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300 lines
8.7 KiB
300 lines
8.7 KiB
/* |
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* Descending-priority-sorted double-linked list |
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* |
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* (C) 2002-2003 Intel Corp |
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* Inaky Perez-Gonzalez <[email protected]>. |
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* |
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* 2001-2005 (c) MontaVista Software, Inc. |
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* Daniel Walker <[email protected]> |
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* |
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* (C) 2005 Thomas Gleixner <[email protected]> |
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* |
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* Simplifications of the original code by |
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* Oleg Nesterov <[email protected]> |
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* |
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* Licensed under the FSF's GNU Public License v2 or later. |
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* |
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* Based on simple lists (include/linux/list.h). |
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* |
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* This is a priority-sorted list of nodes; each node has a |
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* priority from INT_MIN (highest) to INT_MAX (lowest). |
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* |
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* Addition is O(K), removal is O(1), change of priority of a node is |
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* O(K) and K is the number of RT priority levels used in the system. |
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* (1 <= K <= 99) |
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* |
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* This list is really a list of lists: |
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* |
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* - The tier 1 list is the prio_list, different priority nodes. |
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* |
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* - The tier 2 list is the node_list, serialized nodes. |
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* |
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* Simple ASCII art explanation: |
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* |
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* pl:prio_list (only for plist_node) |
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* nl:node_list |
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* HEAD| NODE(S) |
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* | |
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* ||------------------------------------| |
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* ||->|pl|<->|pl|<--------------->|pl|<-| |
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* | |10| |21| |21| |21| |40| (prio) |
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* | | | | | | | | | | | |
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* | | | | | | | | | | | |
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* |->|nl|<->|nl|<->|nl|<->|nl|<->|nl|<->|nl|<-| |
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* |-------------------------------------------| |
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* |
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* The nodes on the prio_list list are sorted by priority to simplify |
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* the insertion of new nodes. There are no nodes with duplicate |
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* priorites on the list. |
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* |
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* The nodes on the node_list are ordered by priority and can contain |
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* entries which have the same priority. Those entries are ordered |
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* FIFO |
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* |
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* Addition means: look for the prio_list node in the prio_list |
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* for the priority of the node and insert it before the node_list |
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* entry of the next prio_list node. If it is the first node of |
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* that priority, add it to the prio_list in the right position and |
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* insert it into the serialized node_list list |
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* |
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* Removal means remove it from the node_list and remove it from |
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* the prio_list if the node_list list_head is non empty. In case |
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* of removal from the prio_list it must be checked whether other |
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* entries of the same priority are on the list or not. If there |
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* is another entry of the same priority then this entry has to |
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* replace the removed entry on the prio_list. If the entry which |
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* is removed is the only entry of this priority then a simple |
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* remove from both list is sufficient. |
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* |
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* INT_MIN is the highest priority, 0 is the medium highest, INT_MAX |
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* is lowest priority. |
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* |
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* No locking is done, up to the caller. |
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* |
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*/ |
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#ifndef _LINUX_PLIST_H_ |
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#define _LINUX_PLIST_H_ |
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#include <linux/kernel.h> |
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#include <linux/list.h> |
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struct plist_head { |
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struct list_head node_list; |
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}; |
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struct plist_node { |
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int prio; |
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struct list_head prio_list; |
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struct list_head node_list; |
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}; |
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/** |
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* PLIST_HEAD_INIT - static struct plist_head initializer |
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* @head: struct plist_head variable name |
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*/ |
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#define PLIST_HEAD_INIT(head) \ |
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{ \ |
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.node_list = LIST_HEAD_INIT((head).node_list) \ |
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} |
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/** |
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* PLIST_HEAD - declare and init plist_head |
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* @head: name for struct plist_head variable |
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*/ |
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#define PLIST_HEAD(head) \ |
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struct plist_head head = PLIST_HEAD_INIT(head) |
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/** |
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* PLIST_NODE_INIT - static struct plist_node initializer |
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* @node: struct plist_node variable name |
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* @__prio: initial node priority |
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*/ |
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#define PLIST_NODE_INIT(node, __prio) \ |
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{ \ |
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.prio = (__prio), \ |
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.prio_list = LIST_HEAD_INIT((node).prio_list), \ |
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.node_list = LIST_HEAD_INIT((node).node_list), \ |
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} |
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/** |
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* plist_head_init - dynamic struct plist_head initializer |
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* @head: &struct plist_head pointer |
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*/ |
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static inline void |
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plist_head_init(struct plist_head *head) |
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{ |
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INIT_LIST_HEAD(&head->node_list); |
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} |
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/** |
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* plist_node_init - Dynamic struct plist_node initializer |
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* @node: &struct plist_node pointer |
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* @prio: initial node priority |
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*/ |
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static inline void plist_node_init(struct plist_node *node, int prio) |
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{ |
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node->prio = prio; |
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INIT_LIST_HEAD(&node->prio_list); |
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INIT_LIST_HEAD(&node->node_list); |
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} |
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extern void plist_add(struct plist_node *node, struct plist_head *head); |
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extern void plist_del(struct plist_node *node, struct plist_head *head); |
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extern void plist_requeue(struct plist_node *node, struct plist_head *head); |
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/** |
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* plist_for_each - iterate over the plist |
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* @pos: the type * to use as a loop counter |
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* @head: the head for your list |
