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/backing-dev.h>
  18 #include <linux/hdreg.h>
  19 #include <linux/completion.h>
  20 #include <linux/kobject.h>
  21
  22 #include "dm-stats.h"
  23
  24 /*
  25  * Suspend feature flags
  26  */
  27 #define DM_SUSPEND_LOCKFS_FLAG          (1 << 0)
  28 #define DM_SUSPEND_NOFLUSH_FLAG         (1 << 1)
  29
  30 /*
  31  * Status feature flags
  32  */
  33 #define DM_STATUS_NOFLUSH_FLAG          (1 << 0)
  34
  35 /*
  36  * Type of table and mapped_device's mempool
  37  */
  38 #define DM_TYPE_NONE                    0
  39 #define DM_TYPE_BIO_BASED               1
  40 #define DM_TYPE_REQUEST_BASED           2
  41 #define DM_TYPE_MQ_REQUEST_BASED        3
  42
  43 /*
  44  * List of devices that a metadevice uses and should open/close.
  45  */
  46 struct dm_dev_internal {
  47         struct list_head list;
  48         atomic_t count;
  49         struct dm_dev *dm_dev;
  50 };
  51
  52 struct dm_table;
  53 struct dm_md_mempools;
  54
  55 /*-----------------------------------------------------------------
  56  * Internal table functions.
  57  *---------------------------------------------------------------*/
  58 void dm_table_destroy(struct dm_table *t);
  59 void dm_table_event_callback(struct dm_table *t,
  60                              void (*fn)(void *), void *context);
  61 struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index);
  62 struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector);
  63 bool dm_table_has_no_data_devices(struct dm_table *table);
  64 int dm_calculate_queue_limits(struct dm_table *table,
  65                               struct queue_limits *limits);
  66 void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
  67                                struct queue_limits *limits);
  68 struct list_head *dm_table_get_devices(struct dm_table *t);
  69 void dm_table_presuspend_targets(struct dm_table *t);
  70 void dm_table_presuspend_undo_targets(struct dm_table *t);
  71 void dm_table_postsuspend_targets(struct dm_table *t);
  72 int dm_table_resume_targets(struct dm_table *t);
  73 int dm_table_any_congested(struct dm_table *t, int bdi_bits);
  74 unsigned dm_table_get_type(struct dm_table *t);
  75 struct target_type *dm_table_get_immutable_target_type(struct dm_table *t);
  76 bool dm_table_request_based(struct dm_table *t);
  77 bool dm_table_mq_request_based(struct dm_table *t);
  78 void dm_table_free_md_mempools(struct dm_table *t);
  79 struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t);
  80
  81 void dm_lock_md_type(struct mapped_device *md);
  82 void dm_unlock_md_type(struct mapped_device *md);
  83 void dm_set_md_type(struct mapped_device *md, unsigned type);
  84 unsigned dm_get_md_type(struct mapped_device *md);
  85 struct target_type *dm_get_immutable_target_type(struct mapped_device *md);
  86
  87 int dm_setup_md_queue(struct mapped_device *md);
  88
  89 /*
  90  * To check the return value from dm_table_find_target().
  91  */
  92 #define dm_target_is_valid(t) ((t)->table)
  93
  94 /*
  95  * To check whether the target type is bio-based or not (request-based).
  96  */
  97 #define dm_target_bio_based(t) ((t)->type->map != NULL)
  98
  99 /*
 100  * To check whether the target type is request-based or not (bio-based).
 101  */
 102 #define dm_target_request_based(t) (((t)->type->map_rq != NULL) || \
 103                                     ((t)->type->clone_and_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  * Internal suspend and resume methods.
 135  */
 136 int dm_suspended_internally_md(struct mapped_device *md);
 137 void dm_internal_suspend_fast(struct mapped_device *md);
 138 void dm_internal_resume_fast(struct mapped_device *md);
 139 void dm_internal_suspend_noflush(struct mapped_device *md);
 140 void dm_internal_resume(struct mapped_device *md);
 141
 142 /*
 143  * Test if the device is scheduled for deferred remove.
 144  */
 145 int dm_test_deferred_remove_flag(struct mapped_device *md);
 146
 147 /*
 148  * Try to remove devices marked for deferred removal.
 149  */
 150 void dm_deferred_remove(void);
 151
 152 /*
 153  * The device-mapper can be driven through one of two interfaces;
 154  * ioctl or filesystem, depending which patch you have applied.
 155  */
 156 int dm_interface_init(void);
 157 void dm_interface_exit(void);
 158
 159 /*
 160  * sysfs interface
 161  */
 162 struct dm_kobject_holder {
 163         struct kobject kobj;
 164         struct completion completion;
 165 };
 166
 167 static inline struct completion *dm_get_completion_from_kobject(struct kobject *kobj)
 168 {
 169         return &container_of(kobj, struct dm_kobject_holder, kobj)->completion;
 170 }
 171
 172 int dm_sysfs_init(struct mapped_device *md);
 173 void dm_sysfs_exit(struct mapped_device *md);
 174 struct kobject *dm_kobject(struct mapped_device *md);
 175 struct mapped_device *dm_get_from_kobject(struct kobject *kobj);
 176
 177 /*
 178  * The kobject helper
 179  */
 180 void dm_kobject_release(struct kobject *kobj);
 181
 182 /*
 183  * Targets for linear and striped mappings
 184  */
 185 int dm_linear_init(void);
 186 void dm_linear_exit(void);
 187
 188 int dm_stripe_init(void);
 189 void dm_stripe_exit(void);
 190
 191 /*
 192  * mapped_device operations
 193  */
 194 void dm_destroy(struct mapped_device *md);
 195 void dm_destroy_immediate(struct mapped_device *md);
 196 int dm_open_count(struct mapped_device *md);
 197 int dm_lock_for_deletion(struct mapped_device *md, bool mark_deferred, bool only_deferred);
 198 int dm_cancel_deferred_remove(struct mapped_device *md);
 199 int dm_request_based(struct mapped_device *md);
 200 sector_t dm_get_size(struct mapped_device *md);
 201 struct request_queue *dm_get_md_queue(struct mapped_device *md);
 202 int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode,
 203                         struct dm_dev **result);
 204 void dm_put_table_device(struct mapped_device *md, struct dm_dev *d);
 205 struct dm_stats *dm_get_stats(struct mapped_device *md);
 206
 207 int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
 208                       unsigned cookie);
 209
 210 void dm_internal_suspend(struct mapped_device *md);
 211 void dm_internal_resume(struct mapped_device *md);
 212
 213 bool dm_use_blk_mq(struct mapped_device *md);
 214
 215 int dm_io_init(void);
 216 void dm_io_exit(void);
 217
 218 int dm_kcopyd_init(void);
 219 void dm_kcopyd_exit(void);
 220
 221 /*
 222  * Mempool operations
 223  */
 224 struct dm_md_mempools *dm_alloc_md_mempools(struct mapped_device *md, unsigned type,
 225                                             unsigned integrity, unsigned per_bio_data_size);
 226 void dm_free_md_mempools(struct dm_md_mempools *pools);
 227
 228 /*
 229  * Helpers that are used by DM core
 230  */
 231 unsigned dm_get_reserved_bio_based_ios(void);
 232 unsigned dm_get_reserved_rq_based_ios(void);
 233
 234 static inline bool dm_message_test_buffer_overflow(char *result, unsigned maxlen)
 235 {
 236         return !maxlen || strlen(result) + 1 >= maxlen;
 237 }
 238
 239 ssize_t dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device *md, char *buf);
 240 ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md,
 241                                                      const char *buf, size_t count);
 242
 243 #endif