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 struct dm_target *dm_table_get_immutable_target(struct dm_table *t);
  77 struct dm_target *dm_table_get_wildcard_target(struct dm_table *t);
  78 bool dm_table_request_based(struct dm_table *t);
  79 bool dm_table_mq_request_based(struct dm_table *t);
  80 void dm_table_free_md_mempools(struct dm_table *t);
  81 struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t);
  82
  83 void dm_lock_md_type(struct mapped_device *md);
  84 void dm_unlock_md_type(struct mapped_device *md);
  85 void dm_set_md_type(struct mapped_device *md, unsigned type);
  86 unsigned dm_get_md_type(struct mapped_device *md);
  87 struct target_type *dm_get_immutable_target_type(struct mapped_device *md);
  88
  89 int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t);
  90
  91 /*
  92  * To check the return value from dm_table_find_target().
  93  */
  94 #define dm_target_is_valid(t) ((t)->table)
  95
  96 /*
  97  * To check whether the target type is bio-based or not (request-based).
  98  */
  99 #define dm_target_bio_based(t) ((t)->type->map != NULL)
 100
 101 /*
 102  * To check whether the target type is request-based or not (bio-based).
 103  */
 104 #define dm_target_request_based(t) (((t)->type->map_rq != NULL) || \
 105                                     ((t)->type->clone_and_map_rq != NULL))
 106
 107 /*
 108  * To check whether the target type is a hybrid (capable of being
 109  * either request-based or bio-based).
 110  */
 111 #define dm_target_hybrid(t) (dm_target_bio_based(t) && dm_target_request_based(t))
 112
 113 /*-----------------------------------------------------------------
 114  * A registry of target types.
 115  *---------------------------------------------------------------*/
 116 int dm_target_init(void);
 117 void dm_target_exit(void);
 118 struct target_type *dm_get_target_type(const char *name);
 119 void dm_put_target_type(struct target_type *tt);
 120 int dm_target_iterate(void (*iter_func)(struct target_type *tt,
 121                                         void *param), void *param);
 122
 123 int dm_split_args(int *argc, char ***argvp, char *input);
 124
 125 /*
 126  * Is this mapped_device being deleted?
 127  */
 128 int dm_deleting_md(struct mapped_device *md);
 129
 130 /*
 131  * Is this mapped_device suspended?
 132  */
 133 int dm_suspended_md(struct mapped_device *md);
 134
 135 /*
 136  * Internal suspend and resume methods.
 137  */
 138 int dm_suspended_internally_md(struct mapped_device *md);
 139 void dm_internal_suspend_fast(struct mapped_device *md);
 140 void dm_internal_resume_fast(struct mapped_device *md);
 141 void dm_internal_suspend_noflush(struct mapped_device *md);
 142 void dm_internal_resume(struct mapped_device *md);
 143
 144 /*
 145  * Test if the device is scheduled for deferred remove.
 146  */
 147 int dm_test_deferred_remove_flag(struct mapped_device *md);
 148
 149 /*
 150  * Try to remove devices marked for deferred removal.
 151  */
 152 void dm_deferred_remove(void);
 153
 154 /*
 155  * The device-mapper can be driven through one of two interfaces;
 156  * ioctl or filesystem, depending which patch you have applied.
 157  */
 158 int dm_interface_init(void);
 159 void dm_interface_exit(void);
 160
 161 /*
 162  * sysfs interface
 163  */
 164 struct dm_kobject_holder {
 165         struct kobject kobj;
 166         struct completion completion;
 167 };
 168
 169 static inline struct completion *dm_get_completion_from_kobject(struct kobject *kobj)
 170 {
 171         return &container_of(kobj, struct dm_kobject_holder, kobj)->completion;
 172 }
 173
 174 int dm_sysfs_init(struct mapped_device *md);
 175 void dm_sysfs_exit(struct mapped_device *md);
 176 struct kobject *dm_kobject(struct mapped_device *md);
 177 struct mapped_device *dm_get_from_kobject(struct kobject *kobj);
 178
 179 /*
 180  * The kobject helper
 181  */
 182 void dm_kobject_release(struct kobject *kobj);
 183
 184 /*
 185  * Targets for linear and striped mappings
 186  */
 187 int dm_linear_init(void);
 188 void dm_linear_exit(void);
 189
 190 int dm_stripe_init(void);
 191 void dm_stripe_exit(void);
 192
 193 /*
 194  * mapped_device operations
 195  */
 196 void dm_destroy(struct mapped_device *md);
 197 void dm_destroy_immediate(struct mapped_device *md);
 198 int dm_open_count(struct mapped_device *md);
 199 int dm_lock_for_deletion(struct mapped_device *md, bool mark_deferred, bool only_deferred);
 200 int dm_cancel_deferred_remove(struct mapped_device *md);
 201 int dm_request_based(struct mapped_device *md);
 202 sector_t dm_get_size(struct mapped_device *md);
 203 struct request_queue *dm_get_md_queue(struct mapped_device *md);
 204 int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode,
 205                         struct dm_dev **result);
 206 void dm_put_table_device(struct mapped_device *md, struct dm_dev *d);
 207 struct dm_stats *dm_get_stats(struct mapped_device *md);
 208
 209 int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
 210                       unsigned cookie);
 211
 212 void dm_internal_suspend(struct mapped_device *md);
 213 void dm_internal_resume(struct mapped_device *md);
 214
 215 bool dm_use_blk_mq(struct mapped_device *md);
 216
 217 int dm_io_init(void);
 218 void dm_io_exit(void);
 219
 220 int dm_kcopyd_init(void);
 221 void dm_kcopyd_exit(void);
 222
 223 /*
 224  * Mempool operations
 225  */
 226 struct dm_md_mempools *dm_alloc_md_mempools(struct mapped_device *md, unsigned type,
 227                                             unsigned integrity, unsigned per_bio_data_size);
 228 void dm_free_md_mempools(struct dm_md_mempools *pools);
 229
 230 /*
 231  * Helpers that are used by DM core
 232  */
 233 unsigned dm_get_reserved_bio_based_ios(void);
 234 unsigned dm_get_reserved_rq_based_ios(void);
 235
 236 static inline bool dm_message_test_buffer_overflow(char *result, unsigned maxlen)
 237 {
 238         return !maxlen || strlen(result) + 1 >= maxlen;
 239 }
 240
 241 ssize_t dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device *md, char *buf);
 242 ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md,
 243                                                      const char *buf, size_t count);
 244
 245 #endif