drivers/staging/android/sync.c - kernel/bruno - Git at Google

 /*
  * 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 const struct fence_ops android_fence_ops;
 static const struct file_operations sync_fence_fops;

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

 	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;
 	obj->context = fence_context_alloc(1);
 	strlcpy(obj->name, name, sizeof(obj->name));

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

 	sync_timeline_debug_add(obj);

 	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);

 	sync_timeline_debug_remove(obj);

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

 	kfree(obj);
 }

 static void sync_timeline_get(struct sync_timeline *obj)
 {
 	kref_get(&obj->kref);
 }

 static void sync_timeline_put(struct sync_timeline *obj)
 {
 	kref_put(&obj->kref, sync_timeline_free);
 }

 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);
 	sync_timeline_put(obj);
 }
 EXPORT_SYMBOL(sync_timeline_destroy);

 void sync_timeline_signal(struct sync_timeline *obj)
 {
 	unsigned long flags;
 	LIST_HEAD(signaled_pts);
 	struct sync_pt *pt, *next;

 	trace_sync_timeline(obj);

 	spin_lock_irqsave(&obj->child_list_lock, flags);

 	list_for_each_entry_safe(pt, next, &obj->active_list_head,
 				 active_list) {
 		if (fence_is_signaled_locked(&pt->base))
 			list_del(&pt->active_list);
 	}

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

 struct sync_pt *sync_pt_create(struct sync_timeline *obj, int size)
 {
 	unsigned long flags;
 	struct sync_pt *pt;

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

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

 	spin_lock_irqsave(&obj->child_list_lock, flags);
 	sync_timeline_get(obj);
 	fence_init(&pt->base, &android_fence_ops, &obj->child_list_lock,
 		   obj->context, ++obj->value);
 	list_add_tail(&pt->child_list, &obj->child_list_head);
 	INIT_LIST_HEAD(&pt->active_list);
 	spin_unlock_irqrestore(&obj->child_list_lock, flags);
 	return pt;
 }
 EXPORT_SYMBOL(sync_pt_create);

 void sync_pt_free(struct sync_pt *pt)
 {
 	fence_put(&pt->base);
 }
 EXPORT_SYMBOL(sync_pt_free);

 static struct sync_fence *sync_fence_alloc(int size, const char *name)
 {
 	struct sync_fence *fence;

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

 	fence->file = anon_inode_getfile("sync_fence", &sync_fence_fops,
 					 fence, 0);
 	if (IS_ERR(fence->file))
 		goto err;

 	kref_init(&fence->kref);
 	strlcpy(fence->name, name, sizeof(fence->name));

 	init_waitqueue_head(&fence->wq);

 	return fence;

 err:
 	kfree(fence);
 	return NULL;
 }

 static void fence_check_cb_func(struct fence *f, struct fence_cb *cb)
 {
 	struct sync_fence_cb *check;
 	struct sync_fence *fence;

 	check = container_of(cb, struct sync_fence_cb, cb);
 	fence = check->fence;

 	if (atomic_dec_and_test(&fence->status))
 		wake_up_all(&fence->wq);
 }

 /* TODO: implement a create which takes more that one sync_pt */
 struct sync_fence *sync_fence_create(const char *name, struct sync_pt *pt)
 {
 	struct sync_fence *fence;

 	fence = sync_fence_alloc(offsetof(struct sync_fence, cbs[1]), name);
 	if (fence == NULL)
 		return NULL;

 	fence->num_fences = 1;
 	atomic_set(&fence->status, 1);

 	fence->cbs[0].sync_pt = &pt->base;
 	fence->cbs[0].fence = fence;
 	if (fence_add_callback(&pt->base, &fence->cbs[0].cb,
 			       fence_check_cb_func))
 		atomic_dec(&fence->status);

 	sync_fence_debug_add(fence);

 	return fence;
 }
 EXPORT_SYMBOL(sync_fence_create);

 struct sync_fence *sync_fence_fdget(int fd)
 {
 	struct file *file = fget(fd);

 	if (file == NULL)
 		return NULL;

 	if (file->f_op != &sync_fence_fops)
 		goto err;

 	return file->private_data;

 err:
 	fput(file);
 	return NULL;
 }
 EXPORT_SYMBOL(sync_fence_fdget);

 void sync_fence_put(struct sync_fence *fence)
 {
 	fput(fence->file);
 }
 EXPORT_SYMBOL(sync_fence_put);

 void sync_fence_install(struct sync_fence *fence, int fd)
 {
 	fd_install(fd, fence->file);
 }
 EXPORT_SYMBOL(sync_fence_install);

 static void sync_fence_add_pt(struct sync_fence *fence,
 			      int *i, struct fence *pt)
 {
 	fence->cbs[*i].sync_pt = pt;
 	fence->cbs[*i].fence = fence;

