[linux-2.6-block.git] / drivers / media / media-request.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Media device request objects
 *
 * Copyright 2018 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
 * Copyright (C) 2018 Intel Corporation
 * Copyright (C) 2018 Google, Inc.
 *
 * Author: Hans Verkuil <hans.verkuil@cisco.com>
 * Author: Sakari Ailus <sakari.ailus@linux.intel.com>
 */

#include <linux/anon_inodes.h>
#include <linux/file.h>
#include <linux/refcount.h>

#include <media/media-device.h>
#include <media/media-request.h>

static const char * const request_state[] = {
	[MEDIA_REQUEST_STATE_IDLE]	 = "idle",
	[MEDIA_REQUEST_STATE_VALIDATING] = "validating",
	[MEDIA_REQUEST_STATE_QUEUED]	 = "queued",
	[MEDIA_REQUEST_STATE_COMPLETE]	 = "complete",
	[MEDIA_REQUEST_STATE_CLEANING]	 = "cleaning",
	[MEDIA_REQUEST_STATE_UPDATING]	 = "updating",
};

static const char *
media_request_state_str(enum media_request_state state)
{
	BUILD_BUG_ON(ARRAY_SIZE(request_state) != NR_OF_MEDIA_REQUEST_STATE);

	if (WARN_ON(state >= ARRAY_SIZE(request_state)))
		return "invalid";
	return request_state[state];
}

static void media_request_clean(struct media_request *req)
{
	struct media_request_object *obj, *obj_safe;

	/* Just a sanity check. No other code path is allowed to change this. */
	WARN_ON(req->state != MEDIA_REQUEST_STATE_CLEANING);
	WARN_ON(req->updating_count);
	WARN_ON(req->access_count);

	list_for_each_entry_safe(obj, obj_safe, &req->objects, list) {
		media_request_object_unbind(obj);
		media_request_object_put(obj);
	}

	req->updating_count = 0;
	req->access_count = 0;
	WARN_ON(req->num_incomplete_objects);
	req->num_incomplete_objects = 0;
	wake_up_interruptible_all(&req->poll_wait);
}

static void media_request_release(struct kref *kref)
{
	struct media_request *req =
		container_of(kref, struct media_request, kref);
	struct media_device *mdev = req->mdev;

	dev_dbg(mdev->dev, "request: release %s\n", req->debug_str);

	/* No other users, no need for a spinlock */
	req->state = MEDIA_REQUEST_STATE_CLEANING;

	media_request_clean(req);

	if (mdev->ops->req_free)
		mdev->ops->req_free(req);
	else
		kfree(req);
}

void media_request_put(struct media_request *req)
{
	kref_put(&req->kref, media_request_release);
}
EXPORT_SYMBOL_GPL(media_request_put);

static int media_request_close(struct inode *inode, struct file *filp)
{
	struct media_request *req = filp->private_data;

	media_request_put(req);
	return 0;
}

static __poll_t media_request_poll(struct file *filp,
				   struct poll_table_struct *wait)
{
	struct media_request *req = filp->private_data;
	unsigned long flags;
	__poll_t ret = 0;

	if (!(poll_requested_events(wait) & EPOLLPRI))
		return 0;

	spin_lock_irqsave(&req->lock, flags);
	if (req->state == MEDIA_REQUEST_STATE_COMPLETE) {
		ret = EPOLLPRI;
		goto unlock;
	}
	if (req->state != MEDIA_REQUEST_STATE_QUEUED) {
		ret = EPOLLERR;
		goto unlock;
	}

	poll_wait(filp, &req->poll_wait, wait);

unlock:
	spin_unlock_irqrestore(&req->lock, flags);
	return ret;
}

static long media_request_ioctl_queue(struct media_request *req)
{
	struct media_device *mdev = req->mdev;
	enum media_request_state state;
	unsigned long flags;
	int ret;

	dev_dbg(mdev->dev, "request: queue %s\n", req->debug_str);