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*/ |
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#define plist_for_each(pos, head) \ |
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list_for_each_entry(pos, &(head)->node_list, node_list) |
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/** |
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* plist_for_each_continue - continue iteration over the plist |
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* @pos: the type * to use as a loop cursor |
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* @head: the head for your list |
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* |
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* Continue to iterate over plist, continuing after the current position. |
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*/ |
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#define plist_for_each_continue(pos, head) \ |
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list_for_each_entry_continue(pos, &(head)->node_list, node_list) |
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/** |
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* plist_for_each_safe - iterate safely over a plist of given type |
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* @pos: the type * to use as a loop counter |
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* @n: another type * to use as temporary storage |
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* @head: the head for your list |
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* |
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* Iterate over a plist of given type, safe against removal of list entry. |
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*/ |
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#define plist_for_each_safe(pos, n, head) \ |
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list_for_each_entry_safe(pos, n, &(head)->node_list, node_list) |
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/** |
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* plist_for_each_entry - iterate over list of given type |
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* @pos: the type * to use as a loop counter |
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* @head: the head for your list |
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* @mem: the name of the list_head within the struct |
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*/ |
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#define plist_for_each_entry(pos, head, mem) \ |
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list_for_each_entry(pos, &(head)->node_list, mem.node_list) |
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/** |
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* plist_for_each_entry_continue - continue iteration over list of given type |
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* @pos: the type * to use as a loop cursor |
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* @head: the head for your list |
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* @m: the name of the list_head within the struct |
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* |
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* Continue to iterate over list of given type, continuing after |
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* the current position. |
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*/ |
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#define plist_for_each_entry_continue(pos, head, m) \ |
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list_for_each_entry_continue(pos, &(head)->node_list, m.node_list) |
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/** |
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* plist_for_each_entry_safe - iterate safely over list of given type |
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* @pos: the type * to use as a loop counter |
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* @n: another type * to use as temporary storage |
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* @head: the head for your list |
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* @m: the name of the list_head within the struct |
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* |
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* Iterate over list of given type, safe against removal of list entry. |
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*/ |
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#define plist_for_each_entry_safe(pos, n, head, m) \ |
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list_for_each_entry_safe(pos, n, &(head)->node_list, m.node_list) |
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/** |
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* plist_head_empty - return !0 if a plist_head is empty |
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* @head: &struct plist_head pointer |
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*/ |
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static inline int plist_head_empty(const struct plist_head *head) |
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{ |
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return list_empty(&head->node_list); |
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} |
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/** |
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* plist_node_empty - return !0 if plist_node is not on a list |
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* @node: &struct plist_node pointer |
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*/ |
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static inline int plist_node_empty(const struct plist_node *node) |
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{ |
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return list_empty(&node->node_list); |
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} |
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/* All functions below assume the plist_head is not empty. */ |
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/** |
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* plist_first_entry - get the struct for the first entry |
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* @head: the &struct plist_head pointer |
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* @type: the type of the struct this is embedded in |
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* @member: the name of the list_head within the struct |
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*/ |
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#ifdef CONFIG_DEBUG_PI_LIST |
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# define plist_first_entry(head, type, member) \ |
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({ \ |
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WARN_ON(plist_head_empty(head)); \ |
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container_of(plist_first(head), type, member); \ |
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}) |
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#else |
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# define plist_first_entry(head, type, member) \ |
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container_of(plist_first(head), type, member) |
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#endif |
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/** |
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* plist_last_entry - get the struct for the last entry |
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* @head: the &struct plist_head pointer |
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* @type: the type of the struct this is embedded in |
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* @member: the name of the list_head within the struct |
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*/ |
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#ifdef CONFIG_DEBUG_PI_LIST |
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# define plist_last_entry(head, type, member) \ |
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({ \ |
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WARN_ON(plist_head_empty(head)); \ |
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container_of(plist_last(head), type, member); \ |
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}) |
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#else |
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# define plist_last_entry(head, type, member) \ |
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container_of(plist_last(head), type, member) |
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#endif |
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/** |
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* plist_next - get the next entry in list |
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* @pos: the type * to cursor |
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*/ |
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#define plist_next(pos) \ |
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list_next_entry(pos, node_list) |
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/** |
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* plist_prev - get the prev entry in list |
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* @pos: the type * to cursor |
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*/ |
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#define plist_prev(pos) \ |
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list_prev_entry(pos, node_list) |
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/** |
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* plist_first - return the first node (and thus, highest priority) |
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* @head: the &struct plist_head pointer |
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* |
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* Assumes the plist is _not_ empty. |
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*/ |
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static inline struct plist_node *plist_first(const struct plist_head *head) |
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{ |
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return list_entry(head->node_list.next, |
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struct plist_node, node_list); |
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} |
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/** |
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* plist_last - return the last node (and thus, lowest priority) |
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* @head: the &struct plist_head pointer |
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* |
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* Assumes the plist is _not_ empty. |
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*/ |
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static inline struct plist_node *plist_last(const struct plist_head *head) |
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{ |
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return list_entry(head->node_list.prev, |
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struct plist_node, node_list); |
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} |
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#endif
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