Hi Devendra,
Quoting Devendra Tewari (2022-04-22 20:20:31)
> Fixes clang warning: field within 'v4l2_ext_control' is less than
Can you detail which version of clang this occurs with? Have you tried
more than one version?
> 'v4l2_ext_control::(anonymous union
>
> Signed-off-by: Devendra Tewari <devendra.tewari@xxxxxxxxx>
> ---
> include/uapi/linux/videodev2.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index 3768a0a80830..767c52c722cd 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -1765,7 +1765,7 @@ struct v4l2_ext_control {
> struct v4l2_ctrl_vp9_compressed_hdr __user *p_vp9_compressed_hdr_probs;
> struct v4l2_ctrl_vp9_frame __user *p_vp9_frame;
> void __user *ptr;
> - };
> + } __attribute__ ((packed));
This is a curious fix. It's applying a packed attribute to the union,
which I presume means that it's then applying the packed attribute to
any item in the union.
The items are all either: __s32, __s64, values - or pointers.
While applying this attribute here may fix the compiler warning, I'm not
sure it's clear why this is required. This file also has other
locations where a union inside a packed struct is not marked as packed.
Should all unions be marked with the attribute?
Is there any more context from the compiler warning beyond what is
reported above?
--
Kieran
> } __attribute__ ((packed));
>
> struct v4l2_ext_controls {
> --
> 2.25.1
>
