linux/drivers/md/dm-exception-store.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2001-2002 Sistina Software (UK) Limited.
 * Copyright (C) 2006-2008 Red Hat GmbH
 *
 * This file is released under the GPL.
 */

#include "dm-exception-store.h"

#include <linux/ctype.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/vmalloc.h>
#include <linux/module.h>
#include <linux/slab.h>

#define DM_MSG_PREFIX …

static LIST_HEAD(_exception_store_types);
static DEFINE_SPINLOCK(_lock);

static struct dm_exception_store_type *__find_exception_store_type(const char *name)
{ … }

static struct dm_exception_store_type *_get_exception_store_type(const char *name)
{ … }

/*
 * get_type
 * @type_name
 *
 * Attempt to retrieve the dm_exception_store_type by name.  If not already
 * available, attempt to load the appropriate module.
 *
 * Exstore modules are named "dm-exstore-" followed by the 'type_name'.
 * Modules may contain multiple types.
 * This function will first try the module "dm-exstore-<type_name>",
 * then truncate 'type_name' on the last '-' and try again.
 *
 * For example, if type_name was "clustered-shared", it would search
 * 'dm-exstore-clustered-shared' then 'dm-exstore-clustered'.
 *
 * 'dm-exception-store-<type_name>' is too long of a name in my
 * opinion, which is why I've chosen to have the files
 * containing exception store implementations be 'dm-exstore-<type_name>'.
 * If you want your module to be autoloaded, you will follow this
 * naming convention.
 *
 * Returns: dm_exception_store_type* on success, NULL on failure
 */
static struct dm_exception_store_type *get_type(const char *type_name)
{ … }

static void put_type(struct dm_exception_store_type *type)
{ … }

int dm_exception_store_type_register(struct dm_exception_store_type *type)
{ … }
EXPORT_SYMBOL(…);

int dm_exception_store_type_unregister(struct dm_exception_store_type *type)
{ … }
EXPORT_SYMBOL(…);

static int set_chunk_size(struct dm_exception_store *store,
			  const char *chunk_size_arg, char **error)
{ … }

int dm_exception_store_set_chunk_size(struct dm_exception_store *store,
				      unsigned int chunk_size,
				      char **error)
{ … }

int dm_exception_store_create(struct dm_target *ti, int argc, char **argv,
			      struct dm_snapshot *snap,
			      unsigned int *args_used,
			      struct dm_exception_store **store)
{ … }
EXPORT_SYMBOL(…);

void dm_exception_store_destroy(struct dm_exception_store *store)
{ … }
EXPORT_SYMBOL(…);

int dm_exception_store_init(void)
{ … }

void dm_exception_store_exit(void)
{ … }