/*
 * list.h: header for mega_sas
 *
 * Solaris MegaRAID driver for SAS controllers
 * Copyright (c) 2004-2008, LSI Logic Corporation.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the author nor the names of its contributors may be
 *    used to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#ifndef _LIST_H_
#define _LIST_H_

#ifdef __cplusplus
extern "C" {
#endif

/*
 * Simple doubly linked list implementation.
 *
 * Some of the internal functions ("__xxx") are useful when
 * manipulating whole lists rather than single entries, as
 * sometimes we already know the next/prev entries and we can
 * generate better code by using them directly rather than
 * using the generic single-entry routines.
 */

struct mlist_head {
        struct mlist_head *next, *prev;
};

typedef struct mlist_head mlist_t;

#define LIST_HEAD_INIT(name) { &(name), &(name) }

#define LIST_HEAD(name) \
        struct mlist_head name = LIST_HEAD_INIT(name)

#define INIT_LIST_HEAD(ptr) { \
        (ptr)->next = (ptr); (ptr)->prev = (ptr); \
}


/*
 * Insert a new entry between two known consecutive entries.
 *
 * This is only for internal list manipulation where we know
 * the prev/next entries already!
 */
static void __list_add(struct mlist_head *new,
        struct mlist_head *prev,
        struct mlist_head *next)
{
        next->prev = new;
        new->next = next;
        new->prev = prev;
        prev->next = new;
}


/*
 * mlist_add - add a new entry
 * @new: new entry to be added
 * @head: list head to add it after
 *
 * Insert a new entry after the specified head.
 * This is good for implementing stacks.
 */
static void mlist_add(struct mlist_head *new, struct mlist_head *head)
{
        __list_add(new, head, head->next);
}


/*
 * mlist_add_tail - add a new entry
 * @new: new entry to be added
 * @head: list head to add it before
 *
 * Insert a new entry before the specified head.
 * This is useful for implementing queues.
 */
static void mlist_add_tail(struct mlist_head *new, struct mlist_head *head)
{
        __list_add(new, head->prev, head);
}



/*
 * Delete a list entry by making the prev/next entries
 * point to each other.
 *
 * This is only for internal list manipulation where we know
 * the prev/next entries already!
 */
static void __list_del(struct mlist_head *prev,
                        struct mlist_head *next)
{
        next->prev = prev;
        prev->next = next;
}


#if 0
/*
 * mlist_del - deletes entry from list.
 * @entry:      the element to delete from the list.
 * Note:        list_empty on entry does not return true after this, the entry
 * is in an undefined state.
 */

static void mlist_del(struct mlist_head *entry)
{
        __list_del(entry->prev, entry->next);
        entry->next = entry->prev = 0;
}
#endif

/*
 * mlist_del_init - deletes entry from list and reinitialize it.
 * @entry: the element to delete from the list.
 */
static void mlist_del_init(struct mlist_head *entry)
{
        __list_del(entry->prev, entry->next);
        INIT_LIST_HEAD(entry);
}


/*
 * mlist_empty - tests whether a list is empty
 * @head: the list to test.
 */
static int mlist_empty(struct mlist_head *head)
{
        return (head->next == head);
}


/*
 * mlist_splice - join two lists
 * @list: the new list to add.
 * @head: the place to add it in the first list.
 */
static void mlist_splice(struct mlist_head *list, struct mlist_head *head)
{
        struct mlist_head *first = list->next;

        if (first != list) {
                struct mlist_head *last = list->prev;
                struct mlist_head *at = head->next;

                first->prev = head;
                head->next = first;

                last->next = at;
                at->prev = last;
        }
}


/*
 * mlist_entry - get the struct for this entry
 * @ptr:        the &struct mlist_head pointer.
 * @type:       the type of the struct this is embedded in.
 * @member:     the name of the list_struct within the struct.
 */
#define mlist_entry(ptr, type, member) \
        ((type *)((size_t)(ptr) - offsetof(type, member)))


/*
 * mlist_for_each       -       iterate over a list
 * @pos:        the &struct mlist_head to use as a loop counter.
 * @head:       the head for your list.
 */
#define mlist_for_each(pos, head) \
        for (pos = (head)->next, prefetch(pos->next); pos != (head); \
                pos = pos->next, prefetch(pos->next))


/*
 * mlist_for_each_safe - iterate over a list safe against removal of list entry
 * @pos:        the &struct mlist_head to use as a loop counter.
 * @n:          another &struct mlist_head to use as temporary storage
 * @head:       the head for your list.
 */
#define mlist_for_each_safe(pos, n, head) \
        for (pos = (head)->next, n = pos->next; pos != (head); \
                pos = n, n = pos->next)

#ifdef __cplusplus
}
#endif

#endif /* _LIST_H_ */