V4L/DVB: video_ioctl2: do not replace arg with NULL for _IO() ioctls

If the ioctl was defined without direction (e.g. _IO('o', 25)), then
the arg as passed to vidioc_default was NULL instead of the original
argument.

Several ioctls in e.g. include/linux/dvb/video.h and audio.h use this type
of ioctl to pass simple numerical values to the driver.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/media/video/v4l2-ioctl.c b/drivers/media/video/v4l2-ioctl.c
index 7d59c107f13b..d6975f9c3722 100644
--- a/drivers/media/video/v4l2-ioctl.c
+++ b/drivers/media/video/v4l2-ioctl.c
@@ -2006,7 +2006,7 @@ long video_ioctl2(struct file *file,
 {
         char    sbuf[128];
         void    *mbuf = NULL;
-        void    *parg = NULL;
+        void    *parg = (void *)arg;
         long    err  = -EINVAL;
         int     is_ext_ctrl;
         size_t  ctrls_size = 0;