Re: [PATCH linux-next] drm/amd/display: replace kzalloc and memcpy with kmemdup

[Christophe JAILLET]

Le 08/12/2023 à 03:44, yang.guang5@xxxxxxxxxx a écrit :
> From: Yang Guang <yang.guang5@xxxxxxxxxx>
>
> Convert kzalloc/memcpy operations to memdup makes for
> cleaner code and avoids memcpy() failures

Hi,

usually, function's names are written with () in commit description. 
(i.e. kzalloc()/memcpy()).

memdup should be kmemdup().

Finally the proposed change does not avoid memcpy() failures. Should it 
fail (what does it mean in this context?), kmemdup() would behave 
exactly the same.

> Signed-off-by: Chen Haonan <chen.haonan2@xxxxxxxxxx>
> ---
>   drivers/gpu/drm/amd/display/dc/core/dc.c | 10 ++++------
>   1 file changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/core/dc.c b/drivers/gpu/drm/amd/display/dc/core/dc.c
> index 76b47f178127..867e1a0fdef6 100644
> --- a/drivers/gpu/drm/amd/display/dc/core/dc.c
> +++ b/drivers/gpu/drm/amd/display/dc/core/dc.c
> @@ -2264,12 +2264,10 @@ struct dc_state *dc_copy_state(struct dc_state *src_ctx)
>
>   #ifdef CONFIG_DRM_AMD_DC_FP
>   	if (new_ctx->bw_ctx.dml2) {
> -		dml2 = kzalloc(sizeof(struct dml2_context), GFP_KERNEL);
> -		if (!dml2)
> -			return NULL;
> -
> -		memcpy(dml2, src_ctx->bw_ctx.dml2, sizeof(struct dml2_context));
> -		new_ctx->bw_ctx.dml2 = dml2;
> +		dml2 = kmemdup(src_ctx->bw_ctx.dml2, sizeof(struct dml2_context), GFP_KERNEL);

sizeof(struct dml2_context) could be sizeof(*dlm2) to be less verbose.

CJ

> +		if (!dml2)
> +			return NULL;
> +		new_ctx->bw_ctx.dml2 = dml2;
>   	}
>   #endif