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media: v4l2-dev/ioctl: require non-zero device_caps, verify sane querycap results 

Now that all V4L2 drivers set device_caps in struct video_device, we can add
a check for this to ensure all future drivers fill this in.

Also verify that when the querycap ioctl is called the driver didn't mess
with the device_caps value and that capabilities is a superset of device_caps.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
[hverkuil-cisco@xs4all.nl: fix too-long line]
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
This commit is contained in:
Hans Verkuil 2019-07-23 04:21:25 -04:00 committed by Mauro Carvalho Chehab
parent 08aac0e32f
commit 3c1350501c
2 changed files with 14 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/media/v4l2-core/v4l2-dev.c
View File

@ -859,6 +859,9 @@ int __video_register_device(struct video_device *vdev,
/* the v4l2_dev pointer MUST be present */
if (WARN_ON(!vdev->v4l2_dev))
return -EINVAL;
/* the device_caps field MUST be set */
if (WARN_ON(!vdev->device_caps))
return -EINVAL;
/* v4l2_fh support */
spin_lock_init(&vdev->fh_lock);

17
drivers/media/v4l2-core/v4l2-ioctl.c
View File

@ -1057,14 +1057,19 @@ static int v4l_querycap(const struct v4l2_ioctl_ops *ops,
ret = ops->vidioc_querycap(file, fh, cap);
cap->capabilities |= V4L2_CAP_EXT_PIX_FORMAT;
/*
* Drivers MUST fill in device_caps, so check for this and
* warn if it was forgotten.
* Drivers must not change device_caps, so check for this and
* warn if this happened.
*/
WARN(!(cap->capabilities & V4L2_CAP_DEVICE_CAPS) ||
!cap->device_caps, "Bad caps for driver %s, %x %x",
cap->driver, cap->capabilities, cap->device_caps);
WARN_ON(cap->device_caps != vfd->device_caps);
/*
* Check that capabilities is a superset of
* vfd->device_caps | V4L2_CAP_DEVICE_CAPS
*/
WARN_ON((cap->capabilities &
(vfd->device_caps | V4L2_CAP_DEVICE_CAPS)) !=
(vfd->device_caps | V4L2_CAP_DEVICE_CAPS));
cap->capabilities |= V4L2_CAP_EXT_PIX_FORMAT;
cap->device_caps |= V4L2_CAP_EXT_PIX_FORMAT;
return ret;