linux-imx

/*

 * Copyright (C) 2003 Sistina Software.

 * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.

 *

 * Module Author: Heinz Mauelshagen

 *

 * This file is released under the GPL.

 *

 * Round-robin path selector.

 */

​

#include <linux/device-mapper.h>

​

#include "dm-path-selector.h"

​

#include <linux/slab.h>

#include <linux/module.h>

​

#define DM_MSG_PREFIX "multipath round-robin"

#define RR_MIN_IO     1

#define RR_VERSION    "1.2.0"

​

/*-----------------------------------------------------------------

 * Path-handling code, paths are held in lists

 *---------------------------------------------------------------*/

struct path_info {

    struct list_head list;

    struct dm_path *path;

    unsigned repeat_count;

};

​

static void free_paths(struct list_head *paths)

{

    struct path_info *pi, *next;

​

    list_for_each_entry_safe(pi, next, paths, list) {

        list_del(&pi->list);

        kfree(pi);

    }

}

​

/*-----------------------------------------------------------------

 * Round-robin selector

 *---------------------------------------------------------------*/

​

struct selector {

    struct list_head valid_paths;

    struct list_head invalid_paths;

    spinlock_t lock;

};

​

static struct selector *alloc_selector(void)

{

    struct selector *s = kmalloc(sizeof(*s), GFP_KERNEL);

​

    if (s) {

        INIT_LIST_HEAD(&s->valid_paths);

        INIT_LIST_HEAD(&s->invalid_paths);

        spin_lock_init(&s->lock);

    }

​

    return s;

}