	/*
	 * Ensure the request that is validated will be the one that gets queued
	 * next by serialising the queueing process. This mutex is also used
	 * to serialize with canceling a vb2 queue and with setting values such
	 * as controls in a request.
	 */
	mutex_lock(&mdev->req_queue_mutex);

	media_request_get(req);

	spin_lock_irqsave(&req->lock, flags);
	if (req->state == MEDIA_REQUEST_STATE_IDLE)
		req->state = MEDIA_REQUEST_STATE_VALIDATING;
	state = req->state;
	spin_unlock_irqrestore(&req->lock, flags);
	if (state != MEDIA_REQUEST_STATE_VALIDATING) {
		dev_dbg(mdev->dev,
			"request: unable to queue %s, request in state %s\n",
			req->debug_str, media_request_state_str(state));
		media_request_put(req);
		mutex_unlock(&mdev->req_queue_mutex);
		return -EBUSY;
	}

	ret = mdev->ops->req_validate(req);

	/*
	 * If the req_validate was successful, then we mark the state as QUEUED
	 * and call req_queue. The reason we set the state first is that this
	 * allows req_queue to unbind or complete the queued objects in case
	 * they are immediately 'consumed'. State changes from QUEUED to another
	 * state can only happen if either the driver changes the state or if
	 * the user cancels the vb2 queue. The driver can only change the state
	 * after each object is queued through the req_queue op (and note that
	 * that op cannot fail), so setting the state to QUEUED up front is
	 * safe.
	 *
	 * The other reason for changing the state is if the vb2 queue is
	 * canceled, and that uses the req_queue_mutex which is still locked
	 * while req_queue is called, so that's safe as well.
	 */
	spin_lock_irqsave(&req->lock, flags);
	req->state = ret ? MEDIA_REQUEST_STATE_IDLE
			 : MEDIA_REQUEST_STATE_QUEUED;
	spin_unlock_irqrestore(&req->lock, flags);

	if (!ret)
		mdev->ops->req_queue(req);

	mutex_unlock(&mdev->req_queue_mutex);

	if (ret) {
		dev_dbg(mdev->dev, "request: can't queue %s (%d)\n",
			req->debug_str, ret);
		media_request_put(req);
	}

	return ret;
}

static long media_request_ioctl_reinit(struct media_request *req)
{
	struct media_device *mdev = req->mdev;
	unsigned long flags;

	spin_lock_irqsave(&req->lock, flags);
	if (req->state != MEDIA_REQUEST_STATE_IDLE &&
	    req->state != MEDIA_REQUEST_STATE_COMPLETE) {
		dev_dbg(mdev->dev,
			"request: %s not in idle or complete state, cannot reinit\n",
			req->debug_str);
		spin_unlock_irqrestore(&req->lock, flags);
		return -EBUSY;
	}
	if (req->access_count) {
		dev_dbg(mdev->dev,
			"request: %s is being accessed, cannot reinit\n",
			req->debug_str);
		spin_unlock_irqrestore(&req->lock, flags);
		return -EBUSY;
	}
	req->state = MEDIA_REQUEST_STATE_CLEANING;
	spin_unlock_irqrestore(&req->lock, flags);

	media_request_clean(req);

	spin_lock_irqsave(&req->lock, flags);
	req->state = MEDIA_REQUEST_STATE_IDLE;
	spin_unlock_irqrestore(&req->lock, flags);

	return 0;
}

static long media_request_ioctl(struct file *filp, unsigned int cmd,
				unsigned long arg)
{
	struct media_request *req = filp->private_data;

	switch (cmd) {
	case MEDIA_REQUEST_IOC_QUEUE:
		return media_request_ioctl_queue(req);
	case MEDIA_REQUEST_IOC_REINIT:
		return media_request_ioctl_reinit(req);
	default:
		return -ENOIOCTLCMD;
	}
}

static const struct file_operations request_fops = {
	.owner = THIS_MODULE,
	.poll = media_request_poll,
	.unlocked_ioctl = media_request_ioctl,
	.release = media_request_close,
};

struct media_request *
media_request_get_by_fd(struct media_device *mdev, int request_fd)
{
	struct file *filp;
	struct media_request *req;

	if (!mdev || !mdev->ops ||
	    !mdev->ops->req_validate || !mdev->ops->req_queue)
		return ERR_PTR(-EACCES);

	filp = fget(request_fd);
	if (!filp)
		goto err_no_req_fd;

	if (filp->f_op != &request_fops)
		goto err_fput;
	req = filp->private_data;
	if (req->mdev != mdev)
		goto err_fput;

