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[media] uvcvideo: Lock stream mutex when accessing format-related inf…
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…ormation

The stream mutex protects access to the struct uvc_streaming ctrl,
cur_format and cur_frame fields as well as to the hardware probe
control. Lock it appropriately.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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Laurent Pinchart authored and Mauro Carvalho Chehab committed Dec 1, 2010
1 parent 4aa2759 commit 6947756
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Showing 3 changed files with 58 additions and 27 deletions.
78 changes: 55 additions & 23 deletions drivers/media/video/uvc/uvc_v4l2.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -226,12 +226,14 @@ static int uvc_v4l2_try_format(struct uvc_streaming *stream,
* developers test their webcams with the Linux driver as well as with
* the Windows driver).
*/
mutex_lock(&stream->mutex);
if (stream->dev->quirks & UVC_QUIRK_PROBE_EXTRAFIELDS)
probe->dwMaxVideoFrameSize =
stream->ctrl.dwMaxVideoFrameSize;

/* Probe the device. */
ret = uvc_probe_video(stream, probe);
mutex_unlock(&stream->mutex);
if (ret < 0)
goto done;

Expand All @@ -255,14 +257,21 @@ static int uvc_v4l2_try_format(struct uvc_streaming *stream,
static int uvc_v4l2_get_format(struct uvc_streaming *stream,
struct v4l2_format *fmt)
{
struct uvc_format *format = stream->cur_format;
struct uvc_frame *frame = stream->cur_frame;
struct uvc_format *format;
struct uvc_frame *frame;
int ret = 0;

if (fmt->type != stream->type)
return -EINVAL;

if (format == NULL || frame == NULL)
return -EINVAL;
mutex_lock(&stream->mutex);
format = stream->cur_format;
frame = stream->cur_frame;

if (format == NULL || frame == NULL) {
ret = -EINVAL;
goto done;
}

fmt->fmt.pix.pixelformat = format->fcc;
fmt->fmt.pix.width = frame->wWidth;
Expand All @@ -273,7 +282,9 @@ static int uvc_v4l2_get_format(struct uvc_streaming *stream,
fmt->fmt.pix.colorspace = format->colorspace;
fmt->fmt.pix.priv = 0;

return 0;
done:
mutex_unlock(&stream->mutex);
return ret;
}

static int uvc_v4l2_set_format(struct uvc_streaming *stream,
Expand All @@ -287,18 +298,24 @@ static int uvc_v4l2_set_format(struct uvc_streaming *stream,
if (fmt->type != stream->type)
return -EINVAL;

if (uvc_queue_allocated(&stream->queue))
return -EBUSY;

ret = uvc_v4l2_try_format(stream, fmt, &probe, &format, &frame);
if (ret < 0)
return ret;

mutex_lock(&stream->mutex);

if (uvc_queue_allocated(&stream->queue)) {
ret = -EBUSY;
goto done;
}

memcpy(&stream->ctrl, &probe, sizeof probe);
stream->cur_format = format;
stream->cur_frame = frame;

return 0;
done:
mutex_unlock(&stream->mutex);
return ret;
}

static int uvc_v4l2_get_streamparm(struct uvc_streaming *stream,
Expand All @@ -309,7 +326,10 @@ static int uvc_v4l2_get_streamparm(struct uvc_streaming *stream,
if (parm->type != stream->type)
return -EINVAL;

mutex_lock(&stream->mutex);
numerator = stream->ctrl.dwFrameInterval;
mutex_unlock(&stream->mutex);

denominator = 10000000;
uvc_simplify_fraction(&numerator, &denominator, 8, 333);

