text: #ifndef _LINUX_GENHD_H
  #define _LINUX_GENHD_H
  
  /*
   * 	genhd.h Copyright (C) 1992 Drew Eckhardt
   *	Generic hard disk header file by  
   * 		Drew Eckhardt
   *
   *		<drew@colorado.edu>
   */
  
  #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>
  
  #ifdef CONFIG_BLOCK
  
  #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 kobject *block_depr;
  extern struct class block_class;
  
  enum {
  /* These three have identical behaviour; use the second one if DOS FDISK gets
     confused about extended/logical partitions starting past cylinder 1023. */
  	DOS_EXTENDED_PARTITION = 5,
  	LINUX_EXTENDED_PARTITION = 0x85,
  	WIN98_EXTENDED_PARTITION = 0x0f,
  
  	SUN_WHOLE_DISK = DOS_EXTENDED_PARTITION,
  
  	LINUX_SWAP_PARTITION = 0x82,
  	LINUX_DATA_PARTITION = 0x83,
  	LINUX_LVM_PARTITION = 0x8e,
  	LINUX_RAID_PARTITION = 0xfd,	/* autodetect RAID partition */
  
  	SOLARIS_X86_PARTITION =	LINUX_SWAP_PARTITION,
  	NEW_SOLARIS_X86_PARTITION = 0xbf,
  
  	DM6_AUX1PARTITION = 0x51,	/* no DDO:  use xlated geom */
  	DM6_AUX3PARTITION = 0x53,	/* no DDO:  use xlated geom */
  	DM6_PARTITION =	0x54,		/* has DDO: use xlated geom & offset */
  	EZD_PARTITION =	0x55,		/* EZ-DRIVE */
  
  	FREEBSD_PARTITION = 0xa5,	/* FreeBSD Partition ID */
  	OPENBSD_PARTITION = 0xa6,	/* OpenBSD Partition ID */
  	NETBSD_PARTITION = 0xa9,	/* NetBSD Partition ID */
  	BSDI_PARTITION = 0xb7,		/* BSDI Partition ID */
  	MINIX_PARTITION = 0x81,		/* Minix Partition ID */
  	UNIXWARE_PARTITION = 0x63,	/* Same as GNU_HURD and SCO Unix */
  };
  
  #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>
  
  struct partition {
  	unsigned char boot_ind;		/* 0x80 - active */
  	unsigned char head;		/* starting head */
  	unsigned char sector;		/* starting sector */
  	unsigned char cyl;		/* starting cylinder */
  	unsigned char sys_ind;		/* What partition type */
  	unsigned char end_head;		/* end head */
  	unsigned char end_sector;	/* end sector */
  	unsigned char end_cyl;		/* end cylinder */
  	__le32 start_sect;	/* starting sector counting from 0 */
  	__le32 nr_sects;		/* nr of sectors in partition */
  } __attribute__((packed));
  
  struct disk_stats {
  	unsigned long sectors[2];	/* READs and WRITEs */
  	unsigned long ios[2];
  	unsigned long merges[2];
  	unsigned long ticks[2];
  	unsigned long io_ticks;
  	unsigned long time_in_queue;
  };
  
  #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;
  	seqcount_t nr_sects_seq;
  	sector_t alignment_offset;
  	unsigned int discard_alignment;
  	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
  	unsigned long stamp;
  	atomic_t in_flight[2];
  #ifdef	CONFIG_SMP
  	struct disk_stats __percpu *dkstats;
  #else
  	struct disk_stats dkstats;
  #endif
  	struct percpu_ref ref;
  	struct rcu_head rcu_head;
  };
  
  #define GENHD_FL_REMOVABLE			1
  /* 2 is unused */
  #define GENHD_FL_MEDIA_CHANGE_NOTIFY		4
  #define GENHD_FL_CD				8
  #define GENHD_FL_UP				16
  #define GENHD_FL_SUPPRESS_PARTITION_INFO	32
  #define GENHD_FL_EXT_DEVT			64 /* allow extended devt */
  #define GENHD_FL_NATIVE_CAPACITY		128
  #define GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE	256
  #define GENHD_FL_NO_PART_SCAN			512
  
  enum {
  	DISK_EVENT_MEDIA_CHANGE			= 1 << 0, /* media changed */
  	DISK_EVENT_EJECT_REQUEST		= 1 << 1, /* eject requested */
  };
  
