dm request: extend target interface
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / include / linux / device-mapper.h
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1da177e4
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1/*
2 * Copyright (C) 2001 Sistina Software (UK) Limited.
0da336e5 3 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
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4 *
5 * This file is released under the LGPL.
6 */
7
8#ifndef _LINUX_DEVICE_MAPPER_H
9#define _LINUX_DEVICE_MAPPER_H
10
416cd17b 11#include <linux/bio.h>
f6fccb12 12#include <linux/blkdev.h>
416cd17b 13
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14struct dm_target;
15struct dm_table;
17b2f66f 16struct mapped_device;
f6fccb12 17struct bio_vec;
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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
45cbcd79 43 * = 1: simple remap complete
2e93ccc1 44 * = 2: The target wants to push back the io
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45 */
46typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
47 union map_info *map_context);
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48typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone,
49 union map_info *map_context);
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50
51/*
52 * Returns:
53 * < 0 : error (currently ignored)
54 * 0 : ended successfully
55 * 1 : for some reason the io has still not completed (eg,
56 * multipath target might want to requeue a failed io).
2e93ccc1 57 * 2 : The target wants to push back the io
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58 */
59typedef int (*dm_endio_fn) (struct dm_target *ti,
60 struct bio *bio, int error,
61 union map_info *map_context);
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62typedef int (*dm_request_endio_fn) (struct dm_target *ti,
63 struct request *clone, int error,
64 union map_info *map_context);
1da177e4 65
999d8168 66typedef void (*dm_flush_fn) (struct dm_target *ti);
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67typedef void (*dm_presuspend_fn) (struct dm_target *ti);
68typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
8757b776 69typedef int (*dm_preresume_fn) (struct dm_target *ti);
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70typedef void (*dm_resume_fn) (struct dm_target *ti);
71
72typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
73 char *result, unsigned int maxlen);
74
75typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
76
647b3d00 77typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd,
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78 unsigned long arg);
79
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80typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm,
81 struct bio_vec *biovec, int max_size);
82
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83/*
84 * Returns:
85 * 0: The target can handle the next I/O immediately.
86 * 1: The target can't handle the next I/O immediately.
87 */
88typedef int (*dm_busy_fn) (struct dm_target *ti);
89
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90void dm_error(const char *message);
91
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92/*
93 * Combine device limits.
94 */
95void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev);
96
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97struct dm_dev {
98 struct block_device *bdev;
aeb5d727 99 fmode_t mode;
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100 char name[16];
101};
102
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103/*
104 * Constructors should call these functions to ensure destination devices
105 * are opened/closed correctly.
106 * FIXME: too many arguments.
107 */
108int dm_get_device(struct dm_target *ti, const char *path, sector_t start,
aeb5d727 109 sector_t len, fmode_t mode, struct dm_dev **result);
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110void dm_put_device(struct dm_target *ti, struct dm_dev *d);
111
112/*
113 * Information about a target type
114 */
115struct target_type {
116 const char *name;
117 struct module *module;
17b2f66f 118 unsigned version[3];
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119 dm_ctr_fn ctr;
120 dm_dtr_fn dtr;
121 dm_map_fn map;
7d76345d 122 dm_map_request_fn map_rq;
1da177e4 123 dm_endio_fn end_io;
7d76345d 124 dm_request_endio_fn rq_end_io;
999d8168 125 dm_flush_fn flush;
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126 dm_presuspend_fn presuspend;
127 dm_postsuspend_fn postsuspend;
8757b776 128 dm_preresume_fn preresume;
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129 dm_resume_fn resume;
130 dm_status_fn status;
131 dm_message_fn message;
aa129a22 132 dm_ioctl_fn ioctl;
f6fccb12 133 dm_merge_fn merge;
7d76345d 134 dm_busy_fn busy;
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135};
136
137struct io_restrictions {
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138 unsigned long bounce_pfn;
139 unsigned long seg_boundary_mask;
140 unsigned max_hw_sectors;
141 unsigned max_sectors;
142 unsigned max_segment_size;
143 unsigned short hardsect_size;
144 unsigned short max_hw_segments;
145 unsigned short max_phys_segments;
146 unsigned char no_cluster; /* inverted so that 0 is default */
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147};
148
149struct dm_target {
150 struct dm_table *table;
151 struct target_type *type;
152
153 /* target limits */
154 sector_t begin;
155 sector_t len;
156
157 /* FIXME: turn this into a mask, and merge with io_restrictions */
158 /* Always a power of 2 */
159 sector_t split_io;
160
161 /*
162 * These are automatically filled in by
163 * dm_table_get_device.
164 */
165 struct io_restrictions limits;
166
167 /* target specific data */
168 void *private;
169
170 /* Used to provide an error string from the ctr */
171 char *error;
172};
173
174int dm_register_target(struct target_type *t);
10d3bd09 175void dm_unregister_target(struct target_type *t);
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176
177/*-----------------------------------------------------------------
178 * Functions for creating and manipulating mapped devices.
179 * Drop the reference with dm_put when you finish with the object.
180 *---------------------------------------------------------------*/
181
182/*
183 * DM_ANY_MINOR chooses the next available minor number.
184 */
185#define DM_ANY_MINOR (-1)
186int dm_create(int minor, struct mapped_device **md);
187
188/*
189 * Reference counting for md.
190 */
191struct mapped_device *dm_get_md(dev_t dev);
192void dm_get(struct mapped_device *md);
193void dm_put(struct mapped_device *md);
194
195/*
196 * An arbitrary pointer may be stored alongside a mapped device.
