1 /* 2 * Copyright (C) 2001 Sistina Software (UK) Limited. 3 * Copyright (C) 2004 Red Hat, Inc. All rights reserved. 4 * 5 * This file is released under the LGPL. 6 */ 7 8 #ifndef _LINUX_DEVICE_MAPPER_H 9 #define _LINUX_DEVICE_MAPPER_H 10 11 struct dm_target; 12 struct dm_table; 13 struct dm_dev; 14 15 typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t; 16 17 union map_info { 18 void *ptr; 19 unsigned long long ll; 20 }; 21 22 /* 23 * In the constructor the target parameter will already have the 24 * table, type, begin and len fields filled in. 25 */ 26 typedef int (*dm_ctr_fn) (struct dm_target *target, 27 unsigned int argc, char **argv); 28 29 /* 30 * The destructor doesn't need to free the dm_target, just 31 * anything hidden ti->private. 32 */ 33 typedef void (*dm_dtr_fn) (struct dm_target *ti); 34 35 /* 36 * The map function must return: 37 * < 0: error 38 * = 0: The target will handle the io by resubmitting it later 39 * > 0: simple remap complete 40 */ 41 typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio, 42 union map_info *map_context); 43 44 /* 45 * Returns: 46 * < 0 : error (currently ignored) 47 * 0 : ended successfully 48 * 1 : for some reason the io has still not completed (eg, 49 * multipath target might want to requeue a failed io). 50 */ 51 typedef int (*dm_endio_fn) (struct dm_target *ti, 52 struct bio *bio, int error, 53 union map_info *map_context); 54 55 typedef void (*dm_presuspend_fn) (struct dm_target *ti); 56 typedef void (*dm_postsuspend_fn) (struct dm_target *ti); 57 typedef void (*dm_resume_fn) (struct dm_target *ti); 58 59 typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type, 60 char *result, unsigned int maxlen); 61 62 typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv); 63 64 void dm_error(const char *message); 65 66 /* 67 * Constructors should call these functions to ensure destination devices 68 * are opened/closed correctly. 69 * FIXME: too many arguments. 70 */ 71 int dm_get_device(struct dm_target *ti, const char *path, sector_t start, 72 sector_t len, int mode, struct dm_dev **result); 73 void dm_put_device(struct dm_target *ti, struct dm_dev *d); 74 75 /* 76 * Information about a target type 77 */ 78 struct target_type { 79 const char *name; 80 struct module *module; 81 unsigned version[3]; 82 dm_ctr_fn ctr; 83 dm_dtr_fn dtr; 84 dm_map_fn map; 85 dm_endio_fn end_io; 86 dm_presuspend_fn presuspend; 87 dm_postsuspend_fn postsuspend; 88 dm_resume_fn resume; 89 dm_status_fn status; 90 dm_message_fn message; 91 }; 92 93 struct io_restrictions { 94 unsigned int max_sectors; 95 unsigned short max_phys_segments; 96 unsigned short max_hw_segments; 97 unsigned short hardsect_size; 98 unsigned int max_segment_size; 99 unsigned long seg_boundary_mask; 100 unsigned char no_cluster; /* inverted so that 0 is default */ 101 }; 102 103 struct dm_target { 104 struct dm_table *table; 105 struct target_type *type; 106 107 /* target limits */ 108 sector_t begin; 109 sector_t len; 110 111 /* FIXME: turn this into a mask, and merge with io_restrictions */ 112 /* Always a power of 2 */ 113 sector_t split_io; 114 115 /* 116 * These are automatically filled in by 117 * dm_table_get_device. 118 */ 119 struct io_restrictions limits; 120 121 /* target specific data */ 122 void *private; 123 124 /* Used to provide an error string from the ctr */ 125 char *error; 126 }; 127 128 int dm_register_target(struct target_type *t); 129 int dm_unregister_target(struct target_type *t); 130 131 #endif /* _LINUX_DEVICE_MAPPER_H */ 132