  #define BLK_SCSI_MAX_CMDS	(256)
  #define BLK_SCSI_CMD_PER_LONG	(BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
  
  struct blk_scsi_cmd_filter {
  	unsigned long read_ok[BLK_SCSI_CMD_PER_LONG];
  	unsigned long write_ok[BLK_SCSI_CMD_PER_LONG];
  	struct kobject kobj;
  };
  
  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;
  
  #if defined(CONFIG_BLK_DEV_INTEGRITY)
  
  struct blk_integrity {
  	struct blk_integrity_profile	*profile;
  	unsigned char			flags;
  	unsigned char			tuple_size;
  	unsigned char			interval_exp;
  	unsigned char			tag_size;
  };
  
  #endif	/* CONFIG_BLK_DEV_INTEGRITY */
  
  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 */
  	char *(*devnode)(struct gendisk *gd, umode_t *mode);
  
  	unsigned int events;		/* supported events */
  	unsigned int async_events;	/* async events, subset of all */
  
  	/* 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 device *driverfs_dev;  // FIXME: remove
  	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 */
  	int node_id;
  	struct badblocks *bb;
  };
  
  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 blk_part_pack_uuid(const u8 *uuid_str, u8 *to)
  {
  	uuid_be_to_bin(uuid_str, (uuid_be *)to);
  	return 0;
  }
  
  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 disk_to_dev(disk)->devt;
  }
  
  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);
  
  static inline void disk_put_part(struct hd_struct *part)
  {
  	if (likely(part))
  		put_device(part_to_dev(part));
  }
  
  /*
   * 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 struct hd_struct *disk_map_sector_rcu(struct gendisk *disk,
  					     sector_t sector);
  
  /*
   * Macros to operate on percpu disk statistics:
   *
   * {disk|part|all}_stat_{add|sub|inc|dec}() modify the stat counters
   * and should be called between disk_stat_lock() and
   * disk_stat_unlock().
   *
   * part_stat_read() can be called at any time.
   *
   * part_stat_{add|set_all}() and {init|free}_part_stats are for
   * internal use only.
   */
  #ifdef	CONFIG_SMP
  #define part_stat_lock()	({ rcu_read_lock(); get_cpu(); })
  #define part_stat_unlock()	do { put_cpu(); rcu_read_unlock(); } while (0)
  
  #define __part_stat_add(cpu, part, field, addnd)			\
  	(per_cpu_ptr((part)->dkstats, (cpu))->field += (addnd))
  
  #define part_stat_read(part, field)					\
  ({									\
  	typeof((part)->dkstats->field) res = 0;				\
  	unsigned int _cpu;						\
  	for_each_possible_cpu(_cpu)					\
  		res += per_cpu_ptr((part)->dkstats, _cpu)->field;	\
  	res;								\
  })
  
  static inline void part_stat_set_all(struct hd_struct *part, int value)
  {
  	int i;
  
  	for_each_possible_cpu(i)
  		memset(per_cpu_ptr(part->dkstats, i), value,
  				sizeof(struct disk_stats));
  }
  
  static inline int init_part_stats(struct hd_struct *part)
  {
  	part->dkstats = alloc_percpu(struct disk_stats);
  	if (!part->dkstats)
  		return 0;
  	return 1;
  }
  
  static inline void free_part_stats(struct hd_struct *part)
  {
  	free_percpu(part->dkstats);
  }
  
  #else /* !CONFIG_SMP */
  #define part_stat_lock()	({ rcu_read_lock(); 0; })
  #define part_stat_unlock()	rcu_read_unlock()
  