197 */
198void dm_set_mdptr(struct mapped_device *md, void *ptr);
199void *dm_get_mdptr(struct mapped_device *md);
200
201/*
202 * A device can still be used while suspended, but I/O is deferred.
203 */
a3d77d35 204int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
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205int dm_resume(struct mapped_device *md);
206
207/*
208 * Event functions.
209 */
210uint32_t dm_get_event_nr(struct mapped_device *md);
211int dm_wait_event(struct mapped_device *md, int event_nr);
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212uint32_t dm_next_uevent_seq(struct mapped_device *md);
213void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
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214
215/*
216 * Info functions.
217 */
72d94861 218const char *dm_device_name(struct mapped_device *md);
96a1f7db 219int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
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220struct gendisk *dm_disk(struct mapped_device *md);
221int dm_suspended(struct mapped_device *md);
2e93ccc1 222int dm_noflush_suspending(struct dm_target *ti);
89343da0 223union map_info *dm_get_mapinfo(struct bio *bio);
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224
225/*
226 * Geometry functions.
227 */
228int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
229int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
230
231
232/*-----------------------------------------------------------------
233 * Functions for manipulating device-mapper tables.
234 *---------------------------------------------------------------*/
235
236/*
237 * First create an empty table.
238 */
aeb5d727 239int dm_table_create(struct dm_table **result, fmode_t mode,
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240 unsigned num_targets, struct mapped_device *md);
241
242/*
243 * Then call this once for each target.
244 */
245int dm_table_add_target(struct dm_table *t, const char *type,
246 sector_t start, sector_t len, char *params);
247
248/*
249 * Finally call this to make the table ready for use.
250 */
251int dm_table_complete(struct dm_table *t);
252
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253/*
254 * Unplug all devices in a table.
255 */
256void dm_table_unplug_all(struct dm_table *t);
257
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258/*
259 * Table reference counting.
260 */
261struct dm_table *dm_get_table(struct mapped_device *md);
262void dm_table_get(struct dm_table *t);
263void dm_table_put(struct dm_table *t);
264
265/*
266 * Queries
267 */
268sector_t dm_table_get_size(struct dm_table *t);
269unsigned int dm_table_get_num_targets(struct dm_table *t);
aeb5d727 270fmode_t dm_table_get_mode(struct dm_table *t);
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271struct mapped_device *dm_table_get_md(struct dm_table *t);
272
273/*
274 * Trigger an event.
275 */
276void dm_table_event(struct dm_table *t);
277
278/*
279 * The device must be suspended before calling this method.
280 */
281int dm_swap_table(struct mapped_device *md, struct dm_table *t);
282
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283/*
284 * A wrapper around vmalloc.
285 */
286void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
287
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288/*-----------------------------------------------------------------
289 * Macros.
290 *---------------------------------------------------------------*/
291#define DM_NAME "device-mapper"
292
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293#define DMCRIT(f, arg...) \
294 printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
295
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296#define DMERR(f, arg...) \
297 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
298#define DMERR_LIMIT(f, arg...) \
299 do { \
300 if (printk_ratelimit()) \
301 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
302 f "\n", ## arg); \
303 } while (0)
304
305#define DMWARN(f, arg...) \
306 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
307#define DMWARN_LIMIT(f, arg...) \
308 do { \
309 if (printk_ratelimit()) \
310 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
311 f "\n", ## arg); \
312 } while (0)
313
314#define DMINFO(f, arg...) \
315 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
316#define DMINFO_LIMIT(f, arg...) \
317 do { \
318 if (printk_ratelimit()) \
319 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
320 "\n", ## arg); \
321 } while (0)
322
323#ifdef CONFIG_DM_DEBUG
324# define DMDEBUG(f, arg...) \
325 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
326# define DMDEBUG_LIMIT(f, arg...) \
327 do { \
328 if (printk_ratelimit()) \
329 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
330 "\n", ## arg); \
331 } while (0)
332#else
333# define DMDEBUG(f, arg...) do {} while (0)
334# define DMDEBUG_LIMIT(f, arg...) do {} while (0)
335#endif
336
337#define DMEMIT(x...) sz += ((sz >= maxlen) ? \
338 0 : scnprintf(result + sz, maxlen - sz, x))
339
340#define SECTOR_SHIFT 9
341
342/*
343 * Definitions of return values from target end_io function.
344 */
345#define DM_ENDIO_INCOMPLETE 1
346#define DM_ENDIO_REQUEUE 2
347
348/*
349 * Definitions of return values from target map function.
350 */
351#define DM_MAPIO_SUBMITTED 0
352#define DM_MAPIO_REMAPPED 1
353#define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
354
355/*
356 * Ceiling(n / sz)
357 */
358#define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
359
360#define dm_sector_div_up(n, sz) ( \
361{ \
362 sector_t _r = ((n) + (sz) - 1); \
363 sector_div(_r, (sz)); \
364 _r; \
365} \
366)
367
368/*
369 * ceiling(n / size) * size
370 */
371#define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
372
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373#define dm_array_too_big(fixed, obj, num) \
374 ((num) > (UINT_MAX - (fixed)) / (obj))
375
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376static inline sector_t to_sector(unsigned long n)
377{
378 return (n >> SECTOR_SHIFT);
379}
380
381static inline unsigned long to_bytes(sector_t n)
382{
383 return (n << SECTOR_SHIFT);
384}
385
17b2f66f 386#endif /* _LINUX_DEVICE_MAPPER_H */