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 #include <linux/mutex.h>
  21
  22 /* Possible states of device */
  23 enum {
  24         Lo_unbound,
  25         Lo_bound,
  26         Lo_rundown,
  27 };
  28
  29 struct loop_func_table;
  30
  31 struct 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  */
  76 enum {
  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 <linux/types.h>        /* for __u64 */
  84
  85 /* Backwards compatibility version */
  86 struct 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
 101 struct 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 */
 135 struct 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
 148 int loop_register_transfer(struct loop_func_table *funcs);
 149 int 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 #define LOOP_SET_CAPACITY       0x4C07
 164
 165 #endif