  #define __part_stat_add(cpu, part, field, addnd)				\
  	((part)->dkstats.field += addnd)
  
  #define part_stat_read(part, field)	((part)->dkstats.field)
  
  static inline void part_stat_set_all(struct hd_struct *part, int value)
  {
  	memset(&part->dkstats, value, sizeof(struct disk_stats));
  }
  
  static inline int init_part_stats(struct hd_struct *part)
  {
  	return 1;
  }
  
  static inline void free_part_stats(struct hd_struct *part)
  {
  }
  
  #endif /* CONFIG_SMP */
  
  #define part_stat_add(cpu, part, field, addnd)	do {			\
  	__part_stat_add((cpu), (part), field, addnd);			\
  	if ((part)->partno)						\
  		__part_stat_add((cpu), &part_to_disk((part))->part0,	\
  				field, addnd);				\
  } while (0)
  
  #define part_stat_dec(cpu, gendiskp, field)				\
  	part_stat_add(cpu, gendiskp, field, -1)
  #define part_stat_inc(cpu, gendiskp, field)				\
  	part_stat_add(cpu, gendiskp, field, 1)
  #define part_stat_sub(cpu, gendiskp, field, subnd)			\
  	part_stat_add(cpu, gendiskp, field, -subnd)
  
  static inline void part_inc_in_flight(struct hd_struct *part, int rw)
  {
  	atomic_inc(&part->in_flight[rw]);
  	if (part->partno)
  		atomic_inc(&part_to_disk(part)->part0.in_flight[rw]);
  }
  
  static inline void part_dec_in_flight(struct hd_struct *part, int rw)
  {
  	atomic_dec(&part->in_flight[rw]);
  	if (part->partno)
  		atomic_dec(&part_to_disk(part)->part0.in_flight[rw]);
  }
  
  static inline int part_in_flight(struct hd_struct *part)
  {
  	return atomic_read(&part->in_flight[0]) + atomic_read(&part->in_flight[1]);
  }
  
  static inline struct partition_meta_info *alloc_part_info(struct gendisk *disk)
  {
  	if (disk)
  		return kzalloc_node(sizeof(struct partition_meta_info),
  				    GFP_KERNEL, disk->node_id);
  	return kzalloc(sizeof(struct partition_meta_info), GFP_KERNEL);
  }
  
  static inline void free_part_info(struct hd_struct *part)
  {
  	kfree(part->info);
  }
  
  /* block/blk-core.c */
  extern void part_round_stats(int cpu, struct hd_struct *part);
  
  /* block/genhd.c */
  extern void add_disk(struct gendisk *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 unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask);
  
  /* drivers/char/random.c */
  extern void add_disk_randomness(struct gendisk *disk);
  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;
  }
  
  #ifdef CONFIG_SOLARIS_X86_PARTITION
  
  #define SOLARIS_X86_NUMSLICE	16
  #define SOLARIS_X86_VTOC_SANE	(0x600DDEEEUL)
  
  struct solaris_x86_slice {
  	__le16 s_tag;		/* ID tag of partition */
  	__le16 s_flag;		/* permission flags */
  	__le32 s_start;		/* start sector no of partition */
  	__le32 s_size;		/* # of blocks in partition */
  };
  
  struct solaris_x86_vtoc {
  	unsigned int v_bootinfo[3];	/* info needed by mboot (unsupported) */
  	__le32 v_sanity;		/* to verify vtoc sanity */
  	__le32 v_version;		/* layout version */
  	char	v_volume[8];		/* volume name */
  	__le16	v_sectorsz;		/* sector size in bytes */
  	__le16	v_nparts;		/* number of partitions */
  	unsigned int v_reserved[10];	/* free space */
  	struct solaris_x86_slice
  		v_slice[SOLARIS_X86_NUMSLICE]; /* slice headers */
  	unsigned int timestamp[SOLARIS_X86_NUMSLICE]; /* timestamp (unsupported) */
  	char	v_asciilabel[128];	/* for compatibility */
  };
  
