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android_kernel_xiaomi_sm8350/include/linux/genhd.h
David Howells 9361401eb7 [PATCH] BLOCK: Make it possible to disable the block layer [try #6] 
Make it possible to disable the block layer.  Not all embedded devices require
it, some can make do with just JFFS2, NFS, ramfs, etc - none of which require
the block layer to be present.

This patch does the following:

 (*) Introduces CONFIG_BLOCK to disable the block layer, buffering and blockdev
     support.

 (*) Adds dependencies on CONFIG_BLOCK to any configuration item that controls
     an item that uses the block layer.  This includes:

     (*) Block I/O tracing.

     (*) Disk partition code.

     (*) All filesystems that are block based, eg: Ext3, ReiserFS, ISOFS.

     (*) The SCSI layer.  As far as I can tell, even SCSI chardevs use the
     	 block layer to do scheduling.  Some drivers that use SCSI facilities -
     	 such as USB storage - end up disabled indirectly from this.

     (*) Various block-based device drivers, such as IDE and the old CDROM
     	 drivers.

     (*) MTD blockdev handling and FTL.

     (*) JFFS - which uses set_bdev_super(), something it could avoid doing by
     	 taking a leaf out of JFFS2's book.

 (*) Makes most of the contents of linux/blkdev.h, linux/buffer_head.h and
     linux/elevator.h contingent on CONFIG_BLOCK being set.  sector_div() is,
     however, still used in places, and so is still available.

 (*) Also made contingent are the contents of linux/mpage.h, linux/genhd.h and
     parts of linux/fs.h.

 (*) Makes a number of files in fs/ contingent on CONFIG_BLOCK.

 (*) Makes mm/bounce.c (bounce buffering) contingent on CONFIG_BLOCK.

 (*) set_page_dirty() doesn't call __set_page_dirty_buffers() if CONFIG_BLOCK
     is not enabled.

 (*) fs/no-block.c is created to hold out-of-line stubs and things that are
     required when CONFIG_BLOCK is not set:

     (*) Default blockdev file operations (to give error ENODEV on opening).

 (*) Makes some /proc changes:

     (*) /proc/devices does not list any blockdevs.

     (*) /proc/diskstats and /proc/partitions are contingent on CONFIG_BLOCK.

 (*) Makes some compat ioctl handling contingent on CONFIG_BLOCK.

 (*) If CONFIG_BLOCK is not defined, makes sys_quotactl() return -ENODEV if
     given command other than Q_SYNC or if a special device is specified.

 (*) In init/do_mounts.c, no reference is made to the blockdev routines if
     CONFIG_BLOCK is not defined.  This does not prohibit NFS roots or JFFS2.

 (*) The bdflush, ioprio_set and ioprio_get syscalls can now be absent (return
     error ENOSYS by way of cond_syscall if so).

 (*) The seclvl_bd_claim() and seclvl_bd_release() security calls do nothing if
     CONFIG_BLOCK is not set, since they can't then happen.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:31 +02:00

427 lines
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#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>
#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,
LINUX_SWAP_PARTITION = 0x82,
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;
};
#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
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 <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 */
#ifdef __KERNEL__
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);
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
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