Commit | Line | Data |
---|---|---|
aded9cb8 | 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
77ba89c5 IM |
2 | /* |
3 | * Descending-priority-sorted double-linked list | |
4 | * | |
5 | * (C) 2002-2003 Intel Corp | |
6 | * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>. | |
7 | * | |
8 | * 2001-2005 (c) MontaVista Software, Inc. | |
9 | * Daniel Walker <dwalker@mvista.com> | |
10 | * | |
11 | * (C) 2005 Thomas Gleixner <tglx@linutronix.de> | |
12 | * | |
13 | * Simplifications of the original code by | |
14 | * Oleg Nesterov <oleg@tv-sign.ru> | |
15 | * | |
77ba89c5 IM |
16 | * Based on simple lists (include/linux/list.h). |
17 | * | |
18 | * This is a priority-sorted list of nodes; each node has a | |
19 | * priority from INT_MIN (highest) to INT_MAX (lowest). | |
20 | * | |
21 | * Addition is O(K), removal is O(1), change of priority of a node is | |
22 | * O(K) and K is the number of RT priority levels used in the system. | |
23 | * (1 <= K <= 99) | |
24 | * | |
25 | * This list is really a list of lists: | |
26 | * | |
27 | * - The tier 1 list is the prio_list, different priority nodes. | |
28 | * | |
29 | * - The tier 2 list is the node_list, serialized nodes. | |
30 | * | |
31 | * Simple ASCII art explanation: | |
32 | * | |
bf6a9b83 LJ |
33 | * pl:prio_list (only for plist_node) |
34 | * nl:node_list | |
35 | * HEAD| NODE(S) | |
36 | * | | |
37 | * ||------------------------------------| | |
38 | * ||->|pl|<->|pl|<--------------->|pl|<-| | |
39 | * | |10| |21| |21| |21| |40| (prio) | |
40 | * | | | | | | | | | | | | |
41 | * | | | | | | | | | | | | |
42 | * |->|nl|<->|nl|<->|nl|<->|nl|<->|nl|<->|nl|<-| | |
43 | * |-------------------------------------------| | |
77ba89c5 IM |
44 | * |
45 | * The nodes on the prio_list list are sorted by priority to simplify | |
46 | * the insertion of new nodes. There are no nodes with duplicate | |
47 | * priorites on the list. | |
48 | * | |
9ca94d7c | 49 | * The nodes on the node_list are ordered by priority and can contain |
77ba89c5 IM |
50 | * entries which have the same priority. Those entries are ordered |
51 | * FIFO | |
52 | * | |
53 | * Addition means: look for the prio_list node in the prio_list | |
54 | * for the priority of the node and insert it before the node_list | |
55 | * entry of the next prio_list node. If it is the first node of | |
56 | * that priority, add it to the prio_list in the right position and | |
57 | * insert it into the serialized node_list list | |
58 | * | |
59 | * Removal means remove it from the node_list and remove it from | |
60 | * the prio_list if the node_list list_head is non empty. In case | |
61 | * of removal from the prio_list it must be checked whether other | |
62 | * entries of the same priority are on the list or not. If there | |
63 | * is another entry of the same priority then this entry has to | |
64 | * replace the removed entry on the prio_list. If the entry which | |
65 | * is removed is the only entry of this priority then a simple | |
66 | * remove from both list is sufficient. | |
67 | * | |
68 | * INT_MIN is the highest priority, 0 is the medium highest, INT_MAX | |
69 | * is lowest priority. | |
70 | * | |
71 | * No locking is done, up to the caller. | |
77ba89c5 IM |
72 | */ |
73 | #ifndef _LINUX_PLIST_H_ | |
74 | #define _LINUX_PLIST_H_ | |
75 | ||
c540f959 | 76 | #include <linux/container_of.h> |
77ba89c5 | 77 | #include <linux/list.h> |
c540f959 AS |
78 | #include <linux/types.h> |
79 | ||
80 | #include <asm/bug.h> | |
77ba89c5 IM |
81 | |
82 | struct plist_head { | |
77ba89c5 | 83 | struct list_head node_list; |
77ba89c5 IM |
84 | }; |
85 | ||
86 | struct plist_node { | |
87 | int prio; | |
bf6a9b83 LJ |
88 | struct list_head prio_list; |
89 | struct list_head node_list; | |
77ba89c5 IM |
90 | }; |
91 | ||
77ba89c5 | 92 | /** |
11265420 | 93 | * PLIST_HEAD_INIT - static struct plist_head initializer |
77ba89c5 | 94 | * @head: struct plist_head variable name |
a2672459 | 95 | */ |
732375c6 | 96 | #define PLIST_HEAD_INIT(head) \ |
a2672459 | 97 | { \ |
732375c6 | 98 | .node_list = LIST_HEAD_INIT((head).node_list) \ |
a2672459 TG |
99 | } |
100 | ||
fd16618e DS |
