From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Romanick <idr@freedesktop.org>
Subject: Re: [PATCH 01/13] drm/mgag200: Remove unnecessary NULL check in
 bo_unref
Date: Mon, 07 Apr 2014 08:19:45 -0700
Message-ID: <5342C211.1010506@freedesktop.org>
References: <1396691102-22904-1-git-send-email-daniel.vetter@ffwll.ch>
 <1396691102-22904-3-git-send-email-daniel.vetter@ffwll.ch>
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To: Daniel Vetter <daniel.vetter@ffwll.ch>, DRI Development <dri-devel@lists.freedesktop.org>
Cc: Dave Jones <davej@redhat.com>
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On 04/05/2014 02:44 AM, Daniel Vetter wrote:
> ttm_bo_unref unconditionally calls kref_put on it's argument, so the
> thing can't be NULL without already causing Oopses.

Doesn't this mean the NULL check is in the wrong place (rather than the
NULL check should be removed)?

> Spotted by coverity.
> 
> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> ---
>  drivers/gpu/drm/mgag200/mgag200_main.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mgag200/mgag200_main.c b/drivers/gpu/drm/mgag200/mgag200_main.c
> index 26868e5c55b0..0722d18992f4 100644
> --- a/drivers/gpu/drm/mgag200/mgag200_main.c
> +++ b/drivers/gpu/drm/mgag200/mgag200_main.c
> @@ -322,9 +322,7 @@ static void mgag200_bo_unref(struct mgag200_bo **bo)
>  
>  	tbo = &((*bo)->bo);
>  	ttm_bo_unref(&tbo);
> -	if (tbo == NULL)
> -		*bo = NULL;
> -
> +	*bo = NULL;
>  }
>  
>  void mgag200_gem_free_object(struct drm_gem_object *obj)
>