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/* SPDX-License-Identifier: GPL-2.0 */
/*
* loop_file_fmt.h
*
* File format subsystem for the loop device module.
*
* Copyright (C) 2019 Manuel Bentele <development@manuel-bentele.de>
*/
#ifndef _LINUX_LOOP_FILE_FMT_H
#define _LINUX_LOOP_FILE_FMT_H
#include "loop_main.h"
struct loop_file_fmt;
/* data structure representing the file format subsystem interface */
struct loop_file_fmt_ops {
int (*init) (struct loop_file_fmt *lo_fmt);
void (*exit) (struct loop_file_fmt *lo_fmt);
int (*read) (struct loop_file_fmt *lo_fmt,
struct request *rq);
int (*write) (struct loop_file_fmt *lo_fmt,
struct request *rq);
int (*read_aio) (struct loop_file_fmt *lo_fmt,
struct request *rq);
int (*write_aio) (struct loop_file_fmt *lo_fmt,
struct request *rq);
int (*discard) (struct loop_file_fmt *lo_fmt,
struct request *rq);
int (*flush) (struct loop_file_fmt *lo_fmt);
loff_t (*sector_size) (struct loop_file_fmt *lo_fmt);
};
/* data structure for implementing file format drivers */
struct loop_file_fmt_driver {
const char *name;
const u32 file_fmt_type;
struct loop_file_fmt_ops *ops;
struct module *owner;
};
/*
* states of the file format
*
* transitions:
* loop_file_fmt_init(...)
* ---> uninitialized ------------------------------> initialized
* loop_file_fmt_exit(...)
* initialized ------------------------------> uninitialized
* loop_file_fmt_read(...)
* initialized ------------------------------> initialized
* loop_file_fmt_read_aio(...)
* initialized ------------------------------> initialized
* loop_file_fmt_write(...)
* initialized ------------------------------> initialized
* loop_file_fmt_write_aio(...)
* initialized ------------------------------> initialized
* loop_file_fmt_discard(...)
* initialized ------------------------------> initialized
* loop_file_fmt_flush(...)
* initialized ------------------------------> initialized
* loop_file_fmt_sector_size(...)
* initialized ------------------------------> initialized
*
* loop_file_fmt_change(...)
* +-----------------------------------------------------------+
* | exit(...) init(...) |
* | initialized -------> uninitialized -------> initialized |
* +-----------------------------------------------------------+
*/
enum {
file_fmt_uninitialized = 0,
file_fmt_initialized
};
/* data structure for using with the file format subsystem */
struct loop_file_fmt {
u32 file_fmt_type;
int file_fmt_state;
struct loop_device *lo;
void *private_data;
};
/* subsystem functions for the driver implementation */
extern int loop_file_fmt_register_driver(struct loop_file_fmt_driver *drv);
extern void loop_file_fmt_unregister_driver(struct loop_file_fmt_driver *drv);
/* subsystem functions for subsystem usage */
extern struct loop_file_fmt *loop_file_fmt_alloc(void);
extern void loop_file_fmt_free(struct loop_file_fmt *lo_fmt);
extern int loop_file_fmt_set_lo(struct loop_file_fmt *lo_fmt,
struct loop_device *lo);
extern struct loop_device *loop_file_fmt_get_lo(struct loop_file_fmt *lo_fmt);
extern int loop_file_fmt_init(struct loop_file_fmt *lo_fmt,
u32 file_fmt_type);
extern void loop_file_fmt_exit(struct loop_file_fmt *lo_fmt);
extern int loop_file_fmt_read(struct loop_file_fmt *lo_fmt,
struct request *rq);
extern int loop_file_fmt_read_aio(struct loop_file_fmt *lo_fmt,
struct request *rq);
extern int loop_file_fmt_write(struct loop_file_fmt *lo_fmt,
struct request *rq);
extern int loop_file_fmt_write_aio(struct loop_file_fmt *lo_fmt,
struct request *rq);
extern int loop_file_fmt_discard(struct loop_file_fmt *lo_fmt,
struct request *rq);
extern int loop_file_fmt_flush(struct loop_file_fmt *lo_fmt);
extern loff_t loop_file_fmt_sector_size(struct loop_file_fmt *lo_fmt);
extern int loop_file_fmt_change(struct loop_file_fmt *lo_fmt,
u32 file_fmt_type_new);
/* helper functions of the subsystem */
extern ssize_t loop_file_fmt_print_type(u32 file_fmt_type,
char *file_fmt_name);
#endif
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