drivers/dma-buf/sync_file.c - kernel/quantenna - Git at Google

 /*
  * drivers/dma-buf/sync_file.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/export.h>
 #include <linux/file.h>
 #include <linux/fs.h>
 #include <linux/kernel.h>
 #include <linux/poll.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/uaccess.h>
 #include <linux/anon_inodes.h>
 #include <linux/sync_file.h>
 #include <uapi/linux/sync_file.h>

 static const struct file_operations sync_file_fops;

 static struct sync_file *sync_file_alloc(int size)
 {
 	struct sync_file *sync_file;

 	sync_file = kzalloc(size, GFP_KERNEL);
 	if (!sync_file)
 		return NULL;

 	sync_file->file = anon_inode_getfile("sync_file", &sync_file_fops,
 					     sync_file, 0);
 	if (IS_ERR(sync_file->file))
 		goto err;

 	kref_init(&sync_file->kref);

 	init_waitqueue_head(&sync_file->wq);

 	return sync_file;

 err:
 	kfree(sync_file);
 	return NULL;
 }

 static void fence_check_cb_func(struct fence *f, struct fence_cb *cb)
 {
 	struct sync_file_cb *check;
 	struct sync_file *sync_file;

 	check = container_of(cb, struct sync_file_cb, cb);
 	sync_file = check->sync_file;

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

 /**
  * sync_file_create() - creates a sync file
  * @fence:	fence to add to the sync_fence
  *
  * Creates a sync_file containg @fence. Once this is called, the sync_file
  * takes ownership of @fence. The sync_file can be released with
  * fput(sync_file->file). Returns the sync_file or NULL in case of error.
  */
 struct sync_file *sync_file_create(struct fence *fence)
 {
 	struct sync_file *sync_file;

 	sync_file = sync_file_alloc(offsetof(struct sync_file, cbs[1]));
 	if (!sync_file)
 		return NULL;

 	sync_file->num_fences = 1;
 	atomic_set(&sync_file->status, 1);
 	snprintf(sync_file->name, sizeof(sync_file->name), "%s-%s%d-%d",
 		 fence->ops->get_driver_name(fence),
 		 fence->ops->get_timeline_name(fence), fence->context,
 		 fence->seqno);

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

 	return sync_file;
 }
 EXPORT_SYMBOL(sync_file_create);

 /**
  * sync_file_fdget() - get a sync_file from an fd
  * @fd:		fd referencing a fence
  *
  * Ensures @fd references a valid sync_file, increments the refcount of the
  * backing file. Returns the sync_file or NULL in case of error.
  */
 static struct sync_file *sync_file_fdget(int fd)
 {
 	struct file *file = fget(fd);

 	if (!file)
 		return NULL;

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

 	return file->private_data;

 err:
 	fput(file);
 	return NULL;
 }

 static void sync_file_add_pt(struct sync_file *sync_file, int *i,
 			     struct fence *fence)
 {
 	sync_file->cbs[*i].fence = fence;
 	sync_file->cbs[*i].sync_file = sync_file;

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

 /**
  * sync_file_merge() - merge two sync_files
  * @name:	name of new fence
  * @a:		sync_file a
  * @b:		sync_file b
  *
  * Creates a new sync_file which contains copies of all the fences in both
  * @a and @b.  @a and @b remain valid, independent sync_file. Returns the
  * new merged sync_file or NULL in case of error.
  */
 static struct sync_file *sync_file_merge(const char *name, struct sync_file *a,
 					 struct sync_file *b)
 {
 	int num_fences = a->num_fences + b->num_fences;
 	struct sync_file *sync_file;
 	int i, i_a, i_b;
 	unsigned long size = offsetof(struct sync_file, cbs[num_fences]);

 	sync_file = sync_file_alloc(size);
 	if (!sync_file)
 		return NULL;

 	atomic_set(&sync_file->status, num_fences);

 	/*
 	 * Assume sync_file a and b are both ordered and have no
 	 * duplicates with the same context.
 	 *
 	 * If a sync_file can only be created with sync_file_merge
 	 * and sync_file_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].fence;
 		struct fence *pt_b = b->cbs[i_b].fence;

 		if (pt_a->context < pt_b->context) {
 			sync_file_add_pt(sync_file, &i, pt_a);