	/*
	 * Note: as long as someone has an open filehandle of the request,
	 * the request can never be released. The fget() above ensures that
	 * even if userspace closes the request filehandle, the release()
	 * fop won't be called, so the media_request_get() always succeeds
	 * and there is no race condition where the request was released
	 * before media_request_get() is called.
	 */
	media_request_get(req);
	fput(filp);

	return req;

err_fput:
	fput(filp);

err_no_req_fd:
	dev_dbg(mdev->dev, "cannot find request_fd %d\n", request_fd);
	return ERR_PTR(-EINVAL);
}
EXPORT_SYMBOL_GPL(media_request_get_by_fd);

int media_request_alloc(struct media_device *mdev, int *alloc_fd)
{
	struct media_request *req;
	struct file *filp;
	int fd;
	int ret;

	/* Either both are NULL or both are non-NULL */
	if (WARN_ON(!mdev->ops->req_alloc ^ !mdev->ops->req_free))
		return -ENOMEM;

	fd = get_unused_fd_flags(O_CLOEXEC);
	if (fd < 0)
		return fd;

	filp = anon_inode_getfile("request", &request_fops, NULL, O_CLOEXEC);
	if (IS_ERR(filp)) {
		ret = PTR_ERR(filp);
		goto err_put_fd;
	}

	if (mdev->ops->req_alloc)
		req = mdev->ops->req_alloc(mdev);
	else
		req = kzalloc(sizeof(*req), GFP_KERNEL);
	if (!req) {
		ret = -ENOMEM;
		goto err_fput;
	}

	filp->private_data = req;
	req->mdev = mdev;
	req->state = MEDIA_REQUEST_STATE_IDLE;
	req->num_incomplete_objects = 0;
	kref_init(&req->kref);
	INIT_LIST_HEAD(&req->objects);
	spin_lock_init(&req->lock);
	init_waitqueue_head(&req->poll_wait);
	req->updating_count = 0;
	req->access_count = 0;

	*alloc_fd = fd;

	snprintf(req->debug_str, sizeof(req->debug_str), "%u:%d",
		 atomic_inc_return(&mdev->request_id), fd);
	dev_dbg(mdev->dev, "request: allocated %s\n", req->debug_str);

	fd_install(fd, filp);

	return 0;

err_fput:
	fput(filp);

err_put_fd:
	put_unused_fd(fd);

	return ret;
}

static void media_request_object_release(struct kref *kref)
{
	struct media_request_object *obj =
		container_of(kref, struct media_request_object, kref);
	struct media_request *req = obj->req;

	if (WARN_ON(req))
		media_request_object_unbind(obj);
	obj->ops->release(obj);
}

struct media_request_object *
media_request_object_find(struct media_request *req,
			  const struct media_request_object_ops *ops,
			  void *priv)
{
	struct media_request_object *obj;
	struct media_request_object *found = NULL;
	unsigned long flags;

	if (WARN_ON(!ops || !priv))
		return NULL;

	spin_lock_irqsave(&req->lock, flags);
	list_for_each_entry(obj, &req->objects, list) {
		if (obj->ops == ops && obj->priv == priv) {
			media_request_object_get(obj);
			found = obj;
			break;
		}
	}
	spin_unlock_irqrestore(&req->lock, flags);
	return found;
}
EXPORT_SYMBOL_GPL(media_request_object_find);

void media_request_object_put(struct media_request_object *obj)
{
	kref_put(&obj->kref, media_request_object_release);
}
EXPORT_SYMBOL_GPL(media_request_object_put);

void media_request_object_init(struct media_request_object *obj)
{
	obj->ops = NULL;
	obj->req = NULL;
	obj->priv = NULL;
	obj->completed = false;
	INIT_LIST_HEAD(&obj->list);
	kref_init(&obj->kref);
}
EXPORT_SYMBOL_GPL(media_request_object_init);

int media_request_object_bind(struct media_request *req,
			      const struct media_request_object_ops *ops,
			      void *priv, bool is_buffer,
			      struct media_request_object *obj)
{
	unsigned long flags;
	int ret = -EBUSY;

	if (WARN_ON(!ops->release))
		return -EACCES;

