linux-kernel - Re: [PATCH -next] drm/amd/display: Remove redundant assignment to variable dc

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Date:   Thu, 5 Jan 2023 14:19:50 -0500
From:   Harry Wentland <harry.wentland@....com>
To:     Yi Yang <yiyang13@...wei.com>, sunpeng.li@....com,
        Rodrigo.Siqueira@....com, alexander.deucher@....com,
        christian.koenig@....com, Xinhui.Pan@....com, airlied@...il.com,
        daniel@...ll.ch
Cc:     amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH -next] drm/amd/display: Remove redundant assignment to
 variable dc

On 12/16/22 05:23, Yi Yang wrote:
> Smatch report warning as follows:
> 
> Line 53679: drivers/gpu/drm/amd/display/dc/core/dc_stream.c:402
> dc_stream_set_cursor_position() warn: variable dereferenced before
> check 'stream'
> 
> The value of 'dc' has been assigned after check whether 'stream' is
> NULL. Fix it by remove redundant assignment.
> 
> Signed-off-by: Yi Yang <yiyang13@...wei.com>

If this didn't blow up until now we might not even need
the NULL check below, but either way this is correct and

Reviewed-by: Harry Wentland <harry.wentland@....com>

Harry

> ---
>  drivers/gpu/drm/amd/display/dc/core/dc_stream.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_stream.c b/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
> index 20e534f73513..78d31bb875d1 100644
> --- a/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
> +++ b/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
> @@ -408,7 +408,7 @@ bool dc_stream_set_cursor_position(
>  	struct dc_stream_state *stream,
>  	const struct dc_cursor_position *position)
>  {
> -	struct dc  *dc = stream->ctx->dc;
> +	struct dc *dc;
>  	bool reset_idle_optimizations = false;
>  
>  	if (NULL == stream) {