  #endif /* CONFIG_SOLARIS_X86_PARTITION */
  
  #ifdef CONFIG_BSD_DISKLABEL
  /*
   * BSD disklabel support by Yossi Gottlieb <yogo@math.tau.ac.il>
   * updated by Marc Espie <Marc.Espie@openbsd.org>
   */
  
  /* check against BSD src/sys/sys/disklabel.h for consistency */
  
  #define BSD_DISKMAGIC	(0x82564557UL)	/* The disk magic number */
  #define BSD_MAXPARTITIONS	16
  #define OPENBSD_MAXPARTITIONS	16
  #define BSD_FS_UNUSED		0	/* disklabel unused partition entry ID */
  struct bsd_disklabel {
  	__le32	d_magic;		/* the magic number */
  	__s16	d_type;			/* drive type */
  	__s16	d_subtype;		/* controller/d_type specific */
  	char	d_typename[16];		/* type name, e.g. "eagle" */
  	char	d_packname[16];			/* pack identifier */ 
  	__u32	d_secsize;		/* # of bytes per sector */
  	__u32	d_nsectors;		/* # of data sectors per track */
  	__u32	d_ntracks;		/* # of tracks per cylinder */
  	__u32	d_ncylinders;		/* # of data cylinders per unit */
  	__u32	d_secpercyl;		/* # of data sectors per cylinder */
  	__u32	d_secperunit;		/* # of data sectors per unit */
  	__u16	d_sparespertrack;	/* # of spare sectors per track */
  	__u16	d_sparespercyl;		/* # of spare sectors per cylinder */
  	__u32	d_acylinders;		/* # of alt. cylinders per unit */
  	__u16	d_rpm;			/* rotational speed */
  	__u16	d_interleave;		/* hardware sector interleave */
  	__u16	d_trackskew;		/* sector 0 skew, per track */
  	__u16	d_cylskew;		/* sector 0 skew, per cylinder */
  	__u32	d_headswitch;		/* head switch time, usec */
  	__u32	d_trkseek;		/* track-to-track seek, usec */
  	__u32	d_flags;		/* generic flags */
  #define NDDATA 5
  	__u32	d_drivedata[NDDATA];	/* drive-type specific information */
  #define NSPARE 5
  	__u32	d_spare[NSPARE];	/* reserved for future use */
  	__le32	d_magic2;		/* the magic number (again) */
  	__le16	d_checksum;		/* xor of data incl. partitions */
  
  			/* filesystem and partition information: */
  	__le16	d_npartitions;		/* number of partitions in following */
  	__le32	d_bbsize;		/* size of boot area at sn0, bytes */
  	__le32	d_sbsize;		/* max size of fs superblock, bytes */
  	struct	bsd_partition {		/* the partition table */
  		__le32	p_size;		/* number of sectors in partition */
  		__le32	p_offset;	/* starting sector */
  		__le32	p_fsize;	/* filesystem basic fragment size */
  		__u8	p_fstype;	/* filesystem type, see below */
  		__u8	p_frag;		/* filesystem fragments per block */
  		__le16	p_cpg;		/* filesystem cylinders per group */
  	} d_partitions[BSD_MAXPARTITIONS];	/* actually may be more */
  };
  
  #endif	/* CONFIG_BSD_DISKLABEL */
  
  #ifdef CONFIG_UNIXWARE_DISKLABEL
  /*
   * Unixware slices support by Andrzej Krzysztofowicz <ankry@mif.pg.gda.pl>
   * and Krzysztof G. Baranowski <kgb@knm.org.pl>
   */
  
