linux/drivers/md/dm.h
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   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#include "dm-stats.h"
  20
  21/*
  22 * Suspend feature flags
  23 */
  24#define DM_SUSPEND_LOCKFS_FLAG          (1 << 0)
  25#define DM_SUSPEND_NOFLUSH_FLAG         (1 << 1)
  26
  27/*
  28 * Status feature flags
  29 */
  30#define DM_STATUS_NOFLUSH_FLAG          (1 << 0)
  31
  32/*
  33 * Type of table and mapped_device's mempool
  34 */
  35#define DM_TYPE_NONE            0
  36#define DM_TYPE_BIO_BASED       1
  37#define DM_TYPE_REQUEST_BASED   2
  38
  39/*
  40 * List of devices that a metadevice uses and should open/close.
  41 */
  42struct dm_dev_internal {
  43        struct list_head list;
  44        atomic_t count;
  45        struct dm_dev dm_dev;
  46};
  47
  48struct dm_table;
  49struct dm_md_mempools;
  50
  51/*-----------------------------------------------------------------
  52 * Internal table functions.
  53 *---------------------------------------------------------------*/
  54void dm_table_destroy(struct dm_table *t);
  55void dm_table_event_callback(struct dm_table *t,
  56                             void (*fn)(void *), void *context);
  57struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index);
  58struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector);
  59bool dm_table_has_no_data_devices(struct dm_table *table);
  60int dm_calculate_queue_limits(struct dm_table *table,
  61                              struct queue_limits *limits);
  62void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
  63                               struct queue_limits *limits);
  64struct list_head *dm_table_get_devices(struct dm_table *t);
  65void dm_table_presuspend_targets(struct dm_table *t);
  66void dm_table_postsuspend_targets(struct dm_table *t);
  67int dm_table_resume_targets(struct dm_table *t);
  68int dm_table_any_congested(struct dm_table *t, int bdi_bits);
  69int dm_table_any_busy_target(struct dm_table *t);
  70unsigned dm_table_get_type(struct dm_table *t);
  71struct target_type *dm_table_get_immutable_target_type(struct dm_table *t);
  72bool dm_table_request_based(struct dm_table *t);
  73bool dm_table_supports_discards(struct dm_table *t);
  74int dm_table_alloc_md_mempools(struct dm_table *t);
  75void dm_table_free_md_mempools(struct dm_table *t);
  76struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t);
  77
  78int dm_queue_merge_is_compulsory(struct request_queue *q);
  79
  80void dm_lock_md_type(struct mapped_device *md);
  81void dm_unlock_md_type(struct mapped_device *md);
  82void dm_set_md_type(struct mapped_device *md, unsigned type);
  83unsigned dm_get_md_type(struct mapped_device *md);
  84struct target_type *dm_get_immutable_target_type(struct mapped_device *md);
  85
  86int dm_setup_md_queue(struct mapped_device *md);
  87
  88/*
  89 * To check the return value from dm_table_find_target().
  90 */
  91#define dm_target_is_valid(t) ((t)->table)
  92
  93/*
  94 * To check whether the target type is bio-based or not (request-based).
  95 */
  96#define dm_target_bio_based(t) ((t)->type->map != NULL)
  97
  98/*
  99 * To check whether the target type is request-based or not (bio-based).
 100 */
 101#define dm_target_request_based(t) ((t)->type->map_rq != NULL)
 102
 103/*
 104 * To check whether the target type is a hybrid (capable of being
 105 * either request-based or bio-based).
 106 */
 107#define dm_target_hybrid(t) (dm_target_bio_based(t) && dm_target_request_based(t))
 108
 109/*-----------------------------------------------------------------
 110 * A registry of target types.
 111 *---------------------------------------------------------------*/
 112int dm_target_init(void);
 113void dm_target_exit(void);
 114struct target_type *dm_get_target_type(const char *name);
 115void dm_put_target_type(struct target_type *tt);
 116int dm_target_iterate(void (*iter_func)(struct target_type *tt,
 117                                        void *param), void *param);
 118
 119int dm_split_args(int *argc, char ***argvp, char *input);
 120
 121/*
 122 * Is this mapped_device being deleted?
 123 */
 124int dm_deleting_md(struct mapped_device *md);
 125
 126/*
 127 * Is this mapped_device suspended?
 128 */
 129int dm_suspended_md(struct mapped_device *md);
 130
 131/*
 132 * The device-mapper can be driven through one of two interfaces;
 133 * ioctl or filesystem, depending which patch you have applied.
 134 */
 135int dm_interface_init(void);
 136void dm_interface_exit(void);
 137
 138/*
 139 * sysfs interface
 140 */
 141int dm_sysfs_init(struct mapped_device *md);
 142void dm_sysfs_exit(struct mapped_device *md);
 143struct kobject *dm_kobject(struct mapped_device *md);
 144struct mapped_device *dm_get_from_kobject(struct kobject *kobj);
 145
 146/*
 147 * Targets for linear and striped mappings
 148 */
 149int dm_linear_init(void);
 150void dm_linear_exit(void);
 151
 152int dm_stripe_init(void);
 153void dm_stripe_exit(void);
 154
 155/*
 156 * mapped_device operations
 157 */
 158void dm_destroy(struct mapped_device *md);
 159void dm_destroy_immediate(struct mapped_device *md);
 160int dm_open_count(struct mapped_device *md);
 161int dm_lock_for_deletion(struct mapped_device *md);
 162int dm_request_based(struct mapped_device *md);
 163sector_t dm_get_size(struct mapped_device *md);
 164struct dm_stats *dm_get_stats(struct mapped_device *md);
 165
 166int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
 167                      unsigned cookie);
 168
 169void dm_internal_suspend(struct mapped_device *md);
 170void dm_internal_resume(struct mapped_device *md);
 171
 172int dm_io_init(void);
 173void dm_io_exit(void);
 174
 175int dm_kcopyd_init(void);
 176void dm_kcopyd_exit(void);
 177
 178/*
 179 * Mempool operations
 180 */
 181struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity, unsigned per_bio_data_size);
 182void dm_free_md_mempools(struct dm_md_mempools *pools);
 183
 184/*
 185 * Helpers that are used by DM core
 186 */
 187unsigned dm_get_reserved_bio_based_ios(void);
 188unsigned dm_get_reserved_rq_based_ios(void);
 189
 190static inline bool dm_message_test_buffer_overflow(char *result, unsigned maxlen)
 191{
 192        return !maxlen || strlen(result) + 1 >= maxlen;
 193}
 194
 195#endif
 196
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