 	if (!fence_add_callback(pt, &fence->cbs[*i].cb, fence_check_cb_func)) {
 		fence_get(pt);
 		(*i)++;
 	}
 }

 struct sync_fence *sync_fence_merge(const char *name,
 				    struct sync_fence *a, struct sync_fence *b)
 {
 	int num_fences = a->num_fences + b->num_fences;
 	struct sync_fence *fence;
 	int i, i_a, i_b;
 	unsigned long size = offsetof(struct sync_fence, cbs[num_fences]);

 	fence = sync_fence_alloc(size, name);
 	if (fence == NULL)
 		return NULL;

 	atomic_set(&fence->status, num_fences);

 	/*
 	 * Assume sync_fence a and b are both ordered and have no
 	 * duplicates with the same context.
 	 *
 	 * If a sync_fence can only be created with sync_fence_merge
 	 * and sync_fence_create, this is a reasonable assumption.
 	 */
 	for (i = i_a = i_b = 0; i_a < a->num_fences && i_b < b->num_fences; ) {
 		struct fence *pt_a = a->cbs[i_a].sync_pt;
 		struct fence *pt_b = b->cbs[i_b].sync_pt;

 		if (pt_a->context < pt_b->context) {
 			sync_fence_add_pt(fence, &i, pt_a);

 			i_a++;
 		} else if (pt_a->context > pt_b->context) {
 			sync_fence_add_pt(fence, &i, pt_b);

 			i_b++;
 		} else {
 			if (pt_a->seqno - pt_b->seqno <= INT_MAX)
 				sync_fence_add_pt(fence, &i, pt_a);
 			else
 				sync_fence_add_pt(fence, &i, pt_b);

 			i_a++;
 			i_b++;
 		}
 	}

 	for (; i_a < a->num_fences; i_a++)
 		sync_fence_add_pt(fence, &i, a->cbs[i_a].sync_pt);

 	for (; i_b < b->num_fences; i_b++)
 		sync_fence_add_pt(fence, &i, b->cbs[i_b].sync_pt);

 	if (num_fences > i)
 		atomic_sub(num_fences - i, &fence->status);
 	fence->num_fences = i;

 	sync_fence_debug_add(fence);
 	return fence;
 }
 EXPORT_SYMBOL(sync_fence_merge);

 int sync_fence_wake_up_wq(wait_queue_t *curr, unsigned mode,
 				 int wake_flags, void *key)
 {
 	struct sync_fence_waiter *wait;

 	wait = container_of(curr, struct sync_fence_waiter, work);
 	list_del_init(&wait->work.task_list);

 	wait->callback(wait->work.private, wait);
 	return 1;
 }

 int sync_fence_wait_async(struct sync_fence *fence,
 			  struct sync_fence_waiter *waiter)
 {
 	int err = atomic_read(&fence->status);
 	unsigned long flags;

 	if (err < 0)
 		return err;

 	if (!err)
 		return 1;

 	init_waitqueue_func_entry(&waiter->work, sync_fence_wake_up_wq);
 	waiter->work.private = fence;

 	spin_lock_irqsave(&fence->wq.lock, flags);
 	err = atomic_read(&fence->status);
 	if (err > 0)
 		__add_wait_queue_tail(&fence->wq, &waiter->work);
 	spin_unlock_irqrestore(&fence->wq.lock, flags);

 	if (err < 0)
 		return err;

 	return !err;
 }
 EXPORT_SYMBOL(sync_fence_wait_async);

 int sync_fence_cancel_async(struct sync_fence *fence,
 			     struct sync_fence_waiter *waiter)
 {
 	unsigned long flags;
 	int ret = 0;

 	spin_lock_irqsave(&fence->wq.lock, flags);
 	if (!list_empty(&waiter->work.task_list))
 		list_del_init(&waiter->work.task_list);
 	else
 		ret = -ENOENT;
 	spin_unlock_irqrestore(&fence->wq.lock, flags);
 	return ret;
 }
 EXPORT_SYMBOL(sync_fence_cancel_async);

 int sync_fence_wait(struct sync_fence *fence, long timeout)
 {
 	long ret;
 	int i;

 	if (timeout < 0)
 		timeout = MAX_SCHEDULE_TIMEOUT;
 	else
 		timeout = msecs_to_jiffies(timeout);

 	trace_sync_wait(fence, 1);
 	for (i = 0; i < fence->num_fences; ++i)
 		trace_sync_pt(fence->cbs[i].sync_pt);
 	ret = wait_event_interruptible_timeout(fence->wq,
 					       atomic_read(&fence->status) <= 0,
 					       timeout);
 	trace_sync_wait(fence, 0);