	spin_lock_irqsave(&req->lock, flags);

	if (WARN_ON(req->state != MEDIA_REQUEST_STATE_UPDATING))
		goto unlock;

	obj->req = req;
	obj->ops = ops;
	obj->priv = priv;

	if (is_buffer)
		list_add_tail(&obj->list, &req->objects);
	else
		list_add(&obj->list, &req->objects);
	req->num_incomplete_objects++;
	ret = 0;

unlock:
	spin_unlock_irqrestore(&req->lock, flags);
	return ret;
}
EXPORT_SYMBOL_GPL(media_request_object_bind);

void media_request_object_unbind(struct media_request_object *obj)
{
	struct media_request *req = obj->req;
	unsigned long flags;
	bool completed = false;

	if (WARN_ON(!req))
		return;

	spin_lock_irqsave(&req->lock, flags);
	list_del(&obj->list);
	obj->req = NULL;

	if (req->state == MEDIA_REQUEST_STATE_COMPLETE)
		goto unlock;

	if (WARN_ON(req->state == MEDIA_REQUEST_STATE_VALIDATING))
		goto unlock;

	if (req->state == MEDIA_REQUEST_STATE_CLEANING) {
		if (!obj->completed)
			req->num_incomplete_objects--;
		goto unlock;
	}

	if (WARN_ON(!req->num_incomplete_objects))
		goto unlock;

	req->num_incomplete_objects--;
	if (req->state == MEDIA_REQUEST_STATE_QUEUED &&
	    !req->num_incomplete_objects) {
		req->state = MEDIA_REQUEST_STATE_COMPLETE;
		completed = true;
		wake_up_interruptible_all(&req->poll_wait);
	}

unlock:
	spin_unlock_irqrestore(&req->lock, flags);
	if (obj->ops->unbind)
		obj->ops->unbind(obj);
	if (completed)
		media_request_put(req);
}
EXPORT_SYMBOL_GPL(media_request_object_unbind);

void media_request_object_complete(struct media_request_object *obj)
{
	struct media_request *req = obj->req;
	unsigned long flags;
	bool completed = false;

	spin_lock_irqsave(&req->lock, flags);
	if (obj->completed)
		goto unlock;
	obj->completed = true;
	if (WARN_ON(!req->num_incomplete_objects) ||
	    WARN_ON(req->state != MEDIA_REQUEST_STATE_QUEUED))
		goto unlock;

