[PATCH] pi-futex: add plist implementation (77ba89c5) · Commits · e / devices / android_kernel_fairphone_FP3

include/linux/plist.h

0 → 100644

+247 −0

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		/*
		* 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:
		*
		* \|HEAD \|
		* \| \|
		* \|prio_list.prev\|<------------------------------------\|
		* \|prio_list.next\|<->\|pl\|<->\|pl\|<--------------->\|pl\|<-\|
		* \|10 \| \|10\| \|21\| \|21\| \|21\| \|40\| (prio)
		* \| \| \| \| \| \| \| \| \| \| \| \|
		* \| \| \| \| \| \| \| \| \| \| \| \|
		* \|node_list.next\|<->\|nl\|<->\|nl\|<->\|nl\|<->\|nl\|<->\|nl\|<-\|
		* \|node_list.prev\|<------------------------------------\|
		*
		* 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 is 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/list.h>
		#include <linux/spinlock_types.h>

		struct plist_head {
		struct list_head prio_list;
		struct list_head node_list;
		#ifdef CONFIG_DEBUG_PI_LIST
		spinlock_t *lock;
		#endif
		};

		struct plist_node {
		int prio;
		struct plist_head plist;
		};

		#ifdef CONFIG_DEBUG_PI_LIST
		# define PLIST_HEAD_LOCK_INIT(_lock) .lock = _lock
		#else
		# define PLIST_HEAD_LOCK_INIT(_lock)
		#endif

		/**
		* #PLIST_HEAD_INIT - static struct plist_head initializer
		*
		* @head: struct plist_head variable name
		*/
		#define PLIST_HEAD_INIT(head, _lock) \
		{ \
		.prio_list = LIST_HEAD_INIT((head).prio_list), \
		.node_list = LIST_HEAD_INIT((head).node_list), \
		PLIST_HEAD_LOCK_INIT(&(_lock)) \
		}

		/**
		* #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), \
		.plist = PLIST_HEAD_INIT((node).plist, NULL), \
		}

		/**
		* plist_head_init - dynamic struct plist_head initializer
		*
		* @head: &struct plist_head pointer
		*/
		static inline void
		plist_head_init(struct plist_head head, spinlock_t lock)
		{
		INIT_LIST_HEAD(&head->prio_list);
		INIT_LIST_HEAD(&head->node_list);
		#ifdef CONFIG_DEBUG_PI_LIST
		head->lock = lock;
		#endif
		}

		/**
		* 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;
		plist_head_init(&node->plist, NULL);
		}

		extern void plist_add(struct plist_node node, struct plist_head head);
		extern void plist_del(struct plist_node node, struct plist_head head);

		/**
		* plist_for_each - iterate over the plist
		*
		* @pos1: 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, plist.node_list)

		/**
		* plist_for_each_entry_safe - iterate over a plist of given type safe
		* against removal of list entry
		*
		* @pos1: the type * to use as a loop counter.
		* @n1: another type * to use as temporary storage
		* @head: the head for your list.
		*/
		#define plist_for_each_safe(pos, n, head) \
		list_for_each_entry_safe(pos, n, &(head)->node_list, plist.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.
		* @member: 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.plist.node_list)

		/**
		* plist_for_each_entry_safe - iterate over list of given type safe against
		* removal of list entry
		*
		* @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.
		*/
		#define plist_for_each_entry_safe(pos, n, head, m) \
		list_for_each_entry_safe(pos, n, &(head)->node_list, m.plist.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 plist_head_empty(&node->plist);
		}

		/* All functions below assume the plist_head is not empty. */

		/**
		* plist_first_entry - get the struct for the first entry
		*
		* @ptr: 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_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, plist.node_list);
		}

		#endif

lib/Kconfig

+6 −0

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		@@ -86,4 +86,10 @@ config TEXTSEARCH_BM
		config TEXTSEARCH_FSM
		tristate

		#
		# plist support is select#ed if needed
		#
		config PLIST
		boolean

		endmenu

lib/Makefile

+1 −0

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		@@ -25,6 +25,7 @@ lib-$(CONFIG_SEMAPHORE_SLEEPERS) += semaphore-sleepers.o
		lib-$(CONFIG_GENERIC_FIND_NEXT_BIT) += find_next_bit.o
		lib-$(CONFIG_GENERIC_HWEIGHT) += hweight.o
		obj-$(CONFIG_LOCK_KERNEL) += kernel_lock.o
		obj-$(CONFIG_PLIST) += plist.o
		obj-$(CONFIG_DEBUG_PREEMPT) += smp_processor_id.o

		ifneq ($(CONFIG_HAVE_DEC_LOCK),y)

lib/plist.c

0 → 100644

+118 −0

Original line number	Diff line number	Diff line
		/*
		* lib/plist.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 file contains the add / del functions which are considered to
		* be too large to inline. See include/linux/plist.h for further
		* information.
		*/

		#include <linux/plist.h>
		#include <linux/spinlock.h>

		#ifdef CONFIG_DEBUG_PI_LIST

		static void plist_check_prev_next(struct list_head t, struct list_head p,
		struct list_head *n)
		{
		if (n->prev != p \|\| p->next != n) {
		printk("top: %p, n: %p, p: %p\n", t, t->next, t->prev);
		printk("prev: %p, n: %p, p: %p\n", p, p->next, p->prev);
		printk("next: %p, n: %p, p: %p\n", n, n->next, n->prev);
		WARN_ON(1);
		}
		}

		static void plist_check_list(struct list_head *top)
		{
		struct list_head prev = top, next = top->next;

		plist_check_prev_next(top, prev, next);
		while (next != top) {
		prev = next;
		next = prev->next;
		plist_check_prev_next(top, prev, next);
		}
		}

		static void plist_check_head(struct plist_head *head)
		{
		WARN_ON(!head->lock);
		if (head->lock)
		WARN_ON_SMP(!spin_is_locked(head->lock));
		plist_check_list(&head->prio_list);
		plist_check_list(&head->node_list);
		}

		#else
		# define plist_check_head(h) do { } while (0)
		#endif

		/**
		* plist_add - add @node to @head
		*
		* @node: &struct plist_node pointer
		* @head: &struct plist_head pointer
		*/
		void plist_add(struct plist_node node, struct plist_head head)
		{
		struct plist_node *iter;

		plist_check_head(head);
		WARN_ON(!plist_node_empty(node));

		list_for_each_entry(iter, &head->prio_list, plist.prio_list) {
		if (node->prio < iter->prio)
		goto lt_prio;
		else if (node->prio == iter->prio) {
		iter = list_entry(iter->plist.prio_list.next,
		struct plist_node, plist.prio_list);
		goto eq_prio;
		}
		}

		lt_prio:
		list_add_tail(&node->plist.prio_list, &iter->plist.prio_list);
		eq_prio:
		list_add_tail(&node->plist.node_list, &iter->plist.node_list);

		plist_check_head(head);
		}

		/**
		* plist_del - Remove a @node from plist.
		*
		* @node: &struct plist_node pointer - entry to be removed
		* @head: &struct plist_head pointer - list head
		*/
		void plist_del(struct plist_node node, struct plist_head head)
		{
		plist_check_head(head);

		if (!list_empty(&node->plist.prio_list)) {
		struct plist_node *next = plist_first(&node->plist);

		list_move_tail(&next->plist.prio_list, &node->plist.prio_list);
		list_del_init(&node->plist.prio_list);
		}

		list_del_init(&node->plist.node_list);

		plist_check_head(head);
		}