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

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

 			i_a++;
 			i_b++;
 		}
 	}

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

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

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

 	strlcpy(sync_file->name, name, sizeof(sync_file->name));
 	return sync_file;
 }

 static void sync_file_free(struct kref *kref)
 {
 	struct sync_file *sync_file = container_of(kref, struct sync_file,
 						     kref);
 	int i;

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

 	kfree(sync_file);
 }

 static int sync_file_release(struct inode *inode, struct file *file)
 {
 	struct sync_file *sync_file = file->private_data;

 	kref_put(&sync_file->kref, sync_file_free);
 	return 0;
 }

 static unsigned int sync_file_poll(struct file *file, poll_table *wait)
 {
 	struct sync_file *sync_file = file->private_data;
 	int status;

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

 	status = atomic_read(&sync_file->status);

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

 static long sync_file_ioctl_merge(struct sync_file *sync_file,
 				  unsigned long arg)
 {
 	int fd = get_unused_fd_flags(O_CLOEXEC);
 	int err;
 	struct sync_file *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;
 	}

 	if (data.flags || data.pad) {
 		err = -EINVAL;
 		goto err_put_fd;
 	}

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

 	data.name[sizeof(data.name) - 1] = '\0';
 	fence3 = sync_file_merge(data.name, sync_file, fence2);
 	if (!fence3) {
 		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;
 	}

 	fd_install(fd, fence3->file);
 	fput(fence2->file);
 	return 0;

 err_put_fence3:
 	fput(fence3->file);

 err_put_fence2:
 	fput(fence2->file);

 err_put_fd:
 	put_unused_fd(fd);
 	return err;
 }

 static void sync_fill_fence_info(struct fence *fence,
 				 struct sync_fence_info *info)
 {
 	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);
 }

 static long sync_file_ioctl_fence_info(struct sync_file *sync_file,
 				       unsigned long arg)
 {
 	struct sync_file_info info;
 	struct sync_fence_info *fence_info = NULL;
 	__u32 size;
 	int ret, i;

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

 	if (info.flags || info.pad)
 		return -EINVAL;

 	/*
 	 * Passing num_fences = 0 means that userspace doesn't want to
 	 * retrieve any sync_fence_info. If num_fences = 0 we skip filling
 	 * sync_fence_info and return the actual number of fences on
 	 * info->num_fences.
 	 */
 	if (!info.num_fences)
 		goto no_fences;

 	if (info.num_fences < sync_file->num_fences)
 		return -EINVAL;

 	size = sync_file->num_fences * sizeof(*fence_info);
 	fence_info = kzalloc(size, GFP_KERNEL);
 	if (!fence_info)
 		return -ENOMEM;

 	for (i = 0; i < sync_file->num_fences; ++i)
 		sync_fill_fence_info(sync_file->cbs[i].fence, &fence_info[i]);

 	if (copy_to_user(u64_to_user_ptr(info.sync_fence_info), fence_info,
 			 size)) {
 		ret = -EFAULT;
 		goto out;
 	}

 no_fences:
 	strlcpy(info.name, sync_file->name, sizeof(info.name));
 	info.status = atomic_read(&sync_file->status);
 	if (info.status >= 0)
 		info.status = !info.status;

 	info.num_fences = sync_file->num_fences;

 	if (copy_to_user((void __user *)arg, &info, sizeof(info)))
 		ret = -EFAULT;
 	else
 		ret = 0;

 out:
 	kfree(fence_info);

 	return ret;
 }

 static long sync_file_ioctl(struct file *file, unsigned int cmd,
 			    unsigned long arg)
 {
 	struct sync_file *sync_file = file->private_data;

 	switch (cmd) {
 	case SYNC_IOC_MERGE:
 		return sync_file_ioctl_merge(sync_file, arg);

 	case SYNC_IOC_FILE_INFO:
 		return sync_file_ioctl_fence_info(sync_file, arg);