Expand All @@ -336,7 +356,6 @@ static int uvc_v4l2_get_streamparm(struct uvc_streaming *stream,
static int uvc_v4l2_set_streamparm(struct uvc_streaming *stream,
struct v4l2_streamparm *parm)
{
struct uvc_frame *frame = stream->cur_frame;
struct uvc_streaming_control probe;
struct v4l2_fract timeperframe;
uint32_t interval;
Expand All @@ -345,28 +364,36 @@ static int uvc_v4l2_set_streamparm(struct uvc_streaming *stream,
if (parm->type != stream->type)
return -EINVAL;

if (uvc_queue_streaming(&stream->queue))
return -EBUSY;

if (parm->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
timeperframe = parm->parm.capture.timeperframe;
else
timeperframe = parm->parm.output.timeperframe;

memcpy(&probe, &stream->ctrl, sizeof probe);
interval = uvc_fraction_to_interval(timeperframe.numerator,
timeperframe.denominator);

uvc_trace(UVC_TRACE_FORMAT, "Setting frame interval to %u/%u (%u).\n",
timeperframe.numerator, timeperframe.denominator, interval);
probe.dwFrameInterval = uvc_try_frame_interval(frame, interval);

mutex_lock(&stream->mutex);

if (uvc_queue_streaming(&stream->queue)) {
mutex_unlock(&stream->mutex);
return -EBUSY;
}

memcpy(&probe, &stream->ctrl, sizeof probe);
probe.dwFrameInterval =
uvc_try_frame_interval(stream->cur_frame, interval);

/* Probe the device with the new settings. */
ret = uvc_probe_video(stream, &probe);
if (ret < 0)
if (ret < 0) {
mutex_unlock(&stream->mutex);
return ret;
}

memcpy(&stream->ctrl, &probe, sizeof probe);
mutex_unlock(&stream->mutex);

/* Return the actual frame period. */
timeperframe.numerator = probe.dwFrameInterval;
Expand Down Expand Up @@ -869,15 +896,17 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
case VIDIOC_CROPCAP:
{
struct v4l2_cropcap *ccap = arg;
struct uvc_frame *frame = stream->cur_frame;

if (ccap->type != stream->type)
return -EINVAL;

ccap->bounds.left = 0;
ccap->bounds.top = 0;
ccap->bounds.width = frame->wWidth;
ccap->bounds.height = frame->wHeight;

mutex_lock(&stream->mutex);
ccap->bounds.width = stream->cur_frame->wWidth;
ccap->bounds.height = stream->cur_frame->wHeight;
mutex_unlock(&stream->mutex);

ccap->defrect = ccap->bounds;

Expand All @@ -894,8 +923,6 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
case VIDIOC_REQBUFS:
{
struct v4l2_requestbuffers *rb = arg;
unsigned int bufsize =
stream->ctrl.dwMaxVideoFrameSize;

if (rb->type != stream->type ||
rb->memory != V4L2_MEMORY_MMAP)
Expand All @@ -904,7 +931,10 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
if ((ret = uvc_acquire_privileges(handle)) < 0)
return ret;

ret = uvc_alloc_buffers(&stream->queue, rb->count, bufsize);
mutex_lock(&stream->mutex);
ret = uvc_alloc_buffers(&stream->queue, rb->count,
stream->ctrl.dwMaxVideoFrameSize);
mutex_unlock(&stream->mutex);
if (ret < 0)
return ret;

Expand Down Expand Up @@ -952,7 +982,9 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
if (!uvc_has_privileges(handle))
return -EBUSY;

mutex_lock(&stream->mutex);
ret = uvc_video_enable(stream, 1);
mutex_unlock(&stream->mutex);
if (ret < 0)
return ret;
break;
Expand Down
3 changes: 0 additions & 3 deletions drivers/media/video/uvc/uvc_video.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -293,8 +293,6 @@ int uvc_probe_video(struct uvc_streaming *stream,
unsigned int i;
int ret;

mutex_lock(&stream->mutex);

/* Perform probing. The device should adjust the requested values
* according to its capabilities. However, some devices, namely the
* first generation UVC Logitech webcams, don't implement the Video
Expand Down Expand Up @@ -346,7 +344,6 @@ int uvc_probe_video(struct uvc_streaming *stream,
}

done:
mutex_unlock(&stream->mutex);
return ret;
}

Expand Down
4 changes: 3 additions & 1 deletion drivers/media/video/uvc/uvcvideo.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -436,7 +436,9 @@ struct uvc_streaming {
struct uvc_streaming_control ctrl;
struct uvc_format *cur_format;
struct uvc_frame *cur_frame;

/* Protect access to ctrl, cur_format, cur_frame and hardware video
* probe control.
*/
struct mutex mutex;

unsigned int frozen : 1;
Expand Down

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