path: root/drivers/staging/android/sync.c

/*
 * drivers/base/sync.c
 *
 * Copyright (C) 2012 Google, Inc.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * 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.
 *
 */

#include <linux/debugfs.h>
#include <linux/export.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/anon_inodes.h>

#include "sync.h"

#define CREATE_TRACE_POINTS
#include "trace/sync.h"

static void sync_fence_signal_pt(struct sync_pt *pt);
static int _sync_pt_has_signaled(struct sync_pt *pt);
static void sync_fence_free(struct kref *kref);
static void sync_dump(void);

static LIST_HEAD(sync_timeline_list_head);
static DEFINE_SPINLOCK(sync_timeline_list_lock);

static LIST_HEAD(sync_fence_list_head);
static DEFINE_SPINLOCK(sync_fence_list_lock);

struct sync_timeline *sync_timeline_create(const struct sync_timeline_ops *ops,
					   int size, const char *name)
{
	struct sync_timeline *obj;
	unsigned long flags;

	if (size < sizeof(struct sync_timeline))
		return NULL;

	obj = kzalloc(size, GFP_KERNEL);
	if (obj == NULL)
		return NULL;

	kref_init(&obj->kref);
	obj->ops = ops;
	strlcpy(obj->name, name, sizeof(obj->name));

	INIT_LIST_HEAD(&obj->child_list_head);
	spin_lock_init(&obj->child_list_lock);

	INIT_LIST_HEAD(&obj->active_list_head);
	spin_lock_init(&obj->active_list_lock);

	spin_lock_irqsave(&sync_timeline_list_lock, flags);
	list_add_tail(&obj->sync_timeline_list, &sync_timeline_list_head);
	spin_unlock_irqrestore(&sync_timeline_list_lock, flags);

	return obj;
}
EXPORT_SYMBOL(sync_timeline_create);

static void sync_timeline_free(struct kref *kref)
{
	struct sync_timeline *obj =
		container_of(kref, struct sync_timeline, kref);
	unsigned long flags;

	spin_lock_irqsave(&sync_timeline_list_lock, flags);
	list_del(&obj->sync_timeline_list);
	spin_unlock_irqrestore(&sync_timeline_list_lock, flags);

	if (obj->ops->release_obj)
		obj->ops->release_obj(obj);

	kfree(obj);
}

void sync_timeline_destroy(struct sync_timeline *obj)
{
	obj->destroyed = true;
	/*
	 * Ensure timeline is marked as destroyed before
	 * changing timeline's fences status.
	 */
	smp_wmb();

	/*
	 * signal any children that their parent is going away.
	 */
	sync_timeline_signal(obj);

	kref_put(&obj->kref, sync_timeline_free);
}
EXPORT_SYMBOL(sync_timeline_destroy);

static void sync_timeline_add_pt(struct sync_timeline *obj, struct sync_pt *pt)
{
	unsigned long flags;

	pt->parent = obj;

	spin_lock_irqsave(&obj->child_list_lock, flags);
	list_add_tail(&pt->child_list, &obj->child_list_head);
	spin_unlock_irqrestore(&obj->child_list_lock, flags);
}

static void sync_timeline_remove_pt(struct sync_pt *pt)
{
	struct sync_timeline *obj = pt->parent;
	unsigned long flags;

	spin_lock_irqsave(&obj->active_list_lock, flags);
	if (!list_empty(&pt->active_list))
		list_del_init(&pt->active_list);
	spin_unlock_irqrestore(&obj->active_list_lock, flags);

	spin_lock_irqsave(&obj->child_list_lock, flags);
	if (!list_empty(&pt->child_list))
		list_del_init(&pt->child_list);

	spin_unlock_irqrestore(&obj->child_list_lock, flags);
}

void sync_timeline_signal(struct sync_timeline *obj)
{
	unsigned long flags;
	LIST_HEAD(signaled_pts);
	struct list_head *pos, *n;

	trace_sync_timeline(obj);

	spin_lock_irqsave(&obj->active_list_lock, flags);

	list_for_each_safe(pos, n, &obj->active_list_head) {
		struct sync_pt *pt =
			container_of(pos, struct sync_pt, active_list);

		if (_sync_pt_has_signaled(pt)) {
			list_del_init(pos);
			list_add(&pt->signaled_list, &signaled_pts);
			kref_get(&pt->fence->kref);
		}
	}

	<