/*
* Copyright (C) 2003 Sistina Software.
* Copyright (C) 2004 Red Hat, Inc. All rights reserved.
*
* Module Author: Heinz Mauelshagen
* This file is released under the GPL.
* Path selector registration.
*/
#include <linux/device-mapper.h>
#include "dm-path-selector.h"
#include <linux/slab.h>
struct ps_internal {
struct path_selector_type pst;
struct list_head list;
};
#define pst_to_psi(__pst) container_of((__pst), struct ps_internal, pst)
static LIST_HEAD(_path_selectors);
static DECLARE_RWSEM(_ps_lock);
static struct ps_internal *__find_path_selector_type(const char *name)
{
struct ps_internal *psi;
list_for_each_entry(psi, &_path_selectors, list) {
if (!strcmp(name, psi->pst.name))
return psi;
}
return NULL;
static struct ps_internal *get_path_selector(const char *name)
down_read(&_ps_lock);
psi = __find_path_selector_type(name);
if (psi && !try_module_get(psi->pst.module))
psi = NULL;
up_read(&_ps_lock);
struct path_selector_type *dm_get_path_selector(const char *name)
if (!name)
psi = get_path_selector(name);
if (!psi) {
request_module("dm-%s", name);
return psi ? &psi->pst : NULL;
void dm_put_path_selector(struct path_selector_type *pst)
if (!pst)
return;
psi = __find_path_selector_type(pst->name);
if (!psi)
goto out;
module_put(psi->pst.module);
out:
static struct ps_internal *_alloc_path_selector(struct path_selector_type *pst)
struct ps_internal *psi = kzalloc(sizeof(*psi), GFP_KERNEL);
if (psi)
psi->pst = *pst;
int dm_register_path_selector(struct path_selector_type *pst)
int r = 0;
struct ps_internal *psi = _alloc_path_selector(pst);
return -ENOMEM;
down_write(&_ps_lock);
if (__find_path_selector_type(pst->name)) {
kfree(psi);
r = -EEXIST;
} else
list_add(&psi->list, &_path_selectors);
up_write(&_ps_lock);
return r;
int dm_unregister_path_selector(struct path_selector_type *pst)
return -EINVAL;
list_del(&psi->list);
return 0;
EXPORT_SYMBOL_GPL(dm_register_path_selector);
EXPORT_SYMBOL_GPL(dm_unregister_path_selector);