1 /* 2 * include/linux/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/spinlock.h> 15 #include <linux/mutex.h> 16 #include <uapi/linux/loop.h> 17 18 /* Possible states of device */ 19 enum { 20 Lo_unbound, 21 Lo_bound, 22 Lo_rundown, 23 }; 24 25 struct loop_func_table; 26 27 struct loop_device { 28 int lo_number; 29 int lo_refcnt; 30 loff_t lo_offset; 31 loff_t lo_sizelimit; 32 int lo_flags; 33 int (*transfer)(struct loop_device *, int cmd, 34 struct page *raw_page, unsigned raw_off, 35 struct page *loop_page, unsigned loop_off, 36 int size, sector_t real_block); 37 char lo_file_name[LO_NAME_SIZE]; 38 char lo_crypt_name[LO_NAME_SIZE]; 39 char lo_encrypt_key[LO_KEY_SIZE]; 40 int lo_encrypt_key_size; 41 struct loop_func_table *lo_encryption; 42 __u32 lo_init[2]; 43 kuid_t lo_key_owner; /* Who set the key */ 44 int (*ioctl)(struct loop_device *, int cmd, 45 unsigned long arg); 46 47 struct file * lo_backing_file; 48 struct block_device *lo_device; 49 unsigned lo_blocksize; 50 void *key_data; 51 52 gfp_t old_gfp_mask; 53 54 spinlock_t lo_lock; 55 struct bio_list lo_bio_list; 56 unsigned int lo_bio_count; 57 int lo_state; 58 struct mutex lo_ctl_mutex; 59 struct task_struct *lo_thread; 60 wait_queue_head_t lo_event; 61 /* wait queue for incoming requests */ 62 wait_queue_head_t lo_req_wait; 63 64 struct request_queue *lo_queue; 65 struct gendisk *lo_disk; 66 }; 67 68 /* Support for loadable transfer modules */ 69 struct loop_func_table { 70 int number; /* filter type */ 71 int (*transfer)(struct loop_device *lo, int cmd, 72 struct page *raw_page, unsigned raw_off, 73 struct page *loop_page, unsigned loop_off, 74 int size, sector_t real_block); 75 int (*init)(struct loop_device *, const struct loop_info64 *); 76 /* release is called from loop_unregister_transfer or clr_fd */ 77 int (*release)(struct loop_device *); 78 int (*ioctl)(struct loop_device *, int cmd, unsigned long arg); 79 struct module *owner; 80 }; 81 82 int loop_register_transfer(struct loop_func_table *funcs); 83 int loop_unregister_transfer(int number); 84 85 #endif 86