| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 short 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 | }; |
| 101 | |
| 102 | struct dm_target { |
| 103 | struct dm_table *table; |
| 104 | struct target_type *type; |
| 105 | |
| 106 | /* target limits */ |
| 107 | sector_t begin; |
| 108 | sector_t len; |
| 109 | |
| 110 | /* FIXME: turn this into a mask, and merge with io_restrictions */ |
| 111 | /* Always a power of 2 */ |
| 112 | sector_t split_io; |
| 113 | |
| 114 | /* |
| 115 | * These are automatically filled in by |
| 116 | * dm_table_get_device. |
| 117 | */ |
| 118 | struct io_restrictions limits; |
| 119 | |
| 120 | /* target specific data */ |
| 121 | void *private; |
| 122 | |
| 123 | /* Used to provide an error string from the ctr */ |
| 124 | char *error; |
| 125 | }; |
| 126 | |
| 127 | int dm_register_target(struct target_type *t); |
| 128 | int dm_unregister_target(struct target_type *t); |
| 129 | |
| 130 | #endif /* _LINUX_DEVICE_MAPPER_H */ |