	if (!--req->num_incomplete_objects) {
		req->state = MEDIA_REQUEST_STATE_COMPLETE;
		wake_up_interruptible_all(&req->poll_wait);
		completed = true;
	}
unlock:
	spin_unlock_irqrestore(&req->lock, flags);
	if (completed)
		media_request_put(req);
}
EXPORT_SYMBOL_GPL(media_request_object_complete);
Commit	Line	Data
10905d70 HV	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* Media device request objects
	4	*
	5	* Copyright 2018 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
	6	* Copyright (C) 2018 Intel Corporation
	7	* Copyright (C) 2018 Google, Inc.
	8	*
	9	* Author: Hans Verkuil <hans.verkuil@cisco.com>
	10	* Author: Sakari Ailus <sakari.ailus@linux.intel.com>
	11	*/
	12
	13	#include <linux/anon_inodes.h>
	14	#include <linux/file.h>
	15	#include <linux/refcount.h>
	16
	17	#include <media/media-device.h>
	18	#include <media/media-request.h>
	19
	20	static const char * const request_state[] = {
	21	[MEDIA_REQUEST_STATE_IDLE] = "idle",
	22	[MEDIA_REQUEST_STATE_VALIDATING] = "validating",
	23	[MEDIA_REQUEST_STATE_QUEUED] = "queued",
	24	[MEDIA_REQUEST_STATE_COMPLETE] = "complete",
	25	[MEDIA_REQUEST_STATE_CLEANING] = "cleaning",
	26	[MEDIA_REQUEST_STATE_UPDATING] = "updating",
	27	};
	28
	29	static const char *
	30	media_request_state_str(enum media_request_state state)
	31	{
	32	BUILD_BUG_ON(ARRAY_SIZE(request_state) != NR_OF_MEDIA_REQUEST_STATE);
	33
	34	if (WARN_ON(state >= ARRAY_SIZE(request_state)))
	35	return "invalid";
	36	return request_state[state];
	37	}
	38
	39	static void media_request_clean(struct media_request *req)
	40	{
	41	struct media_request_object obj, obj_safe;
	42
	43	/* Just a sanity check. No other code path is allowed to change this. */
	44	WARN_ON(req->state != MEDIA_REQUEST_STATE_CLEANING);
	45	WARN_ON(req->updating_count);
6736f4e9	46	WARN_ON(req->access_count);
10905d70 HV	47
	48	list_for_each_entry_safe(obj, obj_safe, &req->objects, list) {
	49	media_request_object_unbind(obj);
	50	media_request_object_put(obj);
	51	}
	52
	53	req->updating_count = 0;
6736f4e9	54	req->access_count = 0;
10905d70 HV	55	WARN_ON(req->num_incomplete_objects);
	56	req->num_incomplete_objects = 0;
	57	wake_up_interruptible_all(&req->poll_wait);
	58	}
	59
	60	static void media_request_release(struct kref *kref)
	61	{
	62	struct media_request *req =
	63	container_of(kref, struct media_request, kref);
	64	struct media_device *mdev = req->mdev;
	65
	66	dev_dbg(mdev->dev, "request: release %s\n", req->debug_str);
	67
	68	/* No other users, no need for a spinlock */
	69	req->state = MEDIA_REQUEST_STATE_CLEANING;
	70
	71	media_request_clean(req);
	72
	73	if (mdev->ops->req_free)
	74	mdev->ops->req_free(req);
	75	else
	76	kfree(req);
	77	}
	78
	79	void media_request_put(struct media_request *req)
	80	{
	81	kref_put(&req->kref, media_request_release);
	82	}
	83	EXPORT_SYMBOL_GPL(media_request_put);
	84
	85	static int media_request_close(struct inode inode, struct file filp)
	86	{
	87	struct media_request *req = filp->private_data;
	88
	89	media_request_put(req);
	90	return 0;
	91	}
	92
	93	static __poll_t media_request_poll(struct file *filp,
	94	struct poll_table_struct *wait)
	95	{
	96	struct media_request *req = filp->private_data;
	97	unsigned long flags;
	98	__poll_t ret = 0;
	99
	100	if (!(poll_requested_events(wait) & EPOLLPRI))
	101	return 0;
	102
	103	spin_lock_irqsave(&req->lock, flags);
	104	if (req->state == MEDIA_REQUEST_STATE_COMPLETE) {
	105	ret = EPOLLPRI;
	106	goto unlock;
	107	}
	108	if (req->state != MEDIA_REQUEST_STATE_QUEUED) {
	109	ret = EPOLLERR;
	110	goto unlock;
	111	}
	112
	113	poll_wait(filp, &req->poll_wait, wait);
	114
	115	unlock:
	116	spin_unlock_irqrestore(&req->lock, flags);
	117	return ret;
