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

 #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>

 #ifdef CONFIG_BLOCK

 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 */
 };

 #ifndef __KERNEL__

 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 */
 	unsigned int start_sect;	/* starting sector counting from 0 */
 	unsigned int nr_sects;		/* nr of sectors in partition */
 } __attribute__((packed));

 #endif

 #ifdef __KERNEL__
 #include <linux/major.h>
 #include <linux/device.h>
 #include <linux/smp.h>
 #include <linux/string.h>
 #include <linux/fs.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 hd_struct {
 	sector_t start_sect;
 	sector_t nr_sects;
 	struct kobject kobj;
 	struct kobject *holder_dir;
 	unsigned ios[2], sectors[2];	/* READs and WRITEs */
 	int policy, partno;
 #ifdef CONFIG_FAIL_MAKE_REQUEST
 	int make_it_fail;
 #endif
 };

 #define GENHD_FL_REMOVABLE			1
 #define GENHD_FL_DRIVERFS			2
 #define GENHD_FL_CD				8
 #define GENHD_FL_UP				16
 #define GENHD_FL_SUPPRESS_PARTITION_INFO	32
 #define GENHD_FL_FAIL				64

 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;
 };

 struct gendisk {
 	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[32];		/* name of major driver */
 	struct hd_struct **part;	/* [indexed by minor] */
 	int part_uevent_suppress;
 	struct block_device_operations *fops;
 	struct request_queue *queue;
 	void *private_data;
 	sector_t capacity;

 	int flags;
 	struct device *driverfs_dev;
 	struct kobject kobj;
 	struct kobject *holder_dir;
 	struct kobject *slave_dir;

 	struct timer_rand_state *random;
 	int policy;

 	atomic_t sync_io;		/* RAID */
 	unsigned long stamp;
 	int in_flight;
 #ifdef	CONFIG_SMP
 	struct disk_stats *dkstats;
 #else
 	struct disk_stats dkstats;
 #endif
 };

 /* Structure for sysfs attributes on block devices */
 struct disk_attribute {
 	struct attribute attr;
 	ssize_t (*show)(struct gendisk *, char *);
 	ssize_t (*store)(struct gendisk *, const char *, size_t);
 };

 /*
  * Macros to operate on percpu disk statistics:
  *
  * The __ variants should only be called in critical sections. The full
  * variants disable/enable preemption.
  */
 #ifdef	CONFIG_SMP
 #define __disk_stat_add(gendiskp, field, addnd) 	\
 	(per_cpu_ptr(gendiskp->dkstats, smp_processor_id())->field += addnd)

 #define disk_stat_read(gendiskp, field)					\
 ({									\
 	typeof(gendiskp->dkstats->field) res = 0;			\
 	int i;								\
 	for_each_possible_cpu(i)					\
 		res += per_cpu_ptr(gendiskp->dkstats, i)->field;	\
 	res;								\
 })

 static inline void disk_stat_set_all(struct gendisk *gendiskp, int value)	{
 	int i;
 	for_each_possible_cpu(i)
 		memset(per_cpu_ptr(gendiskp->dkstats, i), value,
 				sizeof (struct disk_stats));
 }

 #else
 #define __disk_stat_add(gendiskp, field, addnd) \
 				(gendiskp->dkstats.field += addnd)
 #define disk_stat_read(gendiskp, field)	(gendiskp->dkstats.field)

 static inline void disk_stat_set_all(struct gendisk *gendiskp, int value)	{
 	memset(&gendiskp->dkstats, value, sizeof (struct disk_stats));
 }
 #endif

 #define disk_stat_add(gendiskp, field, addnd)			\
 	do {							\
 		preempt_disable();				\
 		__disk_stat_add(gendiskp, field, addnd);	\
 		preempt_enable();				\
 	} while (0)

 #define __disk_stat_dec(gendiskp, field) __disk_stat_add(gendiskp, field, -1)
 #define disk_stat_dec(gendiskp, field) disk_stat_add(gendiskp, field, -1)

 #define __disk_stat_inc(gendiskp, field) __disk_stat_add(gendiskp, field, 1)
 #define disk_stat_inc(gendiskp, field) disk_stat_add(gendiskp, field, 1)

 #define __disk_stat_sub(gendiskp, field, subnd) \
 		__disk_stat_add(gendiskp, field, -subnd)
 #define disk_stat_sub(gendiskp, field, subnd) \
 		disk_stat_add(gendiskp, field, -subnd)


