]>
Commit | Line | Data |
---|---|---|
77ba89c5 IM |
1 | /* |
2 | * Descending-priority-sorted double-linked list | |
3 | * | |
4 | * (C) 2002-2003 Intel Corp | |
5 | * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>. | |
6 | * | |
7 | * 2001-2005 (c) MontaVista Software, Inc. | |
8 | * Daniel Walker <dwalker@mvista.com> | |
9 | * | |
10 | * (C) 2005 Thomas Gleixner <tglx@linutronix.de> | |
11 | * | |
12 | * Simplifications of the original code by | |
13 | * Oleg Nesterov <oleg@tv-sign.ru> | |
14 | * | |
15 | * Licensed under the FSF's GNU Public License v2 or later. | |
16 | * | |
17 | * Based on simple lists (include/linux/list.h). | |
18 | * | |
19 | * This is a priority-sorted list of nodes; each node has a | |
20 | * priority from INT_MIN (highest) to INT_MAX (lowest). | |
21 | * | |
22 | * Addition is O(K), removal is O(1), change of priority of a node is | |
23 | * O(K) and K is the number of RT priority levels used in the system. | |
24 | * (1 <= K <= 99) | |
25 | * | |
26 | * This list is really a list of lists: | |
27 | * | |
28 | * - The tier 1 list is the prio_list, different priority nodes. | |
29 | * | |
30 | * - The tier 2 list is the node_list, serialized nodes. | |
31 | * | |
32 | * Simple ASCII art explanation: | |
33 | * | |
34 | * |HEAD | | |
35 | * | | | |
36 | * |prio_list.prev|<------------------------------------| | |
37 | * |prio_list.next|<->|pl|<->|pl|<--------------->|pl|<-| | |
38 | * |10 | |10| |21| |21| |21| |40| (prio) | |
39 | * | | | | | | | | | | | | | |
40 | * | | | | | | | | | | | | | |
41 | * |node_list.next|<->|nl|<->|nl|<->|nl|<->|nl|<->|nl|<-| | |
42 | * |node_list.prev|<------------------------------------| | |
43 | * | |
44 | * The nodes on the prio_list list are sorted by priority to simplify | |
45 | * the insertion of new nodes. There are no nodes with duplicate | |
46 | * priorites on the list. | |
47 | * | |
48 | * The nodes on the node_list is ordered by priority and can contain | |
49 | * entries which have the same priority. Those entries are ordered | |
50 | * FIFO | |
51 | * | |
52 | * Addition means: look for the prio_list node in the prio_list | |
53 | * for the priority of the node and insert it before the node_list | |
54 | * entry of the next prio_list node. If it is the first node of | |
55 | * that priority, add it to the prio_list in the right position and | |
56 | * insert it into the serialized node_list list | |
57 | * | |
58 | * Removal means remove it from the node_list and remove it from | |
59 | * the prio_list if the node_list list_head is non empty. In case | |
60 | * of removal from the prio_list it must be checked whether other | |
61 | * entries of the same priority are on the list or not. If there | |
62 | * is another entry of the same priority then this entry has to | |
63 | * replace the removed entry on the prio_list. If the entry which | |
64 | * is removed is the only entry of this priority then a simple | |
65 | * remove from both list is sufficient. | |
66 | * | |
67 | * INT_MIN is the highest priority, 0 is the medium highest, INT_MAX | |
68 | * is lowest priority. | |
69 | * | |
70 | * No locking is done, up to the caller. | |
71 | * | |
72 | */ | |
73 | #ifndef _LINUX_PLIST_H_ | |
74 | #define _LINUX_PLIST_H_ | |
75 | ||
b4459790 | 76 | #include <linux/kernel.h> |
77ba89c5 IM |
77 | #include <linux/list.h> |
78 | #include <linux/spinlock_types.h> | |
79 | ||
80 | struct plist_head { | |
81 | struct list_head prio_list; | |
82 | struct list_head node_list; | |
83 | #ifdef CONFIG_DEBUG_PI_LIST | |
84 | spinlock_t *lock; | |
85 | #endif | |
86 | }; | |
87 | ||
88 | struct plist_node { | |
89 | int prio; | |
90 | struct plist_head plist; | |
91 | }; | |
92 | ||
93 | #ifdef CONFIG_DEBUG_PI_LIST | |
94 | # define PLIST_HEAD_LOCK_INIT(_lock) .lock = _lock | |
95 | #else | |
96 | # define PLIST_HEAD_LOCK_INIT(_lock) | |
97 | #endif | |
98 | ||
99 | /** | |
11265420 | 100 | * PLIST_HEAD_INIT - static struct plist_head initializer |
77ba89c5 | 101 | * @head: struct plist_head variable name |
11265420 | 102 | * @_lock: lock to initialize for this list |
77ba89c5 IM |
103 | */ |
104 | #define PLIST_HEAD_INIT(head, _lock) \ | |
105 | { \ | |
106 | .prio_list = LIST_HEAD_INIT((head).prio_list), \ | |
107 | .node_list = LIST_HEAD_INIT((head).node_list), \ | |
108 | PLIST_HEAD_LOCK_INIT(&(_lock)) \ | |
109 | } | |
110 | ||
111 | /** | |
11265420 | 112 | * PLIST_NODE_INIT - static struct plist_node initializer |
77ba89c5 IM |
113 | * @node: struct plist_node variable name |
114 | * @__prio: initial node priority | |
115 | */ | |
116 | #define PLIST_NODE_INIT(node, __prio) \ | |
117 | { \ | |
118 | .prio = (__prio), \ | |
119 | .plist = PLIST_HEAD_INIT((node).plist, NULL), \ | |
120 | } | |
121 | ||
122 | /** | |