	118	}
119
120	static long media_request_ioctl_queue(struct media_request *req)
121	{
122	struct media_device *mdev = req->mdev;
123	enum media_request_state state;
124	unsigned long flags;
125	int ret;
126
127	dev_dbg(mdev->dev, "request: queue %s\n", req->debug_str);
128
129	/*
130	* Ensure the request that is validated will be the one that gets queued
131	* next by serialising the queueing process. This mutex is also used
132	* to serialize with canceling a vb2 queue and with setting values such
133	* as controls in a request.
134	*/
135	mutex_lock(&mdev->req_queue_mutex);
136
137	media_request_get(req);
138
139	spin_lock_irqsave(&req->lock, flags);
140	if (req->state == MEDIA_REQUEST_STATE_IDLE)
141	req->state = MEDIA_REQUEST_STATE_VALIDATING;
142	state = req->state;
143	spin_unlock_irqrestore(&req->lock, flags);
144	if (state != MEDIA_REQUEST_STATE_VALIDATING) {
145	dev_dbg(mdev->dev,
146	"request: unable to queue %s, request in state %s\n",
147	req->debug_str, media_request_state_str(state));
148	media_request_put(req);
149	mutex_unlock(&mdev->req_queue_mutex);
150	return -EBUSY;
151	}
152
153	ret = mdev->ops->req_validate(req);
154
155	/*
156	* If the req_validate was successful, then we mark the state as QUEUED
157	* and call req_queue. The reason we set the state first is that this
158	* allows req_queue to unbind or complete the queued objects in case
159	* they are immediately 'consumed'. State changes from QUEUED to another
160	* state can only happen if either the driver changes the state or if
161	* the user cancels the vb2 queue. The driver can only change the state
162	* after each object is queued through the req_queue op (and note that
163	* that op cannot fail), so setting the state to QUEUED up front is
164	* safe.
165	*
166	* The other reason for changing the state is if the vb2 queue is
167	* canceled, and that uses the req_queue_mutex which is still locked
168	* while req_queue is called, so that's safe as well.
169	*/
170	spin_lock_irqsave(&req->lock, flags);
171	req->state = ret ? MEDIA_REQUEST_STATE_IDLE
172	: MEDIA_REQUEST_STATE_QUEUED;
173	spin_unlock_irqrestore(&req->lock, flags);
174
175	if (!ret)
176	mdev->ops->req_queue(req);
177
178	mutex_unlock(&mdev->req_queue_mutex);
179
180	if (ret) {
181	dev_dbg(mdev->dev, "request: can't queue %s (%d)\n",
182	req->debug_str, ret);
183	media_request_put(req);
184	}
185
186	return ret;
187	}
188
189	static long media_request_ioctl_reinit(struct media_request *req)
190	{
191	struct media_device *mdev = req->mdev;
192	unsigned long flags;
193
194	spin_lock_irqsave(&req->lock, flags);
195	if (req->state != MEDIA_REQUEST_STATE_IDLE &&
196	req->state != MEDIA_REQUEST_STATE_COMPLETE) {
197	dev_dbg(mdev->dev,
198	"request: %s not in idle or complete state, cannot reinit\n",
199	req->debug_str);
200	spin_unlock_irqrestore(&req->lock, flags);
201	return -EBUSY;
202	}
6736f4e9 HV	203	if (req->access_count) {
	204	dev_dbg(mdev->dev,
	205	"request: %s is being accessed, cannot reinit\n",
	206	req->debug_str);
	207	spin_unlock_irqrestore(&req->lock, flags);
	208	return -EBUSY;
	209	}
10905d70 HV	210	req->state = MEDIA_REQUEST_STATE_CLEANING;
	211	spin_unlock_irqrestore(&req->lock, flags);
	212
	213	media_request_clean(req);
	214
	215	spin_lock_irqsave(&req->lock, flags);
	216	req->state = MEDIA_REQUEST_STATE_IDLE;
	217	spin_unlock_irqrestore(&req->lock, flags);
	218
	219	return 0;
	220	}
	221
	222	static long media_request_ioctl(struct file *filp, unsigned int cmd,
	223	unsigned long arg)
	224	{
	225	struct media_request *req = filp->private_data;
	226
	227	switch (cmd) {
	228	case MEDIA_REQUEST_IOC_QUEUE:
	229	return media_request_ioctl_queue(req);