 	if (ret < 0) {
 		return ret;
 	} else if (ret == 0) {
 		if (timeout) {
 			pr_info("fence timeout on [%p] after %dms\n", fence,
 				jiffies_to_msecs(timeout));
 			sync_dump();
 		}
 		return -ETIME;
 	}

 	ret = atomic_read(&fence->status);
 	if (ret) {
 		pr_info("fence error %ld on [%p]\n", ret, fence);
 		sync_dump();
 	}
 	return ret;
 }
 EXPORT_SYMBOL(sync_fence_wait);

 static const char *android_fence_get_driver_name(struct fence *fence)
 {
 	struct sync_pt *pt = container_of(fence, struct sync_pt, base);
 	struct sync_timeline *parent = sync_pt_parent(pt);

 	return parent->ops->driver_name;
 }

 static const char *android_fence_get_timeline_name(struct fence *fence)
 {
 	struct sync_pt *pt = container_of(fence, struct sync_pt, base);
 	struct sync_timeline *parent = sync_pt_parent(pt);

 	return parent->name;
 }

 static void android_fence_release(struct fence *fence)
 {
 	struct sync_pt *pt = container_of(fence, struct sync_pt, base);
 	struct sync_timeline *parent = sync_pt_parent(pt);
 	unsigned long flags;

 	spin_lock_irqsave(fence->lock, flags);
 	list_del(&pt->child_list);
 	if (WARN_ON_ONCE(!list_empty(&pt->active_list)))
 		list_del(&pt->active_list);
 	spin_unlock_irqrestore(fence->lock, flags);

 	if (parent->ops->free_pt)
 		parent->ops->free_pt(pt);

 	sync_timeline_put(parent);
 	fence_free(&pt->base);
 }

 static bool android_fence_signaled(struct fence *fence)
 {
 	struct sync_pt *pt = container_of(fence, struct sync_pt, base);
 	struct sync_timeline *parent = sync_pt_parent(pt);
 	int ret;

 	ret = parent->ops->has_signaled(pt);
 	if (ret < 0)
 		fence->status = ret;
 	return ret;
 }

 static bool android_fence_enable_signaling(struct fence *fence)
 {
 	struct sync_pt *pt = container_of(fence, struct sync_pt, base);
 	struct sync_timeline *parent = sync_pt_parent(pt);

 	if (android_fence_signaled(fence))
 		return false;

 	list_add_tail(&pt->active_list, &parent->active_list_head);
 	return true;
 }

 static int android_fence_fill_driver_data(struct fence *fence,
 					  void *data, int size)
 {
 	struct sync_pt *pt = container_of(fence, struct sync_pt, base);
 	struct sync_timeline *parent = sync_pt_parent(pt);

 	if (!parent->ops->fill_driver_data)
 		return 0;
 	return parent->ops->fill_driver_data(pt, data, size);
 }

 static void android_fence_value_str(struct fence *fence,
 				    char *str, int size)
 {
 	struct sync_pt *pt = container_of(fence, struct sync_pt, base);
 	struct sync_timeline *parent = sync_pt_parent(pt);

 	if (!parent->ops->pt_value_str) {
 		if (size)
 			*str = 0;
 		return;
 	}
 	parent->ops->pt_value_str(pt, str, size);
 }

 static void android_fence_timeline_value_str(struct fence *fence,
 					     char *str, int size)
 {
 	struct sync_pt *pt = container_of(fence, struct sync_pt, base);
 	struct sync_timeline *parent = sync_pt_parent(pt);

 	if (!parent->ops->timeline_value_str) {
 		if (size)
 			*str = 0;
 		return;
 	}
 	parent->ops->timeline_value_str(parent, str, size);
 }

 static const struct fence_ops android_fence_ops = {
 	.get_driver_name = android_fence_get_driver_name,
 	.get_timeline_name = android_fence_get_timeline_name,
 	.enable_signaling = android_fence_enable_signaling,
 	.signaled = android_fence_signaled,
 	.wait = fence_default_wait,
 	.release = android_fence_release,
 	.fill_driver_data = android_fence_fill_driver_data,
 	.fence_value_str = android_fence_value_str,
 	.timeline_value_str = android_fence_timeline_value_str,
 };

 static void sync_fence_free(struct kref *kref)
 {
 	struct sync_fence *fence = container_of(kref, struct sync_fence, kref);
 	int i, status = atomic_read(&fence->status);

 	for (i = 0; i < fence->num_fences; ++i) {
 		if (status)
 			fence_remove_callback(fence->cbs[i].sync_pt,
 					      &fence->cbs[i].cb);
 		fence_put(fence->cbs[i].sync_pt);
 	}

 	kfree(fence);
 }

 static int sync_fence_release(struct inode *inode, struct file *file)
 {
 	struct sync_fence *fence = file->private_data;