101 | /** |
102 | * PLIST_HEAD - declare and init plist_head | |
103 | * @head: name for struct plist_head variable | |
104 | */ | |
105 | #define PLIST_HEAD(head) \ | |
106 | struct plist_head head = PLIST_HEAD_INIT(head) | |
107 | ||
77ba89c5 | 108 | /** |
11265420 | 109 | * PLIST_NODE_INIT - static struct plist_node initializer |
77ba89c5 IM |
110 | * @node: struct plist_node variable name |
111 | * @__prio: initial node priority | |
112 | */ | |
113 | #define PLIST_NODE_INIT(node, __prio) \ | |
114 | { \ | |
115 | .prio = (__prio), \ | |
bf6a9b83 LJ |
116 | .prio_list = LIST_HEAD_INIT((node).prio_list), \ |
117 | .node_list = LIST_HEAD_INIT((node).node_list), \ | |
77ba89c5 IM |
118 | } |
119 | ||
120 | /** | |
121 | * plist_head_init - dynamic struct plist_head initializer | |
77ba89c5 | 122 | * @head: &struct plist_head pointer |
a2672459 TG |
123 | */ |
124 | static inline void | |
732375c6 | 125 | plist_head_init(struct plist_head *head) |
a2672459 | 126 | { |
a2672459 | 127 | INIT_LIST_HEAD(&head->node_list); |
77ba89c5 IM |
128 | } |
129 | ||
130 | /** | |
131 | * plist_node_init - Dynamic struct plist_node initializer | |
77ba89c5 IM |
132 | * @node: &struct plist_node pointer |
133 | * @prio: initial node priority | |
134 | */ | |
135 | static inline void plist_node_init(struct plist_node *node, int prio) | |
136 | { | |
137 | node->prio = prio; | |
bf6a9b83 LJ |
138 | INIT_LIST_HEAD(&node->prio_list); |
139 | INIT_LIST_HEAD(&node->node_list); | |
77ba89c5 IM |
140 | } |
141 | ||
142 | extern void plist_add(struct plist_node *node, struct plist_head *head); | |
143 | extern void plist_del(struct plist_node *node, struct plist_head *head); | |
144 | ||
a75f232c DS |
145 | extern void plist_requeue(struct plist_node *node, struct plist_head *head); |
146 | ||
77ba89c5 IM |
147 | /** |
148 | * plist_for_each - iterate over the plist | |
11265420 RD |
149 | * @pos: the type * to use as a loop counter |
150 | * @head: the head for your list | |
77ba89c5 IM |
151 | */ |
152 | #define plist_for_each(pos, head) \ | |
bf6a9b83 | 153 | list_for_each_entry(pos, &(head)->node_list, node_list) |
77ba89c5 | 154 | |
fd16618e DS |
155 | /** |
156 | * plist_for_each_continue - continue iteration over the plist | |
157 | * @pos: the type * to use as a loop cursor | |
158 | * @head: the head for your list | |
159 | * | |
160 | * Continue to iterate over plist, continuing after the current position. | |
161 | */ | |
162 | #define plist_for_each_continue(pos, head) \ | |
163 | list_for_each_entry_continue(pos, &(head)->node_list, node_list) | |
164 | ||
77ba89c5 | 165 | /** |
11265420 RD |
166 | * plist_for_each_safe - iterate safely over a plist of given type |
167 | * @pos: the type * to use as a loop counter | |
168 | * @n: another type * to use as temporary storage | |
169 | * @head: the head for your list | |
77ba89c5 | 170 | * |
11265420 | 171 | * Iterate over a plist of given type, safe against removal of list entry. |
77ba89c5 IM |
172 | */ |
173 | #define plist_for_each_safe(pos, n, head) \ | |
bf6a9b83 | 174 | list_for_each_entry_safe(pos, n, &(head)->node_list, node_list) |
77ba89c5 IM |
175 | |
176 | /** | |
177 | * plist_for_each_entry - iterate over list of given type | |
11265420 RD |
178 | * @pos: the type * to use as a loop counter |
179 | * @head: the head for your list | |
3943f42c | 180 | * @mem: the name of the list_head within the struct |
77ba89c5 IM |
181 | */ |
182 | #define plist_for_each_entry(pos, head, mem) \ | |
bf6a9b83 | 183 | list_for_each_entry(pos, &(head)->node_list, mem.node_list) |
77ba89c5 | 184 | |
fd16618e DS |
185 | /** |
186 | * plist_for_each_entry_continue - continue iteration over list of given type | |
187 | * @pos: the type * to use as a loop cursor | |
188 | * @head: the head for your list | |
3943f42c | 189 | * @m: the name of the list_head within the struct |
fd16618e DS |
190 | * |
191 | * Continue to iterate over list of given type, continuing after | |
192 | * the current position. | |
193 | */ | |
194 | #define plist_for_each_entry_continue(pos, head, m) \ | |
195 | list_for_each_entry_continue(pos, &(head)->node_list, m.node_list) | |
196 | ||