	230	case MEDIA_REQUEST_IOC_REINIT:
	231	return media_request_ioctl_reinit(req);
	232	default:
	233	return -ENOIOCTLCMD;
	234	}
	235	}
	236
	237	static const struct file_operations request_fops = {
	238	.owner = THIS_MODULE,
	239	.poll = media_request_poll,
	240	.unlocked_ioctl = media_request_ioctl,
	241	.release = media_request_close,
	242	};
	243
	244	struct media_request *
	245	media_request_get_by_fd(struct media_device *mdev, int request_fd)
	246	{
	247	struct file *filp;
	248	struct media_request *req;
	249
	250	if (!mdev \|\| !mdev->ops \|\|
	251	!mdev->ops->req_validate \|\| !mdev->ops->req_queue)
15cd442e	252	return ERR_PTR(-EACCES);
10905d70 HV	253
	254	filp = fget(request_fd);
	255	if (!filp)
34b41472	256	goto err_no_req_fd;
10905d70 HV	257
	258	if (filp->f_op != &request_fops)
	259	goto err_fput;
	260	req = filp->private_data;
	261	if (req->mdev != mdev)
	262	goto err_fput;
	263
	264	/*
	265	* Note: as long as someone has an open filehandle of the request,
	266	* the request can never be released. The fget() above ensures that
	267	* even if userspace closes the request filehandle, the release()
	268	* fop won't be called, so the media_request_get() always succeeds
	269	* and there is no race condition where the request was released
	270	* before media_request_get() is called.
	271	*/
	272	media_request_get(req);
	273	fput(filp);
	274
	275	return req;
	276
	277	err_fput:
	278	fput(filp);
	279
34b41472 HV	280	err_no_req_fd:
	281	dev_dbg(mdev->dev, "cannot find request_fd %d\n", request_fd);
	282	return ERR_PTR(-EINVAL);
10905d70 HV	283	}
	284	EXPORT_SYMBOL_GPL(media_request_get_by_fd);
	285
	286	int media_request_alloc(struct media_device mdev, int alloc_fd)
	287	{
	288	struct media_request *req;
	289	struct file *filp;
	290	int fd;
	291	int ret;
	292
	293	/* Either both are NULL or both are non-NULL */
	294	if (WARN_ON(!mdev->ops->req_alloc ^ !mdev->ops->req_free))
	295	return -ENOMEM;
	296
	297	fd = get_unused_fd_flags(O_CLOEXEC);
	298	if (fd < 0)
	299	return fd;
	300
	301	filp = anon_inode_getfile("request", &request_fops, NULL, O_CLOEXEC);
	302	if (IS_ERR(filp)) {
	303	ret = PTR_ERR(filp);
	304	goto err_put_fd;
	305	}
	306
	307	if (mdev->ops->req_alloc)
	308	req = mdev->ops->req_alloc(mdev);
	309	else
	310	req = kzalloc(sizeof(*req), GFP_KERNEL);
	311	if (!req) {
	312	ret = -ENOMEM;
	313	goto err_fput;
	314	}
	315
	316	filp->private_data = req;
	317	req->mdev = mdev;
	318	req->state = MEDIA_REQUEST_STATE_IDLE;
	319	req->num_incomplete_objects = 0;
	320	kref_init(&req->kref);
	321	INIT_LIST_HEAD(&req->objects);
	322	spin_lock_init(&req->lock);
	323	init_waitqueue_head(&req->poll_wait);
	324	req->updating_count = 0;
6736f4e9	325	req->access_count = 0;
10905d70 HV	326
	327	*alloc_fd = fd;
	328
	329	snprintf(req->debug_str, sizeof(req->debug_str), "%u:%d",
	330	atomic_inc_return(&mdev->request_id), fd);
	331	dev_dbg(mdev->dev, "request: allocated %s\n", req->debug_str);
	332
	333	fd_install(fd, filp);
	334
	335	return 0;
	336
	337	err_fput:
	338	fput(filp);
	339
	340	err_put_fd:
	341	put_unused_fd(fd);
	342
	343	return ret;
	344	}
	345
	346	static void media_request_object_release(struct kref *kref)
	347	{
	348	struct media_request_object *obj =
	349	container_of(kref, struct media_request_object, kref);
	350	struct media_request *req = obj->req;
	351
	352	if (WARN_ON(req))
	353	media_request_object_unbind(obj);
	354	obj->ops->release(obj);
	355	}
	356
0ca0e844 HV	357	struct media_request_object *
	358	media_request_object_find(struct media_request *req,
	359	const struct media_request_object_ops *ops,
	360	void *priv)
	361	{
	362	struct media_request_object *obj;
	363	struct media_request_object *found = NULL;
	364	unsigned long flags;
