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
45 extern "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
58 struct mlist_head {
59 struct mlist_head *next, *prev;
60 };
61
62 typedef 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 */
__list_add(struct mlist_head * new,struct mlist_head * prev,struct mlist_head * next)80 static 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 */
mlist_add(struct mlist_head * new,struct mlist_head * head)99 static 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 */
mlist_add_tail(struct mlist_head * new,struct mlist_head * head)113 static 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 */
__list_del(struct mlist_head * prev,struct mlist_head * next)127 static 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
143 static 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 */
mlist_del_init(struct mlist_head * entry)154 static 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 */
mlist_empty(struct mlist_head * head)165 static 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 */
mlist_splice(struct mlist_head * list,struct mlist_head * head)176 static 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