include/linux/loop.h

   1 /*
   2  * include/linux/loop.h
   3  *
   4  * Written by Theodore Ts'o, 3/29/93.
   5  *
   6  * Copyright 1993 by Theodore Ts'o.  Redistribution of this file is
   7  * permitted under the GNU General Public License.
   8  */
   9 #ifndef _LINUX_LOOP_H
  10 #define _LINUX_LOOP_H
  11
  12 #include <linux/bio.h>
  13 #include <linux/blkdev.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/mutex.h>
  16 #include <uapi/linux/loop.h>
  17
  18 /* Possible states of device */
  19 enum {
  20         Lo_unbound,
  21         Lo_bound,
  22         Lo_rundown,
  23 };
  24
  25 struct loop_func_table;
  26
  27 struct loop_device {
  28         int             lo_number;
  29         int             lo_refcnt;
  30         loff_t          lo_offset;
  31         loff_t          lo_sizelimit;
  32         int             lo_flags;
  33         int             (*transfer)(struct loop_device *, int cmd,
  34                                     struct page *raw_page, unsigned raw_off,
  35                                     struct page *loop_page, unsigned loop_off,
  36                                     int size, sector_t real_block);
  37         char            lo_file_name[LO_NAME_SIZE];
  38         char            lo_crypt_name[LO_NAME_SIZE];
  39         char            lo_encrypt_key[LO_KEY_SIZE];
  40         int             lo_encrypt_key_size;
  41         struct loop_func_table *lo_encryption;
  42         __u32           lo_init[2];
  43         kuid_t          lo_key_owner;   /* Who set the key */
  44         int             (*ioctl)(struct loop_device *, int cmd,
  45                                  unsigned long arg);
  46
  47         struct file *   lo_backing_file;
  48         struct block_device *lo_device;
  49         unsigned        lo_blocksize;
  50         void            *key_data;
  51
  52         gfp_t           old_gfp_mask;
  53
  54         spinlock_t              lo_lock;
  55         struct bio_list         lo_bio_list;
  56         unsigned int            lo_bio_count;
  57         int                     lo_state;
  58         struct mutex            lo_ctl_mutex;
  59         struct task_struct      *lo_thread;
  60         wait_queue_head_t       lo_event;
  61         /* wait queue for incoming requests */
  62         wait_queue_head_t       lo_req_wait;
  63
  64         struct request_queue    *lo_queue;
  65         struct gendisk          *lo_disk;
  66 };
  67
  68 /* Support for loadable transfer modules */
  69 struct loop_func_table {
  70         int number;     /* filter type */
  71         int (*transfer)(struct loop_device *lo, int cmd,
  72                         struct page *raw_page, unsigned raw_off,
  73                         struct page *loop_page, unsigned loop_off,
  74                         int size, sector_t real_block);
  75         int (*init)(struct loop_device *, const struct loop_info64 *);
  76         /* release is called from loop_unregister_transfer or clr_fd */
  77         int (*release)(struct loop_device *);
  78         int (*ioctl)(struct loop_device *, int cmd, unsigned long arg);
  79         struct module *owner;
  80 };
  81
  82 int loop_register_transfer(struct loop_func_table *funcs);
  83 int loop_unregister_transfer(int number);
  84
  85 #endif