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 #define DM_TYPE_MQ_REQUEST_BASED        3
  41
  42 /*
  43  * List of devices that a metadevice uses and should open/close.
  44  */
  45 struct dm_dev_internal {
  46         struct list_head list;
  47         atomic_t count;
  48         struct dm_dev *dm_dev;
  49 };
  50
  51 struct dm_table;
  52 struct dm_md_mempools;
  53
  54 /*-----------------------------------------------------------------
  55  * Internal table functions.
  56  *---------------------------------------------------------------*/
  57 void dm_table_destroy(struct dm_table *t);
  58 void dm_table_event_callback(struct dm_table *t,
  59                              void (*fn)(void *), void *context);
  60 struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index);
  61 struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector);
  62 bool dm_table_has_no_data_devices(struct dm_table *table);
  63 int dm_calculate_queue_limits(struct dm_table *table,
  64                               struct queue_limits *limits);
  65 void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
  66                                struct queue_limits *limits);
  67 struct list_head *dm_table_get_devices(struct dm_table *t);
  68 void dm_table_presuspend_targets(struct dm_table *t);
  69 void dm_table_presuspend_undo_targets(struct dm_table *t);
  70 void dm_table_postsuspend_targets(struct dm_table *t);
  71 int dm_table_resume_targets(struct dm_table *t);
  72 int dm_table_any_congested(struct dm_table *t, int bdi_bits);
  73 unsigned dm_table_get_type(struct dm_table *t);
  74 struct target_type *dm_table_get_immutable_target_type(struct dm_table *t);
  75 bool dm_table_request_based(struct dm_table *t);
  76 bool dm_table_mq_request_based(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                                     ((t)->type->clone_and_map_rq != NULL))
 105
 106 /*
 107  * To check whether the target type is a hybrid (capable of being
 108  * either request-based or bio-based).
 109  */
 110 #define dm_target_hybrid(t) (dm_target_bio_based(t) && dm_target_request_based(t))
 111
 112 /*-----------------------------------------------------------------
 113  * A registry of target types.
 114  *---------------------------------------------------------------*/
 115 int dm_target_init(void);
 116 void dm_target_exit(void);
 117 struct target_type *dm_get_target_type(const char *name);
 118 void dm_put_target_type(struct target_type *tt);
 119 int dm_target_iterate(void (*iter_func)(struct target_type *tt,
 120                                         void *param), void *param);
 121
 122 int dm_split_args(int *argc, char ***argvp, char *input);
 123
 124 /*
 125  * Is this mapped_device being deleted?
 126  */
 127 int dm_deleting_md(struct mapped_device *md);
 128
 129 /*
 130  * Is this mapped_device suspended?
 131  */
 132 int dm_suspended_md(struct mapped_device *md);
 133
 134 /*
 135  * Internal suspend and resume methods.
 136  */
 137 int dm_suspended_internally_md(struct mapped_device *md);
 138 void dm_internal_suspend_fast(struct mapped_device *md);
 139 void dm_internal_resume_fast(struct mapped_device *md);
 140 void dm_internal_suspend_noflush(struct mapped_device *md);
 141 void dm_internal_resume(struct mapped_device *md);
 142
 143 /*
 144  * Test if the device is scheduled for deferred remove.
 145  */
 146 int dm_test_deferred_remove_flag(struct mapped_device *md);
 147
 148 /*
 149  * Try to remove devices marked for deferred removal.
 150  */
 151 void dm_deferred_remove(void);
 152
 153 /*
 154  * The device-mapper can be driven through one of two interfaces;
 155  * ioctl or filesystem, depending which patch you have applied.
 156  */
 157 int dm_interface_init(void);
 158 void dm_interface_exit(void);
 159
 160 /*
 161  * sysfs interface
 162  */
 163 struct dm_kobject_holder {
 164         struct kobject kobj;
 165         struct completion completion;
 166 };
 167
 168 static inline struct completion *dm_get_completion_from_kobject(struct kobject *kobj)
 169 {
 170         return &container_of(kobj, struct dm_kobject_holder, kobj)->completion;
 171 }
 172
 173 int dm_sysfs_init(struct mapped_device *md);
 174 void dm_sysfs_exit(struct mapped_device *md);
 175 struct kobject *dm_kobject(struct mapped_device *md);
 176 struct mapped_device *dm_get_from_kobject(struct kobject *kobj);
 177
 178 /*
 179  * The kobject helper
 180  */
 181 void dm_kobject_release(struct kobject *kobj);
 182
 183 /*
 184  * Targets for linear and striped mappings
 185  */
 186 int dm_linear_init(void);
 187 void dm_linear_exit(void);
 188
 189 int dm_stripe_init(void);
 190 void dm_stripe_exit(void);
 191
 192 /*
 193  * mapped_device operations
 194  */
 195 void dm_destroy(struct mapped_device *md);
 196 void dm_destroy_immediate(struct mapped_device *md);
 197 int dm_open_count(struct mapped_device *md);
 198 int dm_lock_for_deletion(struct mapped_device *md, bool mark_deferred, bool only_deferred);
 199 int dm_cancel_deferred_remove(struct mapped_device *md);
 200 int dm_request_based(struct mapped_device *md);
 201 sector_t dm_get_size(struct mapped_device *md);
 202 struct request_queue *dm_get_md_queue(struct mapped_device *md);
 203 int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode,
 204                         struct dm_dev **result);
 205 void dm_put_table_device(struct mapped_device *md, struct dm_dev *d);
 206 struct dm_stats *dm_get_stats(struct mapped_device *md);
 207
 208 int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
 209                       unsigned cookie);
 210
 211 void dm_internal_suspend(struct mapped_device *md);
 212 void dm_internal_resume(struct mapped_device *md);
 213
 214 bool dm_use_blk_mq(struct mapped_device *md);
 215
 216 int dm_io_init(void);
 217 void dm_io_exit(void);
 218
 219 int dm_kcopyd_init(void);
 220 void dm_kcopyd_exit(void);
 221
 222 /*
 223  * Mempool operations
 224  */
 225 struct dm_md_mempools *dm_alloc_md_mempools(struct mapped_device *md, unsigned type,
 226                                             unsigned integrity, unsigned per_bio_data_size);
 227 void dm_free_md_mempools(struct dm_md_mempools *pools);
 228
 229 /*
 230  * Helpers that are used by DM core
 231  */
 232 unsigned dm_get_reserved_bio_based_ios(void);
 233 unsigned dm_get_reserved_rq_based_ios(void);
 234
 235 static inline bool dm_message_test_buffer_overflow(char *result, unsigned maxlen)
 236 {
 237         return !maxlen || strlen(result) + 1 >= maxlen;
 238 }
 239
 240 ssize_t dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device *md, char *buf);
 241 ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md,
 242                                                      const char *buf, size_t count);
 243
 244 #endif