 	sync_fence_debug_remove(fence);

 	kref_put(&fence->kref, sync_fence_free);
 	return 0;
 }

 static unsigned int sync_fence_poll(struct file *file, poll_table *wait)
 {
 	struct sync_fence *fence = file->private_data;
 	int status;

 	poll_wait(file, &fence->wq, wait);

 	status = atomic_read(&fence->status);

 	if (!status)
 		return POLLIN;
 	else if (status < 0)
 		return POLLERR;
 	return 0;
 }

 static long sync_fence_ioctl_wait(struct sync_fence *fence, unsigned long arg)
 {
 	__s32 value;

 	if (copy_from_user(&value, (void __user *)arg, sizeof(value)))
 		return -EFAULT;

 	return sync_fence_wait(fence, value);
 }

 static long sync_fence_ioctl_merge(struct sync_fence *fence, unsigned long arg)
 {
 	int fd = get_unused_fd_flags(O_CLOEXEC);
 	int err;
 	struct sync_fence *fence2, *fence3;
 	struct sync_merge_data data;

 	if (fd < 0)
 		return fd;

 	if (copy_from_user(&data, (void __user *)arg, sizeof(data))) {
 		err = -EFAULT;
 		goto err_put_fd;
 	}

 	fence2 = sync_fence_fdget(data.fd2);
 	if (fence2 == NULL) {
 		err = -ENOENT;
 		goto err_put_fd;
 	}

 	data.name[sizeof(data.name) - 1] = '\0';
 	fence3 = sync_fence_merge(data.name, fence, fence2);
 	if (fence3 == NULL) {
 		err = -ENOMEM;
 		goto err_put_fence2;
 	}

 	data.fence = fd;
 	if (copy_to_user((void __user *)arg, &data, sizeof(data))) {
 		err = -EFAULT;
 		goto err_put_fence3;
 	}

 	sync_fence_install(fence3, fd);
 	sync_fence_put(fence2);
 	return 0;

 err_put_fence3:
 	sync_fence_put(fence3);

 err_put_fence2:
 	sync_fence_put(fence2);

 err_put_fd:
 	put_unused_fd(fd);
 	return err;
 }

 static int sync_fill_pt_info(struct fence *fence, void *data, int size)
 {
 	struct sync_pt_info *info = data;
 	int ret;

 	if (size < sizeof(struct sync_pt_info))
 		return -ENOMEM;

 	info->len = sizeof(struct sync_pt_info);

 	if (fence->ops->fill_driver_data) {
 		ret = fence->ops->fill_driver_data(fence, info->driver_data,
 						   size - sizeof(*info));
 		if (ret < 0)
 			return ret;

 		info->len += ret;
 	}

 	strlcpy(info->obj_name, fence->ops->get_timeline_name(fence),
 		sizeof(info->obj_name));
 	strlcpy(info->driver_name, fence->ops->get_driver_name(fence),
 		sizeof(info->driver_name));
 	if (fence_is_signaled(fence))
 		info->status = fence->status >= 0 ? 1 : fence->status;
 	else
 		info->status = 0;
 	info->timestamp_ns = ktime_to_ns(fence->timestamp);

 	return info->len;
 }

 static long sync_fence_ioctl_fence_info(struct sync_fence *fence,
 					unsigned long arg)
 {
 	struct sync_fence_info_data *data;
 	__u32 size;
 	__u32 len = 0;
 	int ret, i;

 	if (copy_from_user(&size, (void __user *)arg, sizeof(size)))
 		return -EFAULT;

 	if (size < sizeof(struct sync_fence_info_data))
 		return -EINVAL;

 	if (size > 4096)
 		size = 4096;

 	data = kzalloc(size, GFP_KERNEL);
 	if (data == NULL)
 		return -ENOMEM;

 	strlcpy(data->name, fence->name, sizeof(data->name));
 	data->status = atomic_read(&fence->status);
 	if (data->status >= 0)
 		data->status = !data->status;

 	len = sizeof(struct sync_fence_info_data);

 	for (i = 0; i < fence->num_fences; ++i) {
 		struct fence *pt = fence->cbs[i].sync_pt;

 		ret = sync_fill_pt_info(pt, (u8 *)data + len, size - len);

 		if (ret < 0)
 			goto out;

 		len += ret;
 	}

 	data->len = len;

 	if (copy_to_user((void __user *)arg, data, len))
 		ret = -EFAULT;
 	else
 		ret = 0;

 out:
 	kfree(data);

 	return ret;
 }

 static long sync_fence_ioctl(struct file *file, unsigned int cmd,
 			     unsigned long arg)
 {
 	struct sync_fence *fence = file->private_data;

 	switch (cmd) {
 	case SYNC_IOC_WAIT:
 		return sync_fence_ioctl_wait(fence, arg);

 	case SYNC_IOC_MERGE:
 		return sync_fence_ioctl_merge(fence, arg);

 	case SYNC_IOC_FENCE_INFO:
 		return sync_fence_ioctl_fence_info(fence, arg);

 	default:
 		return -ENOTTY;
 	}
 }

 static const struct file_operations sync_fence_fops = {
 	.release = sync_fence_release,
 	.poll = sync_fence_poll,
 	.unlocked_ioctl = sync_fence_ioctl,
 	.compat_ioctl = sync_fence_ioctl,
 };
	/*
	* 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 const struct fence_ops android_fence_ops;
	static const struct file_operations sync_fence_fops;

