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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Al Viro83a87612013-05-12 10:14:07 -04002 * loop.h
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
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 */
David Howells607ca462012-10-13 10:46:48 +01009#ifndef _LINUX_LOOP_H
10#define _LINUX_LOOP_H
Linus Torvalds1da177e2005-04-16 15:20:36 -070011
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/bio.h>
13#include <linux/blkdev.h>
Jens Axboe78e367a2015-01-02 15:20:25 -070014#include <linux/blk-mq.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/spinlock.h>
Ingo Molnarf85221d2006-03-23 03:00:38 -080016#include <linux/mutex.h>
Ming Leib5dd2f62014-12-31 13:22:57 +000017#include <linux/workqueue.h>
David Howells607ca462012-10-13 10:46:48 +010018#include <uapi/linux/loop.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019
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;
Ming Leif8933662015-05-06 12:26:23 +080031 atomic_t lo_refcnt;
Linus Torvalds1da177e2005-04-16 15:20:36 -070032 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];
Eric W. Biedermane4849732012-02-11 11:23:51 -080045 kuid_t lo_key_owner; /* Who set the key */
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 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
Al Virob4e3ca12005-10-21 03:22:34 -040054 gfp_t old_gfp_mask;
Linus Torvalds1da177e2005-04-16 15:20:36 -070055
56 spinlock_t lo_lock;
Ming Leif4aa4c72015-05-05 19:49:54 +080057 struct workqueue_struct *wq;
Ming Leib5dd2f62014-12-31 13:22:57 +000058 struct list_head write_cmd_head;
59 struct work_struct write_work;
60 bool write_started;
Linus Torvalds1da177e2005-04-16 15:20:36 -070061 int lo_state;
Ingo Molnarf85221d2006-03-23 03:00:38 -080062 struct mutex lo_ctl_mutex;
Linus Torvalds1da177e2005-04-16 15:20:36 -070063
Arnd Bergmann01e457c2007-07-23 18:44:00 -070064 struct request_queue *lo_queue;
Ming Leib5dd2f62014-12-31 13:22:57 +000065 struct blk_mq_tag_set tag_set;
Ken Chen73285082007-05-08 00:28:20 -070066 struct gendisk *lo_disk;
Linus Torvalds1da177e2005-04-16 15:20:36 -070067};
68
Ming Leib5dd2f62014-12-31 13:22:57 +000069struct loop_cmd {
70 struct work_struct read_work;
71 struct request *rq;
72 struct list_head list;
73};
74
Linus Torvalds1da177e2005-04-16 15:20:36 -070075/* 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