  #define UNIXWARE_DISKMAGIC     (0xCA5E600DUL)	/* The disk magic number */
  #define UNIXWARE_DISKMAGIC2    (0x600DDEEEUL)	/* The slice table magic nr */
  #define UNIXWARE_NUMSLICE      16
  #define UNIXWARE_FS_UNUSED     0		/* Unused slice entry ID */
  
  struct unixware_slice {
  	__le16   s_label;	/* label */
  	__le16   s_flags;	/* permission flags */
  	__le32   start_sect;	/* starting sector */
  	__le32   nr_sects;	/* number of sectors in slice */
  };
  
  struct unixware_disklabel {
  	__le32   d_type;               	/* drive type */
  	__le32   d_magic;                /* the magic number */
  	__le32   d_version;              /* version number */
  	char    d_serial[12];           /* serial number of the device */
  	__le32   d_ncylinders;           /* # of data cylinders per device */
  	__le32   d_ntracks;              /* # of tracks per cylinder */
  	__le32   d_nsectors;             /* # of data sectors per track */
  	__le32   d_secsize;              /* # of bytes per sector */
  	__le32   d_part_start;           /* # of first sector of this partition */
  	__le32   d_unknown1[12];         /* ? */
   	__le32	d_alt_tbl;              /* byte offset of alternate table */
   	__le32	d_alt_len;              /* byte length of alternate table */
   	__le32	d_phys_cyl;             /* # of physical cylinders per device */
   	__le32	d_phys_trk;             /* # of physical tracks per cylinder */
   	__le32	d_phys_sec;             /* # of physical sectors per track */
   	__le32	d_phys_bytes;           /* # of physical bytes per sector */
   	__le32	d_unknown2;             /* ? */
  	__le32   d_unknown3;             /* ? */
  	__le32	d_pad[8];               /* pad */
  
  	struct unixware_vtoc {
  		__le32	v_magic;		/* the magic number */
  		__le32	v_version;		/* version number */
  		char	v_name[8];		/* volume name */
  		__le16	v_nslices;		/* # of slices */
  		__le16	v_unknown1;		/* ? */
  		__le32	v_reserved[10];		/* reserved */
  		struct unixware_slice
  			v_slice[UNIXWARE_NUMSLICE];	/* slice headers */
  	} vtoc;
  
  };  /* 408 */
  
  #endif /* CONFIG_UNIXWARE_DISKLABEL */
  
  #ifdef CONFIG_MINIX_SUBPARTITION
  #   define MINIX_NR_SUBPARTITIONS  4
  #endif /* CONFIG_MINIX_SUBPARTITION */
  
  #define ADDPART_FLAG_NONE	0
  #define ADDPART_FLAG_RAID	1
  #define ADDPART_FLAG_WHOLEDISK	2
  
  extern int blk_alloc_devt(struct hd_struct *part, dev_t *devt);
  extern void blk_free_devt(dev_t devt);
  extern dev_t blk_lookup_devt(const char *name, int partno);
  extern char *disk_name (struct gendisk *hd, int partno, char *buf);
  
  extern int disk_expand_part_tbl(struct gendisk *disk, int target);
  extern int rescan_partitions(struct gendisk *disk, struct block_device *bdev);
  extern int invalidate_partitions(struct gendisk *disk, struct block_device *bdev);
  extern struct hd_struct * __must_check add_partition(struct gendisk *disk,
  						     int partno, sector_t start,
  						     sector_t len, int flags,
  						     struct partition_meta_info
  						       *info);
  extern void __delete_partition(struct percpu_ref *);
  extern void delete_partition(struct gendisk *, int);
  extern void printk_all_partitions(void);
  
  extern struct gendisk *alloc_disk_node(int minors, int node_id);
  extern struct gendisk *alloc_disk(int minors);
  extern struct kobject *get_disk(struct gendisk *disk);
  extern void put_disk(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);
  
  extern ssize_t part_size_show(struct device *dev,
  			      struct device_attribute *attr, char *buf);
  extern ssize_t part_stat_show(struct device *dev,
  			      struct device_attribute *attr, char *buf);
  extern ssize_t part_inflight_show(struct device *dev,
  			      struct device_attribute *attr, char *buf);
  #ifdef CONFIG_FAIL_MAKE_REQUEST
  extern ssize_t part_fail_show(struct device *dev,
  			      struct device_attribute *attr, char *buf);
  extern ssize_t part_fail_store(struct device *dev,
  			       struct device_attribute *attr,
  			       const char *buf, size_t count);
  #endif /* CONFIG_FAIL_MAKE_REQUEST */
  
