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 workqueue_struct *wq;
58	struct list_head	write_cmd_head;
59	struct work_struct	write_work;
60	bool			write_started;
61	int			lo_state;
62	struct mutex		lo_ctl_mutex;
63
64	struct request_queue	*lo_queue;
65	struct blk_mq_tag_set	tag_set;
66	struct gendisk		*lo_disk;
67};
68
69struct loop_cmd {
70	struct work_struct read_work;
71	struct request *rq;
72	struct list_head list;
73};
74
75/* Support for loadable transfer modules */
76struct loop_func_table {
77	int number;	/* filter type */
78	int (*transfer)(struct loop_device *lo, int cmd,
79			struct page *raw_page, unsigned raw_off,
80			struct page *loop_page, unsigned loop_off,
81			int size, sector_t real_block);
82	int (*init)(struct loop_device *, const struct loop_info64 *);
83	/* release is called from loop_unregister_transfer or clr_fd */
84	int (*release)(struct loop_device *);
85	int (*ioctl)(struct loop_device *, int cmd, unsigned long arg);
86	struct module *owner;
87};
88
89int loop_register_transfer(struct loop_func_table *funcs);
90int loop_unregister_transfer(int number);
91
92#endif
93