drivers/md/dm.h

   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 #include <linux/completion.h>
  19 #include <linux/kobject.h>
  20
  21 #include "dm-stats.h"
  22
  23 /*
  24  * Suspend feature flags
  25  */
  26 #define DM_SUSPEND_LOCKFS_FLAG          (1 << 0)
  27 #define DM_SUSPEND_NOFLUSH_FLAG         (1 << 1)
  28
  29 /*
  30  * Status feature flags
  31  */
  32 #define DM_STATUS_NOFLUSH_FLAG          (1 << 0)
  33
  34 /*
  35  * Type of table and mapped_device's mempool
  36  */
  37 #define DM_TYPE_NONE            0
  38 #define DM_TYPE_BIO_BASED       1
  39 #define DM_TYPE_REQUEST_BASED   2
  40
  41 /*
  42  * List of devices that a metadevice uses and should open/close.
  43  */
  44 struct dm_dev_internal {
  45         struct list_head list;
  46         atomic_t count;
  47         struct dm_dev dm_dev;
  48 };
  49
  50 struct dm_table;
  51 struct dm_md_mempools;
  52
  53 /*-----------------------------------------------------------------
  54  * Internal table functions.
  55  *---------------------------------------------------------------*/
  56 void dm_table_destroy(struct dm_table *t);
  57 void dm_table_event_callback(struct dm_table *t,
  58                              void (*fn)(void *), void *context);
  59 struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index);
  60 struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector);
  61 bool dm_table_has_no_data_devices(struct dm_table *table);
  62 int dm_calculate_queue_limits(struct dm_table *table,
  63                               struct queue_limits *limits);
  64 void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
  65                                struct queue_limits *limits);
  66 struct list_head *dm_table_get_devices(struct dm_table *t);
  67 void dm_table_presuspend_targets(struct dm_table *t);
  68 void dm_table_postsuspend_targets(struct dm_table *t);
  69 int dm_table_resume_targets(struct dm_table *t);
  70 int dm_table_any_congested(struct dm_table *t, int bdi_bits);
  71 int dm_table_any_busy_target(struct dm_table *t);
  72 unsigned dm_table_get_type(struct dm_table *t);
  73 struct target_type *dm_table_get_immutable_target_type(struct dm_table *t);
  74 bool dm_table_request_based(struct dm_table *t);
  75 bool dm_table_supports_discards(struct dm_table *t);
  76 int dm_table_alloc_md_mempools(struct dm_table *t);
  77 void dm_table_free_md_mempools(struct dm_table *t);
  78 struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t);
  79
  80 int dm_queue_merge_is_compulsory(struct request_queue *q);
  81
  82 void dm_lock_md_type(struct mapped_device *md);
  83 void dm_unlock_md_type(struct mapped_device *md);
  84 void dm_set_md_type(struct mapped_device *md, unsigned type);
  85 unsigned dm_get_md_type(struct mapped_device *md);
  86 struct target_type *dm_get_immutable_target_type(struct mapped_device *md);
  87
  88 int dm_setup_md_queue(struct mapped_device *md);
  89
  90 /*
  91  * To check the return value from dm_table_find_target().
  92  */
  93 #define dm_target_is_valid(t) ((t)->table)
  94
  95 /*
  96  * To check whether the target type is bio-based or not (request-based).
  97  */
  98 #define dm_target_bio_based(t) ((t)->type->map != NULL)
  99
 100 /*
 101  * To check whether the target type is request-based or not (bio-based).
 102  */
 103 #define dm_target_request_based(t) ((t)->type->map_rq != NULL)
 104
 105 /*
 106  * To check whether the target type is a hybrid (capable of being
 107  * either request-based or bio-based).
 108  */
 109 #define dm_target_hybrid(t) (dm_target_bio_based(t) && dm_target_request_based(t))
 110
 111 /*-----------------------------------------------------------------
 112  * A registry of target types.
 113  *---------------------------------------------------------------*/
 114 int dm_target_init(void);
 115 void dm_target_exit(void);
 116 struct target_type *dm_get_target_type(const char *name);
 117 void dm_put_target_type(struct target_type *tt);
 118 int dm_target_iterate(void (*iter_func)(struct target_type *tt,
 119                                         void *param), void *param);
 120
 121 int dm_split_args(int *argc, char ***argvp, char *input);
 122
 123 /*
 124  * Is this mapped_device being deleted?
 125  */
 126 int dm_deleting_md(struct mapped_device *md);
 127
 128 /*
 129  * Is this mapped_device suspended?
 130  */
 131 int dm_suspended_md(struct mapped_device *md);
 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  * sysfs interface
 142  */
 143 struct dm_kobject_holder {
 144         struct kobject kobj;
 145         struct completion completion;
 146 };
 147
 148 static inline struct completion *dm_get_completion_from_kobject(struct kobject *kobj)
 149 {
 150         return &container_of(kobj, struct dm_kobject_holder, kobj)->completion;
 151 }
 152
 153 int dm_sysfs_init(struct mapped_device *md);
 154 void dm_sysfs_exit(struct mapped_device *md);
 155 struct kobject *dm_kobject(struct mapped_device *md);
 156 struct mapped_device *dm_get_from_kobject(struct kobject *kobj);
 157
 158 /*
 159  * The kobject helper
 160  */
 161 void dm_kobject_release(struct kobject *kobj);
 162
 163 /*
 164  * Targets for linear and striped mappings
 165  */
 166 int dm_linear_init(void);
 167 void dm_linear_exit(void);
 168
 169 int dm_stripe_init(void);
 170 void dm_stripe_exit(void);
 171
 172 /*
 173  * mapped_device operations
 174  */
 175 void dm_destroy(struct mapped_device *md);
 176 void dm_destroy_immediate(struct mapped_device *md);
 177 int dm_open_count(struct mapped_device *md);
 178 int dm_lock_for_deletion(struct mapped_device *md);
 179 int dm_request_based(struct mapped_device *md);
 180 sector_t dm_get_size(struct mapped_device *md);
 181 struct dm_stats *dm_get_stats(struct mapped_device *md);
 182
 183 int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
 184                       unsigned cookie);
 185
 186 void dm_internal_suspend(struct mapped_device *md);
 187 void dm_internal_resume(struct mapped_device *md);
 188
 189 int dm_io_init(void);
 190 void dm_io_exit(void);
 191
 192 int dm_kcopyd_init(void);
 193 void dm_kcopyd_exit(void);
 194
 195 /*
 196  * Mempool operations
 197  */
 198 struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity, unsigned per_bio_data_size);
 199 void dm_free_md_mempools(struct dm_md_mempools *pools);
 200
 201 /*
 202  * Helpers that are used by DM core
 203  */
 204 unsigned dm_get_reserved_bio_based_ios(void);
 205 unsigned dm_get_reserved_rq_based_ios(void);
 206
 207 static inline bool dm_message_test_buffer_overflow(char *result, unsigned maxlen)
 208 {
 209         return !maxlen || strlen(result) + 1 >= maxlen;
 210 }
 211
 212 #endif