123 | * plist_head_init - dynamic struct plist_head initializer | |
77ba89c5 | 124 | * @head: &struct plist_head pointer |
11265420 | 125 | * @lock: list spinlock, remembered for debugging |
77ba89c5 IM |
126 | */ |
127 | static inline void | |
128 | plist_head_init(struct plist_head *head, spinlock_t *lock) | |
129 | { | |
130 | INIT_LIST_HEAD(&head->prio_list); | |
131 | INIT_LIST_HEAD(&head->node_list); | |
132 | #ifdef CONFIG_DEBUG_PI_LIST | |
133 | head->lock = lock; | |
134 | #endif | |
135 | } | |
136 | ||
137 | /** | |
138 | * plist_node_init - Dynamic struct plist_node initializer | |
77ba89c5 IM |
139 | * @node: &struct plist_node pointer |
140 | * @prio: initial node priority | |
141 | */ | |
142 | static inline void plist_node_init(struct plist_node *node, int prio) | |
143 | { | |
144 | node->prio = prio; | |
145 | plist_head_init(&node->plist, NULL); | |
146 | } | |
147 | ||
148 | extern void plist_add(struct plist_node *node, struct plist_head *head); | |
149 | extern void plist_del(struct plist_node *node, struct plist_head *head); | |
150 | ||
151 | /** | |
152 | * plist_for_each - iterate over the plist | |
11265420 RD |
153 | * @pos: the type * to use as a loop counter |
154 | * @head: the head for your list | |
77ba89c5 IM |
155 | */ |
156 | #define plist_for_each(pos, head) \ | |
157 | list_for_each_entry(pos, &(head)->node_list, plist.node_list) | |
158 | ||
159 | /** | |
11265420 RD |
160 | * plist_for_each_safe - iterate safely over a plist of given type |
161 | * @pos: the type * to use as a loop counter | |
162 | * @n: another type * to use as temporary storage | |
163 | * @head: the head for your list | |
77ba89c5 | 164 | * |
11265420 | 165 | * Iterate over a plist of given type, safe against removal of list entry. |
77ba89c5 IM |
166 | */ |
167 | #define plist_for_each_safe(pos, n, head) \ | |
168 | list_for_each_entry_safe(pos, n, &(head)->node_list, plist.node_list) | |
169 | ||
170 | /** | |
171 | * plist_for_each_entry - iterate over list of given type | |
11265420 RD |
172 | * @pos: the type * to use as a loop counter |
173 | * @head: the head for your list | |
174 | * @mem: the name of the list_struct within the struct | |
77ba89c5 IM |
175 | */ |
176 | #define plist_for_each_entry(pos, head, mem) \ | |
177 | list_for_each_entry(pos, &(head)->node_list, mem.plist.node_list) | |
178 | ||
179 | /** | |
11265420 RD |
180 | * plist_for_each_entry_safe - iterate safely over list of given type |
181 | * @pos: the type * to use as a loop counter | |
77ba89c5 | 182 | * @n: another type * to use as temporary storage |
11265420 RD |
183 | * @head: the head for your list |
184 | * @m: the name of the list_struct within the struct | |
185 | * | |
186 | * Iterate over list of given type, safe against removal of list entry. | |
77ba89c5 IM |
187 | */ |
188 | #define plist_for_each_entry_safe(pos, n, head, m) \ | |
189 | list_for_each_entry_safe(pos, n, &(head)->node_list, m.plist.node_list) | |
190 | ||
191 | /** | |
192 | * plist_head_empty - return !0 if a plist_head is empty | |
77ba89c5 IM |
193 | * @head: &struct plist_head pointer |
194 | */ | |
195 | static inline int plist_head_empty(const struct plist_head *head) | |
196 | { | |
197 | return list_empty(&head->node_list); | |
198 | } | |
199 | ||
200 | /** | |
201 | * plist_node_empty - return !0 if plist_node is not on a list | |
77ba89c5 IM |
202 | * @node: &struct plist_node pointer |
203 | */ | |
204 | static inline int plist_node_empty(const struct plist_node *node) | |
205 | { | |
206 | return plist_head_empty(&node->plist); | |
207 | } | |
208 | ||
209 | /* All functions below assume the plist_head is not empty. */ | |
210 | ||
211 | /** | |
212 | * plist_first_entry - get the struct for the first entry | |
11265420 RD |
213 | * @head: the &struct plist_head pointer |
214 | * @type: the type of the struct this is embedded in | |
215 | * @member: the name of the list_struct within the struct | |
77ba89c5 IM |
216 | */ |
217 | #ifdef CONFIG_DEBUG_PI_LIST | |
218 | # define plist_first_entry(head, type, member) \ | |
219 | ({ \ | |
220 | WARN_ON(plist_head_empty(head)); \ | |
221 | container_of(plist_first(head), type, member); \ | |
222 | }) | |
223 | #else | |
224 | # define plist_first_entry(head, type, member) \ | |
225 | container_of(plist_first(head), type, member) | |
226 | #endif | |
227 | ||
228 | /** | |
229 | * plist_first - return the first node (and thus, highest priority) | |
77ba89c5 IM |
230 | * @head: the &struct plist_head pointer |
231 | * | |
232 | * Assumes the plist is _not_ empty. | |
233 | */ | |
234 | static inline struct plist_node* plist_first(const struct plist_head *head) | |
235 | { | |
236 | return list_entry(head->node_list.next, | |
237 | struct plist_node, plist.node_list); | |
238 | } | |
239 | ||
240 | #endif |