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