LXR linux/drivers/block/loop.h

   1/*
   2 * 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/blk-mq.h>
  15#include <linux/spinlock.h>
  16#include <linux/mutex.h>
  17#include <linux/workqueue.h>
  18#include <uapi/linux/loop.h>
  19
  20/* Possible states of device */
  21enum {
  22        Lo_unbound,
  23        Lo_bound,
  24        Lo_rundown,
  25};
  26
  27struct loop_func_table;
  28
  29struct loop_device {
  30        int             lo_number;
  31        int             lo_refcnt;
  32        loff_t          lo_offset;
  33        loff_t          lo_sizelimit;
  34        int             lo_flags;
  35        int             (*transfer)(struct loop_device *, int cmd,
  36                                    struct page *raw_page, unsigned raw_off,
  37                                    struct page *loop_page, unsigned loop_off,
  38                                    int size, sector_t real_block);
  39        char            lo_file_name[LO_NAME_SIZE];
  40        char            lo_crypt_name[LO_NAME_SIZE];
  41        char            lo_encrypt_key[LO_KEY_SIZE];
  42        int             lo_encrypt_key_size;
  43        struct loop_func_table *lo_encryption;
  44        __u32           lo_init[2];
  45        kuid_t          lo_key_owner;   /* Who set the key */
  46        int             (*ioctl)(struct loop_device *, int cmd, 
  47                                 unsigned long arg); 
  48
  49        struct file *   lo_backing_file;
  50        struct block_device *lo_device;
  51        unsigned        lo_blocksize;
  52        void            *key_data; 
  53
  54        gfp_t           old_gfp_mask;
  55
  56        spinlock_t              lo_lock;
  57        struct list_head        write_cmd_head;
  58        struct work_struct      write_work;
  59        bool                    write_started;
  60        int                     lo_state;
  61        struct mutex            lo_ctl_mutex;
  62
  63        struct request_queue    *lo_queue;
  64        struct blk_mq_tag_set   tag_set;
  65        struct gendisk          *lo_disk;
  66};
  67
  68struct loop_cmd {
  69        struct work_struct read_work;
  70        struct request *rq;
  71        struct list_head list;
  72};
  73
  74/* Support for loadable transfer modules */
  75struct loop_func_table {
  76        int number;     /* filter type */ 
  77        int (*transfer)(struct loop_device *lo, int cmd,
  78                        struct page *raw_page, unsigned raw_off,
  79                        struct page *loop_page, unsigned loop_off,
  80                        int size, sector_t real_block);
  81        int (*init)(struct loop_device *, const struct loop_info64 *); 
  82        /* release is called from loop_unregister_transfer or clr_fd */
  83        int (*release)(struct loop_device *); 
  84        int (*ioctl)(struct loop_device *, int cmd, unsigned long arg);
  85        struct module *owner;
  86}; 
  87
  88int loop_register_transfer(struct loop_func_table *funcs);
  89int loop_unregister_transfer(int number); 
  90
  91#endif
  92