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

	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;
	obj->context = fence_context_alloc(1);
	strlcpy(obj->name, name, sizeof(obj->name));

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

	sync_timeline_debug_add(obj);

	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);

	sync_timeline_debug_remove(obj);

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

	kfree(obj);
	}

	static void sync_timeline_get(struct sync_timeline *obj)
	{
	kref_get(&obj->kref);
	}

	static void sync_timeline_put(struct sync_timeline *obj)
	{
	kref_put(&obj->kref, sync_timeline_free);
	}

	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);
	sync_timeline_put(obj);
	}
	EXPORT_SYMBOL(sync_timeline_destroy);

	void sync_timeline_signal(struct sync_timeline *obj)
	{
	unsigned long flags;
	LIST_HEAD(signaled_pts);
	struct sync_pt pt, next;

	trace_sync_timeline(obj);

	spin_lock_irqsave(&obj->child_list_lock, flags);

	list_for_each_entry_safe(pt, next, &obj->active_list_head,
	active_list) {
	if (fence_is_signaled_locked(&pt->base))
	list_del(&pt->active_list);
	}

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

	struct sync_pt sync_pt_create(struct sync_timeline obj, int size)
	{
	unsigned long flags;
	struct sync_pt *pt;

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

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

	spin_lock_irqsave(&obj->child_list_lock, flags);
	sync_timeline_get(obj);
	fence_init(&pt->base, &android_fence_ops, &obj->child_list_lock,
	obj->context, ++obj->value);
	list_add_tail(&pt->child_list, &obj->child_list_head);
	INIT_LIST_HEAD(&pt->active_list);
	spin_unlock_irqrestore(&obj->child_list_lock, flags);
	return pt;
	}
	EXPORT_SYMBOL(sync_pt_create);

	void sync_pt_free(struct sync_pt *pt)
	{
	fence_put(&pt->base);
	}
	EXPORT_SYMBOL(sync_pt_free);

	static struct sync_fence sync_fence_alloc(int size, const char name)
	{
	struct sync_fence *fence;

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

	fence->file = anon_inode_getfile("sync_fence", &sync_fence_fops,
	fence, 0);
	if (IS_ERR(fence->file))
	goto err;

	kref_init(&fence->kref);
	strlcpy(fence->name, name, sizeof(fence->name));

	init_waitqueue_head(&fence->wq);

	return fence;

	err:
	kfree(fence);
	return NULL;
	}

	static void fence_check_cb_func(struct fence f, struct fence_cb cb)
	{
	struct sync_fence_cb *check;
	struct sync_fence *fence;

	check = container_of(cb, struct sync_fence_cb, cb);
	fence = check->fence;

	if (atomic_dec_and_test(&fence->status))
	wake_up_all(&fence->wq);
	}

	/* TODO: implement a create which takes more that one sync_pt */
	struct sync_fence sync_fence_create(const char name, struct sync_pt *pt)
	{
	struct sync_fence *fence;

	fence = sync_fence_alloc(offsetof(struct sync_fence, cbs[1]), name);
	if (fence == NULL)
	return NULL;

	fence->num_fences = 1;
	atomic_set(&fence->status, 1);

	fence->cbs[0].sync_pt = &pt->base;
	fence->cbs[0].fence = fence;
	if (fence_add_callback(&pt->base, &fence->cbs[0].cb,
	fence_check_cb_func))
	atomic_dec(&fence->status);

	sync_fence_debug_add(fence);

	return fence;
	}
	EXPORT_SYMBOL(sync_fence_create);

	struct sync_fence *sync_fence_fdget(int fd)
	{
	struct file *file = fget(fd);

	if (file == NULL)
	return NULL;

	if (file->f_op != &sync_fence_fops)
	goto err;

	return file->private_data;

	err:
	fput(file);
	return NULL;
	}
	EXPORT_SYMBOL(sync_fence_fdget);

	void sync_fence_put(struct sync_fence *fence)
	{
	fput(fence->file);
	}
	EXPORT_SYMBOL(sync_fence_put);

