Commit b2f2f047 authored by Hans Verkuil's avatar Hans Verkuil Committed by Mauro Carvalho Chehab
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[media] vb2: remove the 'fileio = NULL' hack 



The read/write implementation in vb2 reuses existing vb2 functions, but
it sets q->fileio to NULL before calling them in order to skip the
'q->fileio != NULL' check.

This works today due to the synchronous nature of read/write, but it
1) is ugly, and 2) will fail in an asynchronous use-case such as a
thread queuing and dequeuing buffers. This last example will be necessary
in order to implement vb2 DVB support.

This patch removes the hack by splitting up the dqbuf/qbuf/streamon/streamoff
functions into an external and an internal version. The external version
checks q->fileio and then calls the internal version. The read/write
implementation now just uses the internal version, removing the need to
set q->fileio to NULL.

Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: default avatarMauro Carvalho Chehab <m.chehab@samsung.com>
parent 63faabfd

drivers/media/v4l2-core/videobuf2-core.c

+112 −111
Original line number Diff line number Diff line
@@ -1307,11 +1307,6 @@ static int __buf_prepare(struct vb2_buffer *vb, const struct v4l2_buffer *b) 
static int vb2_queue_or_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b,

				    const char *opname)

{

	if (q->fileio) {

		dprintk(1, "%s(): file io in progress\n", opname);

		return -EBUSY;

	}



	if (b->type != q->type) {

		dprintk(1, "%s(): invalid buffer type\n", opname);

		return -EINVAL;
@@ -1353,9 +1348,15 @@ static int vb2_queue_or_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b, 
 */

int vb2_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b)

{

	int ret = vb2_queue_or_prepare_buf(q, b, "prepare_buf");

	struct vb2_buffer *vb;

	int ret;



	if (q->fileio) {

		dprintk(1, "%s(): file io in progress\n", __func__);

		return -EBUSY;

	}



	ret = vb2_queue_or_prepare_buf(q, b, "prepare_buf");

	if (ret)

		return ret;
@@ -1377,24 +1378,7 @@ int vb2_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b) 
}

EXPORT_SYMBOL_GPL(vb2_prepare_buf);



/**

 * vb2_qbuf() - Queue a buffer from userspace

 * @q:		videobuf2 queue

 * @b:		buffer structure passed from userspace to vidioc_qbuf handler

 *		in driver

 *

 * Should be called from vidioc_qbuf ioctl handler of a driver.

 * This function:

 * 1) verifies the passed buffer,

 * 2) if necessary, calls buf_prepare callback in the driver (if provided), in

 *    which driver-specific buffer initialization can be performed,

 * 3) if streaming is on, queues the buffer in driver by the means of buf_queue

 *    callback for processing.

 *

 * The return values from this function are intended to be directly returned

 * from vidioc_qbuf handler in driver.

 */

int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)

static int vb2_internal_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)

{

	int ret = vb2_queue_or_prepare_buf(q, b, "qbuf");

	struct vb2_buffer *vb;
@@ -1445,6 +1429,33 @@ int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b) 
	dprintk(1, "%s() of buffer %d succeeded\n", __func__, vb->v4l2_buf.index);

	return 0;

}



/**

 * vb2_qbuf() - Queue a buffer from userspace

 * @q:		videobuf2 queue

 * @b:		buffer structure passed from userspace to vidioc_qbuf handler

 *		in driver

 *

 * Should be called from vidioc_qbuf ioctl handler of a driver.

 * This function:

 * 1) verifies the passed buffer,

 * 2) if necessary, calls buf_prepare callback in the driver (if provided), in

 *    which driver-specific buffer initialization can be performed,

 * 3) if streaming is on, queues the buffer in driver by the means of buf_queue

 *    callback for processing.

 *

 * The return values from this function are intended to be directly returned

 * from vidioc_qbuf handler in driver.

 */

int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)

{

	if (q->fileio) {

		dprintk(1, "%s(): file io in progress\n", __func__);

		return -EBUSY;

	}



	return vb2_internal_qbuf(q, b);

}

EXPORT_SYMBOL_GPL(vb2_qbuf);



/**
@@ -1593,37 +1604,11 @@ static void __vb2_dqbuf(struct vb2_buffer *vb) 
		}

}



/**

 * vb2_dqbuf() - Dequeue a buffer to the userspace

 * @q:		videobuf2 queue

 * @b:		buffer structure passed from userspace to vidioc_dqbuf handler

 *		in driver

 * @nonblocking: if true, this call will not sleep waiting for a buffer if no

 *		 buffers ready for dequeuing are present. Normally the driver

 *		 would be passing (file->f_flags & O_NONBLOCK) here

 *

 * Should be called from vidioc_dqbuf ioctl handler of a driver.