 	default:
 		return -ENOTTY;
 	}
 }

 static const struct file_operations sync_file_fops = {
 	.release = sync_file_release,
 	.poll = sync_file_poll,
 	.unlocked_ioctl = sync_file_ioctl,
 	.compat_ioctl = sync_file_ioctl,
 };
	/*
	* drivers/dma-buf/sync_file.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/export.h>
	#include <linux/file.h>
	#include <linux/fs.h>
	#include <linux/kernel.h>
	#include <linux/poll.h>
	#include <linux/sched.h>
	#include <linux/slab.h>
	#include <linux/uaccess.h>
	#include <linux/anon_inodes.h>
	#include <linux/sync_file.h>
	#include <uapi/linux/sync_file.h>

	static const struct file_operations sync_file_fops;

	static struct sync_file *sync_file_alloc(int size)
	{
	struct sync_file *sync_file;

	sync_file = kzalloc(size, GFP_KERNEL);
	if (!sync_file)
	return NULL;

	sync_file->file = anon_inode_getfile("sync_file", &sync_file_fops,
	sync_file, 0);
	if (IS_ERR(sync_file->file))
	goto err;

	kref_init(&sync_file->kref);

	init_waitqueue_head(&sync_file->wq);

	return sync_file;

	err:
	kfree(sync_file);
	return NULL;
	}

	static void fence_check_cb_func(struct fence f, struct fence_cb cb)
	{
	struct sync_file_cb *check;
	struct sync_file *sync_file;

	check = container_of(cb, struct sync_file_cb, cb);
	sync_file = check->sync_file;

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

	/**
	* sync_file_create() - creates a sync file
	* @fence: fence to add to the sync_fence
	*
	* Creates a sync_file containg @fence. Once this is called, the sync_file
	* takes ownership of @fence. The sync_file can be released with
	* fput(sync_file->file). Returns the sync_file or NULL in case of error.
	*/
	struct sync_file sync_file_create(struct fence fence)
	{
	struct sync_file *sync_file;

	sync_file = sync_file_alloc(offsetof(struct sync_file, cbs[1]));
	if (!sync_file)
	return NULL;

	sync_file->num_fences = 1;
	atomic_set(&sync_file->status, 1);
	snprintf(sync_file->name, sizeof(sync_file->name), "%s-%s%d-%d",
	fence->ops->get_driver_name(fence),
	fence->ops->get_timeline_name(fence), fence->context,
	fence->seqno);

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

	return sync_file;
	}
	EXPORT_SYMBOL(sync_file_create);

	/**
	* sync_file_fdget() - get a sync_file from an fd
	* @fd: fd referencing a fence
	*
	* Ensures @fd references a valid sync_file, increments the refcount of the
	* backing file. Returns the sync_file or NULL in case of error.
	*/
	static struct sync_file *sync_file_fdget(int fd)
	{
	struct file *file = fget(fd);

	if (!file)
	return NULL;

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

	return file->private_data;

	err:
	fput(file);
	return NULL;
	}

	static void sync_file_add_pt(struct sync_file sync_file, int i,
	struct fence *fence)
	{
	sync_file->cbs[*i].fence = fence;
	sync_file->cbs[*i].sync_file = sync_file;

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

	/**
	* sync_file_merge() - merge two sync_files
	* @name: name of new fence
	* @a: sync_file a
	* @b: sync_file b
	*
	* Creates a new sync_file which contains copies of all the fences in both
	* @a and @b. @a and @b remain valid, independent sync_file. Returns the
	* new merged sync_file or NULL in case of error.
	*/
	static struct sync_file sync_file_merge(const char name, struct sync_file *a,
	struct sync_file *b)
	{
	int num_fences = a->num_fences + b->num_fences;
	struct sync_file *sync_file;
	int i, i_a, i_b;
	unsigned long size = offsetof(struct sync_file, cbs[num_fences]);

	sync_file = sync_file_alloc(size);
	if (!sync_file)
	return NULL;

	atomic_set(&sync_file->status, num_fences);

	/*
	* Assume sync_file a and b are both ordered and have no
	* duplicates with the same context.
	*
	* If a sync_file can only be created with sync_file_merge
	* and sync_file_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].fence;
	struct fence *pt_b = b->cbs[i_b].fence;

	if (pt_a->context < pt_b->context) {
	sync_file_add_pt(sync_file, &i, pt_a);

