 */
	DISK_EVENT_FLAG_POLL = 1 << 0,
	/* Forward events to udev */
	DISK_EVENT_FLAG_UEVENT = 1 << 1,
	};

	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;
	unsigned long state;
	#define GD_NEED_PART_SCAN 0
	struct rw_semaphore lookup_sem;
	struct kobject *slave_dir;

	struct timer_rand_state *random;
	atomic_t sync_io; /* RAID */
	struct disk_events *ev;
	#ifdef CONFIG_BLK_DEV_INTEGRITY
	struct kobject integrity_kobj;
	#endif /* CONFIG_BLK_DEV_INTEGRITY */
	#if IS_ENABLED(CONFIG_CDROM)
	struct cdrom_device_info *cdi;
	#endif
	int node_id;
	struct badblocks *bb;
	struct lockdep_map lockdep_map;
	};

	#if IS_REACHABLE(CONFIG_CDROM)
	#define disk_to_cdi(disk) ((disk)->cdi)
	#else
	#define disk_to_cdi(disk) NULL
	#endif

	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);
	else
	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_MAX_PARTS;
	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))
	put_device(part_to_dev(part));
	}

	static inline void hd_sects_seq_init(struct hd_struct *p)
	{
	#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
	seqcount_init(&p->nr_sects_seq);
	#endif
	}

	/*
	* 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);
	bool set_capacity_revalidate_and_notify(struct gendisk *disk, sector_t size,
	bool update_bdev);

	/* 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;
	}

	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 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)

	int register_blkdev(unsigned int major, const char *name);
	void unregister_blkdev(unsigned int major, const char *name);

	void revalidate_disk_size(struct gendisk *disk, bool verbose);
	bool bdev_check_media_change(struct block_device *bdev);
	int __invalidate_device(struct block_device *bdev, bool kill_dirty);
	void bd_set_nr_sectors(struct block_device *bdev, sector_t sectors);

	/* for drivers/char/raw.c: */
	int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long);
	long compat_blkdev_ioctl(struct file *, unsigned, unsigned long);

	#ifdef CONFIG_SYSFS
	int bd_link_disk_holder(struct block_device bdev, struct gendisk disk);
	void bd_unlink_disk_holder(struct block_device bdev, struct gendisk disk);
	#else
	static inline int bd_link_disk_holder(struct block_device *bdev,
	struct gendisk *disk)
	{
	return 0;
	}
	static inline void bd_unlink_disk_holder(struct block_device *bdev,
	struct gendisk *disk)
	{
	}
	#endif /* CONFIG_SYSFS */

	#ifdef CONFIG_BLOCK
	void printk_all_partitions(void);
	dev_t blk_lookup_devt(const char *name, int partno);
	#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 */