projects/linux·blob v4.13 · refs

94 lines · 2.3 KiB

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 unsigned lo_blocksize;
52 void *key_data;
53
54 gfp_t old_gfp_mask;
55
56 spinlock_t lo_lock;
57 int lo_state;
58 struct mutex lo_ctl_mutex;
59 struct kthread_worker worker;
60 struct task_struct *worker_task;
61 bool use_dio;
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 kthread_work work;
70 struct request *rq;
71 struct list_head list;
72 bool use_aio; /* use AIO interface to handle I/O */
73 long ret;
74 struct kiocb iocb;
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