  static inline int hd_ref_init(struct hd_struct *part)
  {
  	if (percpu_ref_init(&part->ref, __delete_partition, 0,
  				GFP_KERNEL))
  		return -ENOMEM;
  	return 0;
  }
  
  static inline void hd_struct_get(struct hd_struct *part)
  {
  	percpu_ref_get(&part->ref);
  }
  
  static inline int hd_struct_try_get(struct hd_struct *part)
  {
  	return percpu_ref_tryget_live(&part->ref);
  }
  
  static inline void hd_struct_put(struct hd_struct *part)
  {
  	percpu_ref_put(&part->ref);
  }
  
  static inline void hd_struct_kill(struct hd_struct *part)
  {
  	percpu_ref_kill(&part->ref);
  }
  
  static inline void hd_free_part(struct hd_struct *part)
  {
  	free_part_stats(part);
  	free_part_info(part);
  	percpu_ref_exit(&part->ref);
  }
  
  /*
   * Any access of part->nr_sects which is not protected by partition
   * bd_mutex or gendisk bdev bd_mutex, should be done using this
   * accessor function.
   *
   * Code written along the lines of i_size_read() and i_size_write().
   * CONFIG_PREEMPT case optimizes the case of UP kernel with preemption
   * on.
   */
  static inline sector_t part_nr_sects_read(struct hd_struct *part)
  {
  #if BITS_PER_LONG==32 && defined(CONFIG_LBDAF) && defined(CONFIG_SMP)
  	sector_t nr_sects;
  	unsigned seq;
  	do {
  		seq = read_seqcount_begin(&part->nr_sects_seq);
  		nr_sects = part->nr_sects;
  	} while (read_seqcount_retry(&part->nr_sects_seq, seq));
  	return nr_sects;
  #elif BITS_PER_LONG==32 && defined(CONFIG_LBDAF) && defined(CONFIG_PREEMPT)
  	sector_t nr_sects;
  
  	preempt_disable();
  	nr_sects = part->nr_sects;
  	preempt_enable();
  	return nr_sects;
  #else
  	return part->nr_sects;
  #endif
  }
  
  /*
   * Should be called with mutex lock held (typically bd_mutex) of partition
   * to provide mutual exlusion among writers otherwise seqcount might be
   * left in wrong state leaving the readers spinning infinitely.
   */
  static inline void part_nr_sects_write(struct hd_struct *part, sector_t size)
  {
  #if BITS_PER_LONG==32 && defined(CONFIG_LBDAF) && defined(CONFIG_SMP)
  	write_seqcount_begin(&part->nr_sects_seq);
  	part->nr_sects = size;
  	write_seqcount_end(&part->nr_sects_seq);
  #elif BITS_PER_LONG==32 && defined(CONFIG_LBDAF) && defined(CONFIG_PREEMPT)
  	preempt_disable();
  	part->nr_sects = size;
  	preempt_enable();
  #else
  	part->nr_sects = size;
  #endif
  }
  
  #if defined(CONFIG_BLK_DEV_INTEGRITY)
  extern void blk_integrity_add(struct gendisk *);
  extern void blk_integrity_del(struct gendisk *);
  extern void blk_integrity_revalidate(struct gendisk *);
  #else	/* CONFIG_BLK_DEV_INTEGRITY */
  static inline void blk_integrity_add(struct gendisk *disk) { }
  static inline void blk_integrity_del(struct gendisk *disk) { }
  static inline void blk_integrity_revalidate(struct gendisk *disk) { }
  #endif	/* CONFIG_BLK_DEV_INTEGRITY */
  
  #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;
  }
  
  static inline int blk_part_pack_uuid(const u8 *uuid_str, u8 *to)
  {
  	return -EINVAL;
  }
  #endif /* CONFIG_BLOCK */
  
  #endif /* _LINUX_GENHD_H */
  