Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * Copyright (C) 2001 Sistina Software (UK) Limited.
3 * Copyright (C) 2004-2008 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#include <linux/bio.h>
12#include <linux/blkdev.h>
13
14struct dm_target;
15struct dm_table;
16struct mapped_device;
17struct bio_vec;
18
19typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
20
21union map_info {
22 void *ptr;
23 unsigned long long ll;
24};
25
26/*
27 * In the constructor the target parameter will already have the
28 * table, type, begin and len fields filled in.
29 */
30typedef int (*dm_ctr_fn) (struct dm_target *target,
31 unsigned int argc, char **argv);
32
33/*
34 * The destructor doesn't need to free the dm_target, just
35 * anything hidden ti->private.
36 */
37typedef void (*dm_dtr_fn) (struct dm_target *ti);
38
39/*
40 * The map function must return:
41 * < 0: error
42 * = 0: The target will handle the io by resubmitting it later
43 * = 1: simple remap complete
44 * = 2: The target wants to push back the io
45 */
46typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
47 union map_info *map_context);
48
49/*
50 * Returns:
51 * < 0 : error (currently ignored)
52 * 0 : ended successfully
53 * 1 : for some reason the io has still not completed (eg,
54 * multipath target might want to requeue a failed io).
55 * 2 : The target wants to push back the io
56 */
57typedef int (*dm_endio_fn) (struct dm_target *ti,
58 struct bio *bio, int error,
59 union map_info *map_context);
60
61typedef void (*dm_flush_fn) (struct dm_target *ti);
62typedef void (*dm_presuspend_fn) (struct dm_target *ti);
63typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
64typedef int (*dm_preresume_fn) (struct dm_target *ti);
65typedef void (*dm_resume_fn) (struct dm_target *ti);
66
67typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
68 char *result, unsigned int maxlen);
69
70typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
71
72typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd,
73 unsigned long arg);
74
75typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm,
76 struct bio_vec *biovec, int max_size);
77
78void dm_error(const char *message);
79
80/*
81 * Combine device limits.
82 */
83void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev);
84
85struct dm_dev {
86 struct block_device *bdev;
87 fmode_t mode;
88 char name[16];
89};
90
91/*
92 * Constructors should call these functions to ensure destination devices
93 * are opened/closed correctly.
94 * FIXME: too many arguments.
95 */
96int dm_get_device(struct dm_target *ti, const char *path, sector_t start,
97 sector_t len, fmode_t mode, struct dm_dev **result);
98void dm_put_device(struct dm_target *ti, struct dm_dev *d);
99
100/*
101 * Information about a target type
102 */
103struct target_type {
104 const char *name;
105 struct module *module;
106 unsigned version[3];
107 dm_ctr_fn ctr;
108 dm_dtr_fn dtr;
109 dm_map_fn map;
110 dm_endio_fn end_io;
111 dm_flush_fn flush;
112 dm_presuspend_fn presuspend;
113 dm_postsuspend_fn postsuspend;
114 dm_preresume_fn preresume;
115 dm_resume_fn resume;
116 dm_status_fn status;
117 dm_message_fn message;
118 dm_ioctl_fn ioctl;
119 dm_merge_fn merge;
120};
121
122struct io_restrictions {
123 unsigned long bounce_pfn;
124 unsigned long seg_boundary_mask;
125 unsigned max_hw_sectors;
126 unsigned max_sectors;
127 unsigned max_segment_size;
128 unsigned short hardsect_size;
129 unsigned short max_hw_segments;
130 unsigned short max_phys_segments;
131 unsigned char no_cluster; /* inverted so that 0 is default */
132};
133
134struct dm_target {
135 struct dm_table *table;
136 struct target_type *type;
137
138 /* target limits */
139 sector_t begin;
140 sector_t len;
141
142 /* FIXME: turn this into a mask, and merge with io_restrictions */
143 /* Always a power of 2 */
144 sector_t split_io;
145
146 /*
147 * These are automatically filled in by
148 * dm_table_get_device.
149 */
150 struct io_restrictions limits;
151
152 /* target specific data */
153 void *private;
154
155 /* Used to provide an error string from the ctr */
156 char *error;
157};
158
159int dm_register_target(struct target_type *t);
160int dm_unregister_target(struct target_type *t);
161
162
163/*-----------------------------------------------------------------
164 * Functions for creating and manipulating mapped devices.
165 * Drop the reference with dm_put when you finish with the object.
166 *---------------------------------------------------------------*/
167
168/*
169 * DM_ANY_MINOR chooses the next available minor number.
170 */
171#define DM_ANY_MINOR (-1)
172int dm_create(int minor, struct mapped_device **md);
173
174/*
175 * Reference counting for md.
176 */
177struct mapped_device *dm_get_md(dev_t dev);
178void dm_get(struct mapped_device *md);
179void dm_put(struct mapped_device *md);
180
181/*
182 * An arbitrary pointer may be stored alongside a mapped device.
183 */
184void dm_set_mdptr(struct mapped_device *md, void *ptr);
185void *dm_get_mdptr(struct mapped_device *md);
186
187/*
188 * A device can still be used while suspended, but I/O is deferred.
