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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: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
This commit is contained in:
Hans Verkuil 2013-12-13 13:13:41 -03:00 committed by Mauro Carvalho Chehab
parent 63faabfd89
commit b2f2f04719
1 changed files with 119 additions and 118 deletions
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237
drivers/media/v4l2-core/videobuf2-core.c
View File

@ -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;
@ -1756,8 +1753,51 @@ int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type)
dprintk(3, "Streamon successful\n");
return 0;
}
/**
* 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)
{
if (q->fileio) {
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;
}
if (!q->streaming) {
dprintk(3, "streamoff successful: not streaming\n");
return 0;
}
/*
* Cancel will pause streaming and remove all buffers from the driver
* and videobuf, effectively returning control over them to userspace.
*/
__vb2_queue_cancel(q);
dprintk(3, "Streamoff successful\n");
return 0;
}
/**
* vb2_streamoff - stop streaming
@ -1780,25 +1820,7 @@ int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type)
dprintk(1, "streamoff: file io in progress\n");
return -EBUSY;
}
if (type != q->type) {
dprintk(1, "streamoff: invalid stream type\n");
return -EINVAL;
}
if (!q->streaming) {
dprintk(3, "streamoff successful: not streaming\n");
return 0;
}
/*
* Cancel will pause streaming and remove all buffers from the driver
* and videobuf, effectively returning control over them to userspace.
*/
__vb2_queue_cancel(q);
dprintk(3, "Streamoff successful\n");
return 0;
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;
}