xref: /openbmc/linux/drivers/md/dm.h (revision e868d61272caa648214046a096e5a6bfc068dc8c)
1 /*
2  * Internal header file for device mapper
3  *
4  * Copyright (C) 2001, 2002 Sistina Software
5  * Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
6  *
7  * This file is released under the LGPL.
8  */
9 
10 #ifndef DM_INTERNAL_H
11 #define DM_INTERNAL_H
12 
13 #include <linux/fs.h>
14 #include <linux/device-mapper.h>
15 #include <linux/list.h>
16 #include <linux/blkdev.h>
17 #include <linux/hdreg.h>
18 
19 #define DM_NAME "device-mapper"
20 
21 #define DMERR(f, arg...) printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
22 #define DMWARN(f, arg...) printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
23 #define DMINFO(f, arg...) printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
24 #ifdef CONFIG_DM_DEBUG
25 #  define DMDEBUG(f, arg...) printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
26 #else
27 #  define DMDEBUG(f, arg...) do {} while (0)
28 #endif
29 
30 #define DMEMIT(x...) sz += ((sz >= maxlen) ? \
31 			  0 : scnprintf(result + sz, maxlen - sz, x))
32 
33 #define SECTOR_SHIFT 9
34 
35 /*
36  * Definitions of return values from target end_io function.
37  */
38 #define DM_ENDIO_INCOMPLETE	1
39 #define DM_ENDIO_REQUEUE	2
40 
41 /*
42  * Definitions of return values from target map function.
43  */
44 #define DM_MAPIO_SUBMITTED	0
45 #define DM_MAPIO_REMAPPED	1
46 #define DM_MAPIO_REQUEUE	DM_ENDIO_REQUEUE
47 
48 /*
49  * Suspend feature flags
50  */
51 #define DM_SUSPEND_LOCKFS_FLAG		(1 << 0)
52 #define DM_SUSPEND_NOFLUSH_FLAG		(1 << 1)
53 
54 /*
55  * List of devices that a metadevice uses and should open/close.
56  */
57 struct dm_dev {
58 	struct list_head list;
59 
60 	atomic_t count;
61 	int mode;
62 	struct block_device *bdev;
63 	char name[16];
64 };
65 
66 struct dm_table;
67 
68 /*-----------------------------------------------------------------
69  * Internal table functions.
70  *---------------------------------------------------------------*/
71 void dm_table_event_callback(struct dm_table *t,
72 			     void (*fn)(void *), void *context);
73 struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index);
74 struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector);
75 void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q);
76 struct list_head *dm_table_get_devices(struct dm_table *t);
77 void dm_table_presuspend_targets(struct dm_table *t);
78 void dm_table_postsuspend_targets(struct dm_table *t);
79 int dm_table_resume_targets(struct dm_table *t);
80 int dm_table_any_congested(struct dm_table *t, int bdi_bits);
81 void dm_table_unplug_all(struct dm_table *t);
82 int dm_table_flush_all(struct dm_table *t);
83 
84 /*-----------------------------------------------------------------
85  * A registry of target types.
86  *---------------------------------------------------------------*/
87 int dm_target_init(void);
88 void dm_target_exit(void);
89 struct target_type *dm_get_target_type(const char *name);
90 void dm_put_target_type(struct target_type *t);
91 int dm_target_iterate(void (*iter_func)(struct target_type *tt,
92 					void *param), void *param);
93 
94 /*-----------------------------------------------------------------
95  * Useful inlines.
96  *---------------------------------------------------------------*/
97 static inline int array_too_big(unsigned long fixed, unsigned long obj,
98 				unsigned long num)
99 {
100 	return (num > (ULONG_MAX - fixed) / obj);
101 }
102 
103 /*
104  * Ceiling(n / sz)
105  */
106 #define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
107 
108 #define dm_sector_div_up(n, sz) ( \
109 { \
110 	sector_t _r = ((n) + (sz) - 1); \
111 	sector_div(_r, (sz)); \
112 	_r; \
113 } \
114 )
115 
116 /*
117  * ceiling(n / size) * size
118  */
119 #define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
120 
121 static inline sector_t to_sector(unsigned long n)
122 {
123 	return (n >> 9);
124 }
125 
126 static inline unsigned long to_bytes(sector_t n)
127 {
128 	return (n << 9);
129 }
130 
131 int dm_split_args(int *argc, char ***argvp, char *input);
132 
133 /*
134  * The device-mapper can be driven through one of two interfaces;
135  * ioctl or filesystem, depending which patch you have applied.
136  */
137 int dm_interface_init(void);
138 void dm_interface_exit(void);
139 
140 /*
141  * Targets for linear and striped mappings
142  */
143 int dm_linear_init(void);
144 void dm_linear_exit(void);
145 
146 int dm_stripe_init(void);
147 void dm_stripe_exit(void);
148 
149 void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
150 union map_info *dm_get_mapinfo(struct bio *bio);
151 int dm_open_count(struct mapped_device *md);
152 int dm_lock_for_deletion(struct mapped_device *md);
153 
154 #endif
155