	void sync_fence_install(struct sync_fence *fence, int fd)
	{
	fd_install(fd, fence->file);
	}
	EXPORT_SYMBOL(sync_fence_install);

	static void sync_fence_add_pt(struct sync_fence *fence,
	int i, struct fence pt)
	{
	fence->cbs[*i].sync_pt = pt;
	fence->cbs[*i].fence = fence;

	if (!fence_add_callback(pt, &fence->cbs[*i].cb, fence_check_cb_func)) {
	fence_get(pt);
	(*i)++;
	}
	}

	struct sync_fence sync_fence_merge(const char name,
	struct sync_fence a, struct sync_fence b)
	{
	int num_fences = a->num_fences + b->num_fences;
	struct sync_fence *fence;
	int i, i_a, i_b;
	unsigned long size = offsetof(struct sync_fence, cbs[num_fences]);

	fence = sync_fence_alloc(size, name);
	if (fence == NULL)
	return NULL;

	atomic_set(&fence->status, num_fences);

	/*
	* Assume sync_fence a and b are both ordered and have no
	* duplicates with the same context.
	*
	* If a sync_fence can only be created with sync_fence_merge
	* and sync_fence_create, this is a reasonable assumption.
	*/
	for (i = i_a = i_b = 0; i_a < a->num_fences && i_b < b->num_fences; ) {
	struct fence *pt_a = a->cbs[i_a].sync_pt;
	struct fence *pt_b = b->cbs[i_b].sync_pt;

	if (pt_a->context < pt_b->context) {
	sync_fence_add_pt(fence, &i, pt_a);

	i_a++;
	} else if (pt_a->context > pt_b->context) {
	sync_fence_add_pt(fence, &i, pt_b);

	i_b++;
	} else {
	if (pt_a->seqno - pt_b->seqno <= INT_MAX)
	sync_fence_add_pt(fence, &i, pt_a);
	else
	sync_fence_add_pt(fence, &i, pt_b);

	i_a++;
	i_b++;
	}
	}

	for (; i_a < a->num_fences; i_a++)
	sync_fence_add_pt(fence, &i, a->cbs[i_a].sync_pt);

	for (; i_b < b->num_fences; i_b++)
	sync_fence_add_pt(fence, &i, b->cbs[i_b].sync_pt);

	if (num_fences > i)
	atomic_sub(num_fences - i, &fence->status);
	fence->num_fences = i;

	sync_fence_debug_add(fence);
	return fence;
	}
	EXPORT_SYMBOL(sync_fence_merge);

	int sync_fence_wake_up_wq(wait_queue_t *curr, unsigned mode,
	int wake_flags, void *key)
	{
	struct sync_fence_waiter *wait;

	wait = container_of(curr, struct sync_fence_waiter, work);
	list_del_init(&wait->work.task_list);

	wait->callback(wait->work.private, wait);
	return 1;
	}

	int sync_fence_wait_async(struct sync_fence *fence,
	struct sync_fence_waiter *waiter)
	{
	int err = atomic_read(&fence->status);
	unsigned long flags;

	if (err < 0)
	return err;

	if (!err)
	return 1;

	init_waitqueue_func_entry(&waiter->work, sync_fence_wake_up_wq);
	waiter->work.private = fence;

	spin_lock_irqsave(&fence->wq.lock, flags);
	err = atomic_read(&fence->status);
	if (err > 0)
	__add_wait_queue_tail(&fence->wq, &waiter->work);
	spin_unlock_irqrestore(&fence->wq.lock, flags);

	if (err < 0)
	return err;

	return !err;
	}
	EXPORT_SYMBOL(sync_fence_wait_async);

	int sync_fence_cancel_async(struct sync_fence *fence,
	struct sync_fence_waiter *waiter)
	{
	unsigned long flags;
	int ret = 0;

	spin_lock_irqsave(&fence->wq.lock, flags);
	if (!list_empty(&waiter->work.task_list))
	list_del_init(&waiter->work.task_list);
	else
	ret = -ENOENT;
	spin_unlock_irqrestore(&fence->wq.lock, flags);
	return ret;
	}
	EXPORT_SYMBOL(sync_fence_cancel_async);

	int sync_fence_wait(struct sync_fence *fence, long timeout)
	{
	long ret;
	int i;

	if (timeout < 0)
	timeout = MAX_SCHEDULE_TIMEOUT;
	else
	timeout = msecs_to_jiffies(timeout);

	trace_sync_wait(fence, 1);
	for (i = 0; i < fence->num_fences; ++i)
	trace_sync_pt(fence->cbs[i].sync_pt);
	ret = wait_event_interruptible_timeout(fence->wq,
	atomic_read(&fence->status) <= 0,
	timeout);
	trace_sync_wait(fence, 0);