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

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

	i_a++;
	i_b++;
	}
	}

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

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

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

	strlcpy(sync_file->name, name, sizeof(sync_file->name));
	return sync_file;
	}

	static void sync_file_free(struct kref *kref)
	{
	struct sync_file *sync_file = container_of(kref, struct sync_file,
	kref);
	int i;

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

	kfree(sync_file);
	}

	static int sync_file_release(struct inode inode, struct file file)
	{
	struct sync_file *sync_file = file->private_data;

	kref_put(&sync_file->kref, sync_file_free);
	return 0;
	}

	static unsigned int sync_file_poll(struct file file, poll_table wait)
	{
	struct sync_file *sync_file = file->private_data;
	int status;

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

	status = atomic_read(&sync_file->status);

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

	static long sync_file_ioctl_merge(struct sync_file *sync_file,
	unsigned long arg)
	{
	int fd = get_unused_fd_flags(O_CLOEXEC);
	int err;
	struct sync_file 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;
	}

	if (data.flags \|\| data.pad) {
	err = -EINVAL;
	goto err_put_fd;
	}

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

	data.name[sizeof(data.name) - 1] = '\0';
	fence3 = sync_file_merge(data.name, sync_file, fence2);
	if (!fence3) {
	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;
	}

	fd_install(fd, fence3->file);
	fput(fence2->file);
	return 0;

	err_put_fence3:
	fput(fence3->file);

	err_put_fence2:
	fput(fence2->file);

	err_put_fd:
	put_unused_fd(fd);
	return err;
	}

	static void sync_fill_fence_info(struct fence *fence,
	struct sync_fence_info *info)
	{
	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);
	}

	static long sync_file_ioctl_fence_info(struct sync_file *sync_file,
	unsigned long arg)
	{
	struct sync_file_info info;
	struct sync_fence_info *fence_info = NULL;
	__u32 size;
	int ret, i;

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

	if (info.flags \|\| info.pad)
	return -EINVAL;

	/*
	* Passing num_fences = 0 means that userspace doesn't want to
	* retrieve any sync_fence_info. If num_fences = 0 we skip filling
	* sync_fence_info and return the actual number of fences on
	* info->num_fences.
	*/
	if (!info.num_fences)
	goto no_fences;

	if (info.num_fences < sync_file->num_fences)
	return -EINVAL;

	size = sync_file->num_fences * sizeof(*fence_info);
	fence_info = kzalloc(size, GFP_KERNEL);
	if (!fence_info)
	return -ENOMEM;

	for (i = 0; i < sync_file->num_fences; ++i)
	sync_fill_fence_info(sync_file->cbs[i].fence, &fence_info[i]);

	if (copy_to_user(u64_to_user_ptr(info.sync_fence_info), fence_info,
	size)) {
	ret = -EFAULT;
	goto out;
	}

	no_fences:
	strlcpy(info.name, sync_file->name, sizeof(info.name));
	info.status = atomic_read(&sync_file->status);
	if (info.status >= 0)
	info.status = !info.status;

	info.num_fences = sync_file->num_fences;

	if (copy_to_user((void __user *)arg, &info, sizeof(info)))
	ret = -EFAULT;
	else
	ret = 0;

	out:
	kfree(fence_info);

	return ret;
	}

	static long sync_file_ioctl(struct file *file, unsigned int cmd,
	unsigned long arg)
	{
	struct sync_file *sync_file = file->private_data;

	switch (cmd) {
	case SYNC_IOC_MERGE:
	return sync_file_ioctl_merge(sync_file, arg);

	case SYNC_IOC_FILE_INFO:
	return sync_file_ioctl_fence_info(sync_file, arg);

	default:
	return -ENOTTY;
	}
	}

	static const struct file_operations sync_file_fops = {
	.release = sync_file_release,
	.poll = sync_file_poll,
	.unlocked_ioctl = sync_file_ioctl,
	.compat_ioctl = sync_file_ioctl,
	};