77ba89c5 | 197 | /** |
11265420 RD |
198 | * plist_for_each_entry_safe - iterate safely over list of given type |
199 | * @pos: the type * to use as a loop counter | |
77ba89c5 | 200 | * @n: another type * to use as temporary storage |
11265420 | 201 | * @head: the head for your list |
3943f42c | 202 | * @m: the name of the list_head within the struct |
11265420 RD |
203 | * |
204 | * Iterate over list of given type, safe against removal of list entry. | |
77ba89c5 IM |
205 | */ |
206 | #define plist_for_each_entry_safe(pos, n, head, m) \ | |
bf6a9b83 | 207 | list_for_each_entry_safe(pos, n, &(head)->node_list, m.node_list) |
77ba89c5 IM |
208 | |
209 | /** | |
210 | * plist_head_empty - return !0 if a plist_head is empty | |
77ba89c5 IM |
211 | * @head: &struct plist_head pointer |
212 | */ | |
213 | static inline int plist_head_empty(const struct plist_head *head) | |
214 | { | |
215 | return list_empty(&head->node_list); | |
216 | } | |
217 | ||
218 | /** | |
219 | * plist_node_empty - return !0 if plist_node is not on a list | |
77ba89c5 IM |
220 | * @node: &struct plist_node pointer |
221 | */ | |
222 | static inline int plist_node_empty(const struct plist_node *node) | |
223 | { | |
bf6a9b83 | 224 | return list_empty(&node->node_list); |
77ba89c5 IM |
225 | } |
226 | ||
227 | /* All functions below assume the plist_head is not empty. */ | |
228 | ||
229 | /** | |
230 | * plist_first_entry - get the struct for the first entry | |
11265420 RD |
231 | * @head: the &struct plist_head pointer |
232 | * @type: the type of the struct this is embedded in | |
3943f42c | 233 | * @member: the name of the list_head within the struct |
77ba89c5 | 234 | */ |
8e18faea | 235 | #ifdef CONFIG_DEBUG_PLIST |
77ba89c5 IM |
236 | # define plist_first_entry(head, type, member) \ |
237 | ({ \ | |
238 | WARN_ON(plist_head_empty(head)); \ | |
239 | container_of(plist_first(head), type, member); \ | |
240 | }) | |
241 | #else | |
242 | # define plist_first_entry(head, type, member) \ | |
243 | container_of(plist_first(head), type, member) | |
244 | #endif | |
245 | ||
12e4d0cc JB |
246 | /** |
247 | * plist_last_entry - get the struct for the last entry | |
248 | * @head: the &struct plist_head pointer | |
249 | * @type: the type of the struct this is embedded in | |
3943f42c | 250 | * @member: the name of the list_head within the struct |
12e4d0cc | 251 | */ |
8e18faea | 252 | #ifdef CONFIG_DEBUG_PLIST |
12e4d0cc JB |
253 | # define plist_last_entry(head, type, member) \ |
254 | ({ \ | |
255 | WARN_ON(plist_head_empty(head)); \ | |
256 | container_of(plist_last(head), type, member); \ | |
257 | }) | |
258 | #else | |
259 | # define plist_last_entry(head, type, member) \ | |
260 | container_of(plist_last(head), type, member) | |
261 | #endif | |
262 | ||
fd16618e DS |
263 | /** |
264 | * plist_next - get the next entry in list | |
265 | * @pos: the type * to cursor | |
266 | */ | |
267 | #define plist_next(pos) \ | |
268 | list_next_entry(pos, node_list) | |
269 | ||
270 | /** | |
271 | * plist_prev - get the prev entry in list | |
272 | * @pos: the type * to cursor | |
273 | */ | |
274 | #define plist_prev(pos) \ | |
275 | list_prev_entry(pos, node_list) | |
276 | ||
77ba89c5 IM |
277 | /** |
278 | * plist_first - return the first node (and thus, highest priority) | |
77ba89c5 IM |
279 | * @head: the &struct plist_head pointer |
280 | * | |
281 | * Assumes the plist is _not_ empty. | |
282 | */ | |
9ca94d7c | 283 | static inline struct plist_node *plist_first(const struct plist_head *head) |
77ba89c5 IM |
284 | { |
285 | return list_entry(head->node_list.next, | |
bf6a9b83 | 286 | struct plist_node, node_list); |
77ba89c5 IM |
287 | } |
288 | ||
12e4d0cc JB |
289 | /** |
290 | * plist_last - return the last node (and thus, lowest priority) | |
291 | * @head: the &struct plist_head pointer | |
292 | * | |
293 | * Assumes the plist is _not_ empty. | |
294 | */ | |
295 | static inline struct plist_node *plist_last(const struct plist_head *head) | |
296 | { | |
297 | return list_entry(head->node_list.prev, | |
bf6a9b83 | 298 | struct plist_node, node_list); |
12e4d0cc JB |
299 | } |
300 | ||
77ba89c5 | 301 | #endif |