	if (ret < 0) {
	return ret;
	} else if (ret == 0) {
	if (timeout) {
	pr_info("fence timeout on [%p] after %dms\n", fence,
	jiffies_to_msecs(timeout));
	sync_dump();
	}
	return -ETIME;
	}

	ret = atomic_read(&fence->status);
	if (ret) {
	pr_info("fence error %ld on [%p]\n", ret, fence);
	sync_dump();
	}
	return ret;
	}
	EXPORT_SYMBOL(sync_fence_wait);

	static const char android_fence_get_driver_name(struct fence fence)
	{
	struct sync_pt *pt = container_of(fence, struct sync_pt, base);
	struct sync_timeline *parent = sync_pt_parent(pt);

	return parent->ops->driver_name;
	}

	static const char android_fence_get_timeline_name(struct fence fence)
	{
	struct sync_pt *pt = container_of(fence, struct sync_pt, base);
	struct sync_timeline *parent = sync_pt_parent(pt);

	return parent->name;
	}

	static void android_fence_release(struct fence *fence)
	{
	struct sync_pt *pt = container_of(fence, struct sync_pt, base);
	struct sync_timeline *parent = sync_pt_parent(pt);
	unsigned long flags;

	spin_lock_irqsave(fence->lock, flags);
	list_del(&pt->child_list);
	if (WARN_ON_ONCE(!list_empty(&pt->active_list)))
	list_del(&pt->active_list);
	spin_unlock_irqrestore(fence->lock, flags);

	if (parent->ops->free_pt)
	parent->ops->free_pt(pt);

	sync_timeline_put(parent);
	fence_free(&pt->base);
	}

	static bool android_fence_signaled(struct fence *fence)
	{
	struct sync_pt *pt = container_of(fence, struct sync_pt, base);
	struct sync_timeline *parent = sync_pt_parent(pt);
	int ret;

	ret = parent->ops->has_signaled(pt);
	if (ret < 0)
	fence->status = ret;
	return ret;
	}

	static bool android_fence_enable_signaling(struct fence *fence)
	{
	struct sync_pt *pt = container_of(fence, struct sync_pt, base);
	struct sync_timeline *parent = sync_pt_parent(pt);

	if (android_fence_signaled(fence))
	return false;

	list_add_tail(&pt->active_list, &parent->active_list_head);
	return true;
	}

	static int android_fence_fill_driver_data(struct fence *fence,
	void *data, int size)
	{
	struct sync_pt *pt = container_of(fence, struct sync_pt, base);
	struct sync_timeline *parent = sync_pt_parent(pt);

	if (!parent->ops->fill_driver_data)
	return 0;
	return parent->ops->fill_driver_data(pt, data, size);
	}

	static void android_fence_value_str(struct fence *fence,
	char *str, int size)
	{
	struct sync_pt *pt = container_of(fence, struct sync_pt, base);
	struct sync_timeline *parent = sync_pt_parent(pt);

	if (!parent->ops->pt_value_str) {
	if (size)
	*str = 0;
	return;
	}
	parent->ops->pt_value_str(pt, str, size);
	}

	static void android_fence_timeline_value_str(struct fence *fence,
	char *str, int size)
	{
	struct sync_pt *pt = container_of(fence, struct sync_pt, base);
	struct sync_timeline *parent = sync_pt_parent(pt);

	if (!parent->ops->timeline_value_str) {
	if (size)
	*str = 0;
	return;
	}
	parent->ops->timeline_value_str(parent, str, size);
	}

	static const struct fence_ops android_fence_ops = {
	.get_driver_name = android_fence_get_driver_name,
	.get_timeline_name = android_fence_get_timeline_name,
	.enable_signaling = android_fence_enable_signaling,
	.signaled = android_fence_signaled,
	.wait = fence_default_wait,
	.release = android_fence_release,
	.fill_driver_data = android_fence_fill_driver_data,
	.fence_value_str = android_fence_value_str,
	.timeline_value_str = android_fence_timeline_value_str,
	};

	static void sync_fence_free(struct kref *kref)
	{
	struct sync_fence *fence = container_of(kref, struct sync_fence, kref);
	int i, status = atomic_read(&fence->status);

	for (i = 0; i < fence->num_fences; ++i) {
	if (status)
	fence_remove_callback(fence->cbs[i].sync_pt,
	&fence->cbs[i].cb);
	fence_put(fence->cbs[i].sync_pt);
	}

	kfree(fence);
	}

	static int sync_fence_release(struct inode inode, struct file file)
	{
	struct sync_fence *fence = file->private_data;

	sync_fence_debug_remove(fence);

	kref_put(&fence->kref, sync_fence_free);
	return 0;
	}

	static unsigned int sync_fence_poll(struct file file, poll_table wait)
	{
	struct sync_fence *fence = file->private_data;
	int status;