	365
	366	if (WARN_ON(!ops \|\| !priv))
	367	return NULL;
	368
	369	spin_lock_irqsave(&req->lock, flags);
	370	list_for_each_entry(obj, &req->objects, list) {
	371	if (obj->ops == ops && obj->priv == priv) {
	372	media_request_object_get(obj);
	373	found = obj;
	374	break;
	375	}
	376	}
	377	spin_unlock_irqrestore(&req->lock, flags);
	378	return found;
	379	}
	380	EXPORT_SYMBOL_GPL(media_request_object_find);
	381
10905d70 HV	382	void media_request_object_put(struct media_request_object *obj)
	383	{
	384	kref_put(&obj->kref, media_request_object_release);
	385	}
	386	EXPORT_SYMBOL_GPL(media_request_object_put);
	387
	388	void media_request_object_init(struct media_request_object *obj)
	389	{
	390	obj->ops = NULL;
	391	obj->req = NULL;
	392	obj->priv = NULL;
	393	obj->completed = false;
	394	INIT_LIST_HEAD(&obj->list);
	395	kref_init(&obj->kref);
	396	}
	397	EXPORT_SYMBOL_GPL(media_request_object_init);
	398
	399	int media_request_object_bind(struct media_request *req,
	400	const struct media_request_object_ops *ops,
	401	void *priv, bool is_buffer,
	402	struct media_request_object *obj)
	403	{
	404	unsigned long flags;
	405	int ret = -EBUSY;
	406
	407	if (WARN_ON(!ops->release))
15cd442e	408	return -EACCES;
10905d70 HV	409
	410	spin_lock_irqsave(&req->lock, flags);
	411
	412	if (WARN_ON(req->state != MEDIA_REQUEST_STATE_UPDATING))
	413	goto unlock;
	414
	415	obj->req = req;
	416	obj->ops = ops;
	417	obj->priv = priv;
	418
	419	if (is_buffer)
	420	list_add_tail(&obj->list, &req->objects);
	421	else
	422	list_add(&obj->list, &req->objects);
	423	req->num_incomplete_objects++;
	424	ret = 0;
	425
	426	unlock:
	427	spin_unlock_irqrestore(&req->lock, flags);
	428	return ret;
	429	}
	430	EXPORT_SYMBOL_GPL(media_request_object_bind);
	431
	432	void media_request_object_unbind(struct media_request_object *obj)
	433	{
	434	struct media_request *req = obj->req;
	435	unsigned long flags;
	436	bool completed = false;
	437
	438	if (WARN_ON(!req))
	439	return;
	440
	441	spin_lock_irqsave(&req->lock, flags);
	442	list_del(&obj->list);
	443	obj->req = NULL;
	444
	445	if (req->state == MEDIA_REQUEST_STATE_COMPLETE)
	446	goto unlock;
	447
	448	if (WARN_ON(req->state == MEDIA_REQUEST_STATE_VALIDATING))
	449	goto unlock;
	450
	451	if (req->state == MEDIA_REQUEST_STATE_CLEANING) {
	452	if (!obj->completed)
	453	req->num_incomplete_objects--;
	454	goto unlock;
	455	}
	456
	457	if (WARN_ON(!req->num_incomplete_objects))
	458	goto unlock;
	459
	460	req->num_incomplete_objects--;
	461	if (req->state == MEDIA_REQUEST_STATE_QUEUED &&
	462	!req->num_incomplete_objects) {
	463	req->state = MEDIA_REQUEST_STATE_COMPLETE;
	464	completed = true;
	465	wake_up_interruptible_all(&req->poll_wait);
	466	}
	467
	468	unlock:
	469	spin_unlock_irqrestore(&req->lock, flags);
	470	if (obj->ops->unbind)
	471	obj->ops->unbind(obj);
	472	if (completed)
473	media_request_put(req);
474	}
475	EXPORT_SYMBOL_GPL(media_request_object_unbind);
476
477	void media_request_object_complete(struct media_request_object *obj)
478	{
479	struct media_request *req = obj->req;
480	unsigned long flags;
481	bool completed = false;
482
483	spin_lock_irqsave(&req->lock, flags);
484	if (obj->completed)
485	goto unlock;
486	obj->completed = true;
487	if (WARN_ON(!req->num_incomplete_objects) \|\|
488	WARN_ON(req->state != MEDIA_REQUEST_STATE_QUEUED))
489	goto unlock;
490
491	if (!--req->num_incomplete_objects) {
492	req->state = MEDIA_REQUEST_STATE_COMPLETE;
493	wake_up_interruptible_all(&req->poll_wait);
494	completed = true;
495	}
496	unlock:
497	spin_unlock_irqrestore(&req->lock, flags);
498	if (completed)
499	media_request_put(req);
500	}
501	EXPORT_SYMBOL_GPL(media_request_object_complete);