loop.h
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/*
* loop.h
*
* Written by Theodore Ts'o, 3/29/93.
*
* Copyright 1993 by Theodore Ts'o. Redistribution of this file is
* permitted under the GNU General Public License.
*/
#ifndef _LINUX_LOOP_H
#define _LINUX_LOOP_H
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/blk-mq.h>
#include <linux/spinlock.h>
#include <linux/mutex.h>
#include <linux/kthread.h>
#include <uapi/linux/loop.h>
/* Possible states of device */
enum {
Lo_unbound,
Lo_bound,
Lo_rundown,
};
struct loop_func_table;
struct loop_device {
int lo_number;
atomic_t lo_refcnt;
loff_t lo_offset;
loff_t lo_sizelimit;
int lo_flags;
int (*transfer)(struct loop_device *, int cmd,
struct page *raw_page, unsigned raw_off,
struct page *loop_page, unsigned loop_off,
int size, sector_t real_block);
char lo_file_name[LO_NAME_SIZE];
char lo_crypt_name[LO_NAME_SIZE];
char lo_encrypt_key[LO_KEY_SIZE];
int lo_encrypt_key_size;
struct loop_func_table *lo_encryption;
__u32 lo_init[2];
kuid_t lo_key_owner; /* Who set the key */
int (*ioctl)(struct loop_device *, int cmd,
unsigned long arg);
struct file * lo_backing_file;
struct block_device *lo_device;
unsigned lo_blocksize;
void *key_data;
gfp_t old_gfp_mask;
spinlock_t lo_lock;
int lo_state;
struct mutex lo_ctl_mutex;
struct kthread_worker worker;
struct task_struct *worker_task;
bool use_dio;
struct request_queue *lo_queue;
struct blk_mq_tag_set tag_set;
struct gendisk *lo_disk;
};
struct loop_cmd {
struct kthread_work work;
struct request *rq;
struct list_head list;
bool use_aio; /* use AIO interface to handle I/O */
struct kiocb iocb;
};
/* Support for loadable transfer modules */
struct loop_func_table {
int number; /* filter type */
int (*transfer)(struct loop_device *lo, int cmd,
struct page *raw_page, unsigned raw_off,
struct page *loop_page, unsigned loop_off,
int size, sector_t real_block);
int (*init)(struct loop_device *, const struct loop_info64 *);
/* release is called from loop_unregister_transfer or clr_fd */
int (*release)(struct loop_device *);
int (*ioctl)(struct loop_device *, int cmd, unsigned long arg);
struct module *owner;
};
int loop_register_transfer(struct loop_func_table *funcs);
int loop_unregister_transfer(int number);
#endif