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![Thomas Gleixner](/assets/img/avatar_default.png)
Based on 1 normalized pattern(s): licensed under the fsf s gnu public license v2 or later extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 2 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Jilayne Lovejoy <opensource@jilayne.com> Reviewed-by: Steve Winslow <swinslow@gmail.com> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190519154041.526489261@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
298 lines
8.7 KiB
C
298 lines
8.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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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 <inaky.perez-gonzalez@intel.com>.
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*
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* 2001-2005 (c) MontaVista Software, Inc.
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* Daniel Walker <dwalker@mvista.com>
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*
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* (C) 2005 Thomas Gleixner <tglx@linutronix.de>
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*
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* Simplifications of the original code by
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* Oleg Nesterov <oleg@tv-sign.ru>
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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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#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_PLIST
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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_PLIST
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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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