 /* Inlines to alloc and free disk stats in struct gendisk */
 #ifdef  CONFIG_SMP
 static inline int init_disk_stats(struct gendisk *disk)
 {
 	disk->dkstats = alloc_percpu(struct disk_stats);
 	if (!disk->dkstats)
 		return 0;
 	return 1;
 }

 static inline void free_disk_stats(struct gendisk *disk)
 {
 	free_percpu(disk->dkstats);
 }
 #else	/* CONFIG_SMP */
 static inline int init_disk_stats(struct gendisk *disk)
 {
 	return 1;
 }

 static inline void free_disk_stats(struct gendisk *disk)
 {
 }
 #endif	/* CONFIG_SMP */

 /* drivers/block/ll_rw_blk.c */
 extern void disk_round_stats(struct gendisk *disk);

 /* drivers/block/genhd.c */
 extern int get_blkdev_list(char *, int);
 extern void add_disk(struct gendisk *disk);
 extern void del_gendisk(struct gendisk *gp);
 extern void unlink_gendisk(struct gendisk *gp);
 extern struct gendisk *get_gendisk(dev_t dev, int *part);

 extern void set_device_ro(struct block_device *bdev, int flag);
 extern void set_disk_ro(struct gendisk *disk, int flag);

 /* 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_contains == bdev ? 0 : bdev->bd_part->start_sect;
 }
 static inline sector_t get_capacity(struct gendisk *disk)
 {
 	return disk->capacity;
 }
 static inline void set_capacity(struct gendisk *disk, sector_t size)
 {
 	disk->capacity = size;
 }

 #endif  /*  __KERNEL__  */

 #ifdef CONFIG_SOLARIS_X86_PARTITION

 #define SOLARIS_X86_NUMSLICE	8
 #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 <[email protected]>
  * updated by Marc Espie <[email protected]>
  */

 /* 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 <[email protected]>
  * and Krzysztof G. Baranowski <[email protected]>
  */

 #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 */

 #ifdef __KERNEL__

 #define ADDPART_FLAG_NONE	0
 #define ADDPART_FLAG_RAID	1
 #define ADDPART_FLAG_WHOLEDISK	2

 char *disk_name (struct gendisk *hd, int part, char *buf);

 extern int rescan_partitions(struct gendisk *disk, struct block_device *bdev);
 extern void add_partition(struct gendisk *, int, sector_t, sector_t, int);
 extern void delete_partition(struct gendisk *, int);

 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 dev, 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 dev, unsigned long range);

 static inline struct block_device *bdget_disk(struct gendisk *disk, int index)
 {
 	return bdget(MKDEV(disk->major, disk->first_minor) + index);
 }

 #endif

 #endif

 #endif
	#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>

	#ifdef CONFIG_BLOCK

	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 */
	};

	#ifndef __KERNEL__

	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 */
	unsigned int start_sect; /* starting sector counting from 0 */
	unsigned int nr_sects; /* nr of sectors in partition */
	} __attribute__((packed));

	#endif

	#ifdef __KERNEL__
	#include <linux/major.h>
	#include <linux/device.h>
	#include <linux/smp.h>
	#include <linux/string.h>
	#include <linux/fs.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 hd_struct {
	sector_t start_sect;
	sector_t nr_sects;
	struct kobject kobj;
	struct kobject *holder_dir;
	unsigned ios[2], sectors[2]; /* READs and WRITEs */
	int policy, partno;
	#ifdef CONFIG_FAIL_MAKE_REQUEST
	int make_it_fail;
	#endif
	};

	#define GENHD_FL_REMOVABLE 1
	#define GENHD_FL_DRIVERFS 2
	#define GENHD_FL_CD 8
	#define GENHD_FL_UP 16
	#define GENHD_FL_SUPPRESS_PARTITION_INFO 32
	#define GENHD_FL_FAIL 64

	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;
	};

	struct gendisk {
	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[32]; /* name of major driver */
	struct hd_struct *part; / [indexed by minor] */
	int part_uevent_suppress;
	struct block_device_operations *fops;
	struct request_queue *queue;
	void *private_data;
	sector_t capacity;

	int flags;
	struct device *driverfs_dev;
	struct kobject kobj;
	struct kobject *holder_dir;
	struct kobject *slave_dir;

	struct timer_rand_state *random;
	int policy;

	atomic_t sync_io; /* RAID */
	unsigned long stamp;
	int in_flight;
	#ifdef CONFIG_SMP
	struct disk_stats *dkstats;
	#else
	struct disk_stats dkstats;
	#endif
	};

	/* Structure for sysfs attributes on block devices */
	struct disk_attribute {
	struct attribute attr;
	ssize_t (show)(struct gendisk , char *);
	ssize_t (store)(struct gendisk , const char *, size_t);
	};

