linux/include/linux/loop.h
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   1#ifndef _LINUX_LOOP_H
   2#define _LINUX_LOOP_H
   3
   4/*
   5 * include/linux/loop.h
   6 *
   7 * Written by Theodore Ts'o, 3/29/93.
   8 *
   9 * Copyright 1993 by Theodore Ts'o.  Redistribution of this file is
  10 * permitted under the GNU General Public License.
  11 */
  12
  13#define LO_NAME_SIZE    64
  14#define LO_KEY_SIZE     32
  15
  16#ifdef __KERNEL__
  17#include <linux/bio.h>
  18#include <linux/blkdev.h>
  19#include <linux/spinlock.h>
  20#include <linux/mutex.h>
  21
  22/* Possible states of device */
  23enum {
  24        Lo_unbound,
  25        Lo_bound,
  26        Lo_rundown,
  27};
  28
  29struct loop_func_table;
  30
  31struct loop_device {
  32        int             lo_number;
  33        int             lo_refcnt;
  34        loff_t          lo_offset;
  35        loff_t          lo_sizelimit;
  36        int             lo_flags;
  37        int             (*transfer)(struct loop_device *, int cmd,
  38                                    struct page *raw_page, unsigned raw_off,
  39                                    struct page *loop_page, unsigned loop_off,
  40                                    int size, sector_t real_block);
  41        char            lo_file_name[LO_NAME_SIZE];
  42        char            lo_crypt_name[LO_NAME_SIZE];
  43        char            lo_encrypt_key[LO_KEY_SIZE];
  44        int             lo_encrypt_key_size;
  45        struct loop_func_table *lo_encryption;
  46        __u32           lo_init[2];
  47        uid_t           lo_key_owner;   /* Who set the key */
  48        int             (*ioctl)(struct loop_device *, int cmd, 
  49                                 unsigned long arg); 
  50
  51        struct file *   lo_backing_file;
  52        struct block_device *lo_device;
  53        unsigned        lo_blocksize;
  54        void            *key_data; 
  55
  56        gfp_t           old_gfp_mask;
  57
  58        spinlock_t              lo_lock;
  59        struct bio              *lo_bio;
  60        struct bio              *lo_biotail;
  61        int                     lo_state;
  62        struct mutex            lo_ctl_mutex;
  63        struct task_struct      *lo_thread;
  64        wait_queue_head_t       lo_event;
  65
  66        struct request_queue    *lo_queue;
  67        struct gendisk          *lo_disk;
  68        struct list_head        lo_list;
  69};
  70
  71#endif /* __KERNEL__ */
  72
  73/*
  74 * Loop flags
  75 */
  76enum {
  77        LO_FLAGS_READ_ONLY      = 1,
  78        LO_FLAGS_USE_AOPS       = 2,
  79        LO_FLAGS_AUTOCLEAR      = 4,
  80};
  81
  82#include <asm/posix_types.h>    /* for __kernel_old_dev_t */
  83#include <asm/types.h>          /* for __u64 */
  84
  85/* Backwards compatibility version */
  86struct loop_info {
  87        int                lo_number;           /* ioctl r/o */
  88        __kernel_old_dev_t lo_device;           /* ioctl r/o */
  89        unsigned long      lo_inode;            /* ioctl r/o */
  90        __kernel_old_dev_t lo_rdevice;          /* ioctl r/o */
  91        int                lo_offset;
  92        int                lo_encrypt_type;
  93        int                lo_encrypt_key_size;         /* ioctl w/o */
  94        int                lo_flags;                    /* ioctl r/o */
  95        char               lo_name[LO_NAME_SIZE];
  96        unsigned char      lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */
  97        unsigned long      lo_init[2];
  98        char               reserved[4];
  99};
 100
 101struct loop_info64 {
 102        __u64              lo_device;                   /* ioctl r/o */
 103        __u64              lo_inode;                    /* ioctl r/o */
 104        __u64              lo_rdevice;                  /* ioctl r/o */
 105        __u64              lo_offset;
 106        __u64              lo_sizelimit;/* bytes, 0 == max available */
 107        __u32              lo_number;                   /* ioctl r/o */
 108        __u32              lo_encrypt_type;
 109        __u32              lo_encrypt_key_size;         /* ioctl w/o */
 110        __u32              lo_flags;                    /* ioctl r/o */
 111        __u8               lo_file_name[LO_NAME_SIZE];
 112        __u8               lo_crypt_name[LO_NAME_SIZE];
 113        __u8               lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */
 114        __u64              lo_init[2];
 115};
 116
 117/*
 118 * Loop filter types
 119 */
 120
 121#define LO_CRYPT_NONE           0
 122#define LO_CRYPT_XOR            1
 123#define LO_CRYPT_DES            2
 124#define LO_CRYPT_FISH2          3    /* Twofish encryption */
 125#define LO_CRYPT_BLOW           4
 126#define LO_CRYPT_CAST128        5
 127#define LO_CRYPT_IDEA           6
 128#define LO_CRYPT_DUMMY          9
 129#define LO_CRYPT_SKIPJACK       10
 130#define LO_CRYPT_CRYPTOAPI      18
 131#define MAX_LO_CRYPT            20
 132
 133#ifdef __KERNEL__
 134/* Support for loadable transfer modules */
 135struct loop_func_table {
 136        int number;     /* filter type */ 
 137        int (*transfer)(struct loop_device *lo, int cmd,
 138                        struct page *raw_page, unsigned raw_off,
 139                        struct page *loop_page, unsigned loop_off,
 140                        int size, sector_t real_block);
 141        int (*init)(struct loop_device *, const struct loop_info64 *); 
 142        /* release is called from loop_unregister_transfer or clr_fd */
 143        int (*release)(struct loop_device *); 
 144        int (*ioctl)(struct loop_device *, int cmd, unsigned long arg);
 145        struct module *owner;
 146}; 
 147
 148int loop_register_transfer(struct loop_func_table *funcs);
 149int loop_unregister_transfer(int number); 
 150
 151#endif
 152/*
 153 * IOCTL commands --- we will commandeer 0x4C ('L')
 154 */
 155
 156#define LOOP_SET_FD             0x4C00
 157#define LOOP_CLR_FD             0x4C01
 158#define LOOP_SET_STATUS         0x4C02
 159#define LOOP_GET_STATUS         0x4C03
 160#define LOOP_SET_STATUS64       0x4C04
 161#define LOOP_GET_STATUS64       0x4C05
 162#define LOOP_CHANGE_FD          0x4C06
 163
 164#endif
 165
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