 * This function:

 * 1) verifies the passed buffer,

 * 2) calls buf_finish callback in the driver (if provided), in which

 *    driver can perform any additional operations that may be required before

 *    returning the buffer to userspace, such as cache sync,

 * 3) the buffer struct members are filled with relevant information for

 *    the userspace.

 *

 * The return values from this function are intended to be directly returned

 * from vidioc_dqbuf handler in driver.

 */

int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking)

static int vb2_internal_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking)

{

	struct vb2_buffer *vb = NULL;

	int ret;



	if (q->fileio) {

		dprintk(1, "dqbuf: file io in progress\n");

		return -EBUSY;

	}



	if (b->type != q->type) {

		dprintk(1, "dqbuf: invalid buffer type\n");

		return -EINVAL;
@@ -1662,6 +1647,36 @@ int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking) 


	return 0;

}



/**

 * vb2_dqbuf() - Dequeue a buffer to the userspace

 * @q:		videobuf2 queue

 * @b:		buffer structure passed from userspace to vidioc_dqbuf handler

 *		in driver

 * @nonblocking: if true, this call will not sleep waiting for a buffer if no

 *		 buffers ready for dequeuing are present. Normally the driver

 *		 would be passing (file->f_flags & O_NONBLOCK) here

 *

 * Should be called from vidioc_dqbuf ioctl handler of a driver.

 * This function:

 * 1) verifies the passed buffer,

 * 2) calls buf_finish callback in the driver (if provided), in which

 *    driver can perform any additional operations that may be required before

 *    returning the buffer to userspace, such as cache sync,

 * 3) the buffer struct members are filled with relevant information for

 *    the userspace.

 *

 * The return values from this function are intended to be directly returned

 * from vidioc_dqbuf handler in driver.

 */

int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking)

{

	if (q->fileio) {

		dprintk(1, "dqbuf: file io in progress\n");

		return -EBUSY;

	}

	return vb2_internal_dqbuf(q, b, nonblocking);

}

EXPORT_SYMBOL_GPL(vb2_dqbuf);



/**
@@ -1701,29 +1716,11 @@ static void __vb2_queue_cancel(struct vb2_queue *q) 
		__vb2_dqbuf(q->bufs[i]);

}



/**

 * vb2_streamon - start streaming

 * @q:		videobuf2 queue

 * @type:	type argument passed from userspace to vidioc_streamon handler

 *

 * Should be called from vidioc_streamon handler of a driver.

 * This function:

 * 1) verifies current state

 * 2) passes any previously queued buffers to the driver and starts streaming

 *

 * The return values from this function are intended to be directly returned

 * from vidioc_streamon handler in the driver.

 */

int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type)

static int vb2_internal_streamon(struct vb2_queue *q, enum v4l2_buf_type type)

{

	struct vb2_buffer *vb;

	int ret;



	if (q->fileio) {

		dprintk(1, "streamon: file io in progress\n");

		return -EBUSY;

	}



	if (type != q->type) {

		dprintk(1, "streamon: invalid stream type\n");

		return -EINVAL;
@@ -1756,31 +1753,32 @@ int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type) 
	dprintk(3, "Streamon successful\n");

	return 0;

}

EXPORT_SYMBOL_GPL(vb2_streamon);





/**

 * vb2_streamoff - stop streaming

 * vb2_streamon - start streaming

 * @q:		videobuf2 queue

 * @type:	type argument passed from userspace to vidioc_streamoff handler

 * @type:	type argument passed from userspace to vidioc_streamon handler

 *

 * Should be called from vidioc_streamoff handler of a driver.

 * Should be called from vidioc_streamon handler of a driver.

 * This function:

 * 1) verifies current state,

 * 2) stop streaming and dequeues any queued buffers, including those previously

 *    passed to the driver (after waiting for the driver to finish).

 * 1) verifies current state

 * 2) passes any previously queued buffers to the driver and starts streaming

 *

 * This call can be used for pausing playback.

 * The return values from this function are intended to be directly returned

 * from vidioc_streamoff handler in the driver

 * from vidioc_streamon handler in the driver.

