Linux kernel mirror (for testing)
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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 Lo_deleting,
26};
27
28struct loop_func_table;
29
30struct loop_device {
31 int lo_number;
32 atomic_t lo_refcnt;
33 loff_t lo_offset;
34 loff_t lo_sizelimit;
35 int lo_flags;
36 int (*transfer)(struct loop_device *, int cmd,
37 struct page *raw_page, unsigned raw_off,
38 struct page *loop_page, unsigned loop_off,
39 int size, sector_t real_block);
40 char lo_file_name[LO_NAME_SIZE];
41 char lo_crypt_name[LO_NAME_SIZE];
42 char lo_encrypt_key[LO_KEY_SIZE];
43 int lo_encrypt_key_size;
44 struct loop_func_table *lo_encryption;
45 __u32 lo_init[2];
46 kuid_t lo_key_owner; /* Who set the key */
47 int (*ioctl)(struct loop_device *, int cmd,
48 unsigned long arg);
49
50 struct file * lo_backing_file;
51 struct block_device *lo_device;
52 void *key_data;
53
54 gfp_t old_gfp_mask;
55
56 spinlock_t lo_lock;
57 int lo_state;
58 struct kthread_worker worker;
59 struct task_struct *worker_task;
60 bool use_dio;
61 bool sysfs_inited;
62
63 struct request_queue *lo_queue;
64 struct blk_mq_tag_set tag_set;
65 struct gendisk *lo_disk;
66 struct mutex lo_mutex;
67};
68
69struct loop_cmd {
70 struct kthread_work work;
71 bool use_aio; /* use AIO interface to handle I/O */
72 atomic_t ref; /* only for aio */
73 long ret;
74 struct kiocb iocb;
75 struct bio_vec *bvec;
76 struct cgroup_subsys_state *css;
77};
78
79/* Support for loadable transfer modules */
80struct loop_func_table {
81 int number; /* filter type */
82 int (*transfer)(struct loop_device *lo, int cmd,
83 struct page *raw_page, unsigned raw_off,
84 struct page *loop_page, unsigned loop_off,
85 int size, sector_t real_block);
86 int (*init)(struct loop_device *, const struct loop_info64 *);
87 /* release is called from loop_unregister_transfer or clr_fd */
88 int (*release)(struct loop_device *);
89 int (*ioctl)(struct loop_device *, int cmd, unsigned long arg);
90 struct module *owner;
91};
92
93int loop_register_transfer(struct loop_func_table *funcs);
94int loop_unregister_transfer(int number);
95
96#endif