	/*
	* Macros to operate on percpu disk statistics:
	*
	* The __ variants should only be called in critical sections. The full
	* variants disable/enable preemption.
	*/
	#ifdef CONFIG_SMP
	#define __disk_stat_add(gendiskp, field, addnd) \
	(per_cpu_ptr(gendiskp->dkstats, smp_processor_id())->field += addnd)

	#define disk_stat_read(gendiskp, field) \
	({ \
	typeof(gendiskp->dkstats->field) res = 0; \
	int i; \
	for_each_possible_cpu(i) \
	res += per_cpu_ptr(gendiskp->dkstats, i)->field; \
	res; \
	})

	static inline void disk_stat_set_all(struct gendisk *gendiskp, int value) {
	int i;
	for_each_possible_cpu(i)
	memset(per_cpu_ptr(gendiskp->dkstats, i), value,
	sizeof (struct disk_stats));
	}

	#else
	#define __disk_stat_add(gendiskp, field, addnd) \
	(gendiskp->dkstats.field += addnd)
	#define disk_stat_read(gendiskp, field) (gendiskp->dkstats.field)

	static inline void disk_stat_set_all(struct gendisk *gendiskp, int value) {
	memset(&gendiskp->dkstats, value, sizeof (struct disk_stats));
	}
	#endif

	#define disk_stat_add(gendiskp, field, addnd) \
	do { \
	preempt_disable(); \
	__disk_stat_add(gendiskp, field, addnd); \
	preempt_enable(); \
	} while (0)

	#define __disk_stat_dec(gendiskp, field) __disk_stat_add(gendiskp, field, -1)
	#define disk_stat_dec(gendiskp, field) disk_stat_add(gendiskp, field, -1)

	#define __disk_stat_inc(gendiskp, field) __disk_stat_add(gendiskp, field, 1)
	#define disk_stat_inc(gendiskp, field) disk_stat_add(gendiskp, field, 1)

	#define __disk_stat_sub(gendiskp, field, subnd) \
	__disk_stat_add(gendiskp, field, -subnd)
	#define disk_stat_sub(gendiskp, field, subnd) \
	disk_stat_add(gendiskp, field, -subnd)


	/* Inlines to alloc and free disk stats in struct gendisk */
	#ifdef CONFIG_SMP
	static inline int init_disk_stats(struct gendisk *disk)
	{
	disk->dkstats = alloc_percpu(struct disk_stats);
	if (!disk->dkstats)
	return 0;
	return 1;
	}

	static inline void free_disk_stats(struct gendisk *disk)
	{
	free_percpu(disk->dkstats);
	}
	#else /* CONFIG_SMP */
	static inline int init_disk_stats(struct gendisk *disk)
	{
	return 1;
	}

	static inline void free_disk_stats(struct gendisk *disk)
	{
	}
	#endif /* CONFIG_SMP */

	/* drivers/block/ll_rw_blk.c */
	extern void disk_round_stats(struct gendisk *disk);

	/* drivers/block/genhd.c */
	extern int get_blkdev_list(char *, int);
	extern void add_disk(struct gendisk *disk);
	extern void del_gendisk(struct gendisk *gp);
	extern void unlink_gendisk(struct gendisk *gp);
	extern struct gendisk get_gendisk(dev_t dev, int part);

	extern void set_device_ro(struct block_device *bdev, int flag);
	extern void set_disk_ro(struct gendisk *disk, int flag);

	/* 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_contains == bdev ? 0 : bdev->bd_part->start_sect;
	}
	static inline sector_t get_capacity(struct gendisk *disk)
	{
	return disk->capacity;
	}
	static inline void set_capacity(struct gendisk *disk, sector_t size)
	{
	disk->capacity = size;
	}

	#endif /* __KERNEL__ */

	#ifdef CONFIG_SOLARIS_X86_PARTITION

	#define SOLARIS_X86_NUMSLICE 8
	#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 <[email protected]>
	* updated by Marc Espie <[email protected]>
	*/

	/* 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 <[email protected]>
	* and Krzysztof G. Baranowski <[email protected]>
	*/

	#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 */

	#ifdef __KERNEL__

	#define ADDPART_FLAG_NONE 0
	#define ADDPART_FLAG_RAID 1
	#define ADDPART_FLAG_WHOLEDISK 2

	char disk_name (struct gendisk hd, int part, char *buf);

	extern int rescan_partitions(struct gendisk disk, struct block_device bdev);
	extern void add_partition(struct gendisk *, int, sector_t, sector_t, int);
	extern void delete_partition(struct gendisk *, int);

	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 dev, 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 dev, unsigned long range);

	static inline struct block_device bdget_disk(struct gendisk disk, int index)
	{
	return bdget(MKDEV(disk->major, disk->first_minor) + index);
	}

	#endif

	#endif

	#endif