include/linux/loop.h

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