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}; 26 27struct loop_func_table; 28 29struct loop_device { 30 int lo_number; 31 atomic_t 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 void *key_data; 52 53 gfp_t old_gfp_mask; 54 55 spinlock_t lo_lock; 56 int lo_state; 57 struct kthread_worker worker; 58 struct task_struct *worker_task; 59 bool use_dio; 60 bool sysfs_inited; 61 62 struct request_queue *lo_queue; 63 struct blk_mq_tag_set tag_set; 64 struct gendisk *lo_disk; 65}; 66 67struct loop_cmd { 68 struct kthread_work work; 69 bool use_aio; /* use AIO interface to handle I/O */ 70 atomic_t ref; /* only for aio */ 71 long ret; 72 struct kiocb iocb; 73 struct bio_vec *bvec; 74 struct cgroup_subsys_state *css; 75}; 76 77/* Support for loadable transfer modules */ 78struct loop_func_table { 79 int number; /* filter type */ 80 int (*transfer)(struct loop_device *lo, int cmd, 81 struct page *raw_page, unsigned raw_off, 82 struct page *loop_page, unsigned loop_off, 83 int size, sector_t real_block); 84 int (*init)(struct loop_device *, const struct loop_info64 *); 85 /* release is called from loop_unregister_transfer or clr_fd */ 86 int (*release)(struct loop_device *); 87 int (*ioctl)(struct loop_device *, int cmd, unsigned long arg); 88 struct module *owner; 89}; 90 91int loop_register_transfer(struct loop_func_table *funcs); 92int loop_unregister_transfer(int number); 93 94#endif 95