timers: Introduce timerlist infrastructure.

#ifndef _LINUX_TIMERLIST_H

#define _LINUX_TIMERLIST_H

#include <linux/rbtree.h>

#include <linux/ktime.h>

struct timerlist_node {

	struct rb_node node;

	ktime_t expires;

};

struct timerlist_head {

	struct rb_root head;

	struct timerlist_node *next;

};

extern void timerlist_add(struct timerlist_head *head,

				struct timerlist_node *node);

extern void timerlist_del(struct timerlist_head *head,

				struct timerlist_node *node);

extern struct timerlist_node *timerlist_getnext(struct timerlist_head *head);

extern struct timerlist_node *timerlist_iterate_next(

						struct timerlist_node *node);

static inline void timerlist_init(struct timerlist_node *node)

{

	RB_CLEAR_NODE(&node->node);

}

static inline void timerlist_init_head(struct timerlist_head *head)

{

	head->head = RB_ROOT;

	head->next = NULL;

}

#endif /* _LINUX_TIMERLIST_H */

endif

lib-y := ctype.o string.o vsprintf.o cmdline.o \

	 rbtree.o radix-tree.o dump_stack.o \

	 rbtree.o radix-tree.o dump_stack.o timerlist.o\

	 idr.o int_sqrt.o extable.o prio_tree.o \

	 sha1.o irq_regs.o reciprocal_div.o argv_split.o \

	 proportions.o prio_heap.o ratelimit.o show_mem.o \

/*

 *  Generic Timer-list

 *

 *  Manages a simple list of timers, ordered by expiration time.

 *  Uses rbtrees for quick list adds and expiration.

 *

 *  NOTE: All of the following functions need to be serialized

 *  to avoid races. No locking is done by this libary code.

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License as published by

 *  the Free Software Foundation; either version 2 of the License, or

 *  (at your option) any later version.

 *

 *  This program is distributed in the hope that it will be useful,

 *  but WITHOUT ANY WARRANTY; without even the implied warranty of

 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *  GNU General Public License for more details.

 *

 *  You should have received a copy of the GNU General Public License

 *  along with this program; if not, write to the Free Software

 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

#include <linux/timerlist.h>

#include <linux/rbtree.h>

/**

 * timerlist_add - Adds timer to timerlist.

 *

 * @head: head of timerlist

 * @node: timer node to be added

 *

 * Adds the timer node to the timerlist, sorted by the

 * node's expires value.

 */

void timerlist_add(struct timerlist_head *head, struct timerlist_node *node)

{

	struct rb_node **p = &head->head.rb_node;

	struct rb_node *parent = NULL;

	struct timerlist_node  *ptr;

	/* Make sure we don't add nodes that are already added */

	WARN_ON_ONCE(!RB_EMPTY_NODE(&node->node));

	while (*p) {

		parent = *p;

		ptr = rb_entry(parent, struct timerlist_node, node);

		if (node->expires.tv64 < ptr->expires.tv64)

			p = &(*p)->rb_left;

		else

			p = &(*p)->rb_right;

	}

	rb_link_node(&node->node, parent, p);

	rb_insert_color(&node->node, &head->head);

	if (!head->next || node->expires.tv64 < head->next->expires.tv64)

		head->next = node;

}

/**

 * timerlist_del - Removes a timer from the timerlist.

 *

 * @head: head of timerlist

 * @node: timer node to be removed

 *

 * Removes the timer node from the timerlist.

 */

void timerlist_del(struct timerlist_head *head, struct timerlist_node *node)

{

	WARN_ON_ONCE(RB_EMPTY_NODE(&node->node));

	/* update next pointer */

	if (head->next == node) {

		struct rb_node *rbn = rb_next(&node->node);

		head->next = rbn ?

			rb_entry(rbn, struct timerlist_node, node) : NULL;

	}

	rb_erase(&node->node, &head->head);

	RB_CLEAR_NODE(&node->node);

}

/**

 * timerlist_getnext - Returns the timer with the earlies expiration time

 *

 * @head: head of timerlist

 *

 * Returns a pointer to the timer node that has the

 * earliest expiration time.

 */

struct timerlist_node *timerlist_getnext(struct timerlist_head *head)

{

	return head->next;

}

/**

 * timerlist_iterate_next - Returns the timer after the provided timer

 *

 * @node: Pointer to a timer.

 *

 * Provides the timer that is after the given node. This is used, when

 * necessary, to iterate through the list of timers in a timer list

 * without modifying the list.

 */

struct timerlist_node *timerlist_iterate_next(struct timerlist_node *node)

{

	struct rb_node *next;

	if (!node)

		return NULL;

	next = rb_next(&node->node);

	if (!next)

		return NULL;

	return container_of(next, struct timerlist_node, node);

}