 */

int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type)

int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type)

{

	if (q->fileio) {

		dprintk(1, "streamoff: file io in progress\n");

		dprintk(1, "streamon: file io in progress\n");

		return -EBUSY;

	}

	return vb2_internal_streamon(q, type);

}

EXPORT_SYMBOL_GPL(vb2_streamon);



static int vb2_internal_streamoff(struct vb2_queue *q, enum v4l2_buf_type type)

{

	if (type != q->type) {

		dprintk(1, "streamoff: invalid stream type\n");

		return -EINVAL;
@@ -1800,6 +1798,30 @@ int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type) 
	dprintk(3, "Streamoff successful\n");

	return 0;

}



/**

 * vb2_streamoff - stop streaming

 * @q:		videobuf2 queue

 * @type:	type argument passed from userspace to vidioc_streamoff handler

 *

 * Should be called from vidioc_streamoff handler of a driver.

 * This function:

 * 1) verifies current state,

 * 2) stop streaming and dequeues any queued buffers, including those previously

 *    passed to the driver (after waiting for the driver to finish).

 *

 * This call can be used for pausing playback.

 * The return values from this function are intended to be directly returned

 * from vidioc_streamoff handler in the driver

 */

int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type)

{

	if (q->fileio) {

		dprintk(1, "streamoff: file io in progress\n");

		return -EBUSY;

	}

	return vb2_internal_streamoff(q, type);

}

EXPORT_SYMBOL_GPL(vb2_streamoff);



/**
@@ -2322,13 +2344,8 @@ static int __vb2_cleanup_fileio(struct vb2_queue *q) 
	struct vb2_fileio_data *fileio = q->fileio;



	if (fileio) {

		/*

		 * Hack fileio context to enable direct calls to vb2 ioctl

		 * interface.

		 */

		vb2_internal_streamoff(q, q->type);

		q->fileio = NULL;



		vb2_streamoff(q, q->type);

		fileio->req.count = 0;

		vb2_reqbufs(q, &fileio->req);

		kfree(fileio);
@@ -2371,12 +2388,6 @@ static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_ 
	}

	fileio = q->fileio;



	/*

	 * Hack fileio context to enable direct calls to vb2 ioctl interface.

	 * The pointer will be restored before returning from this function.

	 */

	q->fileio = NULL;



	index = fileio->index;

	buf = &fileio->bufs[index];
@@ -2393,10 +2404,10 @@ static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_ 
		fileio->b.type = q->type;

		fileio->b.memory = q->memory;

		fileio->b.index = index;

		ret = vb2_dqbuf(q, &fileio->b, nonblock);

		ret = vb2_internal_dqbuf(q, &fileio->b, nonblock);

		dprintk(5, "file io: vb2_dqbuf result: %d\n", ret);

		if (ret)

			goto end;

			return ret;

		fileio->dq_count += 1;



		/*
@@ -2426,8 +2437,7 @@ static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_ 
		ret = copy_from_user(buf->vaddr + buf->pos, data, count);

	if (ret) {

		dprintk(3, "file io: error copying data\n");

		ret = -EFAULT;

		goto end;

		return -EFAULT;

	}



	/*
@@ -2447,10 +2457,6 @@ static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_ 
		if (read && (fileio->flags & VB2_FILEIO_READ_ONCE) &&

		    fileio->dq_count == 1) {

			dprintk(3, "file io: read limit reached\n");

			/*

			 * Restore fileio pointer and release the context.

			 */

			q->fileio = fileio;

			return __vb2_cleanup_fileio(q);

		}
@@ -2462,10 +2468,10 @@ static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_ 
		fileio->b.memory = q->memory;

		fileio->b.index = index;

		fileio->b.bytesused = buf->pos;

		ret = vb2_qbuf(q, &fileio->b);

		ret = vb2_internal_qbuf(q, &fileio->b);

		dprintk(5, "file io: vb2_dbuf result: %d\n", ret);

		if (ret)

			goto end;

			return ret;



		/*

		 * Buffer has been queued, update the status
@@ -2484,9 +2490,9 @@ static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_ 
		 * Start streaming if required.

		 */

		if (!read && !q->streaming) {

			ret = vb2_streamon(q, q->type);

			ret = vb2_internal_streamon(q, q->type);

			if (ret)

				goto end;

				return ret;

		}

	}
@@ -2495,11 +2501,6 @@ static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_ 
	 */

	if (ret == 0)

		ret = count;

end:

	/*

	 * Restore the fileio context and block vb2 ioctl interface.

	 */

	q->fileio = fileio;

	return ret;

}

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