media: v4l2-dev: Check that g/s_selection are valid before selecting crop

The cropcap and g/s_crop ioctls are automatically marked as valid whenever
the g/s_selection ops are filled. The rationale is to auto-enable these
legacy cropcap and g/s_crop ioctls that rely on g/s_selection.

However it's possible that the ops are filled but explicitly disabled with
calls to v4l2_disable_ioctl. In this situation the legacy ioctls should not
be enabled.

Add a check on the video device's valid ioctls field before auto-selecting
them to honor the driver's choice. Note that the meaning of the bitfield
stored in the video device is the opposite of what the name suggests as
v4l2_disable_ioctl will set the bits. Their meaning will be reversed at
the end of the function.

Signed-off-by: Paul Kocialkowski <[e-mail]>
Reviewed-by: Nicolas Dufresne <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

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

···
 		SET_VALID_IOCTL(ops, VIDIOC_TRY_DECODER_CMD, vidioc_try_decoder_cmd);
 		SET_VALID_IOCTL(ops, VIDIOC_ENUM_FRAMESIZES, vidioc_enum_framesizes);
 		SET_VALID_IOCTL(ops, VIDIOC_ENUM_FRAMEINTERVALS, vidioc_enum_frameintervals);
-		if (ops->vidioc_g_selection) {
+		if (ops->vidioc_g_selection &&
+		    !test_bit(_IOC_NR(VIDIOC_G_SELECTION), vdev->valid_ioctls)) {
 			__set_bit(_IOC_NR(VIDIOC_G_CROP), valid_ioctls);
 			__set_bit(_IOC_NR(VIDIOC_CROPCAP), valid_ioctls);
 		}
-		if (ops->vidioc_s_selection)
+		if (ops->vidioc_s_selection &&
+		    !test_bit(_IOC_NR(VIDIOC_S_SELECTION), vdev->valid_ioctls))
 			__set_bit(_IOC_NR(VIDIOC_S_CROP), valid_ioctls);
 		SET_VALID_IOCTL(ops, VIDIOC_G_SELECTION, vidioc_g_selection);
 		SET_VALID_IOCTL(ops, VIDIOC_S_SELECTION, vidioc_s_selection);