Re: [PATCH] drm/msm/dpu: Delete a variable initialisation before a null pointer check in two functions

[Dmitry Baryshkov]

On 11/04/2023 19:38, Markus Elfring wrote:
> Date: Tue, 11 Apr 2023 18:24:24 +0200
>
> The address of a data structure member was determined before
> a corresponding null pointer check in the implementation of
> the functions “dpu_hw_pp_enable_te” and “dpu_hw_pp_get_vsync_info”.
>
> Thus avoid the risk for undefined behaviour by removing extra
> initialisations for the variable “c” (also because it was already
> reassigned with the same value behind this pointer check).
>
> This issue was detected by using the Coccinelle software.
>
> Fixes: 25fdd5933e4c0f5fe2ea5cd59994f8ac5fbe90ef ("drm/msm: Add SDM845 DPU support")

Plese follow the format for the Fixes tags and limit the hash to 12 
chars. Proper tag:

Fixes: 25fdd5933e4c ("drm/msm: Add SDM845 DPU support")

Other than that LGTM.

> Signed-off-by: Markus Elfring <elfring@xxxxxxxxxxxxxxxxxxxxx>
> ---
>   drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.c
> index 0fcad9760b6f..870ab3ebbc94 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.c
> @@ -176,7 +176,7 @@ static int dpu_hw_pp_enable_te(struct dpu_hw_pingpong *pp, bool enable)
>   static int dpu_hw_pp_connect_external_te(struct dpu_hw_pingpong *pp,
>   		bool enable_external_te)
>   {
> -	struct dpu_hw_blk_reg_map *c = &pp->hw;
> +	struct dpu_hw_blk_reg_map *c;
>   	u32 cfg;
>   	int orig;
>
> @@ -221,7 +221,7 @@ static int dpu_hw_pp_get_vsync_info(struct dpu_hw_pingpong *pp,
>
>   static u32 dpu_hw_pp_get_line_count(struct dpu_hw_pingpong *pp)
>   {
> -	struct dpu_hw_blk_reg_map *c = &pp->hw;
> +	struct dpu_hw_blk_reg_map *c;
>   	u32 height, init;
>   	u32 line = 0xFFFF;
>
> --
> 2.40.0

--
With best wishes
Dmitry