	poll_wait(file, &fence->wq, wait);

	status = atomic_read(&fence->status);

	if (!status)
	return POLLIN;
	else if (status < 0)
	return POLLERR;
	return 0;
	}

	static long sync_fence_ioctl_wait(struct sync_fence *fence, unsigned long arg)
	{
	__s32 value;

	if (copy_from_user(&value, (void __user *)arg, sizeof(value)))
	return -EFAULT;

	return sync_fence_wait(fence, value);
	}

	static long sync_fence_ioctl_merge(struct sync_fence *fence, unsigned long arg)
	{
	int fd = get_unused_fd_flags(O_CLOEXEC);
	int err;
	struct sync_fence fence2, fence3;
	struct sync_merge_data data;

	if (fd < 0)
	return fd;

	if (copy_from_user(&data, (void __user *)arg, sizeof(data))) {
	err = -EFAULT;
	goto err_put_fd;
	}

	fence2 = sync_fence_fdget(data.fd2);
	if (fence2 == NULL) {
	err = -ENOENT;
	goto err_put_fd;
	}

	data.name[sizeof(data.name) - 1] = '\0';
	fence3 = sync_fence_merge(data.name, fence, fence2);
	if (fence3 == NULL) {
	err = -ENOMEM;
	goto err_put_fence2;
	}

	data.fence = fd;
	if (copy_to_user((void __user *)arg, &data, sizeof(data))) {
	err = -EFAULT;
	goto err_put_fence3;
	}

	sync_fence_install(fence3, fd);
	sync_fence_put(fence2);
	return 0;

	err_put_fence3:
	sync_fence_put(fence3);

	err_put_fence2:
	sync_fence_put(fence2);

	err_put_fd:
	put_unused_fd(fd);
	return err;
	}

	static int sync_fill_pt_info(struct fence fence, void data, int size)
	{
	struct sync_pt_info *info = data;
	int ret;

	if (size < sizeof(struct sync_pt_info))
	return -ENOMEM;

	info->len = sizeof(struct sync_pt_info);

	if (fence->ops->fill_driver_data) {
	ret = fence->ops->fill_driver_data(fence, info->driver_data,
	size - sizeof(*info));
	if (ret < 0)
	return ret;

	info->len += ret;
	}

	strlcpy(info->obj_name, fence->ops->get_timeline_name(fence),
	sizeof(info->obj_name));
	strlcpy(info->driver_name, fence->ops->get_driver_name(fence),
	sizeof(info->driver_name));
	if (fence_is_signaled(fence))
	info->status = fence->status >= 0 ? 1 : fence->status;
	else
	info->status = 0;
	info->timestamp_ns = ktime_to_ns(fence->timestamp);

	return info->len;
	}

	static long sync_fence_ioctl_fence_info(struct sync_fence *fence,
	unsigned long arg)
	{
	struct sync_fence_info_data *data;
	__u32 size;
	__u32 len = 0;
	int ret, i;

	if (copy_from_user(&size, (void __user *)arg, sizeof(size)))
	return -EFAULT;

	if (size < sizeof(struct sync_fence_info_data))
	return -EINVAL;

	if (size > 4096)
	size = 4096;

	data = kzalloc(size, GFP_KERNEL);
	if (data == NULL)
	return -ENOMEM;

	strlcpy(data->name, fence->name, sizeof(data->name));
	data->status = atomic_read(&fence->status);
	if (data->status >= 0)
	data->status = !data->status;

	len = sizeof(struct sync_fence_info_data);

	for (i = 0; i < fence->num_fences; ++i) {
	struct fence *pt = fence->cbs[i].sync_pt;

	ret = sync_fill_pt_info(pt, (u8 *)data + len, size - len);

	if (ret < 0)
	goto out;

	len += ret;
	}

	data->len = len;

	if (copy_to_user((void __user *)arg, data, len))
	ret = -EFAULT;
	else
	ret = 0;

	out:
	kfree(data);

	return ret;
	}

	static long sync_fence_ioctl(struct file *file, unsigned int cmd,
	unsigned long arg)
	{
	struct sync_fence *fence = file->private_data;

	switch (cmd) {
	case SYNC_IOC_WAIT:
	return sync_fence_ioctl_wait(fence, arg);

	case SYNC_IOC_MERGE:
	return sync_fence_ioctl_merge(fence, arg);

	case SYNC_IOC_FENCE_INFO:
	return sync_fence_ioctl_fence_info(fence, arg);

	default:
	return -ENOTTY;
	}
	}

	static const struct file_operations sync_fence_fops = {
	.release = sync_fence_release,
	.poll = sync_fence_poll,
	.unlocked_ioctl = sync_fence_ioctl,
	.compat_ioctl = sync_fence_ioctl,
	};