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 */ 21 enum { 22 Lo_unbound, 23 Lo_bound, 24 Lo_rundown, 25 }; 26 27 struct loop_func_table; 28 29 struct 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 unsigned lo_blocksize; 52 void *key_data; 53 54 gfp_t old_gfp_mask; 55 56 spinlock_t lo_lock; 57 int lo_state; 58 struct mutex lo_ctl_mutex; 59 struct kthread_worker worker; 60 struct task_struct *worker_task; 61 bool use_dio; 62 bool sysfs_inited; 63 64 struct request_queue *lo_queue; 65 struct blk_mq_tag_set tag_set; 66 struct gendisk *lo_disk; 67 }; 68 69 struct loop_cmd { 70 struct kthread_work work; 71 struct request *rq; 72 struct list_head list; 73 bool use_aio; /* use AIO interface to handle I/O */ 74 struct kiocb iocb; 75 }; 76 77 /* Support for loadable transfer modules */ 78 struct 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 91 int loop_register_transfer(struct loop_func_table *funcs); 92 int loop_unregister_transfer(int number); 93 94 #endif 95