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/kthread.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        atomic_t        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        void            *key_data; 
  52
  53        gfp_t           old_gfp_mask;
  54
  55        spinlock_t              lo_lock;
  56        int                     lo_state;
  57        struct kthread_worker   worker;
  58        struct task_struct      *worker_task;
  59        bool                    use_dio;
  60        bool                    sysfs_inited;
  61
  62        struct request_queue    *lo_queue;
  63        struct blk_mq_tag_set   tag_set;
  64        struct gendisk          *lo_disk;
  65};
  66
  67struct loop_cmd {
  68        struct kthread_work work;
  69        bool use_aio; /* use AIO interface to handle I/O */
  70        atomic_t ref; /* only for aio */
  71        long ret;
  72        struct kiocb iocb;
  73        struct bio_vec *bvec;
  74        struct cgroup_subsys_state *css;
  75};
  76
  77/* Support for loadable transfer modules */
  78struct loop_func_table {
  79        int number;     /* filter type */ 
  80        int (*transfer)(struct loop_device *lo, int cmd,
  81                        struct page *raw_page, unsigned raw_off,
  82                        struct page *loop_page, unsigned loop_off,
  83                        int size, sector_t real_block);
  84        int (*init)(struct loop_device *, const struct loop_info64 *); 
  85        /* release is called from loop_unregister_transfer or clr_fd */
  86        int (*release)(struct loop_device *); 
  87        int (*ioctl)(struct loop_device *, int cmd, unsigned long arg);
  88        struct module *owner;
  89}; 
  90
  91int loop_register_transfer(struct loop_func_table *funcs);
  92int loop_unregister_transfer(int number); 
  93
  94#endif
  95