1/*
2 * list.h: header for mega_sas
3 *
4 * Solaris MegaRAID driver for SAS controllers
5 * Copyright (c) 2004-2008, LSI Logic Corporation.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright notice,
12 *    this list of conditions and the following disclaimer.
13 *
14 * 2. Redistributions in binary form must reproduce the above copyright notice,
15 *    this list of conditions and the following disclaimer in the documentation
16 *    and/or other materials provided with the distribution.
17 *
18 * 3. Neither the name of the author nor the names of its contributors may be
19 *    used to endorse or promote products derived from this software without
20 *    specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
25 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
26 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
28 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
29 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
30 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
31 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
32 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
33 * DAMAGE.
34 */
35
36/*
37 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
38 * Use is subject to license terms.
39 */
40
41#ifndef	_LIST_H_
42#define	_LIST_H_
43
44#ifdef __cplusplus
45extern "C" {
46#endif
47
48/*
49 * Simple doubly linked list implementation.
50 *
51 * Some of the internal functions ("__xxx") are useful when
52 * manipulating whole lists rather than single entries, as
53 * sometimes we already know the next/prev entries and we can
54 * generate better code by using them directly rather than
55 * using the generic single-entry routines.
56 */
57
58struct mlist_head {
59	struct mlist_head *next, *prev;
60};
61
62typedef struct mlist_head mlist_t;
63
64#define	LIST_HEAD_INIT(name) { &(name), &(name) }
65
66#define	LIST_HEAD(name) \
67	struct mlist_head name = LIST_HEAD_INIT(name)
68
69#define	INIT_LIST_HEAD(ptr) { \
70	(ptr)->next = (ptr); (ptr)->prev = (ptr); \
71}
72
73
74/*
75 * Insert a new entry between two known consecutive entries.
76 *
77 * This is only for internal list manipulation where we know
78 * the prev/next entries already!
79 */
80static void __list_add(struct mlist_head *new,
81	struct mlist_head *prev,
82	struct mlist_head *next)
83{
84	next->prev = new;
85	new->next = next;
86	new->prev = prev;
87	prev->next = new;
88}
89
90
91/*
92 * mlist_add - add a new entry
93 * @new: new entry to be added
94 * @head: list head to add it after
95 *
96 * Insert a new entry after the specified head.
97 * This is good for implementing stacks.
98 */
99static void mlist_add(struct mlist_head *new, struct mlist_head *head)
100{
101	__list_add(new, head, head->next);
102}
103
104
105/*
106 * mlist_add_tail - add a new entry
107 * @new: new entry to be added
108 * @head: list head to add it before
109 *
110 * Insert a new entry before the specified head.
111 * This is useful for implementing queues.
112 */
113static void mlist_add_tail(struct mlist_head *new, struct mlist_head *head)
114{
115	__list_add(new, head->prev, head);
116}
117
118
119
120/*
121 * Delete a list entry by making the prev/next entries
122 * point to each other.
123 *
124 * This is only for internal list manipulation where we know
125 * the prev/next entries already!
126 */
127static void __list_del(struct mlist_head *prev,
128			struct mlist_head *next)
129{
130	next->prev = prev;
131	prev->next = next;
132}
133
134
135#if 0
136/*
137 * mlist_del - deletes entry from list.
138 * @entry:	the element to delete from the list.
139 * Note:	list_empty on entry does not return true after this, the entry
140 * is in an undefined state.
141 */
142
143static void mlist_del(struct mlist_head *entry)
144{
145	__list_del(entry->prev, entry->next);
146	entry->next = entry->prev = 0;
147}
148#endif
149
150/*
151 * mlist_del_init - deletes entry from list and reinitialize it.
152 * @entry: the element to delete from the list.
153 */
154static void mlist_del_init(struct mlist_head *entry)
155{
156	__list_del(entry->prev, entry->next);
157	INIT_LIST_HEAD(entry);
158}
159
160
161/*
162 * mlist_empty - tests whether a list is empty
163 * @head: the list to test.
164 */
165static int mlist_empty(struct mlist_head *head)
166{
167	return (head->next == head);
168}
169
170
171/*
172 * mlist_splice - join two lists
173 * @list: the new list to add.
174 * @head: the place to add it in the first list.
175 */
176static void mlist_splice(struct mlist_head *list, struct mlist_head *head)
177{
178	struct mlist_head *first = list->next;
179
180	if (first != list) {
181		struct mlist_head *last = list->prev;
182		struct mlist_head *at = head->next;
183
184		first->prev = head;
185		head->next = first;
186
187		last->next = at;
188		at->prev = last;
189	}
190}
191
192
193
194/* TODO: set this */
195#if 0
196#pragma	inline(list_add, list_add_tail, __list_del, list_del,
197		list_del_init, list_empty, list_splice)
198#endif
199
200
201/*
202 * mlist_entry - get the struct for this entry
203 * @ptr:	the &struct mlist_head pointer.
204 * @type:	the type of the struct this is embedded in.
205 * @member:	the name of the list_struct within the struct.
206 */
207#define	mlist_entry(ptr, type, member) \
208	((type *)((size_t)(ptr) - offsetof(type, member)))
209
210
211/*
212 * mlist_for_each	-	iterate over a list
213 * @pos:	the &struct mlist_head to use as a loop counter.
214 * @head:	the head for your list.
215 */
216#define	mlist_for_each(pos, head) \
217	for (pos = (head)->next, prefetch(pos->next); pos != (head); \
218		pos = pos->next, prefetch(pos->next))
219
220
221/*
222 * mlist_for_each_safe - iterate over a list safe against removal of list entry
223 * @pos:	the &struct mlist_head to use as a loop counter.
224 * @n:		another &struct mlist_head to use as temporary storage
225 * @head:	the head for your list.
226 */
227#define	mlist_for_each_safe(pos, n, head) \
228	for (pos = (head)->next, n = pos->next; pos != (head); \
229		pos = n, n = pos->next)
230
231#ifdef __cplusplus
232}
233#endif
234
235#endif /* _LIST_H_ */
236