[PATCH 2/2] Fix one warning

[Zhou, Jammy]

Thanks for sharing the background. For [0], you mentioned that get_perms may return -1 in some cases for the group, can you help indicate which case it is?

Since the drmSetServerInfo is seldom used, maybe we can just do the 'int' cast at this moment. I will send v2 for this.

Regards,
Jammy

-----Original Message-----
From: Jan Vesely [mailto:jv356 at scarletmail.rutgers.edu] On Behalf Of Jan Vesely
Sent: Friday, April 24, 2015 10:30 PM
To: Zhou, Jammy
Cc: dri-devel at lists.freedesktop.org; Min, Frank
Subject: Re: [PATCH 2/2] Fix one warning

On Fri, 2015-04-24 at 11:44 +0800, Jammy Zhou wrote:
> xf86drm.c:356:2: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits]
>   group = (serv_group >= 0) ? serv_group : DRM_DEV_GID;
>   ^
> 
> Signed-off-by: Jammy Zhou <Jammy.Zhou at amd.com>
> ---
>  xf86drm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/xf86drm.c b/xf86drm.c
> index 4d67861..fbda2aa 100644
> --- a/xf86drm.c
> +++ b/xf86drm.c
> @@ -353,7 +353,7 @@ static int drmOpenDevice(dev_t dev, int minor, int type)
>      }
>  
>      if (drm_server_info) {
> -	group = (serv_group >= 0) ? serv_group : DRM_DEV_GID;
> +	group = serv_group;

I don't think this change is correct. get_perms can return errors as negative values. I found that xserver does, see [0] for my take on fixing this, as well as Emil's response [1].

I think changing the condition to:
((int)serv_group >= 0)

should be ok(I don't think there are systems with GID_MAX greater than 2^31-1), but I never bothered sending v2.

jan


[0]http://lists.freedesktop.org/archives/dri-devel/2015-February/077276.html
[1]http://lists.freedesktop.org/archives/dri-devel/2015-February/078171.html



>  	chown_check_return(buf, user, group);
>  	chmod(buf, devmode);
>      }


--
Jan Vesely <jan.vesely at rutgers.edu>