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_list         lo_bio_list;
  60        int                     lo_state;
  61        struct mutex            lo_ctl_mutex;
  62        struct task_struct      *lo_thread;
  63        wait_queue_head_t       lo_event;
  64
  65        struct request_queue    *lo_queue;
  66        struct gendisk          *lo_disk;
  67};
  68
  69#endif /* __KERNEL__ */
  70
  71/*
  72 * Loop flags
  73 */
  74enum {
  75        LO_FLAGS_READ_ONLY      = 1,
  76        LO_FLAGS_AUTOCLEAR      = 4,
  77        LO_FLAGS_PARTSCAN       = 8,
  78};
  79
  80#include <asm/posix_types.h>    /* for __kernel_old_dev_t */
  81#include <linux/types.h>        /* for __u64 */
  82
  83/* Backwards compatibility version */
  84struct loop_info {
  85        int                lo_number;           /* ioctl r/o */
  86        __kernel_old_dev_t lo_device;           /* ioctl r/o */
  87        unsigned long      lo_inode;            /* ioctl r/o */
  88        __kernel_old_dev_t lo_rdevice;          /* ioctl r/o */
  89        int                lo_offset;
  90        int                lo_encrypt_type;
  91        int                lo_encrypt_key_size;         /* ioctl w/o */
  92        int                lo_flags;                    /* ioctl r/o */
  93        char               lo_name[LO_NAME_SIZE];
  94        unsigned char      lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */
  95        unsigned long      lo_init[2];
  96        char               reserved[4];
  97};
  98
  99struct loop_info64 {
 100        __u64              lo_device;                   /* ioctl r/o */
 101        __u64              lo_inode;                    /* ioctl r/o */
 102        __u64              lo_rdevice;                  /* ioctl r/o */
 103        __u64              lo_offset;
 104        __u64              lo_sizelimit;/* bytes, 0 == max available */
 105        __u32              lo_number;                   /* ioctl r/o */
 106        __u32              lo_encrypt_type;
 107        __u32              lo_encrypt_key_size;         /* ioctl w/o */
 108        __u32              lo_flags;                    /* ioctl r/o */
 109        __u8               lo_file_name[LO_NAME_SIZE];
 110        __u8               lo_crypt_name[LO_NAME_SIZE];
 111        __u8               lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */
 112        __u64              lo_init[2];
 113};
 114
 115/*
 116 * Loop filter types
 117 */
 118
 119#define LO_CRYPT_NONE           0
 120#define LO_CRYPT_XOR            1
 121#define LO_CRYPT_DES            2
 122#define LO_CRYPT_FISH2          3    /* Twofish encryption */
 123#define LO_CRYPT_BLOW           4
 124#define LO_CRYPT_CAST128        5
 125#define LO_CRYPT_IDEA           6
 126#define LO_CRYPT_DUMMY          9
 127#define LO_CRYPT_SKIPJACK       10
 128#define LO_CRYPT_CRYPTOAPI      18
 129#define MAX_LO_CRYPT            20
 130
 131#ifdef __KERNEL__
 132/* Support for loadable transfer modules */
 133struct loop_func_table {
 134        int number;     /* filter type */ 
 135        int (*transfer)(struct loop_device *lo, int cmd,
 136                        struct page *raw_page, unsigned raw_off,
 137                        struct page *loop_page, unsigned loop_off,
 138                        int size, sector_t real_block);
 139        int (*init)(struct loop_device *, const struct loop_info64 *); 
 140        /* release is called from loop_unregister_transfer or clr_fd */
 141        int (*release)(struct loop_device *); 
 142        int (*ioctl)(struct loop_device *, int cmd, unsigned long arg);
 143        struct module *owner;
 144}; 
 145
 146int loop_register_transfer(struct loop_func_table *funcs);
 147int loop_unregister_transfer(int number); 
 148
 149#endif
 150/*
 151 * IOCTL commands --- we will commandeer 0x4C ('L')
 152 */
 153
 154#define LOOP_SET_FD             0x4C00
 155#define LOOP_CLR_FD             0x4C01
 156#define LOOP_SET_STATUS         0x4C02
 157#define LOOP_GET_STATUS         0x4C03
 158#define LOOP_SET_STATUS64       0x4C04
 159#define LOOP_GET_STATUS64       0x4C05
 160#define LOOP_CHANGE_FD          0x4C06
 161#define LOOP_SET_CAPACITY       0x4C07
 162
 163/* /dev/loop-control interface */
 164#define LOOP_CTL_ADD            0x4C80
 165#define LOOP_CTL_REMOVE         0x4C81
 166#define LOOP_CTL_GET_FREE       0x4C82
 167#endif
 168
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