189 */
190int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
191int dm_resume(struct mapped_device *md);
192
193/*
194 * Event functions.
195 */
196uint32_t dm_get_event_nr(struct mapped_device *md);
197int dm_wait_event(struct mapped_device *md, int event_nr);
198uint32_t dm_next_uevent_seq(struct mapped_device *md);
199void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
200
201/*
202 * Info functions.
203 */
204const char *dm_device_name(struct mapped_device *md);
205int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
206struct gendisk *dm_disk(struct mapped_device *md);
207int dm_suspended(struct mapped_device *md);
208int dm_noflush_suspending(struct dm_target *ti);
209union map_info *dm_get_mapinfo(struct bio *bio);
210
211/*
212 * Geometry functions.
213 */
214int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
215int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
216
217
218/*-----------------------------------------------------------------
219 * Functions for manipulating device-mapper tables.
220 *---------------------------------------------------------------*/
221
222/*
223 * First create an empty table.
224 */
225int dm_table_create(struct dm_table **result, fmode_t mode,
226 unsigned num_targets, struct mapped_device *md);
227
228/*
229 * Then call this once for each target.
230 */
231int dm_table_add_target(struct dm_table *t, const char *type,
232 sector_t start, sector_t len, char *params);
233
234/*
235 * Finally call this to make the table ready for use.
236 */
237int dm_table_complete(struct dm_table *t);
238
239/*
240 * Unplug all devices in a table.
241 */
242void dm_table_unplug_all(struct dm_table *t);
243
244/*
245 * Table reference counting.
246 */
247struct dm_table *dm_get_table(struct mapped_device *md);
248void dm_table_get(struct dm_table *t);
249void dm_table_put(struct dm_table *t);
250
251/*
252 * Queries
253 */
254sector_t dm_table_get_size(struct dm_table *t);
255unsigned int dm_table_get_num_targets(struct dm_table *t);
256fmode_t dm_table_get_mode(struct dm_table *t);
257struct mapped_device *dm_table_get_md(struct dm_table *t);
258
259/*
260 * Trigger an event.
261 */
262void dm_table_event(struct dm_table *t);
263
264/*
265 * The device must be suspended before calling this method.
266 */
267int dm_swap_table(struct mapped_device *md, struct dm_table *t);
268
269/*
270 * A wrapper around vmalloc.
271 */
272void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
273
274/*-----------------------------------------------------------------
275 * Macros.
276 *---------------------------------------------------------------*/
277#define DM_NAME "device-mapper"
278
279#define DMERR(f, arg...) \
280 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
281#define DMERR_LIMIT(f, arg...) \
282 do { \
283 if (printk_ratelimit()) \
284 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
285 f "\n", ## arg); \
286 } while (0)
287
288#define DMWARN(f, arg...) \
289 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
290#define DMWARN_LIMIT(f, arg...) \
291 do { \
292 if (printk_ratelimit()) \
293 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
294 f "\n", ## arg); \
295 } while (0)
296
297#define DMINFO(f, arg...) \
298 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
299#define DMINFO_LIMIT(f, arg...) \
300 do { \
301 if (printk_ratelimit()) \
302 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
303 "\n", ## arg); \
304 } while (0)
305
306#ifdef CONFIG_DM_DEBUG
307# define DMDEBUG(f, arg...) \
308 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
309# define DMDEBUG_LIMIT(f, arg...) \
310 do { \
311 if (printk_ratelimit()) \
312 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
313 "\n", ## arg); \
314 } while (0)
315#else
316# define DMDEBUG(f, arg...) do {} while (0)
317# define DMDEBUG_LIMIT(f, arg...) do {} while (0)
318#endif
319
320#define DMEMIT(x...) sz += ((sz >= maxlen) ? \
321 0 : scnprintf(result + sz, maxlen - sz, x))
322
323#define SECTOR_SHIFT 9
324
325/*
326 * Definitions of return values from target end_io function.
327 */
328#define DM_ENDIO_INCOMPLETE 1
329#define DM_ENDIO_REQUEUE 2
330
331/*
332 * Definitions of return values from target map function.
333 */
334#define DM_MAPIO_SUBMITTED 0
335#define DM_MAPIO_REMAPPED 1
336#define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
337
338/*
339 * Ceiling(n / sz)
340 */
341#define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
342
343#define dm_sector_div_up(n, sz) ( \
344{ \
345 sector_t _r = ((n) + (sz) - 1); \
346 sector_div(_r, (sz)); \
347 _r; \
348} \
349)
350
351/*
352 * ceiling(n / size) * size
353 */
354#define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
355
356#define dm_array_too_big(fixed, obj, num) \
357 ((num) > (UINT_MAX - (fixed)) / (obj))
358
359static inline sector_t to_sector(unsigned long n)
360{
361 return (n >> SECTOR_SHIFT);
362}
363
364static inline unsigned long to_bytes(sector_t n)
365{
366 return (n << SECTOR_SHIFT);
367}
368
369#endif /* _LINUX_DEVICE_MAPPER_H */